Version 2.9.2

Works around Zig issue https://github.com/ziglang/zig/issues/25664

Fixes #266

.gitignore

@@ -4,6 +4,8 @@
 *.swp
 *~
 ncurses
+zstd
 static-*/
 zig-cache/
 zig-out/
+.zig-cache/

ChangeLog

@@ -1,6 +1,71 @@
 # SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
 # SPDX-License-Identifier: MIT
 
+2.9.2 - 2025-10-24
+	- Still requires Zig 0.14 or 0.15
+	- Fix hang on loading config file when compiled with Zig 0.15.2
+
+2.9.1 - 2025-08-21
+	- Add support for building with Zig 0.15
+	- Zig 0.14 is still supported
+
+2.9 - 2025-08-16
+	- Still requires Zig 0.14
+	- Add --delete-command option to replace the built-in file deletion
+	- Move term cursor to selected option in delete confirmation window
+	- Support binary import on older Linux kernels lacking statx() (may break
+	  again in the future, Zig does not officially support such old kernels)
+
+2.8.2 - 2025-05-01
+	- Still requires Zig 0.14
+	- Fix a build error on MacOS
+
+2.8.1 - 2025-04-28
+	- Still requires Zig 0.14
+	- Fix integer overflow in binary export
+	- Fix crash when `fstatat()` returns EINVAL
+	- Minor build system improvements
+
+2.8 - 2025-03-05
+	- Now requires Zig 0.14
+	- Add support for @-prefixed lines to ignore errors in config file
+	- List all supported options in `--help`
+	- Use `kB` instead of `KB` in `--si` mode
+
+2.7 - 2024-11-19
+	- Still requires Zig 0.12 or 0.13
+	- Support transparent reading/writing of zstandard-compressed JSON
+	- Add `--compress` and `--export-block-size` options
+	- Perform tilde expansion on paths in the config file
+	- Fix JSON import of escaped UTF-16 surrogate pairs
+	- Fix incorrect field in root item when exporting to the binary format
+	- Add -Dstrip build flag
+
+2.6 - 2024-09-27
+	- Still requires Zig 0.12 or 0.13
+	- Add dependency on libzstd
+	- Add new export format to support threaded export and low-memory browsing
+	- Add `-O` and `--compress-level` CLI flags
+	- Add progress indicator to hardlink counting stage
+	- Fix displaying and exporting zero values when extended info is not available
+	- Fix clearing screen in some error cases
+	- Fix uncommon edge case in hardlink counting on refresh
+	- Use integer math instead of floating point to format numbers
+
+2.5 - 2024-07-24
+	- Still requires Zig 0.12 or 0.13
+	- Add parallel scanning with `-t,--threads` CLI flags
+	- Improve JSON export and import performance
+	- `--exclude-kernfs` is no longer checked on the top-level scan path
+	- Fix entries sometimes not showing up after refresh
+	- Fix file descriptor leak with `--exclude-caches` checking
+	- Fix possible crash on invalid UTF8 when scanning in `-1` UI mode
+	- Fix JSON export and import of the "other filesystem" flag
+	- Fix JSON import containing directories with a read error
+	- Fix mtime display of 'special' files
+	- Fix edge case bad performance when deleting hardlinks with many links
+	- Increased memory use for hardlinks (by ~10% in extreme cases, sorry)
+
 2.4 - 2024-04-21
 	- Now requires Zig 0.12
 	- Revert default color scheme back to 'off'

Makefile

@@ -9,7 +9,7 @@ ZIG ?= zig
 PREFIX ?= /usr/local
 BINDIR ?= ${PREFIX}/bin
 MANDIR ?= ${PREFIX}/share/man/man1
-ZIG_FLAGS ?= --release
+ZIG_FLAGS ?= --release=fast -Dstrip
 
 NCDU_VERSION=$(shell grep 'program_version = "' src/main.zig | sed -e 's/^.*"\(.\+\)".*$$/\1/')
 
@@ -52,27 +52,41 @@ dist:
 	rm -rf ncdu-${NCDU_VERSION}
 
 
-# ASSUMPTION: the ncurses source tree has been extracted into ncurses/
+# ASSUMPTION:
+# - the ncurses source tree has been extracted into ncurses/
+# - the zstd source tree has been extracted into zstd/
+# Would be nicer to do all this with the Zig build system, but no way am I
+# going to write build.zig's for these projects.
 static-%.tar.gz:
 	mkdir -p static-$*/nc static-$*/inst/pkg
+	cp -R zstd/lib static-$*/zstd
+	make -C static-$*/zstd -j8 libzstd.a V=1\
+		ZSTD_LIB_DICTBUILDER=0\
+		ZSTD_LIB_MINIFY=1\
+		ZSTD_LIB_EXCLUDE_COMPRESSORS_DFAST_AND_UP=1\
+		CC="${ZIG} cc --target=$*"\
+		LD="${ZIG} cc --target=$*"\
+		AR="${ZIG} ar" RANLIB="${ZIG} ranlib"
 	cd static-$*/nc && ../../ncurses/configure --prefix="`pwd`/../inst"\
-		--with-pkg-config-libdir="`pwd`/../inst/pkg"\
 		--without-cxx --without-cxx-binding --without-ada --without-manpages --without-progs\
-		--without-tests --enable-pc-files --without-pkg-config --without-shared --without-debug\
+		--without-tests --disable-pc-files --without-pkg-config --without-shared --without-debug\
 		--without-gpm --without-sysmouse --enable-widec --with-default-terminfo-dir=/usr/share/terminfo\
 		--with-terminfo-dirs=/usr/share/terminfo:/lib/terminfo:/usr/local/share/terminfo\
 		--with-fallbacks="screen linux vt100 xterm xterm-256color" --host=$*\
 		CC="${ZIG} cc --target=$*"\
 		LD="${ZIG} cc --target=$*"\
 		AR="${ZIG} ar" RANLIB="${ZIG} ranlib"\
-		CPPFLAGS=-D_GNU_SOURCE && make -j8 && make install.libs
+		CPPFLAGS=-D_GNU_SOURCE && make -j8
 	@# zig-build - cleaner approach but doesn't work, results in a dynamically linked binary.
 	@#cd static-$* && PKG_CONFIG_LIBDIR="`pwd`/inst/pkg" zig build -Dtarget=$*
 	@#	--build-file ../build.zig --search-prefix inst/ --cache-dir zig -Drelease-fast=true
 	@# Alternative approach, bypassing zig-build
 	cd static-$* && ${ZIG} build-exe -target $*\
-		-Iinst/include -Iinst/include/ncursesw -lc inst/lib/libncursesw.a\
+		-Inc/include -Izstd -lc nc/lib/libncursesw.a zstd/libzstd.a\
 		--cache-dir zig-cache -static -fstrip -O ReleaseFast ../src/main.zig
+	@# My system's strip can't deal with arm binaries and zig doesn't wrap a strip alternative.
+	@# Whatever, just let it error for those.
+	strip -R .eh_frame -R .eh_frame_hdr static-$*/main || true
 	cd static-$* && mv main ncdu && tar -czf ../static-$*.tar.gz ncdu
 	rm -rf static-$*
 

README.md

@@ -19,9 +19,10 @@ C version (1.x).
 
 ## Requirements
 
-- Zig 0.12.0
+- Zig 0.14 or 0.15
 - Some sort of POSIX-like OS
-- ncurses libraries and header files
+- ncurses
+- libzstd
 
 ## Install
 

build.zig

@@ -5,24 +5,28 @@ const std = @import("std");
 
 pub fn build(b: *std.Build) void {
     const target = b.standardTargetOptions(.{});
-    const optimize = b.standardOptimizeOption(.{
-        .preferred_optimize_mode = .ReleaseFast,
-    });
+    const optimize = b.standardOptimizeOption(.{});
 
-    const pie = b.option(bool, "pie", "Build with PIE support (by default false)") orelse false;
+    const pie = b.option(bool, "pie", "Build with PIE support (by default: target-dependant)");
+    const strip = b.option(bool, "strip", "Strip debugging info (by default false)") orelse false;
 
-    const exe = b.addExecutable(.{
-        .name = "ncdu",
+    const main_mod = b.createModule(.{
         .root_source_file = b.path("src/main.zig"),
         .target = target,
         .optimize = optimize,
+        .strip = strip,
         .link_libc = true,
     });
+    main_mod.linkSystemLibrary("ncursesw", .{});
+    main_mod.linkSystemLibrary("zstd", .{});
 
+    const exe = b.addExecutable(.{
+        .name = "ncdu",
+        .root_module = main_mod,
+    });
     exe.pie = pie;
-    exe.root_module.linkSystemLibrary("ncursesw", .{});
-    // https://github.com/ziglang/zig/blob/b52be973dfb7d1408218b8e75800a2da3dc69108/build.zig#L551-L554
-    if (target.result.isDarwin()) {
+    // https://github.com/ziglang/zig/blob/faccd79ca5debbe22fe168193b8de54393257604/build.zig#L745-L748
+    if (target.result.os.tag.isDarwin()) {
         // useful for package maintainers
         exe.headerpad_max_install_names = true;
     }
@@ -38,13 +42,9 @@ pub fn build(b: *std.Build) void {
     run_step.dependOn(&run_cmd.step);
 
     const unit_tests = b.addTest(.{
-        .root_source_file = b.path("src/main.zig"),
-        .target = target,
-        .optimize = optimize,
-        .link_libc = true,
+        .root_module = main_mod,
     });
     unit_tests.pie = pie;
-    unit_tests.root_module.linkSystemLibrary("ncursesw", .{});
 
     const run_unit_tests = b.addRunArtifact(unit_tests);
 

ncdu.1

@@ -1,15 +1,17 @@
 .\" SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
 .\" SPDX-License-Identifier: MIT
-.Dd April 20, 2024
+.Dd August 16, 2025
 .Dt NCDU 1
 .Os
 .Sh NAME
 .Nm ncdu
 .Nd NCurses Disk Usage
+.
 .Sh SYNOPSIS
 .Nm
 .Op Fl f Ar file
 .Op Fl o Ar file
+.Op Fl O Ar file
 .Op Fl e , \-extended , \-no\-extended
 .Op Fl \-ignore\-config
 .Op Fl x , \-one\-file\-system , \-cross\-file\-system
@@ -18,6 +20,10 @@
 .Op Fl \-include\-caches , \-exclude\-caches
 .Op Fl L , \-follow\-symlinks , \-no\-follow\-symlinks
 .Op Fl \-include\-kernfs , \-exclude\-kernfs
+.Op Fl t , \-threads Ar num
+.Op Fl c , \-compress , \-no\-compress
+.Op Fl \-compress\-level Ar num
+.Op Fl \-export\-block\-size Ar num
 .Op Fl 0 , 1 , 2
 .Op Fl q , \-slow\-ui\-updates , \-fast\-ui\-updates
 .Op Fl \-enable\-shell , \-disable\-shell
@@ -38,17 +44,20 @@
 .Op Fl \-group\-directories\-first , \-no\-group\-directories\-first
 .Op Fl \-confirm\-quit , \-no\-confirm\-quit
 .Op Fl \-confirm\-delete , \-no\-confirm\-delete
+.Op Fl \-delete\-command Ar command
 .Op Fl \-color Ar off | dark | dark-bg
 .Op Ar path
 .Nm
 .Op Fl h , \-help
 .Nm
 .Op Fl v , V , \-version
+.
 .Sh DESCRIPTION
 .Nm
 (NCurses Disk Usage) is an interactive curses-based version of the well-known
 .Xr du 1 ,
 and provides a fast way to see what directories are using your disk space.
+.
 .Sh OPTIONS
 .Ss Mode Selection
 .Bl -tag -width Ds
@@ -59,10 +68,13 @@ Print version and quit.
 .It Fl f Ar file
 Load the given file, which has earlier been created with the
 .Fl o
+or
+.Fl O
 flag.
 If
 .Ar file
 is equivalent to '\-', the file is read from standard input.
+Reading from standard input is only supported for the JSON format.
 .Pp
 For the sake of preventing a screw-up, the current version of
 .Nm
@@ -73,7 +85,7 @@ will be disabled.
 .It Ar dir
 Scan the given directory.
 .It Fl o Ar file
-Export all necessary information to
+Export the directory tree in JSON format to
 .Ar file
 instead of opening the browser interface.
 If
@@ -87,6 +99,27 @@ directory with many files.
 uncompressed, or a little over 100 KiB when compressed with gzip.
 This scales linearly, so be prepared to handle a few tens of megabytes when
 dealing with millions of files.
+.Pp
+Consider enabling
+.Fl c
+to output Zstandard-compressed JSON, which can significantly reduce size of the
+exported data.
+.Pp
+When running a multi-threaded scan or when scanning a directory tree that may
+not fit in memory, consider using
+.Fl O
+instead.
+.It Fl O Ar file
+Export the directory tree in binary format to
+.Ar file
+instead of opening the browser interface.
+If
+.Ar file
+is '\-', the data is written to standard output.
+The binary format has built-in compression, supports low-memory multi-threaded
+export (in combination with
+.Fl t )
+and can be browsed without importing the entire directory tree into memory.
 .It Fl e , \-extended , \-no\-extended
 Enable/disable extended information mode.
 This will, in addition to the usual file information, also read the ownership,
@@ -105,6 +138,7 @@ using 'm' and 'M', respectively.
 .It Fl \-ignore\-config
 Do not attempt to load any configuration files.
 .El
+.
 .Ss Scan Options
 These options affect the scanning progress, they have no effect when importing
 directory information from a file.
@@ -147,7 +181,52 @@ The exact counting behavior of this flag is subject to change in the future.
 .Pp
 The complete list of currently known pseudo filesystems is: binfmt, bpf, cgroup,
 cgroup2, debug, devpts, proc, pstore, security, selinux, sys, trace.
+.It Fl t , \-threads Ar num
+Number of threads to use when scanning the filesystem, defaults to 1.
+.Pp
+In single-threaded mode, the JSON export (see
+.Fl o )
+can operate with very little memory, but in multi-threaded mode the entire
+directory tree is first constructed in memory and written out after the
+filesystem scan has completed,
+This causes a delay in output and requires significantly more memory for large
+directory trees.
+The binary format (see
+.Fl O )
+does not have this problem and supports efficient exporting with any number of
+threads.
 .El
+.
+.Ss Export Options
+These options affect behavior when exporting to file with the
+.Fl o
+or
+.Fl O
+options.
+.Bl -tag -width Ds
+.It Fl c , \-compress , \-no\-compress
+Enable or disable Zstandard compression when exporting to JSON (see
+.Fl o ) .
+.It Fl \-compress\-level Ar num
+Set the Zstandard compression level when using
+.Fl O
+or
+.Fl c .
+Valid values are 1 (fastest) to 19 (slowest).
+Defaults to 4.
+.It Fl \-export\-block\-size Ar num
+Set the block size, in kibibytes, for the binary export format (see
+.Fl O ) .
+Larger blocks require more memory but result in better compression efficiency.
+This option can be combined with a higher
+.Fl \-compress\-level
+for even better compression.
+.Pp
+Accepted values are between 4 and 16000.
+The defaults is to start at 64 KiB and then gradually increase the block size
+for large exports.
+.El
+.
 .Ss Interface Options
 .Bl -tag -width Ds
 .It Fl 0
@@ -159,9 +238,8 @@ When exporting the data with
 ncurses will not be initialized at all.
 This option is the default when exporting to standard output.
 .It Fl 1
-Similar to
-.Fl 0 ,
-but does give feedback on the scanning progress with a single line of output.
+Write progress information to the terminal, but don't open a full-screen
+ncurses interface.
 This option is the default when exporting to a file.
 .Pp
 In some cases, the ncurses browser interface which you'll see after the
@@ -209,7 +287,7 @@ when given twice it will also add
 thus ensuring that there is no way to modify the file system from within
 .Nm .
 .It Fl \-si , \-no\-si
-List sizes using base 10 prefixes, that is, powers of 1000 (KB, MB, etc), as
+List sizes using base 10 prefixes, that is, powers of 1000 (kB, MB, etc), as
 defined in the International System of Units (SI), instead of the usual base 2
 prefixes (KiB, MiB, etc).
 .It Fl \-disk\-usage , \-apparent\-size
@@ -282,6 +360,31 @@ Can be helpful when you accidentally press 'q' during or after a very long scan.
 Require a confirmation before deleting a file or directory.
 Enabled by default, but can be disabled if you're absolutely sure you won't
 accidentally press 'd'.
+.It Fl \-delete\-command Ar command
+When set to a non-empty string, replace the built-in file deletion feature with
+a custom shell command.
+.Pp
+The absolute path of the item to be deleted is appended to the given command
+and the result is evaluated in a shell.
+The command is run from the same directory that ncdu itself was started in.
+The
+.Ev NCDU_DELETE_PATH
+environment variable is set to the absolute path of the item to be deleted and
+.Ev NCDU_LEVEL
+is set in the same fashion as when spawning a shell from within ncdu.
+.Pp
+After command completion, the in-memory view of the selected item is refreshed
+and directory sizes are adjusted as necessary.
+This is not a full refresh of the complete directory tree, so if the item has
+been renamed or moved to another directory, it's new location is not
+automatically picked up.
+.Pp
+For example, to use
+.Xr rm 1
+interactive mode to prompt before each deletion:
+.Dl ncdu --no-confirm-delete --delete-command \[aq]rm -ri --\[aq]
+Or to move files to trash:
+.Dl ncdu --delete-command \[aq]gio trash --\[aq]
 .It Fl \-color Ar off | dark | dark-bg
 Set the color scheme.
 The following schemes are recognized:
@@ -297,6 +400,7 @@ color scheme that also works in terminals with a light background.
 The default is
 .Ar off .
 .El
+.
 .Sh CONFIGURATION
 .Nm
 can be configured by placing command-line options in
@@ -314,6 +418,7 @@ is given on the command line.
 .Pp
 The configuration file format is simply one command line option per line.
 Lines starting with '#' are ignored.
+A line can be prefixed with '@' to suppress errors while parsing the option.
 Example configuration file:
 .Bd -literal -offset indent
 # Always enable extended mode
@@ -324,7 +429,11 @@ Example configuration file:
 
 # Exclude .git directories
 \-\-exclude .git
+
+# Read excludes from ~/.ncduexcludes, ignore error if the file does not exist
+@--exclude-from ~/.ncduexcludes
 .Ed
+.
 .Sh KEYS
 .Bl -tag -width Ds
 .It ?
@@ -411,6 +520,7 @@ itself does not (currently) warn about or prevent this situation.
 .It q
 Quit
 .El
+.
 .Sh FILE FLAGS
 Entries in the browser interface may be prefixed by a one\-character flag.
 These flags have the following meaning:
@@ -434,37 +544,32 @@ Same file was already counted (hard link).
 .It e
 Empty directory.
 .El
+.
 .Sh EXAMPLES
 To scan and browse the directory you're currently in, all you need is a simple:
 .Dl ncdu
-If you want to scan a full filesystem, for example your root filesystem, then
-you'll want to use
+To scan a full filesystem, for example your root filesystem, you'll want to use
 .Fl x :
 .Dl ncdu \-x /
 .Pp
 Since scanning a large directory may take a while, you can scan a directory and
 export the results for later viewing:
 .Bd -literal -offset indent
-ncdu \-1xo\- / | gzip >export.gz
+ncdu \-1xO export.ncdu /
 # ...some time later:
-zcat export.gz | ncdu \-f\-
+ncdu \-f export.ncdu
 .Ed
 To export from a cron job, make sure to replace
 .Fl 1
 with
 .Fl 0
-to suppress any unnecessary output.
+to suppress unnecessary progress output.
 .Pp
 You can also export a directory and browse it once scanning is done:
-.Dl ncdu \-o\- | tee export.file | ./ncdu \-f\-
-The same is possible with gzip compression, but is a bit kludgey:
-.Dl ncdu \-o\- | gzip | tee export.gz | gunzip | ./ncdu \-f\-
+.Dl ncdu \-co\- | tee export.json.zst | ./ncdu \-f\-
 .Pp
 To scan a system remotely, but browse through the files locally:
-.Dl ssh \-C user@system ncdu \-o\- / | ./ncdu \-f\-
-The
-.Fl C
-option to ssh enables compression, which will be very useful over slow links.
+.Dl ssh user@system ncdu \-co\- / | ./ncdu \-f\-
 Remote scanning and local viewing has two major advantages when
 compared to running
 .Nm
@@ -473,6 +578,7 @@ the local system without any network latency, and
 .Nm
 does not keep the entire directory structure in memory when exporting, so this
 won't consume much memory on the remote system.
+.
 .Sh SEE ALSO
 .Xr du 1 ,
 .Xr tree 1 .
@@ -480,13 +586,15 @@ won't consume much memory on the remote system.
 .Nm
 has a website:
 .Lk https://dev.yorhel.nl/ncdu
+.
 .Sh AUTHORS
 Written by
 .An Yorhel Aq Mt projects@yorhel.nl
+.
 .Sh BUGS
 Directory hard links and firmlinks (MacOS) are not supported.
-They are not detected as being hard links, and will thus get scanned and
-counted multiple times.
+They are not detected as being hard links and will thus get scanned and counted
+multiple times.
 .Pp
 Some minor glitches may appear when displaying filenames that contain multibyte
 or multicolumn characters.

src/bin_export.zig

@@ -0,0 +1,468 @@
+// SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
+// SPDX-License-Identifier: MIT
+
+const std = @import("std");
+const main = @import("main.zig");
+const model = @import("model.zig");
+const sink = @import("sink.zig");
+const util = @import("util.zig");
+const ui = @import("ui.zig");
+const c = @import("c.zig").c;
+
+pub const global = struct {
+    var fd: std.fs.File = undefined;
+    var index: std.ArrayListUnmanaged(u8) = .empty;
+    var file_off: u64 = 0;
+    var lock: std.Thread.Mutex = .{};
+    var root_itemref: u64 = 0;
+};
+
+pub const SIGNATURE = "\xbfncduEX1";
+
+pub const ItemKey = enum(u5) {
+    // all items
+    type = 0, // EType
+    name = 1, // bytes
+    prev = 2, // itemref
+    // Only for non-specials
+    asize = 3, // u64
+    dsize = 4, // u64
+    // Only for .dir
+    dev      =  5, // u64        only if different from parent dir
+    rderr    =  6, // bool       true = error reading directory list, false = error in sub-item, absent = no error
+    cumasize =  7, // u64
+    cumdsize =  8, // u64
+    shrasize =  9, // u64
+    shrdsize = 10, // u64
+    items    = 11, // u64
+    sub      = 12, // itemref    only if dir is not empty
+    // Only for .link
+    ino     = 13, // u64
+    nlink   = 14, // u32
+    // Extended mode
+    uid   = 15, // u32
+    gid   = 16, // u32
+    mode  = 17, // u16
+    mtime = 18, // u64
+    _,
+};
+
+// Pessimistic upper bound on the encoded size of an item, excluding the name field.
+// 2 bytes for map start/end, 11 per field (2 for the key, 9 for a full u64).
+const MAX_ITEM_LEN = 2 + 11 * @typeInfo(ItemKey).@"enum".fields.len;
+
+pub const CborMajor = enum(u3) { pos, neg, bytes, text, array, map, tag, simple };
+
+inline fn bigu16(v: u16) [2]u8 { return @bitCast(std.mem.nativeToBig(u16, v)); }
+inline fn bigu32(v: u32) [4]u8 { return @bitCast(std.mem.nativeToBig(u32, v)); }
+inline fn bigu64(v: u64) [8]u8 { return @bitCast(std.mem.nativeToBig(u64, v)); }
+
+inline fn blockHeader(id: u4, len: u28) [4]u8 { return bigu32((@as(u32, id) << 28) | len); }
+
+inline fn cborByte(major: CborMajor, arg: u5) u8 { return (@as(u8, @intFromEnum(major)) << 5) | arg; }
+
+
+// (Uncompressed) data block size.
+// Start with 64k, then use increasingly larger block sizes as the export file
+// grows. This is both to stay within the block number limit of the index block
+// and because, with a larger index block, the reader will end up using more
+// memory anyway.
+fn blockSize(num: u32) usize {
+    //                        block size    uncompressed data in this num range
+    //                 # mil      # KiB         # GiB
+    return main.config.export_block_size
+    orelse if (num < ( 1<<20))   64<<10  //    64
+      else if (num < ( 2<<20))  128<<10  //   128
+      else if (num < ( 4<<20))  256<<10  //   512
+      else if (num < ( 8<<20))  512<<10  //  2048
+      else if (num < (16<<20)) 1024<<10  //  8192
+      else                     2048<<10; // 32768
+}
+
+// Upper bound on the return value of blockSize()
+// (config.export_block_size may be larger than the sizes listed above, let's
+// stick with the maximum block size supported by the file format to be safe)
+const MAX_BLOCK_SIZE: usize = 1<<28;
+
+
+pub const Thread = struct {
+    buf: []u8 = undefined,
+    off: usize = MAX_BLOCK_SIZE, // pretend we have a full block to trigger a flush() for the first write
+    block_num: u32 = std.math.maxInt(u32),
+    itemref: u64 = 0, // ref of item currently being written
+
+    // unused, but kept around for easy debugging
+    fn compressNone(in: []const u8, out: []u8) usize {
+        @memcpy(out[0..in.len], in);
+        return in.len;
+    }
+
+    fn compressZstd(in: []const u8, out: []u8) usize {
+        while (true) {
+            const r = c.ZSTD_compress(out.ptr, out.len, in.ptr, in.len, main.config.complevel);
+            if (c.ZSTD_isError(r) == 0) return r;
+            ui.oom(); // That *ought* to be the only reason the above call can fail.
+        }
+    }
+
+    fn createBlock(t: *Thread) std.ArrayListUnmanaged(u8) {
+        var out: std.ArrayListUnmanaged(u8) = .empty;
+        if (t.block_num == std.math.maxInt(u32) or t.off == 0) return out;
+
+        out.ensureTotalCapacityPrecise(main.allocator, 12 + @as(usize, @intCast(c.ZSTD_COMPRESSBOUND(@as(c_int, @intCast(t.off)))))) catch unreachable;
+        out.items.len = out.capacity;
+        const bodylen = compressZstd(t.buf[0..t.off], out.items[8..]);
+        out.items.len = 12 + bodylen;
+
+        out.items[0..4].* = blockHeader(0, @intCast(out.items.len));
+        out.items[4..8].* = bigu32(t.block_num);
+        out.items[8+bodylen..][0..4].* = blockHeader(0, @intCast(out.items.len));
+        return out;
+    }
+
+    fn flush(t: *Thread, expected_len: usize) void {
+        @branchHint(.unlikely);
+        var block = createBlock(t);
+        defer block.deinit(main.allocator);
+
+        global.lock.lock();
+        defer global.lock.unlock();
+        // This can only really happen when the root path exceeds our block size,
+        // in which case we would probably have error'ed out earlier anyway.
+        if (expected_len > t.buf.len) ui.die("Error writing data: path too long.\n", .{});
+
+        if (block.items.len > 0) {
+            if (global.file_off >= (1<<40)) ui.die("Export data file has grown too large, please report a bug.\n", .{});
+            global.index.items[4..][t.block_num*8..][0..8].* = bigu64((global.file_off << 24) + block.items.len);
+            global.file_off += block.items.len;
+            global.fd.writeAll(block.items) catch |e|
+                ui.die("Error writing to file: {s}.\n", .{ ui.errorString(e) });
+        }
+
+        t.off = 0;
+        t.block_num = @intCast((global.index.items.len - 4) / 8);
+        global.index.appendSlice(main.allocator, &[1]u8{0}**8) catch unreachable;
+        if (global.index.items.len + 12 >= (1<<28)) ui.die("Too many data blocks, please report a bug.\n", .{});
+
+        const newsize = blockSize(t.block_num);
+        if (t.buf.len != newsize) t.buf = main.allocator.realloc(t.buf, newsize) catch unreachable;
+    }
+
+    fn cborHead(t: *Thread, major: CborMajor, arg: u64) void {
+        if (arg <= 23) {
+            t.buf[t.off] = cborByte(major, @intCast(arg));
+            t.off += 1;
+        } else if (arg <= std.math.maxInt(u8)) {
+            t.buf[t.off] = cborByte(major, 24);
+            t.buf[t.off+1] = @truncate(arg);
+            t.off += 2;
+        } else if (arg <= std.math.maxInt(u16)) {
+            t.buf[t.off] = cborByte(major, 25);
+            t.buf[t.off+1..][0..2].* = bigu16(@intCast(arg));
+            t.off += 3;
+        } else if (arg <= std.math.maxInt(u32)) {
+            t.buf[t.off] = cborByte(major, 26);
+            t.buf[t.off+1..][0..4].* = bigu32(@intCast(arg));
+            t.off += 5;
+        } else {
+            t.buf[t.off] = cborByte(major, 27);
+            t.buf[t.off+1..][0..8].* = bigu64(arg);
+            t.off += 9;
+        }
+    }
+
+    fn cborIndef(t: *Thread, major: CborMajor) void {
+        t.buf[t.off] = cborByte(major, 31);
+        t.off += 1;
+    }
+
+    fn itemKey(t: *Thread, key: ItemKey) void {
+        t.cborHead(.pos, @intFromEnum(key));
+    }
+
+    fn itemRef(t: *Thread, key: ItemKey, ref: ?u64) void {
+        const r = ref orelse return;
+        t.itemKey(key);
+        // Full references compress like shit and most of the references point
+        // into the same block, so optimize that case by using a negative
+        // offset instead.
+        if ((r >> 24) == t.block_num) t.cborHead(.neg, t.itemref - r - 1)
+        else t.cborHead(.pos, r);
+    }
+
+    // Reserve space for a new item, write out the type, prev and name fields and return the itemref.
+    fn itemStart(t: *Thread, itype: model.EType, prev_item: ?u64, name: []const u8) u64 {
+        const min_len = name.len + MAX_ITEM_LEN;
+        if (t.off + min_len > t.buf.len) t.flush(min_len);
+
+        t.itemref = (@as(u64, t.block_num) << 24) | t.off;
+        t.cborIndef(.map);
+        t.itemKey(.type);
+        if (@intFromEnum(itype) >= 0) t.cborHead(.pos, @intCast(@intFromEnum(itype)))
+        else t.cborHead(.neg, @intCast(-1 - @intFromEnum(itype)));
+        t.itemKey(.name);
+        t.cborHead(.bytes, name.len);
+        @memcpy(t.buf[t.off..][0..name.len], name);
+        t.off += name.len;
+        t.itemRef(.prev, prev_item);
+        return t.itemref;
+    }
+
+    fn itemExt(t: *Thread, stat: *const sink.Stat) void {
+        if (!main.config.extended) return;
+        if (stat.ext.pack.hasuid) {
+            t.itemKey(.uid);
+            t.cborHead(.pos, stat.ext.uid);
+        }
+        if (stat.ext.pack.hasgid) {
+            t.itemKey(.gid);
+            t.cborHead(.pos, stat.ext.gid);
+        }
+        if (stat.ext.pack.hasmode) {
+            t.itemKey(.mode);
+            t.cborHead(.pos, stat.ext.mode);
+        }
+        if (stat.ext.pack.hasmtime) {
+            t.itemKey(.mtime);
+            t.cborHead(.pos, stat.ext.mtime);
+        }
+    }
+
+    fn itemEnd(t: *Thread) void {
+        t.cborIndef(.simple);
+    }
+};
+
+
+pub const Dir = struct {
+    // TODO: When items are written out into blocks depth-first, parent dirs
+    // will end up getting their items distributed over many blocks, which will
+    // significantly slow down reading that dir's listing. It may be worth
+    // buffering some items at the Dir level before flushing them out to the
+    // Thread buffer.
+
+    // The lock protects all of the below, and is necessary because final()
+    // accesses the parent dir and may be called from other threads.
+    // I'm not expecting much lock contention, but it's possible to turn
+    // last_item into an atomic integer and other fields could be split up for
+    // subdir use.
+    lock: std.Thread.Mutex = .{},
+    last_sub: ?u64 = null,
+    stat: sink.Stat,
+    items: u64 = 0,
+    size: u64 = 0,
+    blocks: u64 = 0,
+    err: bool = false,
+    suberr: bool = false,
+    shared_size: u64 = 0,
+    shared_blocks: u64 = 0,
+    inodes: Inodes = Inodes.init(main.allocator),
+
+    const Inodes = std.AutoHashMap(u64, Inode);
+    const Inode = struct {
+        size: u64,
+        blocks: u64,
+        nlink: u32,
+        nfound: u32,
+    };
+
+
+    pub fn addSpecial(d: *Dir, t: *Thread, name: []const u8, sp: model.EType) void {
+        d.lock.lock();
+        defer d.lock.unlock();
+        d.items += 1;
+        if (sp == .err) d.suberr = true;
+        d.last_sub = t.itemStart(sp, d.last_sub, name);
+        t.itemEnd();
+    }
+
+    pub fn addStat(d: *Dir, t: *Thread, name: []const u8, stat: *const sink.Stat) void {
+        d.lock.lock();
+        defer d.lock.unlock();
+        d.items += 1;
+        if (stat.etype != .link) {
+            d.size +|= stat.size;
+            d.blocks +|= stat.blocks;
+        }
+        d.last_sub = t.itemStart(stat.etype, d.last_sub, name);
+        t.itemKey(.asize);
+        t.cborHead(.pos, stat.size);
+        t.itemKey(.dsize);
+        t.cborHead(.pos, util.blocksToSize(stat.blocks));
+
+        if (stat.etype == .link) {
+            const lnk = d.inodes.getOrPut(stat.ino) catch unreachable;
+            if (!lnk.found_existing) lnk.value_ptr.* = .{
+                .size = stat.size,
+                .blocks = stat.blocks,
+                .nlink = stat.nlink,
+                .nfound = 1,
+            } else lnk.value_ptr.nfound += 1;
+            t.itemKey(.ino);
+            t.cborHead(.pos, stat.ino);
+            t.itemKey(.nlink);
+            t.cborHead(.pos, stat.nlink);
+        }
+
+        t.itemExt(stat);
+        t.itemEnd();
+    }
+
+    pub fn addDir(d: *Dir, stat: *const sink.Stat) Dir {
+        d.lock.lock();
+        defer d.lock.unlock();
+        d.items += 1;
+        d.size +|= stat.size;
+        d.blocks +|= stat.blocks;
+        return .{ .stat = stat.* };
+    }
+
+    pub fn setReadError(d: *Dir) void {
+        d.lock.lock();
+        defer d.lock.unlock();
+        d.err = true;
+    }
+
+    // XXX: older JSON exports did not include the nlink count and have
+    // this field set to '0'.  We can deal with that when importing to
+    // mem_sink, but the hardlink counting algorithm used here really does need
+    // that information. Current code makes sure to count such links only once
+    // per dir, but does not count them towards the shared_* fields. That
+    // behavior is similar to ncdu 1.x, but the difference between memory
+    // import and this file export might be surprising.
+    fn countLinks(d: *Dir, parent: ?*Dir) void {
+        var parent_new: u32 = 0;
+        var it = d.inodes.iterator();
+        while (it.next()) |kv| {
+            const v = kv.value_ptr;
+            d.size +|= v.size;
+            d.blocks +|= v.blocks;
+            if (v.nlink > 1 and v.nfound < v.nlink) {
+                d.shared_size +|= v.size;
+                d.shared_blocks +|= v.blocks;
+            }
+
+            const p = parent orelse continue;
+            // All contained in this dir, no need to keep this entry around
+            if (v.nlink > 0 and v.nfound >= v.nlink) {
+                p.size +|= v.size;
+                p.blocks +|= v.blocks;
+                _ = d.inodes.remove(kv.key_ptr.*);
+            } else if (!p.inodes.contains(kv.key_ptr.*))
+                parent_new += 1;
+        }
+
+        // Merge remaining inodes into parent
+        const p = parent orelse return;
+        if (d.inodes.count() == 0) return;
+
+        // If parent is empty, just transfer
+        if (p.inodes.count() == 0) {
+            p.inodes.deinit();
+            p.inodes = d.inodes;
+            d.inodes = Inodes.init(main.allocator); // So we can deinit() without affecting parent
+        // Otherwise, merge
+        } else {
+            p.inodes.ensureUnusedCapacity(parent_new) catch unreachable;
+            it = d.inodes.iterator();
+            while (it.next()) |kv| {
+                const v = kv.value_ptr;
+                const plnk = p.inodes.getOrPutAssumeCapacity(kv.key_ptr.*);
+                if (!plnk.found_existing) plnk.value_ptr.* = v.*
+                else plnk.value_ptr.*.nfound += v.nfound;
+            }
+        }
+    }
+
+    pub fn final(d: *Dir, t: *Thread, name: []const u8, parent: ?*Dir) void {
+        if (parent) |p| p.lock.lock();
+        defer if (parent) |p| p.lock.unlock();
+
+        if (parent) |p| {
+            // Different dev? Don't merge the 'inodes' sets, just count the
+            // links here first so the sizes get added to the parent.
+            if (p.stat.dev != d.stat.dev) d.countLinks(null);
+
+            p.items += d.items;
+            p.size +|= d.size;
+            p.blocks +|= d.blocks;
+            if (d.suberr or d.err) p.suberr = true;
+
+            // Same dir, merge inodes
+            if (p.stat.dev == d.stat.dev) d.countLinks(p);
+
+            p.last_sub = t.itemStart(.dir, p.last_sub, name);
+        } else {
+            d.countLinks(null);
+            global.root_itemref = t.itemStart(.dir, null, name);
+        }
+        d.inodes.deinit();
+
+        t.itemKey(.asize);
+        t.cborHead(.pos, d.stat.size);
+        t.itemKey(.dsize);
+        t.cborHead(.pos, util.blocksToSize(d.stat.blocks));
+        if (parent == null or parent.?.stat.dev != d.stat.dev) {
+            t.itemKey(.dev);
+            t.cborHead(.pos, d.stat.dev);
+        }
+        if (d.err or d.suberr) {
+            t.itemKey(.rderr);
+            t.cborHead(.simple, if (d.err) 21 else 20);
+        }
+        t.itemKey(.cumasize);
+        t.cborHead(.pos, d.size +| d.stat.size);
+        t.itemKey(.cumdsize);
+        t.cborHead(.pos, util.blocksToSize(d.blocks +| d.stat.blocks));
+        if (d.shared_size > 0) {
+            t.itemKey(.shrasize);
+            t.cborHead(.pos, d.shared_size);
+        }
+        if (d.shared_blocks > 0) {
+            t.itemKey(.shrdsize);
+            t.cborHead(.pos, util.blocksToSize(d.shared_blocks));
+        }
+        t.itemKey(.items);
+        t.cborHead(.pos, d.items);
+        t.itemRef(.sub, d.last_sub);
+        t.itemExt(&d.stat);
+        t.itemEnd();
+    }
+};
+
+
+pub fn createRoot(stat: *const sink.Stat, threads: []sink.Thread) Dir {
+    for (threads) |*t| {
+        t.sink.bin.buf = main.allocator.alloc(u8, blockSize(0)) catch unreachable;
+    }
+
+    return .{ .stat = stat.* };
+}
+
+pub fn done(threads: []sink.Thread) void {
+    for (threads) |*t| {
+        t.sink.bin.flush(0);
+        main.allocator.free(t.sink.bin.buf);
+    }
+
+    while (std.mem.endsWith(u8, global.index.items, &[1]u8{0}**8))
+        global.index.shrinkRetainingCapacity(global.index.items.len - 8);
+    global.index.appendSlice(main.allocator, &bigu64(global.root_itemref)) catch unreachable;
+    global.index.appendSlice(main.allocator, &blockHeader(1, @intCast(global.index.items.len + 4))) catch unreachable;
+    global.index.items[0..4].* = blockHeader(1, @intCast(global.index.items.len));
+    global.fd.writeAll(global.index.items) catch |e|
+        ui.die("Error writing to file: {s}.\n", .{ ui.errorString(e) });
+    global.index.clearAndFree(main.allocator);
+
+    global.fd.close();
+}
+
+pub fn setupOutput(fd: std.fs.File) void {
+    global.fd = fd;
+    fd.writeAll(SIGNATURE) catch |e|
+        ui.die("Error writing to file: {s}.\n", .{ ui.errorString(e) });
+    global.file_off = 8;
+
+    // Placeholder for the index block header.
+    global.index.appendSlice(main.allocator, "aaaa") catch unreachable;
+}

src/bin_reader.zig

@@ -0,0 +1,521 @@
+// SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
+// SPDX-License-Identifier: MIT
+
+const std = @import("std");
+const main = @import("main.zig");
+const model = @import("model.zig");
+const util = @import("util.zig");
+const sink = @import("sink.zig");
+const ui = @import("ui.zig");
+const bin_export = @import("bin_export.zig");
+const c = @import("c.zig").c;
+
+
+const CborMajor = bin_export.CborMajor;
+const ItemKey = bin_export.ItemKey;
+
+// Two ways to read a bin export:
+//
+// 1. Streaming import
+//   - Read blocks sequentially, assemble items into model.Entry's and stitch
+//     them together on the go.
+//   - Does not use the sink.zig API, since sub-level items are read before their parent dirs.
+//   - Useful when:
+//     - User attempts to do a refresh or delete while browsing a file through (2)
+//     - Reading from a stream
+//
+// 2. Random access browsing
+//   - Read final block first to get the root item, then have browser.zig fetch
+//     dir listings from this file.
+//   - The default reader mode, requires much less memory than (1) and provides
+//     a snappier first-browsing experience.
+//
+// The approach from (2) can also be used to walk through the entire directory
+// tree and stream it to sink.zig (either for importing or converting to JSON).
+// That would allow for better code reuse and low-memory conversion, but
+// performance will not be as good as a direct streaming read. Needs
+// benchmarks.
+//
+// This file only implements (2) at the moment.
+
+pub const global = struct {
+    var fd: std.fs.File = undefined;
+    var index: []u8 = undefined;
+    var blocks: [8]Block = [1]Block{.{}}**8;
+    var counter: u64 = 0;
+
+    // Last itemref being read/parsed. This is a hack to provide *some* context on error.
+    // Providing more context mainly just bloats the binary and decreases
+    // performance for fairly little benefit. Nobody's going to debug a corrupted export.
+    var lastitem: ?u64 = null;
+};
+
+
+const Block = struct {
+    num: u32 = std.math.maxInt(u32),
+    last: u64 = 0,
+    data: []u8 = undefined,
+};
+
+
+inline fn bigu16(v: [2]u8) u16 { return std.mem.bigToNative(u16, @bitCast(v)); }
+inline fn bigu32(v: [4]u8) u32 { return std.mem.bigToNative(u32, @bitCast(v)); }
+inline fn bigu64(v: [8]u8) u64 { return std.mem.bigToNative(u64, @bitCast(v)); }
+
+fn die() noreturn {
+    @branchHint(.cold);
+    if (global.lastitem) |e| ui.die("Error reading item {x} from file\n", .{e})
+    else ui.die("Error reading from file\n", .{});
+}
+
+
+fn readBlock(num: u32) []const u8 {
+    // Simple linear search, only suitable if we keep the number of in-memory blocks small.
+    var block: *Block = &global.blocks[0];
+    for (&global.blocks) |*b| {
+        if (b.num == num) {
+            if (b.last != global.counter) {
+                global.counter += 1;
+                b.last = global.counter;
+            }
+            return b.data;
+        }
+        if (block.last > b.last) block = b;
+    }
+    if (block.num != std.math.maxInt(u32))
+        main.allocator.free(block.data);
+    block.num = num;
+    global.counter += 1;
+    block.last = global.counter;
+
+    if (num > global.index.len/8 - 1) die();
+    const offlen = bigu64(global.index[num*8..][0..8].*);
+    const off = offlen >> 24;
+    const len = offlen & 0xffffff;
+    if (len <= 12) die();
+
+    // Only read the compressed data part, assume block header, number and footer are correct.
+    const buf = main.allocator.alloc(u8, @intCast(len - 12)) catch unreachable;
+    defer main.allocator.free(buf);
+    const rdlen = global.fd.preadAll(buf, off + 8)
+        catch |e| ui.die("Error reading from file: {s}\n", .{ui.errorString(e)});
+    if (rdlen != buf.len) die();
+
+    const rawlen = c.ZSTD_getFrameContentSize(buf.ptr, buf.len);
+    if (rawlen <= 0 or rawlen >= (1<<24)) die();
+    block.data = main.allocator.alloc(u8, @intCast(rawlen)) catch unreachable;
+
+    const res = c.ZSTD_decompress(block.data.ptr, block.data.len, buf.ptr, buf.len);
+    if (res != block.data.len) ui.die("Error decompressing block {} (expected {} got {})\n", .{ num, block.data.len, res });
+
+    return block.data;
+}
+
+
+const CborReader = struct {
+    buf: []const u8,
+
+    fn head(r: *CborReader) CborVal {
+        if (r.buf.len < 1) die();
+        var v = CborVal{
+            .rd = r,
+            .major = @enumFromInt(r.buf[0] >> 5),
+            .indef = false,
+            .arg = 0,
+        };
+        switch (r.buf[0] & 0x1f) {
+            0x00...0x17 => |n| {
+                v.arg = n;
+                r.buf = r.buf[1..];
+            },
+            0x18 => {
+                if (r.buf.len < 2) die();
+                v.arg = r.buf[1];
+                r.buf = r.buf[2..];
+            },
+            0x19 => {
+                if (r.buf.len < 3) die();
+                v.arg = bigu16(r.buf[1..3].*);
+                r.buf = r.buf[3..];
+            },
+            0x1a => {
+                if (r.buf.len < 5) die();
+                v.arg = bigu32(r.buf[1..5].*);
+                r.buf = r.buf[5..];
+            },
+            0x1b => {
+                if (r.buf.len < 9) die();
+                v.arg = bigu64(r.buf[1..9].*);
+                r.buf = r.buf[9..];
+            },
+            0x1f => switch (v.major) {
+                .bytes, .text, .array, .map, .simple => {
+                    v.indef = true;
+                    r.buf = r.buf[1..];
+                },
+                else => die(),
+            },
+            else => die(),
+        }
+        return v;
+    }
+
+    // Read the next CBOR value, skipping any tags
+    fn next(r: *CborReader) CborVal {
+        while (true) {
+            const v = r.head();
+            if (v.major != .tag) return v;
+        }
+    }
+};
+
+const CborVal = struct {
+    rd: *CborReader,
+    major: CborMajor,
+    indef: bool,
+    arg: u64,
+
+    fn end(v: *const CborVal) bool {
+        return v.major == .simple and v.indef;
+    }
+
+    fn int(v: *const CborVal, T: type) T {
+        switch (v.major) {
+            .pos => return std.math.cast(T, v.arg) orelse die(),
+            .neg => {
+                if (std.math.minInt(T) == 0) die();
+                if (v.arg > std.math.maxInt(T)) die();
+                return -@as(T, @intCast(v.arg)) + (-1);
+            },
+            else => die(),
+        }
+    }
+
+    fn isTrue(v: *const CborVal) bool {
+        return v.major == .simple and v.arg == 21;
+    }
+
+    // Read either a byte or text string.
+    // Doesn't validate UTF-8 strings, doesn't support indefinite-length strings.
+    fn bytes(v: *const CborVal) []const u8 {
+        if (v.indef or (v.major != .bytes and v.major != .text)) die();
+        if (v.rd.buf.len < v.arg) die();
+        defer v.rd.buf = v.rd.buf[@intCast(v.arg)..];
+        return v.rd.buf[0..@intCast(v.arg)];
+    }
+
+    // Skip current value.
+    fn skip(v: *const CborVal) void {
+        // indefinite-length bytes, text, array or map; skip till break marker.
+        if (v.major != .simple and v.indef) {
+            while (true) {
+                const n = v.rd.next();
+                if (n.end()) return;
+                n.skip();
+            }
+        }
+        switch (v.major) {
+            .bytes, .text => {
+                if (v.rd.buf.len < v.arg) die();
+                v.rd.buf = v.rd.buf[@intCast(v.arg)..];
+            },
+            .array => {
+                if (v.arg > (1<<24)) die();
+                for (0..@intCast(v.arg)) |_| v.rd.next().skip();
+            },
+            .map => {
+                if (v.arg > (1<<24)) die();
+                for (0..@intCast(v.arg*|2)) |_| v.rd.next().skip();
+            },
+            else => {},
+        }
+    }
+
+    fn etype(v: *const CborVal) model.EType {
+        const n = v.int(i32);
+        return std.meta.intToEnum(model.EType, n)
+            catch if (n < 0) .pattern else .nonreg;
+    }
+
+    fn itemref(v: *const CborVal, cur: u64) u64 {
+        if (v.major == .pos) return v.arg;
+        if (v.major == .neg) {
+            if (v.arg >= (cur & 0xffffff)) die();
+            return cur - v.arg - 1;
+        }
+        return die();
+    }
+};
+
+
+test "CBOR int parsing" {
+    inline for (.{
+        .{ .in = "\x00", .t = u1, .exp = 0 },
+        .{ .in = "\x01", .t = u1, .exp = 1 },
+        .{ .in = "\x18\x18", .t = u8, .exp = 0x18 },
+        .{ .in = "\x18\xff", .t = u8, .exp = 0xff },
+        .{ .in = "\x19\x07\xff", .t = u64, .exp = 0x7ff },
+        .{ .in = "\x19\xff\xff", .t = u64, .exp = 0xffff },
+        .{ .in = "\x1a\x00\x01\x00\x00", .t = u64, .exp = 0x10000 },
+        .{ .in = "\x1b\x7f\xff\xff\xff\xff\xff\xff\xff", .t = i64, .exp = std.math.maxInt(i64) },
+        .{ .in = "\x1b\xff\xff\xff\xff\xff\xff\xff\xff", .t = u64, .exp = std.math.maxInt(u64) },
+        .{ .in = "\x1b\xff\xff\xff\xff\xff\xff\xff\xff", .t = i65, .exp = std.math.maxInt(u64) },
+        .{ .in = "\x20", .t = i1, .exp = -1 },
+        .{ .in = "\x38\x18", .t = i8, .exp = -0x19 },
+        .{ .in = "\x39\x01\xf3", .t = i16, .exp = -500 },
+        .{ .in = "\x3a\xfe\xdc\xba\x97", .t = i33, .exp = -0xfedc_ba98 },
+        .{ .in = "\x3b\x7f\xff\xff\xff\xff\xff\xff\xff", .t = i64, .exp = std.math.minInt(i64) },
+        .{ .in = "\x3b\xff\xff\xff\xff\xff\xff\xff\xff", .t = i65, .exp = std.math.minInt(i65) },
+    }) |t| {
+        var r = CborReader{.buf = t.in};
+        try std.testing.expectEqual(@as(t.t, t.exp), r.next().int(t.t));
+        try std.testing.expectEqual(0, r.buf.len);
+    }
+}
+
+test "CBOR string parsing" {
+    var r = CborReader{.buf="\x40"};
+    try std.testing.expectEqualStrings("", r.next().bytes());
+    r.buf = "\x45\x00\x01\x02\x03\x04x";
+    try std.testing.expectEqualStrings("\x00\x01\x02\x03\x04", r.next().bytes());
+    try std.testing.expectEqualStrings("x", r.buf);
+    r.buf = "\x78\x241234567890abcdefghijklmnopqrstuvwxyz-end";
+    try std.testing.expectEqualStrings("1234567890abcdefghijklmnopqrstuvwxyz", r.next().bytes());
+    try std.testing.expectEqualStrings("-end", r.buf);
+}
+
+test "CBOR skip parsing" {
+    inline for (.{
+        "\x00",
+        "\x40",
+        "\x41a",
+        "\x5f\xff",
+        "\x5f\x41a\xff",
+        "\x80",
+        "\x81\x00",
+        "\x9f\xff",
+        "\x9f\x9f\xff\xff",
+        "\x9f\x9f\x81\x00\xff\xff",
+        "\xa0",
+        "\xa1\x00\x01",
+        "\xbf\xff",
+        "\xbf\xc0\x00\x9f\xff\xff",
+    }) |s| {
+        var r = CborReader{.buf = s ++ "garbage"};
+        r.next().skip();
+        try std.testing.expectEqualStrings(r.buf, "garbage");
+    }
+}
+
+const ItemParser = struct {
+    r: CborReader,
+    len: ?u64 = null,
+
+    const Field = struct {
+        key: ItemKey,
+        val: CborVal,
+    };
+
+    fn init(buf: []const u8) ItemParser {
+        var r = ItemParser{.r = .{.buf = buf}};
+        const head = r.r.next();
+        if (head.major != .map) die();
+        if (!head.indef) r.len = head.arg;
+        return r;
+    }
+
+    fn key(r: *ItemParser) ?CborVal {
+        if (r.len) |*l| {
+            if (l.* == 0) return null;
+            l.* -= 1;
+            return r.r.next();
+        } else {
+            const v = r.r.next();
+            return if (v.end()) null else v;
+        }
+    }
+
+    // Skips over any fields that don't fit into an ItemKey.
+    fn next(r: *ItemParser) ?Field {
+        while (r.key()) |k| {
+            if (k.major == .pos and k.arg <= std.math.maxInt(@typeInfo(ItemKey).@"enum".tag_type)) return .{
+                .key = @enumFromInt(k.arg),
+                .val = r.r.next(),
+            } else {
+                k.skip();
+                r.r.next().skip();
+            }
+        }
+        return null;
+    }
+};
+
+// Returned buffer is valid until the next readItem().
+fn readItem(ref: u64) ItemParser {
+    global.lastitem = ref;
+    if (ref >= (1 << (24 + 32))) die();
+    const block = readBlock(@intCast(ref >> 24));
+    if ((ref & 0xffffff) >= block.len) die();
+    return ItemParser.init(block[@intCast(ref & 0xffffff)..]);
+}
+
+const Import = struct {
+    sink: *sink.Thread,
+    stat: sink.Stat = .{},
+    fields: Fields = .{},
+    p: ItemParser = undefined,
+
+    const Fields = struct {
+        name: []const u8 = "",
+        rderr: bool = false,
+        prev: ?u64 = null,
+        sub: ?u64 = null,
+    };
+
+    fn readFields(ctx: *Import, ref: u64) void {
+        ctx.p = readItem(ref);
+        var hastype = false;
+
+        while (ctx.p.next()) |kv| switch (kv.key) {
+            .type => {
+                ctx.stat.etype = kv.val.etype();
+                hastype = true;
+            },
+            .name => ctx.fields.name = kv.val.bytes(),
+            .prev => ctx.fields.prev = kv.val.itemref(ref),
+            .asize => ctx.stat.size = kv.val.int(u64),
+            .dsize => ctx.stat.blocks = @intCast(kv.val.int(u64)/512),
+            .dev => ctx.stat.dev = kv.val.int(u64),
+            .rderr => ctx.fields.rderr = kv.val.isTrue(),
+            .sub => ctx.fields.sub = kv.val.itemref(ref),
+            .ino => ctx.stat.ino = kv.val.int(u64),
+            .nlink => ctx.stat.nlink = kv.val.int(u31),
+            .uid => { ctx.stat.ext.uid = kv.val.int(u32); ctx.stat.ext.pack.hasuid = true; },
+            .gid => { ctx.stat.ext.gid = kv.val.int(u32); ctx.stat.ext.pack.hasgid = true; },
+            .mode => { ctx.stat.ext.mode = kv.val.int(u16); ctx.stat.ext.pack.hasmode = true; },
+            .mtime => { ctx.stat.ext.mtime = kv.val.int(u64); ctx.stat.ext.pack.hasmtime = true; },
+            else => kv.val.skip(),
+        };
+
+        if (!hastype) die();
+        if (ctx.fields.name.len == 0) die();
+    }
+
+    fn import(ctx: *Import, ref: u64, parent: ?*sink.Dir, dev: u64) void {
+        ctx.stat = .{ .dev = dev };
+        ctx.fields = .{};
+        ctx.readFields(ref);
+
+        if (ctx.stat.etype == .dir) {
+            const prev = ctx.fields.prev;
+            const dir =
+                if (parent) |d| d.addDir(ctx.sink, ctx.fields.name, &ctx.stat)
+                else sink.createRoot(ctx.fields.name, &ctx.stat);
+            ctx.sink.setDir(dir);
+            if (ctx.fields.rderr) dir.setReadError(ctx.sink);
+
+            ctx.fields.prev = ctx.fields.sub;
+            while (ctx.fields.prev) |n| ctx.import(n, dir, ctx.stat.dev);
+
+            ctx.sink.setDir(parent);
+            dir.unref(ctx.sink);
+            ctx.fields.prev = prev;
+
+        } else {
+            const p = parent orelse die();
+            if (@intFromEnum(ctx.stat.etype) < 0)
+                p.addSpecial(ctx.sink, ctx.fields.name, ctx.stat.etype)
+            else
+                p.addStat(ctx.sink, ctx.fields.name, &ctx.stat);
+        }
+
+        if ((ctx.sink.files_seen.load(.monotonic) & 65) == 0)
+            main.handleEvent(false, false);
+    }
+};
+
+// Resolve an itemref and return a newly allocated entry.
+// Dir.parent and Link.next/prev are left uninitialized.
+pub fn get(ref: u64, alloc: std.mem.Allocator) *model.Entry {
+    const parser = readItem(ref);
+
+    var etype: ?model.EType = null;
+    var name: []const u8 = "";
+    var p = parser;
+    var ext = model.Ext{};
+    while (p.next()) |kv| {
+        switch (kv.key) {
+            .type => etype = kv.val.etype(),
+            .name => name = kv.val.bytes(),
+            .uid   => { ext.uid = kv.val.int(u32); ext.pack.hasuid = true; },
+            .gid   => { ext.gid = kv.val.int(u32); ext.pack.hasgid = true; },
+            .mode  => { ext.mode = kv.val.int(u16); ext.pack.hasmode = true; },
+            .mtime => { ext.mtime = kv.val.int(u64); ext.pack.hasmtime = true; },
+            else => kv.val.skip(),
+        }
+    }
+    if (etype == null or name.len == 0) die();
+
+    var entry = model.Entry.create(alloc, etype.?, main.config.extended and !ext.isEmpty(), name);
+    entry.next = .{ .ref = std.math.maxInt(u64) };
+    if (entry.ext()) |e| e.* = ext;
+    if (entry.dir()) |d| d.sub = .{ .ref = std.math.maxInt(u64) };
+    p = parser;
+    while (p.next()) |kv| switch (kv.key) {
+        .prev  => entry.next = .{ .ref = kv.val.itemref(ref) },
+        .asize => { if (entry.pack.etype != .dir) entry.size = kv.val.int(u64); },
+        .dsize => { if (entry.pack.etype != .dir) entry.pack.blocks = @intCast(kv.val.int(u64)/512); },
+
+        .rderr => { if (entry.dir()) |d| {
+            if (kv.val.isTrue()) d.pack.err = true
+            else d.pack.suberr = true;
+        } },
+        .dev      => { if (entry.dir()) |d| d.pack.dev = model.devices.getId(kv.val.int(u64)); },
+        .cumasize => entry.size = kv.val.int(u64),
+        .cumdsize => entry.pack.blocks = @intCast(kv.val.int(u64)/512),
+        .shrasize => { if (entry.dir()) |d| d.shared_size = kv.val.int(u64); },
+        .shrdsize => { if (entry.dir()) |d| d.shared_blocks = kv.val.int(u64)/512; },
+        .items    => { if (entry.dir()) |d| d.items = util.castClamp(u32, kv.val.int(u64)); },
+        .sub      => { if (entry.dir()) |d| d.sub = .{ .ref = kv.val.itemref(ref) }; },
+
+        .ino   => { if (entry.link()) |l| l.ino = kv.val.int(u64); },
+        .nlink => { if (entry.link()) |l| l.pack.nlink = kv.val.int(u31); },
+        else => kv.val.skip(),
+    };
+    return entry;
+}
+
+pub fn getRoot() u64 {
+    return bigu64(global.index[global.index.len-8..][0..8].*);
+}
+
+// Walk through the directory tree in depth-first order and pass results to sink.zig.
+// Depth-first is required for JSON export, but more efficient strategies are
+// possible for other sinks. Parallel import is also an option, but that's more
+// complex and likely less efficient than a streaming import.
+pub fn import() void {
+    const sink_threads = sink.createThreads(1);
+    var ctx = Import{.sink = &sink_threads[0]};
+    ctx.import(getRoot(), null, 0);
+    sink.done();
+}
+
+// Assumes that the file signature has already been read and validated.
+pub fn open(fd: std.fs.File) !void {
+    global.fd = fd;
+
+    // Do not use fd.getEndPos() because that requires newer kernels supporting statx() #261.
+    try fd.seekFromEnd(0);
+    const size = try fd.getPos();
+    if (size < 16) return error.EndOfStream;
+
+    // Read index block
+    var buf: [4]u8 = undefined;
+    if (try fd.preadAll(&buf, size - 4) != 4) return error.EndOfStream;
+    const index_header = bigu32(buf);
+    if ((index_header >> 28) != 1 or (index_header & 7) != 0) die();
+    const len = (index_header & 0x0fffffff) - 8; // excluding block header & footer
+    if (len >= size) die();
+    global.index = main.allocator.alloc(u8, len) catch unreachable;
+    if (try fd.preadAll(global.index, size - len - 4) != global.index.len) return error.EndOfStream;
+}

src/browser.zig

@@ -4,22 +4,32 @@
 const std = @import("std");
 const main = @import("main.zig");
 const model = @import("model.zig");
-const scan = @import("scan.zig");
+const sink = @import("sink.zig");
+const mem_sink = @import("mem_sink.zig");
+const bin_reader = @import("bin_reader.zig");
 const delete = @import("delete.zig");
 const ui = @import("ui.zig");
-const c = @cImport(@cInclude("time.h"));
+const c = @import("c.zig").c;
 const util = @import("util.zig");
 
 // Currently opened directory.
 pub var dir_parent: *model.Dir = undefined;
+pub var dir_path: [:0]u8 = undefined;
+var dir_parents: std.ArrayListUnmanaged(model.Ref) = .empty;
+var dir_alloc = std.heap.ArenaAllocator.init(main.allocator);
+
+// Used to keep track of which dir is which ref, so we can enter it.
+// Only used for binreader browsing.
+var dir_refs: std.ArrayListUnmanaged(struct { ptr: *model.Dir, ref: u64 }) = .empty;
 
 // Sorted list of all items in the currently opened directory.
 // (first item may be null to indicate the "parent directory" item)
-var dir_items = std.ArrayList(?*model.Entry).init(main.allocator);
+var dir_items: std.ArrayListUnmanaged(?*model.Entry) = .empty;
 
 var dir_max_blocks: u64 = 0;
 var dir_max_size: u64 = 0;
 var dir_has_shared: bool = false;
+var dir_loading: u64 = 0;
 
 // Index into dir_items that is currently selected.
 var cursor_idx: usize = 0;
@@ -32,28 +42,28 @@ const View = struct {
 
     // The hash(name) of the selected entry (cursor), this is used to derive
     // cursor_idx after sorting or changing directory.
-    // (collisions may cause the wrong entry to be selected, but dealing with
-    // string allocations sucks and I expect collisions to be rare enough)
     cursor_hash: u64 = 0,
 
-    fn hashEntry(entry: ?*model.Entry) u64 {
-        return if (entry) |e| std.hash.Wyhash.hash(0, e.name()) else 0;
+    fn dirHash() u64 {
+        return std.hash.Wyhash.hash(0, dir_path);
     }
 
     // Update cursor_hash and save the current view to the hash table.
     fn save(self: *@This()) void {
         self.cursor_hash = if (dir_items.items.len == 0) 0
-                           else hashEntry(dir_items.items[cursor_idx]);
-        opened_dir_views.put(@intFromPtr(dir_parent), self.*) catch {};
+                           else if (dir_items.items[cursor_idx]) |e| e.nameHash()
+                           else 0;
+        opened_dir_views.put(dirHash(), self.*) catch {};
     }
 
     // Should be called after dir_parent or dir_items has changed, will load the last saved view and find the proper cursor_idx.
-    fn load(self: *@This(), sel: ?*const model.Entry) void {
-        if (opened_dir_views.get(@intFromPtr(dir_parent))) |v| self.* = v
+    fn load(self: *@This(), sel: u64) void {
+        if (opened_dir_views.get(dirHash())) |v| self.* = v
         else self.* = @This(){};
         cursor_idx = 0;
         for (dir_items.items, 0..) |e, i| {
-            if (if (sel != null) e == sel else self.cursor_hash == hashEntry(e)) {
+            const h = if (e) |x| x.nameHash() else 0;
+            if (if (sel != 0) h == sel else self.cursor_hash == h) {
                 cursor_idx = i;
                 break;
             }
@@ -64,10 +74,8 @@ const View = struct {
 var current_view = View{};
 
 // Directories the user has browsed to before, and which item was last selected.
-// The key is the @intFromPtr() of the opened *Dir; An int because the pointer
-// itself may have gone stale after deletion or refreshing. They're only for
-// lookups, not dereferencing.
-var opened_dir_views = std.AutoHashMap(usize, View).init(main.allocator);
+// The key is the hash of dir_path;
+var opened_dir_views = std.AutoHashMap(u64, View).init(main.allocator);
 
 fn sortIntLt(a: anytype, b: @TypeOf(a)) ?bool {
     return if (a == b) null else if (main.config.sort_order == .asc) a < b else a > b;
@@ -77,8 +85,8 @@ fn sortLt(_: void, ap: ?*model.Entry, bp: ?*model.Entry) bool {
     const a = ap.?;
     const b = bp.?;
 
-    if (main.config.sort_dirsfirst and a.isDirectory() != b.isDirectory())
-        return a.isDirectory();
+    if (main.config.sort_dirsfirst and a.pack.etype.isDirectory() != b.pack.etype.isDirectory())
+        return a.pack.etype.isDirectory();
 
     switch (main.config.sort_col) {
         .name => {}, // name sorting is the fallback
@@ -113,7 +121,7 @@ fn sortLt(_: void, ap: ?*model.Entry, bp: ?*model.Entry) bool {
 // - config.sort_* changes
 // - dir_items changes (i.e. from loadDir())
 // - files in this dir have changed in a way that affects their ordering
-fn sortDir(next_sel: ?*const model.Entry) void {
+fn sortDir(next_sel: u64) void {
     // No need to sort the first item if that's the parent dir reference,
     // excluding that allows sortLt() to ignore null values.
     const lst = dir_items.items[(if (dir_items.items.len > 0 and dir_items.items[0] == null) @as(usize, 1) else 0)..];
@@ -125,31 +133,103 @@ fn sortDir(next_sel: ?*const model.Entry) void {
 // - dir_parent changes (i.e. we change directory)
 // - config.show_hidden changes
 // - files in this dir have been added or removed
-pub fn loadDir(next_sel: ?*const model.Entry) void {
+pub fn loadDir(next_sel: u64) void {
+    // XXX: The current dir listing is wiped before loading the new one, which
+    // causes the screen to flicker a bit when the loading indicator is drawn.
+    // Should we keep the old listing around?
+    main.event_delay_timer.reset();
+    _ = dir_alloc.reset(.free_all);
     dir_items.shrinkRetainingCapacity(0);
+    dir_refs.shrinkRetainingCapacity(0);
     dir_max_size = 1;
     dir_max_blocks = 1;
     dir_has_shared = false;
 
-    if (dir_parent != model.root)
-        dir_items.append(null) catch unreachable;
-    var it = dir_parent.sub;
-    while (it) |e| : (it = e.next) {
+    if (dir_parents.items.len > 1)
+        dir_items.append(main.allocator, null) catch unreachable;
+    var ref = dir_parent.sub;
+    while (!ref.isNull()) {
+        const e =
+            if (main.config.binreader) bin_reader.get(ref.ref, dir_alloc.allocator())
+            else ref.ptr.?;
+
         if (e.pack.blocks > dir_max_blocks) dir_max_blocks = e.pack.blocks;
         if (e.size > dir_max_size) dir_max_size = e.size;
         const shown = main.config.show_hidden or blk: {
-            const excl = if (e.file()) |f| f.pack.excluded else false;
+            const excl = switch (e.pack.etype) {
+                .pattern, .otherfs, .kernfs => true,
+                else => false,
+            };
             const name = e.name();
             break :blk !excl and name[0] != '.' and name[name.len-1] != '~';
         };
         if (shown) {
-            dir_items.append(e) catch unreachable;
-            if (e.dir()) |d| if (d.shared_blocks > 0 or d.shared_size > 0) { dir_has_shared = true; };
+            dir_items.append(main.allocator, e) catch unreachable;
+            if (e.dir()) |d| {
+                if (d.shared_blocks > 0 or d.shared_size > 0) dir_has_shared = true;
+                if (main.config.binreader) dir_refs.append(main.allocator, .{ .ptr = d, .ref = ref.ref }) catch unreachable;
             }
         }
+
+        ref = e.next;
+        dir_loading += 1;
+        if ((dir_loading & 65) == 0)
+            main.handleEvent(false, false);
+    }
     sortDir(next_sel);
+    dir_loading = 0;
 }
 
+
+pub fn initRoot() void {
+    if (main.config.binreader) {
+        const ref = bin_reader.getRoot();
+        dir_parent = bin_reader.get(ref, main.allocator).dir() orelse ui.die("Invalid import\n", .{});
+        dir_parents.append(main.allocator, .{ .ref = ref }) catch unreachable;
+    } else {
+        dir_parent = model.root;
+        dir_parents.append(main.allocator, .{ .ptr = &dir_parent.entry }) catch unreachable;
+    }
+    dir_path = main.allocator.dupeZ(u8, dir_parent.entry.name()) catch unreachable;
+    loadDir(0);
+}
+
+fn enterSub(e: *model.Dir) void {
+    if (main.config.binreader) {
+        const ref = blk: {
+            for (dir_refs.items) |r| if (r.ptr == e) break :blk r.ref;
+            return;
+        };
+        dir_parent.entry.destroy(main.allocator);
+        dir_parent = bin_reader.get(ref, main.allocator).dir() orelse unreachable;
+        dir_parents.append(main.allocator, .{ .ref = ref }) catch unreachable;
+    } else {
+        dir_parent = e;
+        dir_parents.append(main.allocator, .{ .ptr = &e.entry }) catch unreachable;
+    }
+
+    const newpath = std.fs.path.joinZ(main.allocator, &[_][]const u8{ dir_path, e.entry.name() }) catch unreachable;
+    main.allocator.free(dir_path);
+    dir_path = newpath;
+}
+
+fn enterParent() void {
+    std.debug.assert(dir_parents.items.len > 1);
+
+    _ = dir_parents.pop();
+    const p = dir_parents.items[dir_parents.items.len-1];
+    if (main.config.binreader) {
+        dir_parent.entry.destroy(main.allocator);
+        dir_parent = bin_reader.get(p.ref, main.allocator).dir() orelse unreachable;
+    } else
+        dir_parent = p.ptr.?.dir() orelse unreachable;
+
+    const newpath = main.allocator.dupeZ(u8, std.fs.path.dirname(dir_path) orelse unreachable) catch unreachable;
+    main.allocator.free(dir_path);
+    dir_path = newpath;
+}
+
+
 const Row = struct {
     row: u32,
     col: u32 = 0,
@@ -161,19 +241,17 @@ const Row = struct {
     fn flag(self: *Self) void {
         defer self.col += 2;
         const item = self.item orelse return;
-        const ch: u7 = ch: {
-            if (item.file()) |f| {
-                if (f.pack.err) break :ch '!';
-                if (f.pack.excluded) break :ch '<';
-                if (f.pack.other_fs) break :ch '>';
-                if (f.pack.kernfs) break :ch '^';
-                if (f.pack.notreg) break :ch '@';
-            } else if (item.dir()) |d| {
-                if (d.pack.err) break :ch '!';
-                if (d.pack.suberr) break :ch '.';
-                if (d.sub == null) break :ch 'e';
-            } else if (item.link()) |_| break :ch 'H';
-            return;
+        const ch: u7 = switch (item.pack.etype) {
+            .dir => if (item.dir().?.pack.err) '!'
+                    else if (item.dir().?.pack.suberr) '.'
+                    else if (item.dir().?.sub.isNull()) 'e'
+                    else return,
+            .link => 'H',
+            .pattern => '<',
+            .otherfs => '>',
+            .kernfs => '^',
+            .nonreg => '@',
+            else => return,
         };
         ui.move(self.row, self.col);
         self.bg.fg(.flag);
@@ -214,10 +292,13 @@ const Row = struct {
         ui.addch('[');
         if (main.config.show_percent) {
             self.bg.fg(.num);
-            ui.addprint("{d:>5.1}", .{ 100 *
-                if (main.config.show_blocks) @as(f32, @floatFromInt(item.pack.blocks)) / @as(f32, @floatFromInt(@max(1, dir_parent.entry.pack.blocks)))
-                else                         @as(f32, @floatFromInt(item.size))        / @as(f32, @floatFromInt(@max(1, dir_parent.entry.size)))
-            });
+            var num   : u64 = if (main.config.show_blocks)             item.pack.blocks else             item.size;
+            var denom : u64 = if (main.config.show_blocks) dir_parent.entry.pack.blocks else dir_parent.entry.size;
+            if (num > (1<<54)) { // avoid overflow
+                num >>= 10;
+                denom >>= 10;
+            }
+            ui.addstr(&util.fmt5dec(@intCast( @min(1000, (num * 1000 + (denom / 2)) / @max(1, denom) ))));
             self.bg.fg(.default);
             ui.addch('%');
         }
@@ -259,12 +340,12 @@ const Row = struct {
             ui.addnum(self.bg, n);
         } else if (n < 100_000)
             ui.addnum(self.bg, n)
-        else if (n < 1000_000) {
-            ui.addprint("{d:>5.1}", .{ @as(f32, @floatFromInt(n)) / 1000 });
+        else if (n < 999_950) {
+            ui.addstr(&util.fmt5dec(@intCast( (n + 50) / 100 )));
             self.bg.fg(.default);
             ui.addch('k');
-        } else if (n < 1000_000_000) {
-            ui.addprint("{d:>5.1}", .{ @as(f32, @floatFromInt(n)) / 1000_000 });
+        } else if (n < 999_950_000) {
+            ui.addstr(&util.fmt5dec(@intCast( (n + 50_000) / 100_000 )));
             self.bg.fg(.default);
             ui.addch('M');
         } else {
@@ -281,16 +362,21 @@ const Row = struct {
         if (!main.config.show_mtime or self.col + 37 > ui.cols) return;
         defer self.col += 27;
         ui.move(self.row, self.col+1);
-        const ext = (if (self.item) |e| e.ext() else @as(?*model.Ext, null)) orelse dir_parent.entry.ext();
-        if (ext) |e| ui.addts(self.bg, e.mtime)
-        else ui.addstr("                 no mtime");
+        const ext = if (self.item) |e| e.ext() else dir_parent.entry.ext();
+        if (ext) |e| {
+            if (e.pack.hasmtime) {
+                ui.addts(self.bg, e.mtime);
+                return;
+            }
+        }
+        ui.addstr("                 no mtime");
     }
 
     fn name(self: *Self) void {
         ui.move(self.row, self.col);
         if (self.item) |i| {
             self.bg.fg(if (i.pack.etype == .dir) .dir else .default);
-            ui.addch(if (i.isDirectory()) '/' else ' ');
+            ui.addch(if (i.pack.etype.isDirectory()) '/' else ' ');
             ui.addstr(ui.shorten(ui.toUtf8(i.name()), ui.cols -| self.col -| 1));
         } else {
             self.bg.fg(.dir);
@@ -314,7 +400,7 @@ const Row = struct {
 };
 
 var state: enum { main, quit, help, info } = .main;
-var message: ?[:0]const u8 = null;
+var message: ?[]const [:0]const u8 = null;
 
 const quit = struct {
     fn draw() void {
@@ -344,7 +430,7 @@ const info = struct {
 
     var tab: Tab = .info;
     var entry: ?*model.Entry = null;
-    var links: ?std.ArrayList(*model.Link) = null;
+    var links: ?std.ArrayListUnmanaged(*model.Link) = null;
     var links_top: usize = 0;
     var links_idx: usize = 0;
 
@@ -359,7 +445,7 @@ const info = struct {
     // Set the displayed entry to the currently selected item and open the tab.
     fn set(e: ?*model.Entry, t: Tab) void {
         if (e != entry) {
-            if (links) |*l| l.deinit();
+            if (links) |*l| l.deinit(main.allocator);
             links = null;
             links_top = 0;
             links_idx = 0;
@@ -371,25 +457,27 @@ const info = struct {
         }
         state = .info;
         tab = t;
-        if (tab == .links and links == null) {
-            var list = std.ArrayList(*model.Link).init(main.allocator);
+        if (tab == .links and links == null and !main.config.binreader) {
+            var list: std.ArrayListUnmanaged(*model.Link) = .empty;
             var l = e.?.link().?;
             while (true) {
-                list.append(l) catch unreachable;
+                list.append(main.allocator, l) catch unreachable;
                 l = l.next;
                 if (&l.entry == e)
                     break;
             }
-            // TODO: Zig's sort() implementation is type-generic and not very
-            // small. I suspect we can get a good save on our binary size by using
-            // a smaller or non-generic sort. This doesn't have to be very fast.
-            std.mem.sort(*model.Link, list.items, {}, lt);
+            std.sort.heap(*model.Link, list.items, {}, lt);
             for (list.items, 0..) |n,i| if (&n.entry == e) { links_idx = i; };
             links = list;
         }
     }
 
     fn drawLinks(box: ui.Box, row: *u32, rows: u32, cols: u32) void {
+        if (main.config.binreader) {
+            box.move(2, 2);
+            ui.addstr("This feature is not available when reading from file.");
+            return;
+        }
         const numrows = rows -| 4;
         if (links_idx < links_top) links_top = links_idx;
         if (links_idx >= links_top + numrows) links_top = links_idx - numrows + 1;
@@ -443,33 +531,46 @@ const info = struct {
         box.move(row.*, 3);
         ui.style(.bold);
         if (e.ext()) |ext| {
+            var buf: [32]u8 = undefined;
+            if (ext.pack.hasmode) {
                 ui.addstr("Mode: ");
                 ui.style(.default);
                 ui.addmode(ext.mode);
-            var buf: [32]u8 = undefined;
                 ui.style(.bold);
+            }
+            if (ext.pack.hasuid) {
                 ui.addstr("  UID: ");
                 ui.style(.default);
                 ui.addstr(std.fmt.bufPrintZ(&buf, "{d:<6}", .{ ext.uid }) catch unreachable);
                 ui.style(.bold);
+            }
+            if (ext.pack.hasgid) {
                 ui.addstr(" GID: ");
                 ui.style(.default);
                 ui.addstr(std.fmt.bufPrintZ(&buf, "{d:<6}", .{ ext.gid }) catch unreachable);
+            }
         } else {
             ui.addstr("Type: ");
             ui.style(.default);
-            ui.addstr(if (e.isDirectory()) "Directory" else if (if (e.file()) |f| f.pack.notreg else false) "Other" else "File");
+            ui.addstr(switch (e.pack.etype) {
+                .dir => "Directory",
+                .nonreg => "Other",
+                .reg, .link => "File",
+                else => "Excluded",
+            });
         }
         row.* += 1;
 
         // Last modified
         if (e.ext()) |ext| {
+            if (ext.pack.hasmtime) {
                 box.move(row.*, 3);
                 ui.style(.bold);
                 ui.addstr("Last modified: ");
                 ui.addts(.default, ext.mtime);
                 row.* += 1;
             }
+        }
 
         // Disk usage & Apparent size
         drawSize(box, row, "   Disk usage: ", util.blocksToSize(e.pack.blocks), if (e.dir()) |d| util.blocksToSize(d.shared_blocks) else 0);
@@ -489,7 +590,7 @@ const info = struct {
             box.move(row.*, 3);
             ui.style(.bold);
             ui.addstr("   Link count: ");
-            ui.addnum(.default, model.inodes.map.get(l).?.nlink);
+            ui.addnum(.default, l.pack.nlink);
             box.move(row.*, 23);
             ui.style(.bold);
             ui.addstr("  Inode: ");
@@ -507,7 +608,7 @@ const info = struct {
         // for each item. Think it's better to have a dynamic height based on
         // terminal size and scroll if the content doesn't fit.
         const rows = 5 // border + padding + close message
-            + if (tab == .links) 8 else
+            + if (tab == .links and !main.config.binreader) 8 else
               4 // name + type + disk usage + apparent size
             + (if (e.ext() != null) @as(u32, 1) else 0) // last modified
             + (if (e.link() != null) @as(u32, 1) else 0) // link count
@@ -543,18 +644,18 @@ const info = struct {
     fn keyInput(ch: i32) bool {
         if (entry.?.pack.etype == .link) {
             switch (ch) {
-                '1', 'h', ui.c.KEY_LEFT => { set(entry, .info); return true; },
-                '2', 'l', ui.c.KEY_RIGHT => { set(entry, .links); return true; },
+                '1', 'h', c.KEY_LEFT => { set(entry, .info); return true; },
+                '2', 'l', c.KEY_RIGHT => { set(entry, .links); return true; },
                 else => {},
             }
         }
-        if (tab == .links) {
+        if (tab == .links and !main.config.binreader) {
             if (keyInputSelection(ch, &links_idx, links.?.items.len, 5))
                 return true;
             if (ch == 10) { // Enter - go to selected entry
                 const l = links.?.items[links_idx];
                 dir_parent = l.parent;
-                loadDir(&l.entry);
+                loadDir(l.entry.nameHash());
                 set(null, .info);
             }
         }
@@ -701,9 +802,9 @@ const help = struct {
             '1' => tab = .keys,
             '2' => tab = .flags,
             '3' => tab = .about,
-            'h', ui.c.KEY_LEFT => tab = if (tab == .about) .flags else .keys,
-            'l', ui.c.KEY_RIGHT => tab = if (tab == .keys) .flags else .about,
-            'j', ' ', ui.c.KEY_DOWN, ui.c.KEY_NPAGE => {
+            'h', c.KEY_LEFT => tab = if (tab == .about) .flags else .keys,
+            'l', c.KEY_RIGHT => tab = if (tab == .keys) .flags else .about,
+            'j', ' ', c.KEY_DOWN, c.KEY_NPAGE => {
                 const max = switch (tab) {
                     .keys => keys.len/2 - keylines,
                     else => @as(u32, 0),
@@ -711,7 +812,7 @@ const help = struct {
                 if (offset < max)
                     offset += 1;
             },
-            'k', ui.c.KEY_UP, ui.c.KEY_PPAGE => { if (offset > 0) offset -= 1; },
+            'k', c.KEY_UP, c.KEY_PPAGE => { if (offset > 0) offset -= 1; },
             else => state = .main,
         }
     }
@@ -727,7 +828,10 @@ pub fn draw() void {
     ui.addch('?');
     ui.style(.hd);
     ui.addstr(" for help");
-    if (main.config.imported) {
+    if (main.config.binreader) {
+        ui.move(0, ui.cols -| 11);
+        ui.addstr("[from file]");
+    } else if (main.config.imported) {
         ui.move(0, ui.cols -| 10);
         ui.addstr("[imported]");
     } else if (!main.config.can_delete.?) {
@@ -741,12 +845,7 @@ pub fn draw() void {
     ui.move(1,3);
     ui.addch(' ');
     ui.style(.dir);
-
-    var pathbuf = std.ArrayList(u8).init(main.allocator);
-    dir_parent.fmtPath(true, &pathbuf);
-    ui.addstr(ui.shorten(ui.toUtf8(util.arrayListBufZ(&pathbuf)), ui.cols -| 5));
-    pathbuf.deinit();
-
+    ui.addstr(ui.shorten(ui.toUtf8(dir_path), ui.cols -| 5));
     ui.style(.default);
     ui.addch(' ');
 
@@ -754,7 +853,7 @@ pub fn draw() void {
     if (cursor_idx < current_view.top) current_view.top = cursor_idx;
     if (cursor_idx >= current_view.top + numrows) current_view.top = cursor_idx - numrows + 1;
 
-    var i: u32 = 0;
+    var i: u32 = if (dir_loading > 0) numrows else 0;
     var sel_row: u32 = 0;
     while (i < numrows) : (i += 1) {
         if (i+current_view.top >= dir_items.items.len) break;
@@ -771,6 +870,10 @@ pub fn draw() void {
     ui.move(ui.rows-1, 0);
     ui.hline(' ', ui.cols);
     ui.move(ui.rows-1, 0);
+    if (dir_loading > 0) {
+        ui.addstr(" Loading... ");
+        ui.addnum(.hd, dir_loading);
+    } else {
         ui.addch(if (main.config.show_blocks) '*' else ' ');
         ui.style(if (main.config.show_blocks) .bold_hd else .hd);
         ui.addstr("Total disk usage: ");
@@ -782,6 +885,7 @@ pub fn draw() void {
         ui.addsize(.hd, dir_parent.entry.size);
         ui.addstr("   Items: ");
         ui.addnum(.hd, dir_parent.items);
+    }
 
     switch (state) {
         .main => {},
@@ -790,10 +894,14 @@ pub fn draw() void {
         .info => info.draw(),
     }
     if (message) |m| {
-        const box = ui.Box.create(6, 60, "Message");
-        box.move(2, 2);
-        ui.addstr(m);
-        box.move(4, 33);
+        const box = ui.Box.create(@intCast(m.len + 5), 60, "Message");
+        i = 2;
+        for (m) |ln| {
+            box.move(i, 2);
+            ui.addstr(ln);
+            i += 1;
+        }
+        box.move(i+1, 33);
         ui.addstr("Press any key to continue");
     }
     if (sel_row > 0) ui.move(sel_row, 0);
@@ -804,27 +912,29 @@ fn sortToggle(col: main.config.SortCol, default_order: main.config.SortOrder) vo
     else if (main.config.sort_order == .asc) main.config.sort_order = .desc
     else main.config.sort_order = .asc;
     main.config.sort_col = col;
-    sortDir(null);
+    sortDir(0);
 }
 
 fn keyInputSelection(ch: i32, idx: *usize, len: usize, page: u32) bool {
     switch (ch) {
-        'j', ui.c.KEY_DOWN => {
+        'j', c.KEY_DOWN => {
             if (idx.*+1 < len) idx.* += 1;
         },
-        'k', ui.c.KEY_UP => {
+        'k', c.KEY_UP => {
             if (idx.* > 0) idx.* -= 1;
         },
-        ui.c.KEY_HOME => idx.* = 0,
-        ui.c.KEY_END, ui.c.KEY_LL => idx.* = len -| 1,
-        ui.c.KEY_PPAGE => idx.* = idx.* -| page,
-        ui.c.KEY_NPAGE => idx.* = @min(len -| 1, idx.* + page),
+        c.KEY_HOME => idx.* = 0,
+        c.KEY_END, c.KEY_LL => idx.* = len -| 1,
+        c.KEY_PPAGE => idx.* = idx.* -| page,
+        c.KEY_NPAGE => idx.* = @min(len -| 1, idx.* + page),
         else => return false,
     }
     return true;
 }
 
 pub fn keyInput(ch: i32) void {
+    if (dir_loading > 0) return;
+
     defer current_view.save();
 
     if (message != null) {
@@ -844,23 +954,32 @@ pub fn keyInput(ch: i32) void {
         '?' => state = .help,
         'i' => if (dir_items.items.len > 0) info.set(dir_items.items[cursor_idx], .info),
         'r' => {
-            if (!main.config.can_refresh.?)
-                message = "Directory refresh feature disabled."
+            if (main.config.binreader)
+                message = &.{"Refresh feature is not available when reading from file."}
+            else if (!main.config.can_refresh.? and main.config.imported)
+                message = &.{"Refresh feature disabled.", "Re-run with --enable-refresh to enable this option."}
+            else if (!main.config.can_refresh.?)
+                message = &.{"Directory refresh feature disabled."}
             else {
                 main.state = .refresh;
-                scan.setupRefresh(dir_parent);
+                sink.global.sink = .mem;
+                mem_sink.global.root = dir_parent;
             }
         },
         'b' => {
             if (!main.config.can_shell.?)
-                message = "Shell feature disabled."
+                message = &.{"Shell feature disabled.", "Re-run with --enable-shell to enable this option."}
             else
                 main.state = .shell;
         },
         'd' => {
             if (dir_items.items.len == 0) {
-            } else if (!main.config.can_delete.?)
-                message = "Deletion feature disabled."
+            } else if (main.config.binreader)
+                message = &.{"File deletion is not available when reading from file."}
+            else if (!main.config.can_delete.? and main.config.imported)
+                message = &.{"File deletion is disabled.", "Re-run with --enable-delete to enable this option."}
+            else if (!main.config.can_delete.?)
+                message = &.{"File deletion is disabled."}
             else if (dir_items.items[cursor_idx]) |e| {
                 main.state = .delete;
                 const next =
@@ -878,45 +997,46 @@ pub fn keyInput(ch: i32) void {
         'M' => if (main.config.extended) sortToggle(.mtime, .desc),
         'e' => {
             main.config.show_hidden = !main.config.show_hidden;
-            loadDir(null);
+            loadDir(0);
             state = .main;
         },
         't' => {
             main.config.sort_dirsfirst = !main.config.sort_dirsfirst;
-            sortDir(null);
+            sortDir(0);
         },
         'a' => {
             main.config.show_blocks = !main.config.show_blocks;
             if (main.config.show_blocks and main.config.sort_col == .size) {
                 main.config.sort_col = .blocks;
-                sortDir(null);
+                sortDir(0);
             }
             if (!main.config.show_blocks and main.config.sort_col == .blocks) {
                 main.config.sort_col = .size;
-                sortDir(null);
+                sortDir(0);
             }
         },
 
         // Navigation
-        10, 'l', ui.c.KEY_RIGHT => {
+        10, 'l', c.KEY_RIGHT => {
             if (dir_items.items.len == 0) {
             } else if (dir_items.items[cursor_idx]) |e| {
                 if (e.dir()) |d| {
-                    dir_parent = d;
-                    loadDir(null);
+                    enterSub(d);
+                    //dir_parent = d;
+                    loadDir(0);
                     state = .main;
                 }
-            } else if (dir_parent.parent) |p| {
-                dir_parent = p;
-                loadDir(null);
+            } else if (dir_parents.items.len > 1) {
+                enterParent();
+                loadDir(0);
                 state = .main;
             }
         },
-        'h', '<', ui.c.KEY_BACKSPACE, ui.c.KEY_LEFT => {
-            if (dir_parent.parent) |p| {
-                const e = dir_parent;
-                dir_parent = p;
-                loadDir(&e.entry);
+        'h', '<', c.KEY_BACKSPACE, c.KEY_LEFT => {
+            if (dir_parents.items.len > 1) {
+                //const h = dir_parent.entry.nameHash();
+                enterParent();
+                loadDir(0);
                 state = .main;
             }
         },

src/c.zig

@@ -0,0 +1,20 @@
+// SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
+// SPDX-License-Identifier: MIT
+
+pub const c = @cImport({
+    @cDefine("_XOPEN_SOURCE", "1"); // for wcwidth()
+    @cInclude("stdio.h"); // fopen(), used to initialize ncurses
+    @cInclude("string.h"); // strerror()
+    @cInclude("time.h"); // strftime()
+    @cInclude("wchar.h"); // wcwidth()
+    @cInclude("locale.h"); // setlocale() and localeconv()
+    @cInclude("fnmatch.h"); // fnmatch()
+    @cInclude("unistd.h"); // getuid()
+    @cInclude("sys/types.h"); // struct passwd
+    @cInclude("pwd.h"); // getpwnam(), getpwuid()
+    if (@import("builtin").os.tag == .linux) {
+        @cInclude("sys/vfs.h"); // statfs()
+    }
+    @cInclude("curses.h");
+    @cInclude("zstd.h");
+});

src/delete.zig

@@ -6,7 +6,11 @@ const main = @import("main.zig");
 const model = @import("model.zig");
 const ui = @import("ui.zig");
 const browser = @import("browser.zig");
+const scan = @import("scan.zig");
+const sink = @import("sink.zig");
+const mem_sink = @import("mem_sink.zig");
 const util = @import("util.zig");
+const c = @import("c.zig").c;
 
 var parent: *model.Dir = undefined;
 var entry: *model.Entry = undefined;
@@ -46,7 +50,7 @@ fn deleteItem(dir: std.fs.Dir, path: [:0]const u8, ptr: *align(1) ?*model.Entry)
 
     if (entry.dir()) |d| {
         var fd = dir.openDirZ(path, .{ .no_follow = true, .iterate = false }) catch |e| return err(e);
-        var it = &d.sub;
+        var it = &d.sub.ptr;
         parent = d;
         defer parent = parent.parent.?;
         while (it.*) |n| {
@@ -55,15 +59,66 @@ fn deleteItem(dir: std.fs.Dir, path: [:0]const u8, ptr: *align(1) ?*model.Entry)
                 return true;
             }
             if (it.* == n) // item deletion failed, make sure to still advance to next
-                it = &n.next;
+                it = &n.next.ptr;
         }
         fd.close();
         dir.deleteDirZ(path) catch |e|
-            return if (e != error.DirNotEmpty or d.sub == null) err(e) else false;
+            return if (e != error.DirNotEmpty or d.sub.ptr == null) err(e) else false;
     } else
         dir.deleteFileZ(path) catch |e| return err(e);
-    ptr.*.?.delStats(parent);
-    ptr.* = ptr.*.?.next;
+    ptr.*.?.zeroStats(parent);
+    ptr.* = ptr.*.?.next.ptr;
+    return false;
+}
+
+// Returns true if the item has been deleted successfully.
+fn deleteCmd(path: [:0]const u8, ptr: *align(1) ?*model.Entry) bool {
+    {
+        var env = std.process.getEnvMap(main.allocator) catch unreachable;
+        defer env.deinit();
+        env.put("NCDU_DELETE_PATH", path) catch unreachable;
+
+        // Since we're passing the path as an environment variable and go through
+        // the shell anyway, we can refer to the variable and avoid error-prone
+        // shell escaping.
+        const cmd = std.fmt.allocPrint(main.allocator, "{s} \"$NCDU_DELETE_PATH\"", .{main.config.delete_command}) catch unreachable;
+        defer main.allocator.free(cmd);
+        ui.runCmd(&.{"/bin/sh", "-c", cmd}, null, &env, true);
+    }
+
+    const stat = scan.statAt(std.fs.cwd(), path, false, null) catch {
+        // Stat failed. Would be nice to display an error if it's not
+        // 'FileNotFound', but w/e, let's just assume the item has been
+        // deleted as expected.
+        ptr.*.?.zeroStats(parent);
+        ptr.* = ptr.*.?.next.ptr;
+        return true;
+    };
+
+    // If either old or new entry is not a dir, remove & re-add entry in the in-memory tree.
+    if (ptr.*.?.pack.etype != .dir or stat.etype != .dir) {
+        ptr.*.?.zeroStats(parent);
+        const e = model.Entry.create(main.allocator, stat.etype, main.config.extended and !stat.ext.isEmpty(), ptr.*.?.name());
+        e.next.ptr = ptr.*.?.next.ptr;
+        mem_sink.statToEntry(&stat, e, parent);
+        ptr.* = e;
+
+        var it : ?*model.Dir = parent;
+        while (it) |p| : (it = p.parent) {
+            if (stat.etype != .link) {
+                p.entry.pack.blocks +|= e.pack.blocks;
+                p.entry.size +|= e.size;
+            }
+            p.items +|= 1;
+        }
+    }
+
+    // If new entry is a dir, recursively scan.
+    if (ptr.*.?.dir()) |d| {
+        main.state = .refresh;
+        sink.global.sink = .mem;
+        mem_sink.global.root = d;
+    }
     return false;
 }
 
@@ -76,27 +131,34 @@ pub fn delete() ?*model.Entry {
 
     // Find the pointer to this entry
     const e = entry;
-    var it = &parent.sub;
-    while (it.*) |n| : (it = &n.next)
+    var it = &parent.sub.ptr;
+    while (it.*) |n| : (it = &n.next.ptr)
         if (it.* == entry)
             break;
 
-    var path = std.ArrayList(u8).init(main.allocator);
-    defer path.deinit();
-    parent.fmtPath(true, &path);
+    var path: std.ArrayListUnmanaged(u8) = .empty;
+    defer path.deinit(main.allocator);
+    parent.fmtPath(main.allocator, true, &path);
     if (path.items.len == 0 or path.items[path.items.len-1] != '/')
-        path.append('/') catch unreachable;
-    path.appendSlice(entry.name()) catch unreachable;
+        path.append(main.allocator, '/') catch unreachable;
+    path.appendSlice(main.allocator, entry.name()) catch unreachable;
 
-    _ = deleteItem(std.fs.cwd(), util.arrayListBufZ(&path), it);
+    if (main.config.delete_command.len == 0) {
+        _ = deleteItem(std.fs.cwd(), util.arrayListBufZ(&path, main.allocator), it);
         model.inodes.addAllStats();
         return if (it.* == e) e else next_sel;
+    } else {
+        const isdel = deleteCmd(util.arrayListBufZ(&path, main.allocator), it);
+        model.inodes.addAllStats();
+        return if (isdel) next_sel else it.*;
+    }
 }
 
 fn drawConfirm() void {
     browser.draw();
     const box = ui.Box.create(6, 60, "Confirm delete");
     box.move(1, 2);
+    if (main.config.delete_command.len == 0) {
         ui.addstr("Are you sure you want to delete \"");
         ui.addstr(ui.shorten(ui.toUtf8(entry.name()), 21));
         ui.addch('"');
@@ -106,6 +168,15 @@ fn drawConfirm() void {
             box.move(2, 18);
             ui.addstr("and all of its contents?");
         }
+    } else {
+        ui.addstr("Are you sure you want to run \"");
+        ui.addstr(ui.shorten(ui.toUtf8(main.config.delete_command), 25));
+        ui.addch('"');
+        box.move(2, 4);
+        ui.addstr("on \"");
+        ui.addstr(ui.shorten(ui.toUtf8(entry.name()), 50));
+        ui.addch('"');
+    }
 
     box.move(4, 15);
     ui.style(if (confirm == .yes) .sel else .default);
@@ -118,20 +189,25 @@ fn drawConfirm() void {
     box.move(4, 31);
     ui.style(if (confirm == .ignore) .sel else .default);
     ui.addstr("don't ask me again");
+    box.move(4, switch (confirm) {
+        .yes    => 15,
+        .no     => 25,
+        .ignore => 31
+    });
 }
 
 fn drawProgress() void {
-    var path = std.ArrayList(u8).init(main.allocator);
-    defer path.deinit();
-    parent.fmtPath(false, &path);
-    path.append('/') catch unreachable;
-    path.appendSlice(entry.name()) catch unreachable;
+    var path: std.ArrayListUnmanaged(u8) = .empty;
+    defer path.deinit(main.allocator);
+    parent.fmtPath(main.allocator, false, &path);
+    path.append(main.allocator, '/') catch unreachable;
+    path.appendSlice(main.allocator, entry.name()) catch unreachable;
 
     // TODO: Item counts and progress bar would be nice.
 
     const box = ui.Box.create(6, 60, "Deleting...");
     box.move(2, 2);
-    ui.addstr(ui.shorten(ui.toUtf8(util.arrayListBufZ(&path)), 56));
+    ui.addstr(ui.shorten(ui.toUtf8(util.arrayListBufZ(&path, main.allocator)), 56));
     box.move(4, 41);
     ui.addstr("Press ");
     ui.style(.key);
@@ -141,16 +217,16 @@ fn drawProgress() void {
 }
 
 fn drawErr() void {
-    var path = std.ArrayList(u8).init(main.allocator);
-    defer path.deinit();
-    parent.fmtPath(false, &path);
-    path.append('/') catch unreachable;
-    path.appendSlice(entry.name()) catch unreachable;
+    var path: std.ArrayListUnmanaged(u8) = .empty;
+    defer path.deinit(main.allocator);
+    parent.fmtPath(main.allocator, false, &path);
+    path.append(main.allocator, '/') catch unreachable;
+    path.appendSlice(main.allocator, entry.name()) catch unreachable;
 
     const box = ui.Box.create(6, 60, "Error");
     box.move(1, 2);
     ui.addstr("Error deleting ");
-    ui.addstr(ui.shorten(ui.toUtf8(util.arrayListBufZ(&path)), 41));
+    ui.addstr(ui.shorten(ui.toUtf8(util.arrayListBufZ(&path, main.allocator)), 41));
     box.move(2, 4);
     ui.addstr(ui.errorString(error_code));
 
@@ -178,11 +254,11 @@ pub fn draw() void {
 pub fn keyInput(ch: i32) void {
     switch (state) {
         .confirm => switch (ch) {
-            'h', ui.c.KEY_LEFT => confirm = switch (confirm) {
+            'h', c.KEY_LEFT => confirm = switch (confirm) {
                 .ignore => .no,
                 else => .yes,
             },
-            'l', ui.c.KEY_RIGHT => confirm = switch (confirm) {
+            'l', c.KEY_RIGHT => confirm = switch (confirm) {
                 .yes => .no,
                 else => .ignore,
             },
@@ -202,11 +278,11 @@ pub fn keyInput(ch: i32) void {
                 main.state = .browse;
         },
         .err => switch (ch) {
-            'h', ui.c.KEY_LEFT => error_option = switch (error_option) {
+            'h', c.KEY_LEFT => error_option = switch (error_option) {
                 .all => .ignore,
                 else => .abort,
             },
-            'l', ui.c.KEY_RIGHT => error_option = switch (error_option) {
+            'l', c.KEY_RIGHT => error_option = switch (error_option) {
                 .abort => .ignore,
                 else => .all,
             },

src/exclude.zig

@@ -3,7 +3,7 @@
 
 const std = @import("std");
 const main = @import("main.zig");
-const c = @cImport(@cInclude("fnmatch.h"));
+const c = @import("c.zig").c;
 
 // Reference:
 //   https://manned.org/glob.7
@@ -123,7 +123,7 @@ test "parse" {
 fn PatternList(comptime withsub: bool) type {
     return struct {
         literals: std.HashMapUnmanaged(*const Pattern, Val, Ctx, 80) = .{},
-        wild: std.ArrayListUnmanaged(*const Pattern) = .{},
+        wild: std.ArrayListUnmanaged(*const Pattern) = .empty,
 
         // Not a fan of the map-of-arrays approach in the 'withsub' case, it
         // has a lot of extra allocations. Linking the Patterns together in a

src/json_export.zig

@@ -0,0 +1,270 @@
+// SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
+// SPDX-License-Identifier: MIT
+
+const std = @import("std");
+const main = @import("main.zig");
+const model = @import("model.zig");
+const sink = @import("sink.zig");
+const util = @import("util.zig");
+const ui = @import("ui.zig");
+const c = @import("c.zig").c;
+
+// JSON output is necessarily single-threaded and items MUST be added depth-first.
+
+pub const global = struct {
+    var writer: *Writer = undefined;
+};
+
+
+const ZstdWriter = struct {
+    ctx: ?*c.ZSTD_CStream,
+    out: c.ZSTD_outBuffer,
+    outbuf: [c.ZSTD_BLOCKSIZE_MAX + 64]u8,
+
+    fn create() *ZstdWriter {
+        const w = main.allocator.create(ZstdWriter) catch unreachable;
+        w.out = .{
+            .dst = &w.outbuf,
+            .size = w.outbuf.len,
+            .pos = 0,
+        };
+        while (true) {
+            w.ctx = c.ZSTD_createCStream();
+            if (w.ctx != null) break;
+            ui.oom();
+        }
+        _ = c.ZSTD_CCtx_setParameter(w.ctx, c.ZSTD_c_compressionLevel, main.config.complevel);
+        return w;
+    }
+
+    fn destroy(w: *ZstdWriter) void {
+        _ = c.ZSTD_freeCStream(w.ctx);
+        main.allocator.destroy(w);
+    }
+
+    fn write(w: *ZstdWriter, f: std.fs.File, in: []const u8, flush: bool) !void {
+        var arg = c.ZSTD_inBuffer{
+            .src = in.ptr,
+            .size = in.len,
+            .pos = 0,
+        };
+        while (true) {
+            const v = c.ZSTD_compressStream2(w.ctx, &w.out, &arg, if (flush) c.ZSTD_e_end else c.ZSTD_e_continue);
+            if (c.ZSTD_isError(v) != 0) return error.ZstdCompressError;
+            if (flush or w.out.pos > w.outbuf.len / 2) {
+                try f.writeAll(w.outbuf[0..w.out.pos]);
+                w.out.pos = 0;
+            }
+            if (!flush and arg.pos == arg.size) break;
+            if (flush and v == 0) break;
+        }
+    }
+};
+
+pub const Writer = struct {
+    fd: std.fs.File,
+    zstd: ?*ZstdWriter = null,
+    // Must be large enough to hold PATH_MAX*6 plus some overhead.
+    // (The 6 is because, in the worst case, every byte expands to a "\u####"
+    // escape, and we do pessimistic estimates here in order to avoid checking
+    // buffer lengths for each and every write operation)
+    buf: [64*1024]u8 = undefined,
+    off: usize = 0,
+    dir_entry_open: bool = false,
+
+    fn flush(ctx: *Writer, bytes: usize) void {
+        @branchHint(.unlikely);
+        // This can only really happen when the root path exceeds PATH_MAX,
+        // in which case we would probably have error'ed out earlier anyway.
+        if (bytes > ctx.buf.len) ui.die("Error writing JSON export: path too long.\n", .{});
+        const buf = ctx.buf[0..ctx.off];
+        (if (ctx.zstd) |z| z.write(ctx.fd, buf, bytes == 0) else ctx.fd.writeAll(buf)) catch |e|
+            ui.die("Error writing to file: {s}.\n", .{ ui.errorString(e) });
+        ctx.off = 0;
+    }
+
+    fn ensureSpace(ctx: *Writer, bytes: usize) void {
+        if (bytes > ctx.buf.len - ctx.off) ctx.flush(bytes);
+    }
+
+    fn write(ctx: *Writer, s: []const u8) void {
+        @memcpy(ctx.buf[ctx.off..][0..s.len], s);
+        ctx.off += s.len;
+    }
+
+    fn writeByte(ctx: *Writer, b: u8) void {
+        ctx.buf[ctx.off] = b;
+        ctx.off += 1;
+    }
+
+    // Write escaped string contents, excluding the quotes.
+    fn writeStr(ctx: *Writer, s: []const u8) void {
+        for (s) |b| {
+            if (b >= 0x20 and b != '"' and b != '\\' and b != 127) ctx.writeByte(b)
+            else switch (b) {
+                '\n' => ctx.write("\\n"),
+                '\r' => ctx.write("\\r"),
+                0x8  => ctx.write("\\b"),
+                '\t' => ctx.write("\\t"),
+                0xC  => ctx.write("\\f"),
+                '\\' => ctx.write("\\\\"),
+                '"'  => ctx.write("\\\""),
+                else => {
+                    ctx.write("\\u00");
+                    const hexdig = "0123456789abcdef";
+                    ctx.writeByte(hexdig[b>>4]);
+                    ctx.writeByte(hexdig[b&0xf]);
+                },
+            }
+        }
+    }
+
+    fn writeUint(ctx: *Writer, n: u64) void {
+        // Based on std.fmt.formatInt
+        var a = n;
+        var buf: [24]u8 = undefined;
+        var index: usize = buf.len;
+        while (a >= 100) : (a = @divTrunc(a, 100)) {
+            index -= 2;
+            buf[index..][0..2].* = std.fmt.digits2(@as(u8, @intCast(a % 100)));
+        }
+        if (a < 10) {
+            index -= 1;
+            buf[index] = '0' + @as(u8, @intCast(a));
+        } else {
+            index -= 2;
+            buf[index..][0..2].* = std.fmt.digits2(@as(u8, @intCast(a)));
+        }
+        ctx.write(buf[index..]);
+    }
+
+    fn init(out: std.fs.File) *Writer {
+        var ctx = main.allocator.create(Writer) catch unreachable;
+        ctx.* = .{ .fd = out };
+        if (main.config.compress) ctx.zstd = ZstdWriter.create();
+        ctx.write("[1,2,{\"progname\":\"ncdu\",\"progver\":\"" ++ main.program_version ++ "\",\"timestamp\":");
+        ctx.writeUint(@intCast(@max(0, std.time.timestamp())));
+        ctx.writeByte('}');
+        return ctx;
+    }
+
+    // A newly written directory entry is left "open", i.e. the '}' to close
+    // the item object is not written, to allow for a setReadError() to be
+    // caught if one happens before the first sub entry.
+    // Any read errors after the first sub entry are thrown away, but that's
+    // just a limitation of the JSON format.
+    fn closeDirEntry(ctx: *Writer, rderr: bool) void {
+        if (ctx.dir_entry_open) {
+            ctx.dir_entry_open = false;
+            if (rderr) ctx.write(",\"read_error\":true");
+            ctx.writeByte('}');
+        }
+    }
+
+    fn writeSpecial(ctx: *Writer, name: []const u8, t: model.EType) void {
+        ctx.closeDirEntry(false);
+        ctx.ensureSpace(name.len*6 + 1000);
+        ctx.write(if (t.isDirectory()) ",\n[{\"name\":\"" else ",\n{\"name\":\"");
+        ctx.writeStr(name);
+        ctx.write(switch (t) {
+            .err => "\",\"read_error\":true}",
+            .otherfs => "\",\"excluded\":\"otherfs\"}",
+            .kernfs => "\",\"excluded\":\"kernfs\"}",
+            .pattern => "\",\"excluded\":\"pattern\"}",
+            else => unreachable,
+        });
+        if (t.isDirectory()) ctx.writeByte(']');
+    }
+
+    fn writeStat(ctx: *Writer, name: []const u8, stat: *const sink.Stat, parent_dev: u64) void {
+        ctx.ensureSpace(name.len*6 + 1000);
+        ctx.write(if (stat.etype == .dir) ",\n[{\"name\":\"" else ",\n{\"name\":\"");
+        ctx.writeStr(name);
+        ctx.writeByte('"');
+        if (stat.size > 0) {
+            ctx.write(",\"asize\":");
+            ctx.writeUint(stat.size);
+        }
+        if (stat.blocks > 0) {
+            ctx.write(",\"dsize\":");
+            ctx.writeUint(util.blocksToSize(stat.blocks));
+        }
+        if (stat.etype == .dir and stat.dev != parent_dev) {
+            ctx.write(",\"dev\":");
+            ctx.writeUint(stat.dev);
+        }
+        if (stat.etype == .link) {
+            ctx.write(",\"ino\":");
+            ctx.writeUint(stat.ino);
+            ctx.write(",\"hlnkc\":true,\"nlink\":");
+            ctx.writeUint(stat.nlink);
+        }
+        if (stat.etype == .nonreg) ctx.write(",\"notreg\":true");
+        if (main.config.extended) {
+            if (stat.ext.pack.hasuid) {
+                ctx.write(",\"uid\":");
+                ctx.writeUint(stat.ext.uid);
+            }
+            if (stat.ext.pack.hasgid) {
+                ctx.write(",\"gid\":");
+                ctx.writeUint(stat.ext.gid);
+            }
+            if (stat.ext.pack.hasmode) {
+                ctx.write(",\"mode\":");
+                ctx.writeUint(stat.ext.mode);
+            }
+            if (stat.ext.pack.hasmtime) {
+                ctx.write(",\"mtime\":");
+                ctx.writeUint(stat.ext.mtime);
+            }
+        }
+    }
+};
+
+pub const Dir = struct {
+    dev: u64,
+
+    pub fn addSpecial(_: *Dir, name: []const u8, sp: model.EType) void {
+        global.writer.writeSpecial(name, sp);
+    }
+
+    pub fn addStat(_: *Dir, name: []const u8, stat: *const sink.Stat) void {
+        global.writer.closeDirEntry(false);
+        global.writer.writeStat(name, stat, undefined);
+        global.writer.writeByte('}');
+    }
+
+    pub fn addDir(d: *Dir, name: []const u8, stat: *const sink.Stat) Dir {
+        global.writer.closeDirEntry(false);
+        global.writer.writeStat(name, stat, d.dev);
+        global.writer.dir_entry_open = true;
+        return .{ .dev = stat.dev };
+    }
+
+    pub fn setReadError(_: *Dir) void {
+        global.writer.closeDirEntry(true);
+    }
+
+    pub fn final(_: *Dir) void {
+        global.writer.ensureSpace(1000);
+        global.writer.closeDirEntry(false);
+        global.writer.writeByte(']');
+    }
+};
+
+pub fn createRoot(path: []const u8, stat: *const sink.Stat) Dir {
+    var root = Dir{.dev=0};
+    return root.addDir(path, stat);
+}
+
+pub fn done() void {
+    global.writer.write("]\n");
+    global.writer.flush(0);
+    if (global.writer.zstd) |z| z.destroy();
+    global.writer.fd.close();
+    main.allocator.destroy(global.writer);
+}
+
+pub fn setupOutput(out: std.fs.File) void {
+    global.writer = Writer.init(out);
+}

src/json_import.zig

@@ -0,0 +1,562 @@
+// SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
+// SPDX-License-Identifier: MIT
+
+const std = @import("std");
+const main = @import("main.zig");
+const util = @import("util.zig");
+const model = @import("model.zig");
+const sink = @import("sink.zig");
+const ui = @import("ui.zig");
+const c = @import("c.zig").c;
+
+
+const ZstdReader = struct {
+    ctx: ?*c.ZSTD_DStream,
+    in: c.ZSTD_inBuffer,
+    lastret: usize = 0,
+    inbuf: [c.ZSTD_BLOCKSIZE_MAX + 16]u8, // This ZSTD_DStreamInSize() + a little bit extra
+
+    fn create(head: []const u8) *ZstdReader {
+        const r = main.allocator.create(ZstdReader) catch unreachable;
+        @memcpy(r.inbuf[0..head.len], head);
+        r.in = .{
+            .src = &r.inbuf,
+            .size = head.len,
+            .pos = 0,
+        };
+        while (true) {
+            r.ctx = c.ZSTD_createDStream();
+            if (r.ctx != null) break;
+            ui.oom();
+        }
+        return r;
+    }
+
+    fn destroy(r: *ZstdReader) void {
+        _ = c.ZSTD_freeDStream(r.ctx);
+        main.allocator.destroy(r);
+    }
+
+    fn read(r: *ZstdReader, f: std.fs.File, out: []u8) !usize {
+        while (true) {
+            if (r.in.size == r.in.pos) {
+                r.in.pos = 0;
+                r.in.size = try f.read(&r.inbuf);
+                if (r.in.size == 0) {
+                    if (r.lastret == 0) return 0;
+                    return error.ZstdDecompressError; // Early EOF
+                }
+            }
+
+            var arg = c.ZSTD_outBuffer{ .dst = out.ptr, .size = out.len, .pos = 0 };
+            r.lastret = c.ZSTD_decompressStream(r.ctx, &arg, &r.in);
+            if (c.ZSTD_isError(r.lastret) != 0) return error.ZstdDecompressError;
+            if (arg.pos > 0) return arg.pos;
+        }
+    }
+};
+
+
+// Using a custom JSON parser here because, while std.json is great, it does
+// perform strict UTF-8 validation. Which is correct, of course, but ncdu dumps
+// are not always correct JSON as they may contain non-UTF-8 paths encoded as
+// strings.
+
+const Parser = struct {
+    rd: std.fs.File,
+    zstd: ?*ZstdReader = null,
+    rdoff: usize = 0,
+    rdsize: usize = 0,
+    byte: u64 = 1,
+    line: u64 = 1,
+    buf: [129*1024]u8 = undefined,
+
+    fn die(p: *Parser, str: []const u8) noreturn {
+        ui.die("Error importing file on line {}:{}: {s}.\n", .{ p.line, p.byte, str });
+    }
+
+    // Feed back a byte that has just been returned by nextByte()
+    fn undoNextByte(p: *Parser, b: u8) void {
+        p.byte -= 1;
+        p.rdoff -= 1;
+        p.buf[p.rdoff] = b;
+    }
+
+    fn fill(p: *Parser) void {
+        p.rdoff = 0;
+        p.rdsize = (if (p.zstd) |z| z.read(p.rd, &p.buf) else p.rd.read(&p.buf)) catch |e| switch (e) {
+            error.IsDir => p.die("not a file"), // should be detected at open() time, but no flag for that...
+            error.SystemResources => p.die("out of memory"),
+            error.ZstdDecompressError => p.die("decompression error"),
+            else => p.die("I/O error"),
+        };
+    }
+
+    // Returns 0 on EOF.
+    // (or if the file contains a 0 byte, but that's invalid anyway)
+    // (Returning a '?u8' here is nicer but kills performance by about +30%)
+    fn nextByte(p: *Parser) u8 {
+        if (p.rdoff == p.rdsize) {
+            @branchHint(.unlikely);
+            p.fill();
+            if (p.rdsize == 0) return 0;
+        }
+        p.byte += 1;
+        defer p.rdoff += 1;
+        return (&p.buf)[p.rdoff];
+    }
+
+    // next non-whitespace byte
+    fn nextChr(p: *Parser) u8 {
+        while (true) switch (p.nextByte()) {
+            '\n' => {
+                p.line += 1;
+                p.byte = 1;
+            },
+            ' ', '\t', '\r' => {},
+            else => |b| return b,
+        };
+    }
+
+    fn expectLit(p: *Parser, lit: []const u8) void {
+        for (lit) |b| if (b != p.nextByte()) p.die("invalid JSON");
+    }
+
+    fn hexdig(p: *Parser) u16 {
+        const b = p.nextByte();
+        return switch (b) {
+            '0'...'9' => b - '0',
+            'a'...'f' => b - 'a' + 10,
+            'A'...'F' => b - 'A' + 10,
+            else => p.die("invalid hex digit"),
+        };
+    }
+
+    fn stringContentSlow(p: *Parser, buf: []u8, head: u8, off: usize) []u8 {
+        @branchHint(.unlikely);
+        var b = head;
+        var n = off;
+        while (true) {
+            switch (b) {
+                '"' => break,
+                '\\' => switch (p.nextByte()) {
+                    '"' => if (n < buf.len) { buf[n] = '"'; n += 1; },
+                    '\\'=> if (n < buf.len) { buf[n] = '\\';n += 1; },
+                    '/' => if (n < buf.len) { buf[n] = '/'; n += 1; },
+                    'b' => if (n < buf.len) { buf[n] = 0x8; n += 1; },
+                    'f' => if (n < buf.len) { buf[n] = 0xc; n += 1; },
+                    'n' => if (n < buf.len) { buf[n] = 0xa; n += 1; },
+                    'r' => if (n < buf.len) { buf[n] = 0xd; n += 1; },
+                    't' => if (n < buf.len) { buf[n] = 0x9; n += 1; },
+                    'u' => {
+                        const first = (p.hexdig()<<12) + (p.hexdig()<<8) + (p.hexdig()<<4) + p.hexdig();
+                        var unit = @as(u21, first);
+                        if (std.unicode.utf16IsLowSurrogate(first)) p.die("Unexpected low surrogate");
+                        if (std.unicode.utf16IsHighSurrogate(first)) {
+                            p.expectLit("\\u");
+                            const second = (p.hexdig()<<12) + (p.hexdig()<<8) + (p.hexdig()<<4) + p.hexdig();
+                            unit = std.unicode.utf16DecodeSurrogatePair(&.{first, second}) catch p.die("Invalid low surrogate");
+                        }
+                        if (n + 6 < buf.len)
+                            n += std.unicode.utf8Encode(unit, buf[n..n+5]) catch unreachable;
+                    },
+                    else => p.die("invalid escape sequence"),
+                },
+                0x20, 0x21, 0x23...0x5b, 0x5d...0xff => if (n < buf.len) { buf[n] = b; n += 1; },
+                else => p.die("invalid character in string"),
+            }
+            b = p.nextByte();
+        }
+        return buf[0..n];
+    }
+
+    // Read a string (after the ") into buf.
+    // Any characters beyond the size of the buffer are consumed but otherwise discarded.
+    fn stringContent(p: *Parser, buf: []u8) []u8 {
+        // The common case (for ncdu dumps): string fits in the given buffer and does not contain any escapes.
+        var n: usize = 0;
+        var b = p.nextByte();
+        while (n < buf.len and b >= 0x20 and b != '"' and b != '\\') {
+            buf[n] = b;
+            n += 1;
+            b = p.nextByte();
+        }
+        if (b == '"') return buf[0..n];
+        return p.stringContentSlow(buf, b, n);
+    }
+
+    fn string(p: *Parser, buf: []u8) []u8 {
+        if (p.nextChr() != '"') p.die("expected string");
+        return p.stringContent(buf);
+    }
+
+    fn uintTail(p: *Parser, head: u8, T: anytype) T {
+        if (head == '0') return 0;
+        var v: T = head - '0'; // Assumption: T >= u8
+        // Assumption: we don't parse JSON "documents" that are a bare uint.
+        while (true) switch (p.nextByte()) {
+            '0'...'9' => |b| {
+                const newv = v *% 10 +% (b - '0');
+                if (newv < v) p.die("integer out of range");
+                v = newv;
+            },
+            else => |b| break p.undoNextByte(b),
+        };
+        if (v == 0) p.die("expected number");
+        return v;
+    }
+
+    fn uint(p: *Parser, T: anytype) T {
+        switch (p.nextChr()) {
+            '0'...'9' => |b| return p.uintTail(b, T),
+            else => p.die("expected number"),
+        }
+    }
+
+    fn boolean(p: *Parser) bool {
+        switch (p.nextChr()) {
+            't' => { p.expectLit("rue"); return true; },
+            'f' => { p.expectLit("alse"); return false; },
+            else => p.die("expected boolean"),
+        }
+    }
+
+    fn obj(p: *Parser) void {
+        if (p.nextChr() != '{') p.die("expected object");
+    }
+
+    fn key(p: *Parser, first: bool, buf: []u8) ?[]u8 {
+        const k = switch (p.nextChr()) {
+            ',' => blk: {
+                if (first) p.die("invalid JSON");
+                break :blk p.string(buf);
+            },
+            '"' => blk: {
+                if (!first) p.die("invalid JSON");
+                break :blk p.stringContent(buf);
+            },
+            '}' => return null,
+            else => p.die("invalid JSON"),
+        };
+        if (p.nextChr() != ':') p.die("invalid JSON");
+        return k;
+    }
+
+    fn array(p: *Parser) void {
+        if (p.nextChr() != '[') p.die("expected array");
+    }
+
+    fn elem(p: *Parser, first: bool) bool {
+        switch (p.nextChr()) {
+            ',' => if (first) p.die("invalid JSON") else return true,
+            ']' => return false,
+            else => |b| {
+                if (!first) p.die("invalid JSON");
+                p.undoNextByte(b);
+                return true;
+            },
+        }
+    }
+
+    fn skipContent(p: *Parser, head: u8) void {
+        switch (head) {
+            't' => p.expectLit("rue"),
+            'f' => p.expectLit("alse"),
+            'n' => p.expectLit("ull"),
+            '-', '0'...'9' =>
+                // Numbers are kind of annoying, this "parsing" is invalid and ultra-lazy.
+                while (true) switch (p.nextByte()) {
+                    '-', '+', 'e', 'E', '.', '0'...'9' => {},
+                    else => |b| return p.undoNextByte(b),
+                },
+            '"' => _ = p.stringContent(&[0]u8{}),
+            '[' => {
+                var first = true;
+                while (p.elem(first)) {
+                    first = false;
+                    p.skip();
+                }
+            },
+            '{' => {
+                var first = true;
+                while (p.key(first, &[0]u8{})) |_| {
+                    first = false;
+                    p.skip();
+                }
+            },
+            else => p.die("invalid JSON"),
+        }
+    }
+
+    fn skip(p: *Parser) void {
+        p.skipContent(p.nextChr());
+    }
+
+    fn eof(p: *Parser) void {
+        if (p.nextChr() != 0) p.die("trailing garbage");
+    }
+};
+
+
+// Should really add some invalid JSON test cases as well, but I'd first like
+// to benchmark the performance impact of using error returns instead of
+// calling ui.die().
+test "JSON parser" {
+    const json =
+        \\{
+        \\  "null": null,
+        \\  "true": true,
+        \\  "false": false,
+        \\  "zero":0 ,"uint": 123,
+        \\  "emptyObj": {},
+        \\  "emptyArray": [],
+        \\  "emptyString": "",
+        \\  "encString": "\"\\\/\b\f\n\uBe3F",
+        \\  "numbers": [0,1,20,-300, 3.4 ,0e-10  , -100.023e+13 ]
+        \\}
+        ;
+    var p = Parser{ .rd = undefined, .rdsize = json.len };
+    @memcpy(p.buf[0..json.len], json);
+    p.skip();
+
+    p = Parser{ .rd = undefined, .rdsize = json.len };
+    @memcpy(p.buf[0..json.len], json);
+    var buf: [128]u8 = undefined;
+    p.obj();
+
+    try std.testing.expectEqualStrings(p.key(true, &buf).?, "null");
+    p.skip();
+
+    try std.testing.expectEqualStrings(p.key(false, &buf).?, "true");
+    try std.testing.expect(p.boolean());
+
+    try std.testing.expectEqualStrings(p.key(false, &buf).?, "false");
+    try std.testing.expect(!p.boolean());
+
+    try std.testing.expectEqualStrings(p.key(false, &buf).?, "zero");
+    try std.testing.expectEqual(0, p.uint(u8));
+
+    try std.testing.expectEqualStrings(p.key(false, &buf).?, "uint");
+    try std.testing.expectEqual(123, p.uint(u8));
+
+    try std.testing.expectEqualStrings(p.key(false, &buf).?, "emptyObj");
+    p.obj();
+    try std.testing.expect(p.key(true, &buf) == null);
+
+    try std.testing.expectEqualStrings(p.key(false, &buf).?, "emptyArray");
+    p.array();
+    try std.testing.expect(!p.elem(true));
+
+    try std.testing.expectEqualStrings(p.key(false, &buf).?, "emptyString");
+    try std.testing.expectEqualStrings(p.string(&buf), "");
+
+    try std.testing.expectEqualStrings(p.key(false, &buf).?, "encString");
+    try std.testing.expectEqualStrings(p.string(&buf), "\"\\/\x08\x0c\n\u{be3f}");
+
+    try std.testing.expectEqualStrings(p.key(false, &buf).?, "numbers");
+    p.skip();
+
+    try std.testing.expect(p.key(true, &buf) == null);
+}
+
+
+const Ctx = struct {
+    p: *Parser,
+    sink: *sink.Thread,
+    stat: sink.Stat = .{},
+    rderr: bool = false,
+    namelen: usize = 0,
+    namebuf: [32*1024]u8 = undefined,
+};
+
+
+fn itemkey(ctx: *Ctx, key: []const u8) void {
+    const eq = std.mem.eql;
+    switch (if (key.len > 0) key[0] else @as(u8,0)) {
+        'a' => {
+            if (eq(u8, key, "asize")) {
+                ctx.stat.size = ctx.p.uint(u64);
+                return;
+            }
+        },
+        'd' => {
+            if (eq(u8, key, "dsize")) {
+                ctx.stat.blocks = @intCast(ctx.p.uint(u64)>>9);
+                return;
+            }
+            if (eq(u8, key, "dev")) {
+                ctx.stat.dev = ctx.p.uint(u64);
+                return;
+            }
+        },
+        'e' => {
+            if (eq(u8, key, "excluded")) {
+                var buf: [32]u8 = undefined;
+                const typ = ctx.p.string(&buf);
+                // "frmlnk" is also possible, but currently considered equivalent to "pattern".
+                ctx.stat.etype =
+                    if (eq(u8, typ, "otherfs") or eq(u8, typ, "othfs")) .otherfs
+                    else if (eq(u8, typ, "kernfs")) .kernfs
+                    else .pattern;
+                return;
+            }
+        },
+        'g' => {
+            if (eq(u8, key, "gid")) {
+                ctx.stat.ext.gid = ctx.p.uint(u32);
+                ctx.stat.ext.pack.hasgid = true;
+                return;
+            }
+        },
+        'h' => {
+            if (eq(u8, key, "hlnkc")) {
+                if (ctx.p.boolean()) ctx.stat.etype = .link;
+                return;
+            }
+        },
+        'i' => {
+            if (eq(u8, key, "ino")) {
+                ctx.stat.ino = ctx.p.uint(u64);
+                return;
+            }
+        },
+        'm' => {
+            if (eq(u8, key, "mode")) {
+                ctx.stat.ext.mode = ctx.p.uint(u16);
+                ctx.stat.ext.pack.hasmode = true;
+                return;
+            }
+            if (eq(u8, key, "mtime")) {
+                ctx.stat.ext.mtime = ctx.p.uint(u64);
+                ctx.stat.ext.pack.hasmtime = true;
+                // Accept decimal numbers, but discard the fractional part because our data model doesn't support it.
+                switch (ctx.p.nextByte()) {
+                    '.' =>
+                        while (true) switch (ctx.p.nextByte()) {
+                            '0'...'9' => {},
+                            else => |b| return ctx.p.undoNextByte(b),
+                        },
+                    else => |b| return ctx.p.undoNextByte(b),
+                }
+            }
+        },
+        'n' => {
+            if (eq(u8, key, "name")) {
+                if (ctx.namelen != 0) ctx.p.die("duplicate key");
+                ctx.namelen = ctx.p.string(&ctx.namebuf).len;
+                if (ctx.namelen > ctx.namebuf.len-5) ctx.p.die("too long file name");
+                return;
+            }
+            if (eq(u8, key, "nlink")) {
+                ctx.stat.nlink = ctx.p.uint(u31);
+                if (ctx.stat.etype != .dir and ctx.stat.nlink > 1)
+                    ctx.stat.etype = .link;
+                return;
+            }
+            if (eq(u8, key, "notreg")) {
+                if (ctx.p.boolean()) ctx.stat.etype = .nonreg;
+                return;
+            }
+        },
+        'r' => {
+            if (eq(u8, key, "read_error")) {
+                if (ctx.p.boolean()) {
+                    if (ctx.stat.etype == .dir) ctx.rderr = true
+                    else ctx.stat.etype = .err;
+                }
+                return;
+            }
+        },
+        'u' => {
+            if (eq(u8, key, "uid")) {
+                ctx.stat.ext.uid = ctx.p.uint(u32);
+                ctx.stat.ext.pack.hasuid = true;
+                return;
+            }
+        },
+        else => {},
+    }
+    ctx.p.skip();
+}
+
+
+fn item(ctx: *Ctx, parent: ?*sink.Dir, dev: u64) void {
+    ctx.stat = .{ .dev = dev };
+    ctx.namelen = 0;
+    ctx.rderr = false;
+    const isdir = switch (ctx.p.nextChr()) {
+        '[' => blk: {
+            ctx.p.obj();
+            break :blk true;
+        },
+        '{' => false,
+        else => ctx.p.die("expected object or array"),
+    };
+    if (parent == null and !isdir) ctx.p.die("parent item must be a directory");
+    ctx.stat.etype = if (isdir) .dir else .reg;
+
+    var keybuf: [32]u8 = undefined;
+    var first = true;
+    while (ctx.p.key(first, &keybuf)) |k| {
+        first = false;
+        itemkey(ctx, k);
+    }
+    if (ctx.namelen == 0) ctx.p.die("missing \"name\" field");
+    const name = (&ctx.namebuf)[0..ctx.namelen];
+
+    if (ctx.stat.etype == .dir) {
+        const ndev = ctx.stat.dev;
+        const dir =
+            if (parent) |d| d.addDir(ctx.sink, name, &ctx.stat)
+            else sink.createRoot(name, &ctx.stat);
+        ctx.sink.setDir(dir);
+        if (ctx.rderr) dir.setReadError(ctx.sink);
+        while (ctx.p.elem(false)) item(ctx, dir, ndev);
+        ctx.sink.setDir(parent);
+        dir.unref(ctx.sink);
+
+    } else {
+        if (@intFromEnum(ctx.stat.etype) < 0)
+            parent.?.addSpecial(ctx.sink, name, ctx.stat.etype)
+        else
+            parent.?.addStat(ctx.sink, name, &ctx.stat);
+        if (isdir and ctx.p.elem(false)) ctx.p.die("unexpected contents in an excluded directory");
+    }
+
+    if ((ctx.sink.files_seen.load(.monotonic) & 65) == 0)
+        main.handleEvent(false, false);
+}
+
+
+pub fn import(fd: std.fs.File, head: []const u8) void {
+    const sink_threads = sink.createThreads(1);
+    defer sink.done();
+
+    var p = Parser{.rd = fd};
+    defer if (p.zstd) |z| z.destroy();
+
+    if (head.len >= 4 and std.mem.eql(u8, head[0..4], "\x28\xb5\x2f\xfd")) {
+        p.zstd = ZstdReader.create(head);
+    } else {
+        p.rdsize = head.len;
+        @memcpy(p.buf[0..head.len], head);
+    }
+    p.array();
+    if (p.uint(u16) != 1) p.die("incompatible major format version");
+    if (!p.elem(false)) p.die("expected array element");
+    _ = p.uint(u16); // minor version, ignored for now
+    if (!p.elem(false)) p.die("expected array element");
+
+    // metadata object
+    p.obj();
+    p.skipContent('{');
+
+    // Items
+    if (!p.elem(false)) p.die("expected array element");
+    var ctx = Ctx{.p = &p, .sink = &sink_threads[0]};
+    item(&ctx, null, 0);
+
+    // accept more trailing elements
+    while (p.elem(false)) p.skip();
+    p.eof();
+}

src/main.zig

@@ -1,21 +1,35 @@
 // SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
 // SPDX-License-Identifier: MIT
 
-pub const program_version = "2.4";
+pub const program_version = "2.9.2";
 
 const std = @import("std");
 const model = @import("model.zig");
 const scan = @import("scan.zig");
+const json_import = @import("json_import.zig");
+const json_export = @import("json_export.zig");
+const bin_export = @import("bin_export.zig");
+const bin_reader = @import("bin_reader.zig");
+const sink = @import("sink.zig");
+const mem_src = @import("mem_src.zig");
+const mem_sink = @import("mem_sink.zig");
 const ui = @import("ui.zig");
 const browser = @import("browser.zig");
 const delete = @import("delete.zig");
 const util = @import("util.zig");
 const exclude = @import("exclude.zig");
-const c = @cImport(@cInclude("locale.h"));
+const c = @import("c.zig").c;
 
 test "imports" {
     _ = model;
     _ = scan;
+    _ = json_import;
+    _ = json_export;
+    _ = bin_export;
+    _ = bin_reader;
+    _ = sink;
+    _ = mem_src;
+    _ = mem_sink;
     _ = ui;
     _ = browser;
     _ = delete;
@@ -27,7 +41,7 @@ test "imports" {
 // This allocator never returns an error, it either succeeds or causes ncdu to quit.
 // (Which means you'll find a lot of "catch unreachable" sprinkled through the code,
 // they look scarier than they are)
-fn wrapAlloc(_: *anyopaque, len: usize, ptr_alignment: u8, return_address: usize) ?[*]u8 {
+fn wrapAlloc(_: *anyopaque, len: usize, ptr_alignment: std.mem.Alignment, return_address: usize) ?[*]u8 {
     while (true) {
         if (std.heap.c_allocator.vtable.alloc(undefined, len, ptr_alignment, return_address)) |r|
             return r
@@ -42,11 +56,21 @@ pub const allocator = std.mem.Allocator{
         .alloc = wrapAlloc,
         // AFAIK, all uses of resize() to grow an allocation will fall back to alloc() on failure.
         .resize = std.heap.c_allocator.vtable.resize,
+        .remap = std.heap.c_allocator.vtable.remap,
         .free = std.heap.c_allocator.vtable.free,
     },
 };
 
 
+// Custom panic impl to reset the terminal before spewing out an error message.
+pub const panic = std.debug.FullPanic(struct {
+    pub fn panicFn(msg: []const u8, first_trace_addr: ?usize) noreturn {
+        @branchHint(.cold);
+        ui.deinit();
+        std.debug.defaultPanic(msg, first_trace_addr);
+    }
+}.panicFn);
+
 pub const config = struct {
     pub const SortCol = enum { name, blocks, size, items, mtime };
     pub const SortOrder = enum { asc, desc };
@@ -56,7 +80,10 @@ pub const config = struct {
     pub var follow_symlinks: bool = false;
     pub var exclude_caches: bool = false;
     pub var exclude_kernfs: bool = false;
-    pub var exclude_patterns: std.ArrayList([:0]const u8) = std.ArrayList([:0]const u8).init(allocator);
+    pub var threads: usize = 1;
+    pub var complevel: u8 = 4;
+    pub var compress: bool = false;
+    pub var export_block_size: ?usize = null;
 
     pub var update_delay: u64 = 100*std.time.ns_per_ms;
     pub var scan_ui: ?enum { none, line, full } = null;
@@ -79,16 +106,21 @@ pub const config = struct {
     pub var sort_natural: bool = true;
 
     pub var imported: bool = false;
+    pub var binreader: bool = false;
     pub var can_delete: ?bool = null;
     pub var can_shell: ?bool = null;
     pub var can_refresh: ?bool = null;
     pub var confirm_quit: bool = false;
     pub var confirm_delete: bool = true;
     pub var ignore_delete_errors: bool = false;
+    pub var delete_command: [:0]const u8 = "";
 };
 
 pub var state: enum { scan, browse, refresh, shell, delete } = .scan;
 
+const stdin = if (@hasDecl(std.io, "getStdIn")) std.io.getStdIn() else std.fs.File.stdin();
+const stdout = if (@hasDecl(std.io, "getStdOut")) std.io.getStdOut() else std.fs.File.stdout();
+
 // Simple generic argument parser, supports getopt_long() style arguments.
 const Args = struct {
     lst: []const [:0]const u8,
@@ -97,6 +129,7 @@ const Args = struct {
     last_arg: ?[:0]const u8 = null, // In the case of --option=<arg>
     shortbuf: [2]u8 = undefined,
     argsep: bool = false,
+    ignerror: bool = false,
 
     const Self = @This();
     const Option = struct {
@@ -126,22 +159,27 @@ const Args = struct {
         return .{ .opt = true, .val = &self.shortbuf };
     }
 
+    pub fn die(self: *const Self, comptime msg: []const u8, args: anytype) !noreturn {
+        if (self.ignerror) return error.InvalidArg;
+        ui.die(msg, args);
+    }
+
     /// Return the next option or positional argument.
     /// 'opt' indicates whether it's an option or positional argument,
     /// 'val' will be either -x, --something or the argument.
-    pub fn next(self: *Self) ?Option {
-        if (self.last_arg != null) ui.die("Option '{s}' does not expect an argument.\n", .{ self.last.? });
+    pub fn next(self: *Self) !?Option {
+        if (self.last_arg != null) try self.die("Option '{s}' does not expect an argument.\n", .{ self.last.? });
         if (self.short) |s| return self.shortopt(s);
         const val = self.pop() orelse return null;
         if (self.argsep or val.len == 0 or val[0] != '-') return Option{ .opt = false, .val = val };
-        if (val.len == 1) ui.die("Invalid option '-'.\n", .{});
+        if (val.len == 1) try self.die("Invalid option '-'.\n", .{});
         if (val.len == 2 and val[1] == '-') {
             self.argsep = true;
             return self.next();
         }
         if (val[1] == '-') {
             if (std.mem.indexOfScalar(u8, val, '=')) |sep| {
-                if (sep == 2) ui.die("Invalid option '{s}'.\n", .{val});
+                if (sep == 2) try self.die("Invalid option '{s}'.\n", .{val});
                 self.last_arg = val[sep+1.. :0];
                 self.last = val[0..sep];
                 return Option{ .opt = true, .val = self.last.? };
@@ -153,7 +191,7 @@ const Args = struct {
     }
 
     /// Returns the argument given to the last returned option. Dies with an error if no argument is provided.
-    pub fn arg(self: *Self) [:0]const u8 {
+    pub fn arg(self: *Self) ![:0]const u8 {
         if (self.short) |a| {
             defer self.short = null;
             return a;
@@ -163,11 +201,11 @@ const Args = struct {
             return a;
         }
         if (self.pop()) |o| return o;
-        ui.die("Option '{s}' requires an argument.\n", .{ self.last.? });
+        try self.die("Option '{s}' requires an argument.\n", .{ self.last.? });
     }
 };
 
-fn argConfig(args: *Args, opt: Args.Option) bool {
+fn argConfig(args: *Args, opt: Args.Option, infile: bool) !void {
     if (opt.is("-q") or opt.is("--slow-ui-updates")) config.update_delay = 2*std.time.ns_per_s
     else if (opt.is("--fast-ui-updates")) config.update_delay = 100*std.time.ns_per_ms
     else if (opt.is("-x") or opt.is("--one-file-system")) config.same_fs = true
@@ -197,13 +235,13 @@ fn argConfig(args: *Args, opt: Args.Option) bool {
     else if (opt.is("--enable-natsort")) config.sort_natural = true
     else if (opt.is("--disable-natsort")) config.sort_natural = false
     else if (opt.is("--graph-style")) {
-        const val = args.arg();
+        const val = try args.arg();
         if (std.mem.eql(u8, val, "hash")) config.graph_style = .hash
         else if (std.mem.eql(u8, val, "half-block")) config.graph_style = .half
         else if (std.mem.eql(u8, val, "eighth-block") or std.mem.eql(u8, val, "eigth-block")) config.graph_style = .eighth
-        else ui.die("Unknown --graph-style option: {s}.\n", .{val});
+        else try args.die("Unknown --graph-style option: {s}.\n", .{val});
     } else if (opt.is("--sort")) {
-        var val: []const u8 = args.arg();
+        var val: []const u8 = try args.arg();
         var ord: ?config.SortOrder = null;
         if (std.mem.endsWith(u8, val, "-asc")) {
             val = val[0..val.len-4];
@@ -227,13 +265,13 @@ fn argConfig(args: *Args, opt: Args.Option) bool {
         } else if (std.mem.eql(u8, val, "mtime")) {
             config.sort_col = .mtime;
             config.sort_order = ord orelse .asc;
-        } else ui.die("Unknown --sort option: {s}.\n", .{val});
+        } else try args.die("Unknown --sort option: {s}.\n", .{val});
     } else if (opt.is("--shared-column")) {
-        const val = args.arg();
+        const val = try args.arg();
         if (std.mem.eql(u8, val, "off")) config.show_shared = .off
         else if (std.mem.eql(u8, val, "shared")) config.show_shared = .shared
         else if (std.mem.eql(u8, val, "unique")) config.show_shared = .unique
-        else ui.die("Unknown --shared-column option: {s}.\n", .{val});
+        else try args.die("Unknown --shared-column option: {s}.\n", .{val});
     } else if (opt.is("--apparent-size")) config.show_blocks = false
     else if (opt.is("--disk-usage")) config.show_blocks = true
     else if (opt.is("-0")) config.scan_ui = .none
@@ -243,26 +281,45 @@ fn argConfig(args: *Args, opt: Args.Option) bool {
     else if (opt.is("--no-si")) config.si = false
     else if (opt.is("-L") or opt.is("--follow-symlinks")) config.follow_symlinks = true
     else if (opt.is("--no-follow-symlinks")) config.follow_symlinks = false
-    else if (opt.is("--exclude")) exclude.addPattern(args.arg())
-    else if (opt.is("-X") or opt.is("--exclude-from")) {
-        const arg = args.arg();
-        readExcludeFile(arg) catch |e| ui.die("Error reading excludes from {s}: {s}.\n", .{ arg, ui.errorString(e) });
+    else if (opt.is("--exclude")) {
+        const arg = if (infile) (util.expanduser(try args.arg(), allocator) catch unreachable) else try args.arg();
+        defer if (infile) allocator.free(arg);
+        exclude.addPattern(arg);
+    } else if (opt.is("-X") or opt.is("--exclude-from")) {
+        const arg = if (infile) (util.expanduser(try args.arg(), allocator) catch unreachable) else try args.arg();
+        defer if (infile) allocator.free(arg);
+        readExcludeFile(arg) catch |e| try args.die("Error reading excludes from {s}: {s}.\n", .{ arg, ui.errorString(e) });
     } else if (opt.is("--exclude-caches")) config.exclude_caches = true
     else if (opt.is("--include-caches")) config.exclude_caches = false
     else if (opt.is("--exclude-kernfs")) config.exclude_kernfs = true
     else if (opt.is("--include-kernfs")) config.exclude_kernfs = false
-    else if (opt.is("--confirm-quit")) config.confirm_quit = true
+    else if (opt.is("-c") or opt.is("--compress")) config.compress = true
+    else if (opt.is("--no-compress")) config.compress = false
+    else if (opt.is("--compress-level")) {
+        const val = try args.arg();
+        const num = std.fmt.parseInt(u8, val, 10) catch try args.die("Invalid number for --compress-level: {s}.\n", .{val});
+        if (num <= 0 or num > 20) try args.die("Invalid number for --compress-level: {s}.\n", .{val});
+        config.complevel = num;
+    } else if (opt.is("--export-block-size")) {
+        const val = try args.arg();
+        const num = std.fmt.parseInt(u14, val, 10) catch try args.die("Invalid number for --export-block-size: {s}.\n", .{val});
+        if (num < 4 or num > 16000) try args.die("Invalid number for --export-block-size: {s}.\n", .{val});
+        config.export_block_size = @as(usize, num) * 1024;
+    } else if (opt.is("--confirm-quit")) config.confirm_quit = true
     else if (opt.is("--no-confirm-quit")) config.confirm_quit = false
     else if (opt.is("--confirm-delete")) config.confirm_delete = true
     else if (opt.is("--no-confirm-delete")) config.confirm_delete = false
+    else if (opt.is("--delete-command")) config.delete_command = allocator.dupeZ(u8, try args.arg()) catch unreachable
     else if (opt.is("--color")) {
-        const val = args.arg();
+        const val = try args.arg();
         if (std.mem.eql(u8, val, "off")) config.ui_color = .off
         else if (std.mem.eql(u8, val, "dark")) config.ui_color = .dark
         else if (std.mem.eql(u8, val, "dark-bg")) config.ui_color = .darkbg
-        else ui.die("Unknown --color option: {s}.\n", .{val});
-    } else return false;
-    return true;
+        else try args.die("Unknown --color option: {s}.\n", .{val});
+    } else if (opt.is("-t") or opt.is("--threads")) {
+        const val = try args.arg();
+        config.threads = std.fmt.parseInt(u8, val, 10) catch try args.die("Invalid number of --threads: {s}.\n", .{val});
+    } else return error.UnknownOption;
 }
 
 fn tryReadArgsFile(path: [:0]const u8) void {
@@ -273,157 +330,142 @@ fn tryReadArgsFile(path: [:0]const u8) void {
     };
     defer f.close();
 
-    var arglist = std.ArrayList([:0]const u8).init(allocator);
-    
-    var rd_ = std.io.bufferedReader(f.reader());
-    const rd = rd_.reader();
-    
     var line_buf: [4096]u8 = undefined;
-    var line_fbs = std.io.fixedBufferStream(&line_buf);
-    const line_writer = line_fbs.writer();
+    var line_rd = util.LineReader.init(f, &line_buf);
 
-    while (true) : (line_fbs.reset()) {
-        rd.streamUntilDelimiter(line_writer, '\n', line_buf.len) catch |err| switch (err) {
-            error.EndOfStream => if (line_fbs.getPos() catch unreachable == 0) break,
-            else => |e| ui.die("Error reading from {s}: {s}\nRun with --ignore-config to skip reading config files.\n", .{ path, ui.errorString(e) }),
-        };
-        const line_ = line_fbs.getWritten();
+    while (true) {
+        const line_ = (line_rd.read() catch |e|
+            ui.die("Error reading from {s}: {s}\nRun with --ignore-config to skip reading config files.\n", .{ path, ui.errorString(e) })
+        ) orelse break;
+
+        var argc: usize = 0;
+        var ignerror = false;
+        var arglist: [2][:0]const u8 = .{ "", "" };
 
         var line = std.mem.trim(u8, line_, &std.ascii.whitespace);
+        if (line.len > 0 and line[0] == '@') {
+            ignerror = true;
+            line = line[1..];
+        }
         if (line.len == 0 or line[0] == '#') continue;
         if (std.mem.indexOfAny(u8, line, " \t=")) |i| {
-            arglist.append(allocator.dupeZ(u8, line[0..i]) catch unreachable) catch unreachable;
+            arglist[argc] = allocator.dupeZ(u8, line[0..i]) catch unreachable;
+            argc += 1;
             line = std.mem.trimLeft(u8, line[i+1..], &std.ascii.whitespace);
         }
-        arglist.append(allocator.dupeZ(u8, line) catch unreachable) catch unreachable;
-    }
+        arglist[argc] = allocator.dupeZ(u8, line) catch unreachable;
+        argc += 1;
 
-    var args = Args.init(arglist.items);
-    while (args.next()) |opt| {
-        if (!argConfig(&args, opt))
+        var args = Args.init(arglist[0..argc]);
+        args.ignerror = ignerror;
+        while (args.next() catch null) |opt| {
+            if (argConfig(&args, opt, true)) |_| {}
+            else |_| {
+                if (ignerror) break;
                 ui.die("Unrecognized option in config file '{s}': {s}.\nRun with --ignore-config to skip reading config files.\n", .{path, opt.val});
             }
-    for (arglist.items) |i| allocator.free(i);
-    arglist.deinit();
+        }
+        allocator.free(arglist[0]);
+        if (argc == 2) allocator.free(arglist[1]);
+    }
 }
 
 fn version() noreturn {
-    const stdout = std.io.getStdOut();
     stdout.writeAll("ncdu " ++ program_version ++ "\n") catch {};
     std.process.exit(0);
 }
 
 fn help() noreturn {
-    const stdout = std.io.getStdOut();
     stdout.writeAll(
     \\ncdu <options> <directory>
     \\
-    \\Options:
-    \\  -h,--help                  This help message
-    \\  -q                         Quiet mode, refresh interval 2 seconds
-    \\  -v,-V,--version            Print version
-    \\  -x                         Same filesystem
-    \\  -e                         Enable extended information
-    \\  -r                         Read only
-    \\  -o FILE                    Export scanned directory to FILE
+    \\Mode selection:
+    \\  -h, --help                 This help message
+    \\  -v, -V, --version          Print version
     \\  -f FILE                    Import scanned directory from FILE
-    \\  -0,-1,-2                   UI to use when scanning (0=none,2=full ncurses)
-    \\  --si                       Use base 10 (SI) prefixes instead of base 2
-    \\  --exclude PATTERN          Exclude files that match PATTERN
-    \\  -X, --exclude-from FILE    Exclude files that match any pattern in FILE
-    \\  -L, --follow-symlinks      Follow symbolic links (excluding directories)
-    \\  --exclude-caches           Exclude directories containing CACHEDIR.TAG
-    \\  --exclude-kernfs           Exclude Linux pseudo filesystems (procfs,sysfs,cgroup,...)
-    \\  --confirm-quit             Confirm quitting ncdu
-    \\  --color SCHEME             Set color scheme (off/dark/dark-bg)
+    \\  -o FILE                    Export scanned directory to FILE in JSON format
+    \\  -O FILE                    Export scanned directory to FILE in binary format
+    \\  -e, --extended             Enable extended information
     \\  --ignore-config            Don't load config files
     \\
-    \\Refer to `man ncdu` for the full list of options.
+    \\Scan options:
+    \\  -x, --one-file-system      Stay on the same filesystem
+    \\  --exclude PATTERN          Exclude files that match PATTERN
+    \\  -X, --exclude-from FILE    Exclude files that match any pattern in FILE
+    \\  --exclude-caches           Exclude directories containing CACHEDIR.TAG
+    \\  -L, --follow-symlinks      Follow symbolic links (excluding directories)
+    \\  --exclude-kernfs           Exclude Linux pseudo filesystems (procfs,sysfs,cgroup,...)
+    \\  -t NUM                     Scan with NUM threads
+    \\
+    \\Export options:
+    \\  -c, --compress             Use Zstandard compression with `-o`
+    \\  --compress-level NUM       Set compression level
+    \\  --export-block-size KIB    Set export block size with `-O`
+    \\
+    \\Interface options:
+    \\  -0, -1, -2                 UI to use when scanning (0=none,2=full ncurses)
+    \\  -q, --slow-ui-updates      "Quiet" mode, refresh interval 2 seconds
+    \\  --enable-shell             Enable/disable shell spawning feature
+    \\  --enable-delete            Enable/disable file deletion feature
+    \\  --enable-refresh           Enable/disable directory refresh feature
+    \\  -r                         Read only (--disable-delete)
+    \\  -rr                        Read only++ (--disable-delete & --disable-shell)
+    \\  --si                       Use base 10 (SI) prefixes instead of base 2
+    \\  --apparent-size            Show apparent size instead of disk usage by default
+    \\  --hide-hidden              Hide "hidden" or excluded files by default
+    \\  --show-itemcount           Show item count column by default
+    \\  --show-mtime               Show mtime column by default (requires `-e`)
+    \\  --show-graph               Show graph column by default
+    \\  --show-percent             Show percent column by default
+    \\  --graph-style STYLE        hash / half-block / eighth-block
+    \\  --shared-column            off / shared / unique
+    \\  --sort COLUMN-(asc/desc)   disk-usage / name / apparent-size / itemcount / mtime
+    \\  --enable-natsort           Use natural order when sorting by name
+    \\  --group-directories-first  Sort directories before files
+    \\  --confirm-quit             Ask confirmation before quitting ncdu
+    \\  --no-confirm-delete        Don't ask confirmation before deletion
+    \\  --delete-command CMD       Command to run for file deletion
+    \\  --color SCHEME             off / dark / dark-bg
+    \\
+    \\Refer to `man ncdu` for more information.
     \\
     ) catch {};
     std.process.exit(0);
 }
 
 
-fn spawnShell() void {
-    ui.deinit();
-    defer ui.init();
-
-    var path = std.ArrayList(u8).init(allocator);
-    defer path.deinit();
-    browser.dir_parent.fmtPath(true, &path);
-
-    var env = std.process.getEnvMap(allocator) catch unreachable;
-    defer env.deinit();
-    // NCDU_LEVEL can only count to 9, keeps the implementation simple.
-    if (env.get("NCDU_LEVEL")) |l|
-        env.put("NCDU_LEVEL", if (l.len == 0) "1" else switch (l[0]) {
-            '0'...'8' => |d| &[1] u8{d+1},
-            '9' => "9",
-            else => "1"
-        }) catch unreachable
-    else
-        env.put("NCDU_LEVEL", "1") catch unreachable;
-
-    const shell = std.posix.getenvZ("NCDU_SHELL") orelse std.posix.getenvZ("SHELL") orelse "/bin/sh";
-    var child = std.process.Child.init(&.{shell}, allocator);
-    child.cwd = path.items;
-    child.env_map = &env;
-
-    const stdin = std.io.getStdIn();
-    const stderr = std.io.getStdErr();
-    const term = child.spawnAndWait() catch |e| blk: {
-        stderr.writer().print(
-            "Error spawning shell: {s}\n\nPress enter to continue.\n",
-            .{ ui.errorString(e) }
-        ) catch {};
-        stdin.reader().skipUntilDelimiterOrEof('\n') catch unreachable;
-        break :blk std.process.Child.Term{ .Exited = 0 };
-    };
-    if (term != .Exited) {
-        const n = switch (term) {
-            .Exited  => "status",
-            .Signal  => "signal",
-            .Stopped => "stopped",
-            .Unknown => "unknown",
-        };
-        const v = switch (term) {
-            .Exited  => |v| v,
-            .Signal  => |v| v,
-            .Stopped => |v| v,
-            .Unknown => |v| v,
-        };
-        stderr.writer().print(
-            "Shell returned with {s} code {}.\n\nPress enter to continue.\n", .{ n, v }
-        ) catch {};
-        stdin.reader().skipUntilDelimiterOrEof('\n') catch unreachable;
-    }
-}
-
-
 fn readExcludeFile(path: [:0]const u8) !void {
     const f = try std.fs.cwd().openFileZ(path, .{});
     defer f.close();
 
-    var rd_ = std.io.bufferedReader(f.reader());
-    const rd = rd_.reader();
-
     var line_buf: [4096]u8 = undefined;
-    var line_fbs = std.io.fixedBufferStream(&line_buf);
-    const line_writer = line_fbs.writer();
-
-    while (true) : (line_fbs.reset()) {
-        rd.streamUntilDelimiter(line_writer, '\n', line_buf.len) catch |err| switch (err) {
-            error.EndOfStream => if (line_fbs.getPos() catch unreachable == 0) break,
-            else => |e| return e,
-        };
-        const line = line_fbs.getWritten();
+    var line_rd = util.LineReader.init(f, &line_buf);
+    while (try line_rd.read()) |line| {
         if (line.len > 0)
             exclude.addPattern(line);
     }
 }
 
+fn readImport(path: [:0]const u8) !void {
+    const fd =
+        if (std.mem.eql(u8, "-", path)) stdin
+        else try std.fs.cwd().openFileZ(path, .{});
+    errdefer fd.close();
+
+    var buf: [8]u8 = undefined;
+    if (8 != try fd.readAll(&buf)) return error.EndOfStream;
+    if (std.mem.eql(u8, &buf, bin_export.SIGNATURE)) {
+        try bin_reader.open(fd);
+        config.binreader = true;
+    } else {
+        json_import.import(fd, &buf);
+        fd.close();
+    }
+}
+
 pub fn main() void {
+    ui.main_thread = std.Thread.getCurrentId();
+
     // Grab thousands_sep from the current C locale.
     _ = c.setlocale(c.LC_ALL, "");
     if (c.localeconv()) |locale| {
@@ -456,16 +498,17 @@ pub fn main() void {
         }
     }
 
-    var scan_dir: ?[]const u8 = null;
+    var scan_dir: ?[:0]const u8 = null;
     var import_file: ?[:0]const u8 = null;
-    var export_file: ?[:0]const u8 = null;
+    var export_json: ?[:0]const u8 = null;
+    var export_bin: ?[:0]const u8 = null;
     var quit_after_scan = false;
     {
         const arglist = std.process.argsAlloc(allocator) catch unreachable;
         defer std.process.argsFree(allocator, arglist);
         var args = Args.init(arglist);
-        _ = args.next(); // program name
-        while (args.next()) |opt| {
+        _ = args.next() catch unreachable; // program name
+        while (args.next() catch unreachable) |opt| {
             if (!opt.opt) {
                 // XXX: ncdu 1.x doesn't error, it just silently ignores all but the last argument.
                 if (scan_dir != null) ui.die("Multiple directories given, see ncdu -h for help.\n", .{});
@@ -474,49 +517,68 @@ pub fn main() void {
             }
             if (opt.is("-h") or opt.is("-?") or opt.is("--help")) help()
             else if (opt.is("-v") or opt.is("-V") or opt.is("--version")) version()
-            else if (opt.is("-o") and export_file != null) ui.die("The -o flag can only be given once.\n", .{})
-            else if (opt.is("-o")) export_file = allocator.dupeZ(u8, args.arg()) catch unreachable
+            else if (opt.is("-o") and (export_json != null or export_bin != null)) ui.die("The -o flag can only be given once.\n", .{})
+            else if (opt.is("-o")) export_json = allocator.dupeZ(u8, args.arg() catch unreachable) catch unreachable
+            else if (opt.is("-O") and (export_json != null or export_bin != null)) ui.die("The -O flag can only be given once.\n", .{})
+            else if (opt.is("-O")) export_bin = allocator.dupeZ(u8, args.arg() catch unreachable) catch unreachable
             else if (opt.is("-f") and import_file != null) ui.die("The -f flag can only be given once.\n", .{})
-            else if (opt.is("-f")) import_file = allocator.dupeZ(u8, args.arg()) catch unreachable
+            else if (opt.is("-f")) import_file = allocator.dupeZ(u8, args.arg() catch unreachable) catch unreachable
             else if (opt.is("--ignore-config")) {}
             else if (opt.is("--quit-after-scan")) quit_after_scan = true // undocumented feature to help with benchmarking scan/import
-            else if (argConfig(&args, opt)) {}
-            else ui.die("Unrecognized option '{s}'.\n", .{opt.val});
+            else if (argConfig(&args, opt, false)) |_| {}
+            else |_| ui.die("Unrecognized option '{s}'.\n", .{opt.val});
         }
     }
 
+    if (config.threads == 0) config.threads = std.Thread.getCpuCount() catch 1;
+
     if (@import("builtin").os.tag != .linux and config.exclude_kernfs)
         ui.die("The --exclude-kernfs flag is currently only supported on Linux.\n", .{});
 
-    const stdin = std.io.getStdIn();
-    const stdout = std.io.getStdOut();
     const out_tty = stdout.isTty();
     const in_tty = stdin.isTty();
     if (config.scan_ui == null) {
-        if (export_file) |f| {
+        if (export_json orelse export_bin) |f| {
             if (!out_tty or std.mem.eql(u8, f, "-")) config.scan_ui = .none
             else config.scan_ui = .line;
         } else config.scan_ui = .full;
     }
-    if (!in_tty and import_file == null and export_file == null)
+    if (!in_tty and import_file == null and export_json == null and export_bin == null and !quit_after_scan)
         ui.die("Standard input is not a TTY. Did you mean to import a file using '-f -'?\n", .{});
-    config.nc_tty = !in_tty or (if (export_file) |f| std.mem.eql(u8, f, "-") else false);
+    config.nc_tty = !in_tty or (if (export_json orelse export_bin) |f| std.mem.eql(u8, f, "-") else false);
 
     event_delay_timer = std.time.Timer.start() catch unreachable;
     defer ui.deinit();
 
-    const out_file = if (export_file) |f| (
+    if (export_json) |f| {
+        const file =
             if (std.mem.eql(u8, f, "-")) stdout
             else std.fs.cwd().createFileZ(f, .{})
-             catch |e| ui.die("Error opening export file: {s}.\n", .{ui.errorString(e)})
-    ) else null;
+                 catch |e| ui.die("Error opening export file: {s}.\n", .{ui.errorString(e)});
+        json_export.setupOutput(file);
+        sink.global.sink = .json;
+    } else if (export_bin) |f| {
+        const file =
+            if (std.mem.eql(u8, f, "-")) stdout
+            else std.fs.cwd().createFileZ(f, .{})
+                 catch |e| ui.die("Error opening export file: {s}.\n", .{ui.errorString(e)});
+        bin_export.setupOutput(file);
+        sink.global.sink = .bin;
+    }
 
     if (import_file) |f| {
-        scan.importRoot(f, out_file);
+        readImport(f) catch |e| ui.die("Error reading file '{s}': {s}.\n", .{f, ui.errorString(e)});
         config.imported = true;
-    } else scan.scanRoot(scan_dir orelse ".", out_file)
-           catch |e| ui.die("Error opening directory: {s}.\n", .{ui.errorString(e)});
-    if (quit_after_scan or out_file != null) return;
+        if (config.binreader and (export_json != null or export_bin != null))
+            bin_reader.import();
+    } else {
+        var buf: [std.fs.max_path_bytes+1]u8 = @splat(0);
+        const path =
+            if (std.posix.realpathZ(scan_dir orelse ".", buf[0..buf.len-1])) |p| buf[0..p.len:0]
+            else |_| (scan_dir orelse ".");
+        scan.scan(path) catch |e| ui.die("Error opening directory: {s}.\n", .{ui.errorString(e)});
+    }
+    if (quit_after_scan or export_json != null or export_bin != null) return;
 
     config.can_shell = config.can_shell orelse !config.imported;
     config.can_delete = config.can_delete orelse !config.imported;
@@ -525,44 +587,57 @@ pub fn main() void {
     config.scan_ui = .full; // in case we're refreshing from the UI, always in full mode.
     ui.init();
     state = .browse;
-    browser.dir_parent = model.root;
-    browser.loadDir(null);
+    browser.initRoot();
 
     while (true) {
         switch (state) {
             .refresh => {
-                scan.scan();
+                var full_path: std.ArrayListUnmanaged(u8) = .empty;
+                defer full_path.deinit(allocator);
+                mem_sink.global.root.?.fmtPath(allocator, true, &full_path);
+                scan.scan(util.arrayListBufZ(&full_path, allocator)) catch {
+                    sink.global.last_error = allocator.dupeZ(u8, full_path.items) catch unreachable;
+                    sink.global.state = .err;
+                    while (state == .refresh) handleEvent(true, true);
+                };
                 state = .browse;
-                browser.loadDir(null);
+                browser.loadDir(0);
             },
             .shell => {
-                spawnShell();
+                const shell = std.posix.getenvZ("NCDU_SHELL") orelse std.posix.getenvZ("SHELL") orelse "/bin/sh";
+                var env = std.process.getEnvMap(allocator) catch unreachable;
+                defer env.deinit();
+                ui.runCmd(&.{shell}, browser.dir_path, &env, false);
                 state = .browse;
             },
             .delete => {
                 const next = delete.delete();
+                if (state != .refresh) {
                     state = .browse;
-                browser.loadDir(next);
+                    browser.loadDir(if (next) |n| n.nameHash() else 0);
+                }
             },
             else => handleEvent(true, false)
         }
     }
 }
 
-var event_delay_timer: std.time.Timer = undefined;
+pub var event_delay_timer: std.time.Timer = undefined;
 
 // Draw the screen and handle the next input event.
 // In non-blocking mode, screen drawing is rate-limited to keep this function fast.
 pub fn handleEvent(block: bool, force_draw: bool) void {
+    while (ui.oom_threads.load(.monotonic) > 0) ui.oom();
+
     if (block or force_draw or event_delay_timer.read() > config.update_delay) {
-        if (ui.inited) _ = ui.c.erase();
+        if (ui.inited) _ = c.erase();
         switch (state) {
-            .scan, .refresh => scan.draw(),
+            .scan, .refresh => sink.draw(),
             .browse => browser.draw(),
             .delete => delete.draw(),
             .shell => unreachable,
         }
-        if (ui.inited) _ = ui.c.refresh();
+        if (ui.inited) _ = c.refresh();
         event_delay_timer.reset();
     }
     if (!ui.inited) {
@@ -576,7 +651,7 @@ pub fn handleEvent(block: bool, force_draw: bool) void {
         if (ch == 0) return;
         if (ch == -1) return handleEvent(firstblock, true);
         switch (state) {
-            .scan, .refresh => scan.keyInput(ch),
+            .scan, .refresh => sink.keyInput(ch),
             .browse => browser.keyInput(ch),
             .delete => delete.keyInput(ch),
             .shell => unreachable,
@@ -590,13 +665,13 @@ test "argument parser" {
     const T = struct {
         a: Args,
         fn opt(self: *@This(), isopt: bool, val: []const u8) !void {
-            const o = self.a.next().?;
+            const o = (self.a.next() catch unreachable).?;
             try std.testing.expectEqual(isopt, o.opt);
             try std.testing.expectEqualStrings(val, o.val);
             try std.testing.expectEqual(o.is(val), isopt);
         }
         fn arg(self: *@This(), val: []const u8) !void {
-            try std.testing.expectEqualStrings(val, self.a.arg());
+            try std.testing.expectEqualStrings(val, self.a.arg() catch unreachable);
         }
     };
     var t = T{ .a = Args.init(&lst) };

src/mem_sink.zig

@@ -0,0 +1,212 @@
+// SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
+// SPDX-License-Identifier: MIT
+
+const std = @import("std");
+const main = @import("main.zig");
+const model = @import("model.zig");
+const sink = @import("sink.zig");
+
+
+pub const global = struct {
+    pub var root: ?*model.Dir = null;
+    pub var stats: bool = true; // calculate aggregate directory stats
+};
+
+pub const Thread = struct {
+    // Arena allocator for model.Entry structs, these are never freed.
+    arena: std.heap.ArenaAllocator = std.heap.ArenaAllocator.init(std.heap.page_allocator),
+};
+
+pub fn statToEntry(stat: *const sink.Stat, e: *model.Entry, parent: *model.Dir) void {
+    e.pack.blocks = stat.blocks;
+    e.size = stat.size;
+    if (e.dir()) |d| {
+        d.parent = parent;
+        d.pack.dev = model.devices.getId(stat.dev);
+    }
+    if (e.link()) |l| {
+        l.parent = parent;
+        l.ino = stat.ino;
+        l.pack.nlink = stat.nlink;
+        model.inodes.lock.lock();
+        defer model.inodes.lock.unlock();
+        l.addLink();
+    }
+    if (e.ext()) |ext| ext.* = stat.ext;
+}
+
+pub const Dir = struct {
+    dir: *model.Dir,
+    entries: Map,
+
+    own_blocks: model.Blocks,
+    own_bytes: u64,
+
+    // Additional counts collected from subdirectories. Subdirs may run final()
+    // from separate threads so these need to be protected.
+    blocks: model.Blocks = 0,
+    bytes: u64 = 0,
+    items: u32 = 0,
+    mtime: u64 = 0,
+    suberr: bool = false,
+    lock: std.Thread.Mutex = .{},
+
+    const Map = std.HashMap(*model.Entry, void, HashContext, 80);
+
+    const HashContext = struct {
+        pub fn hash(_: @This(), e: *model.Entry) u64 {
+            return std.hash.Wyhash.hash(0, e.name());
+        }
+        pub fn eql(_: @This(), a: *model.Entry, b: *model.Entry) bool {
+            return a == b or std.mem.eql(u8, a.name(), b.name());
+        }
+    };
+
+    const HashContextAdapted = struct {
+        pub fn hash(_: @This(), v: []const u8) u64 {
+            return std.hash.Wyhash.hash(0, v);
+        }
+        pub fn eql(_: @This(), a: []const u8, b: *model.Entry) bool {
+            return std.mem.eql(u8, a, b.name());
+        }
+    };
+
+    fn init(dir: *model.Dir) Dir {
+        var self = Dir{
+            .dir = dir,
+            .entries = Map.initContext(main.allocator, HashContext{}),
+            .own_blocks = dir.entry.pack.blocks,
+            .own_bytes = dir.entry.size,
+        };
+
+        var count: Map.Size = 0;
+        var it = dir.sub.ptr;
+        while (it) |e| : (it = e.next.ptr) count += 1;
+        self.entries.ensureUnusedCapacity(count) catch unreachable;
+
+        it = dir.sub.ptr;
+        while (it) |e| : (it = e.next.ptr)
+            self.entries.putAssumeCapacity(e, {});
+        return self;
+    }
+
+    fn getEntry(self: *Dir, t: *Thread, etype: model.EType, isext: bool, name: []const u8) *model.Entry {
+        if (self.entries.getKeyAdapted(name, HashContextAdapted{})) |e| {
+            // XXX: In-place conversion may be possible in some cases.
+            if (e.pack.etype.base() == etype.base() and (!isext or e.pack.isext)) {
+                e.pack.etype = etype;
+                e.pack.isext = isext;
+                _ = self.entries.removeAdapted(name, HashContextAdapted{});
+                return e;
+            }
+        }
+        const e = model.Entry.create(t.arena.allocator(), etype, isext, name);
+        e.next.ptr = self.dir.sub.ptr;
+        self.dir.sub.ptr = e;
+        return e;
+    }
+
+    pub fn addSpecial(self: *Dir, t: *Thread, name: []const u8, st: model.EType) void {
+        self.dir.items += 1;
+        if (st == .err) self.dir.pack.suberr = true;
+        _ = self.getEntry(t, st, false, name);
+    }
+
+    pub fn addStat(self: *Dir, t: *Thread, name: []const u8, stat: *const sink.Stat) *model.Entry {
+        if (global.stats) {
+            self.dir.items +|= 1;
+            if (stat.etype != .link) {
+                self.dir.entry.pack.blocks +|= stat.blocks;
+                self.dir.entry.size +|= stat.size;
+            }
+            if (self.dir.entry.ext()) |e| {
+                if (stat.ext.mtime > e.mtime) e.mtime = stat.ext.mtime;
+            }
+        }
+
+        const e = self.getEntry(t, stat.etype, main.config.extended and !stat.ext.isEmpty(), name);
+        statToEntry(stat, e, self.dir);
+        return e;
+    }
+
+    pub fn addDir(self: *Dir, t: *Thread, name: []const u8, stat: *const sink.Stat) Dir {
+        return init(self.addStat(t, name, stat).dir().?);
+    }
+
+    pub fn setReadError(self: *Dir) void {
+        self.dir.pack.err = true;
+    }
+
+    pub fn final(self: *Dir, parent: ?*Dir) void {
+        // Remove entries we've not seen
+        if (self.entries.count() > 0) {
+            var it = &self.dir.sub.ptr;
+            while (it.*) |e| {
+                if (self.entries.getKey(e) == e) it.* = e.next.ptr
+                else it = &e.next.ptr;
+            }
+        }
+        self.entries.deinit();
+
+        if (!global.stats) return;
+
+        // Grab counts collected from subdirectories
+        self.dir.entry.pack.blocks +|= self.blocks;
+        self.dir.entry.size +|= self.bytes;
+        self.dir.items +|= self.items;
+        if (self.suberr) self.dir.pack.suberr = true;
+        if (self.dir.entry.ext()) |e| {
+            if (self.mtime > e.mtime) e.mtime = self.mtime;
+        }
+
+        // Add own counts to parent
+        if (parent) |p| {
+            p.lock.lock();
+            defer p.lock.unlock();
+            p.blocks +|= self.dir.entry.pack.blocks - self.own_blocks;
+            p.bytes +|= self.dir.entry.size - self.own_bytes;
+            p.items +|= self.dir.items;
+            if (self.dir.entry.ext()) |e| {
+                if (e.mtime > p.mtime) p.mtime = e.mtime;
+            }
+            if (self.suberr or self.dir.pack.suberr or self.dir.pack.err) p.suberr = true;
+        }
+    }
+};
+
+pub fn createRoot(path: []const u8, stat: *const sink.Stat) Dir {
+    const p = global.root orelse blk: {
+        model.root = model.Entry.create(main.allocator, .dir, main.config.extended and !stat.ext.isEmpty(), path).dir().?;
+        break :blk model.root;
+    };
+    sink.global.state = .zeroing;
+    if (p.items > 10_000) main.handleEvent(false, true);
+    // Do the zeroStats() here, after the "root" entry has been
+    // stat'ed and opened, so that a fatal error on refresh won't
+    // zero-out the requested directory.
+    p.entry.zeroStats(p.parent);
+    sink.global.state = .running;
+    p.entry.pack.blocks = stat.blocks;
+    p.entry.size = stat.size;
+    p.pack.dev = model.devices.getId(stat.dev);
+    if (p.entry.ext()) |e| e.* = stat.ext;
+    return Dir.init(p);
+}
+
+pub fn done() void {
+    if (!global.stats) return;
+
+    sink.global.state = .hlcnt;
+    main.handleEvent(false, true);
+    const dir = global.root orelse model.root;
+    var it: ?*model.Dir = dir;
+    while (it) |p| : (it = p.parent) {
+        p.updateSubErr();
+        if (p != dir) {
+            p.entry.pack.blocks +|= dir.entry.pack.blocks;
+            p.entry.size +|= dir.entry.size;
+            p.items +|= dir.items + 1;
+        }
+    }
+    model.inodes.addAllStats();
+}

src/mem_src.zig

@@ -0,0 +1,73 @@
+// SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
+// SPDX-License-Identifier: MIT
+
+const std = @import("std");
+const main = @import("main.zig");
+const model = @import("model.zig");
+const sink = @import("sink.zig");
+
+// Emit the memory tree to the sink in depth-first order from a single thread,
+// suitable for JSON export.
+
+fn toStat(e: *model.Entry) sink.Stat {
+    const el = e.link();
+    return sink.Stat{
+        .etype = e.pack.etype,
+        .blocks = e.pack.blocks,
+        .size = e.size,
+        .dev =
+            if (e.dir()) |d| model.devices.list.items[d.pack.dev]
+            else if (el) |l| model.devices.list.items[l.parent.pack.dev]
+            else undefined,
+        .ino = if (el) |l| l.ino else undefined,
+        .nlink = if (el) |l| l.pack.nlink else 1,
+        .ext = if (e.ext()) |x| x.* else .{},
+    };
+}
+
+const Ctx = struct {
+    sink: *sink.Thread,
+    stat: sink.Stat,
+};
+
+
+fn rec(ctx: *Ctx, dir: *sink.Dir, entry: *model.Entry) void {
+    if ((ctx.sink.files_seen.load(.monotonic) & 65) == 0)
+        main.handleEvent(false, false);
+
+    ctx.stat = toStat(entry);
+    switch (entry.pack.etype) {
+        .dir => {
+            const d = entry.dir().?;
+            var ndir = dir.addDir(ctx.sink, entry.name(), &ctx.stat);
+            ctx.sink.setDir(ndir);
+            if (d.pack.err) ndir.setReadError(ctx.sink);
+            var it = d.sub.ptr;
+            while (it) |e| : (it = e.next.ptr) rec(ctx, ndir, e);
+            ctx.sink.setDir(dir);
+            ndir.unref(ctx.sink);
+        },
+        .reg, .nonreg, .link => dir.addStat(ctx.sink, entry.name(), &ctx.stat),
+        else => dir.addSpecial(ctx.sink, entry.name(), entry.pack.etype),
+    }
+}
+
+
+pub fn run(d: *model.Dir) void {
+    const sink_threads = sink.createThreads(1);
+
+    var ctx: Ctx = .{
+        .sink = &sink_threads[0],
+        .stat = toStat(&d.entry),
+    };
+    var buf: std.ArrayListUnmanaged(u8) = .empty;
+    d.fmtPath(main.allocator, true, &buf);
+    const root = sink.createRoot(buf.items, &ctx.stat);
+    buf.deinit(main.allocator);
+
+    var it = d.sub.ptr;
+    while (it) |e| : (it = e.next.ptr) rec(&ctx, root, e);
+
+    root.unref(ctx.sink);
+    sink.done();
+}

src/model.zig

@@ -6,20 +6,51 @@ const main = @import("main.zig");
 const ui = @import("ui.zig");
 const util = @import("util.zig");
 
-// While an arena allocator is optimimal for almost all scenarios in which ncdu
-// is used, it doesn't allow for re-using deleted nodes after doing a delete or
-// refresh operation, so a long-running ncdu session with regular refreshes
-// will leak memory, but I'd say that's worth the efficiency gains.
-// TODO: Can still implement a simple bucketed free list on top of this arena
-// allocator to reuse nodes, if necessary.
-var allocator_state = std.heap.ArenaAllocator.init(std.heap.page_allocator);
-const allocator = allocator_state.allocator();
+// Numbers are used in the binfmt export, so must be stable.
+pub const EType = enum(i3) {
+    dir = 0,
+    reg = 1,
+    nonreg = 2,
+    link = 3,
+    err = -1,
+    pattern = -2,
+    otherfs = -3,
+    kernfs = -4,
 
-pub const EType = enum(u2) { dir, link, file };
+    pub fn base(t: EType) EType {
+        return switch (t) {
+            .dir, .link => t,
+            else => .reg,
+        };
+    }
+
+    // Whether this entry should be displayed as a "directory".
+    // Some dirs are actually represented in this data model as a File for efficiency.
+    pub fn isDirectory(t: EType) bool {
+        return switch (t) {
+            .dir, .otherfs, .kernfs => true,
+            else => false,
+        };
+    }
+};
 
 // Type for the Entry.Packed.blocks field. Smaller than a u64 to make room for flags.
 pub const Blocks = u60;
 
+// Entries read from bin_reader may refer to other entries by itemref rather than pointer.
+// This is a hack that allows browser.zig to use the same types for in-memory
+// and bin_reader-backed directory trees. Most code can only deal with
+// in-memory trees and accesses the .ptr field directly.
+pub const Ref = extern union {
+    ptr: ?*Entry align(1),
+    ref: u64 align(1),
+
+    pub fn isNull(r: Ref) bool {
+        if (main.config.binreader) return r.ref == std.math.maxInt(u64)
+        else return r.ptr == null;
+    }
+};
+
 // Memory layout:
 //      (Ext +) Dir + name
 //  or: (Ext +) Link + name
@@ -34,16 +65,11 @@ pub const Blocks = u60;
 pub const Entry = extern struct {
     pack: Packed align(1),
     size: u64 align(1) = 0,
-    next: ?*Entry align(1) = null,
+    next: Ref = .{ .ptr = null },
 
     pub const Packed = packed struct(u64) {
         etype: EType,
         isext: bool,
-        // Whether or not this entry's size has been counted in its parents.
-        // Counting of Link entries is deferred until the scan/delete operation has
-        // completed, so for those entries this flag indicates an intention to be
-        // counted.
-        counted: bool = false,
         blocks: Blocks = 0, // 512-byte blocks
     };
 
@@ -58,34 +84,33 @@ pub const Entry = extern struct {
     }
 
     pub fn file(self: *Self) ?*File {
-        return if (self.pack.etype == .file) @ptrCast(self) else null;
-    }
-
-    // Whether this entry should be displayed as a "directory".
-    // Some dirs are actually represented in this data model as a File for efficiency.
-    pub fn isDirectory(self: *Self) bool {
-        return if (self.file()) |f| f.pack.other_fs or f.pack.kernfs else self.pack.etype == .dir;
+        return if (self.pack.etype != .dir and self.pack.etype != .link) @ptrCast(self) else null;
     }
 
     pub fn name(self: *const Self) [:0]const u8 {
         const self_name = switch (self.pack.etype) {
             .dir => &@as(*const Dir, @ptrCast(self)).name,
             .link => &@as(*const Link, @ptrCast(self)).name,
-            .file => &@as(*const File, @ptrCast(self)).name,
+            else => &@as(*const File, @ptrCast(self)).name,
         };
         const name_ptr: [*:0]const u8 = @ptrCast(self_name);
         return std.mem.sliceTo(name_ptr, 0);
     }
 
+    pub fn nameHash(self: *const Self) u64 {
+        return std.hash.Wyhash.hash(0, self.name());
+    }
+
     pub fn ext(self: *Self) ?*Ext {
         if (!self.pack.isext) return null;
         return @ptrCast(@as([*]Ext, @ptrCast(self)) - 1);
     }
 
-    fn alloc(comptime T: type, etype: EType, isext: bool, ename: []const u8) *Entry {
+    fn alloc(comptime T: type, allocator: std.mem.Allocator, etype: EType, isext: bool, ename: []const u8) *Entry {
         const size = (if (isext) @as(usize, @sizeOf(Ext)) else 0) + @sizeOf(T) + ename.len + 1;
         var ptr = blk: while (true) {
-            if (allocator.allocWithOptions(u8, size, 1, null)) |p| break :blk p
+            const alignment = if (@typeInfo(@TypeOf(std.mem.Allocator.allocWithOptions)).@"fn".params[3].type == ?u29) 1 else std.mem.Alignment.@"1";
+            if (allocator.allocWithOptions(u8, size, alignment, null)) |p| break :blk p
             else |_| {}
             ui.oom();
         };
@@ -101,115 +126,65 @@ pub const Entry = extern struct {
         return &e.entry;
     }
 
-    pub fn create(etype: EType, isext: bool, ename: []const u8) *Entry {
+    pub fn create(allocator: std.mem.Allocator, etype: EType, isext: bool, ename: []const u8) *Entry {
         return switch (etype) {
-            .dir  => alloc(Dir, etype, isext, ename),
-            .file => alloc(File, etype, isext, ename),
-            .link => alloc(Link, etype, isext, ename),
+            .dir  => alloc(Dir, allocator, etype, isext, ename),
+            .link => alloc(Link, allocator, etype, isext, ename),
+            else => alloc(File, allocator, etype, isext, ename),
         };
     }
 
+    pub fn destroy(self: *Self, allocator: std.mem.Allocator) void {
+        const ptr: [*]u8 = if (self.ext()) |e| @ptrCast(e) else @ptrCast(self);
+        const esize: usize = switch (self.pack.etype) {
+            .dir => @sizeOf(Dir),
+            .link => @sizeOf(Link),
+            else => @sizeOf(File),
+        };
+        const size = (if (self.pack.isext) @as(usize, @sizeOf(Ext)) else 0) + esize + self.name().len + 1;
+        allocator.free(ptr[0..size]);
+    }
+
     fn hasErr(self: *Self) bool {
         return
-            if (self.file()) |f| f.pack.err
-            else if (self.dir()) |d| d.pack.err or d.pack.suberr
-            else false;
+            if(self.dir()) |d| d.pack.err or d.pack.suberr
+            else self.pack.etype == .err;
     }
 
-    pub fn addStats(self: *Entry, parent: *Dir, nlink: u31) void {
-        if (self.pack.counted) return;
-        self.pack.counted = true;
-
-        // Add link to the inode map, but don't count its size (yet).
-        if (self.link()) |l| {
-            l.parent = parent;
-            var d = inodes.map.getOrPut(l) catch unreachable;
-            if (!d.found_existing) {
-                d.value_ptr.* = .{ .counted = false, .nlink = nlink };
-                inodes.total_blocks +|= self.pack.blocks;
-                l.next = l;
-            } else {
-                inodes.setStats(.{ .key_ptr = d.key_ptr, .value_ptr = d.value_ptr }, false);
-                // If the nlink counts are not consistent, reset to 0 so we calculate with what we have instead.
-                if (d.value_ptr.nlink != nlink)
-                    d.value_ptr.nlink = 0;
-                l.next = d.key_ptr.*.next;
-                d.key_ptr.*.next = l;
-            }
-            inodes.addUncounted(l);
-        }
-
-        var it: ?*Dir = parent;
-        while(it) |p| : (it = p.parent) {
-            if (self.ext()) |e|
-                if (p.entry.ext()) |pe|
-                    if (e.mtime > pe.mtime) { pe.mtime = e.mtime; };
-            p.items +|= 1;
-            if (self.pack.etype != .link) {
-                p.entry.size +|= self.size;
-                p.entry.pack.blocks +|= self.pack.blocks;
-            }
-        }
-    }
-
-    // Opposite of addStats(), but has some limitations:
-    // - If addStats() saturated adding sizes, then the sizes after delStats()
-    //   will be incorrect.
-    // - mtime of parents is not adjusted (but that's a feature, possibly?)
-    //
-    // This function assumes that, for directories, all sub-entries have
-    // already been un-counted.
-    //
-    // When removing a Link, the entry's nlink counter is reset to zero, so
-    // that it will be recalculated based on our view of the tree. This means
-    // that links outside of the scanned directory will not be considered
-    // anymore, meaning that delStats() followed by addStats() with the same
-    // data may cause information to be lost.
-    pub fn delStats(self: *Entry, parent: *Dir) void {
-        if (!self.pack.counted) return;
-        defer self.pack.counted = false; // defer, to make sure inodes.setStats() still sees it as counted.
-
-        if (self.link()) |l| {
-            var d = inodes.map.getEntry(l).?;
-            inodes.setStats(d, false);
-            d.value_ptr.nlink = 0;
-            if (l.next == l) {
-                _ = inodes.map.remove(l);
-                _ = inodes.uncounted.remove(l);
-                inodes.total_blocks -|= self.pack.blocks;
-            } else {
-                if (d.key_ptr.* == l)
-                    d.key_ptr.* = l.next;
-                inodes.addUncounted(l.next);
-                // This is O(n), which in this context has the potential to
-                // slow ncdu down to a crawl. But this function is only called
-                // on refresh/delete operations and even then it's not common
-                // to have very long lists, so this blowing up should be very
-                // rare. This removal can also be deferred to setStats() to
-                // amortize the costs, if necessary.
-                var it = l.next;
-                while (it.next != l) it = it.next;
-                it.next = l.next;
-            }
-        }
-
-        var it: ?*Dir = parent;
-        while(it) |p| : (it = p.parent) {
-            p.items -|= 1;
-            if (self.pack.etype != .link) {
-                p.entry.size -|= self.size;
-                p.entry.pack.blocks -|= self.pack.blocks;
-            }
-        }
-    }
-
-    pub fn delStatsRec(self: *Entry, parent: *Dir) void {
+    fn removeLinks(self: *Entry) void {
         if (self.dir()) |d| {
-            var it = d.sub;
-            while (it) |e| : (it = e.next)
-                e.delStatsRec(d);
+            var it = d.sub.ptr;
+            while (it) |e| : (it = e.next.ptr) e.removeLinks();
         }
-        self.delStats(parent);
+        if (self.link()) |l| l.removeLink();
+    }
+
+    fn zeroStatsRec(self: *Entry) void {
+        self.pack.blocks = 0;
+        self.size = 0;
+        if (self.dir()) |d| {
+            d.items = 0;
+            d.pack.err = false;
+            d.pack.suberr = false;
+            var it = d.sub.ptr;
+            while (it) |e| : (it = e.next.ptr) e.zeroStatsRec();
+        }
+    }
+
+    // Recursively set stats and those of sub-items to zero and removes counts
+    // from parent directories; as if this item does not exist in the tree.
+    // XXX: Does not update the 'suberr' flag of parent directories, make sure
+    // to call updateSubErr() afterwards.
+    pub fn zeroStats(self: *Entry, parent: ?*Dir) void {
+        self.removeLinks();
+
+        var it = parent;
+        while (it) |p| : (it = p.parent) {
+            p.entry.pack.blocks -|= self.pack.blocks;
+            p.entry.size -|= self.size;
+            p.items -|= 1 + (if (self.dir()) |d| d.items else 0);
+        }
+        self.zeroStatsRec();
     }
 };
 
@@ -218,7 +193,7 @@ const DevId = u30; // Can be reduced to make room for more flags in Dir.Packed.
 pub const Dir = extern struct {
     entry: Entry,
 
-    sub: ?*Entry align(1) = null,
+    sub: Ref = .{ .ptr = null },
     parent: ?*Dir align(1) = null,
 
     // entry.{blocks,size}: Total size of all unique files + dirs. Non-shared hardlinks are counted only once.
@@ -243,19 +218,20 @@ pub const Dir = extern struct {
         suberr: bool = false,
     };
 
-    pub fn fmtPath(self: *const @This(), withRoot: bool, out: *std.ArrayList(u8)) void {
+    pub fn fmtPath(self: *const @This(), alloc: std.mem.Allocator, withRoot: bool, out: *std.ArrayListUnmanaged(u8)) void {
         if (!withRoot and self.parent == null) return;
-        var components = std.ArrayList([:0]const u8).init(main.allocator);
-        defer components.deinit();
+        var components: std.ArrayListUnmanaged([:0]const u8) = .empty;
+        defer components.deinit(main.allocator);
         var it: ?*const @This() = self;
         while (it) |e| : (it = e.parent)
             if (withRoot or e.parent != null)
-                components.append(e.entry.name()) catch unreachable;
+                components.append(main.allocator, e.entry.name()) catch unreachable;
 
         var i: usize = components.items.len-1;
         while (true) {
-            if (i != components.items.len-1 and !(out.items.len != 0 and out.items[out.items.len-1] == '/')) out.append('/') catch unreachable;
-            out.appendSlice(components.items[i]) catch unreachable;
+            if (i != components.items.len-1 and !(out.items.len != 0 and out.items[out.items.len-1] == '/'))
+                out.append(main.allocator, '/') catch unreachable;
+            out.appendSlice(alloc, components.items[i]) catch unreachable;
             if (i == 0) break;
             i -= 1;
         }
@@ -265,8 +241,8 @@ pub const Dir = extern struct {
     // been updated and does not propagate to parents.
     pub fn updateSubErr(self: *@This()) void {
         self.pack.suberr = false;
-        var sub = self.sub;
-        while (sub) |e| : (sub = e.next) {
+        var sub = self.sub.ptr;
+        while (sub) |e| : (sub = e.next.ptr) {
             if (e.hasErr()) {
                 self.pack.suberr = true;
                 break;
@@ -279,58 +255,115 @@ pub const Dir = extern struct {
 pub const Link = extern struct {
     entry: Entry,
     parent: *Dir align(1) = undefined,
-    next: *Link align(1) = undefined, // Singly circular linked list of all *Link nodes with the same dev,ino.
+    next: *Link align(1) = undefined, // circular linked list of all *Link nodes with the same dev,ino.
+    prev: *Link align(1) = undefined,
     // dev is inherited from the parent Dir
     ino: u64 align(1) = undefined,
+    pack: Pack align(1) = .{},
     name: [0]u8 = undefined,
 
+    const Pack = packed struct(u32) {
+        // Whether this Inode is counted towards the parent directories.
+        // Is kept synchronized between all Link nodes with the same dev/ino.
+        counted: bool = false,
+        // Number of links for this inode. When set to '0', we don't know the
+        // actual nlink count; which happens for old JSON dumps.
+        nlink: u31 = undefined,
+    };
+
     // Return value should be freed with main.allocator.
     pub fn path(self: *const @This(), withRoot: bool) [:0]const u8 {
-        var out = std.ArrayList(u8).init(main.allocator);
-        self.parent.fmtPath(withRoot, &out);
-        out.append('/') catch unreachable;
-        out.appendSlice(self.entry.name()) catch unreachable;
-        return out.toOwnedSliceSentinel(0) catch unreachable;
+        var out: std.ArrayListUnmanaged(u8) = .empty;
+        self.parent.fmtPath(main.allocator, withRoot, &out);
+        out.append(main.allocator, '/') catch unreachable;
+        out.appendSlice(main.allocator, self.entry.name()) catch unreachable;
+        return out.toOwnedSliceSentinel(main.allocator, 0) catch unreachable;
+    }
+
+    // Add this link to the inodes map and mark it as 'uncounted'.
+    pub fn addLink(l: *@This()) void {
+        const d = inodes.map.getOrPut(l) catch unreachable;
+        if (!d.found_existing) {
+            l.next = l;
+            l.prev = l;
+        } else {
+            inodes.setStats(d.key_ptr.*, false);
+            l.next = d.key_ptr.*;
+            l.prev = d.key_ptr.*.prev;
+            l.next.prev = l;
+            l.prev.next = l;
+        }
+        inodes.addUncounted(l);
+    }
+
+    // Remove this link from the inodes map and remove its stats from parent directories.
+    fn removeLink(l: *@This()) void {
+        inodes.setStats(l, false);
+        const entry = inodes.map.getEntry(l) orelse return;
+        if (l.next == l) {
+            _ = inodes.map.remove(l);
+            _ = inodes.uncounted.remove(l);
+        } else {
+            // XXX: If this link is actually removed from the filesystem, then
+            // the nlink count of the existing links should be updated to
+            // reflect that. But we can't do that here, because this function
+            // is also called before doing a filesystem refresh - in which case
+            // the nlink count likely won't change. Best we can hope for is
+            // that a refresh will encounter another link to the same inode and
+            // trigger an nlink change.
+            if (entry.key_ptr.* == l)
+                entry.key_ptr.* = l.next;
+            inodes.addUncounted(l.next);
+            l.next.prev = l.prev;
+            l.prev.next = l.next;
+        }
     }
 };
 
 // Anything that's not an (indexed) directory or hardlink. Excluded directories are also "Files".
 pub const File = extern struct {
     entry: Entry,
-    pack: Packed = .{},
     name: [0]u8 = undefined,
-
-    pub const Packed = packed struct(u8) {
-        err: bool = false,
-        excluded: bool = false,
-        other_fs: bool = false,
-        kernfs: bool = false,
-        notreg: bool = false,
-        _pad: u3 = 0, // Make this struct "ABI sized" to allow inclusion in an extern struct
-    };
 };
 
 pub const Ext = extern struct {
+    pack: Pack = .{},
     mtime: u64 align(1) = 0,
     uid: u32 align(1) = 0,
     gid: u32 align(1) = 0,
     mode: u16 align(1) = 0,
+
+    pub const Pack = packed struct(u8) {
+        hasmtime: bool = false,
+        hasuid: bool = false,
+        hasgid: bool = false,
+        hasmode: bool = false,
+        _pad: u4 = 0,
+    };
+
+    pub fn isEmpty(e: *const Ext) bool {
+        return !e.pack.hasmtime and !e.pack.hasuid and !e.pack.hasgid and !e.pack.hasmode;
+    }
 };
 
 
 // List of st_dev entries. Those are typically 64bits, but that's quite a waste
 // of space when a typical scan won't cover many unique devices.
 pub const devices = struct {
+    var lock = std.Thread.Mutex{};
     // id -> dev
-    pub var list = std.ArrayList(u64).init(main.allocator);
+    pub var list: std.ArrayListUnmanaged(u64) = .empty;
     // dev -> id
     var lookup = std.AutoHashMap(u64, DevId).init(main.allocator);
 
     pub fn getId(dev: u64) DevId {
+        lock.lock();
+        defer lock.unlock();
         const d = lookup.getOrPut(dev) catch unreachable;
         if (!d.found_existing) {
+            if (list.items.len >= std.math.maxInt(DevId)) ui.die("Maximum number of device identifiers exceeded.\n", .{});
             d.value_ptr.* = @as(DevId, @intCast(list.items.len));
-            list.append(dev) catch unreachable;
+            list.append(main.allocator, dev) catch unreachable;
         }
         return d.value_ptr.*;
     }
@@ -343,14 +376,9 @@ pub const inodes = struct {
     // node in the list. Link entries with the same dev/ino are part of a
     // circular linked list, so you can iterate through all of them with this
     // single pointer.
-    const Map = std.HashMap(*Link, Inode, HashContext, 80);
+    const Map = std.HashMap(*Link, void, HashContext, 80);
     pub var map = Map.init(main.allocator);
 
-    // Cumulative size of all unique hard links in the map.  This is a somewhat
-    // ugly workaround to provide accurate sizes during the initial scan, when
-    // the hard links are not counted as part of the parent directories yet.
-    pub var total_blocks: Blocks = 0;
-
     // List of nodes in 'map' with !counted, to speed up addAllStats().
     // If this list grows large relative to the number of nodes in 'map', then
     // this list is cleared and uncounted_full is set instead, so that
@@ -358,16 +386,7 @@ pub const inodes = struct {
     var uncounted = std.HashMap(*Link, void, HashContext, 80).init(main.allocator);
     var uncounted_full = true; // start with true for the initial scan
 
-    const Inode = packed struct {
-        // Whether this Inode is counted towards the parent directories.
-        counted: bool,
-        // Number of links for this inode. When set to '0', we don't know the
-        // actual nlink count, either because it wasn't part of the imported
-        // JSON data or because we read inconsistent values from the
-        // filesystem.  The count will then be updated by the actual number of
-        // links in our in-memory tree.
-        nlink: u31,
-    };
+    pub var lock = std.Thread.Mutex{};
 
     const HashContext = struct {
         pub fn hash(_: @This(), l: *Link) u64 {
@@ -395,61 +414,85 @@ pub const inodes = struct {
     // the list of *Links and their sizes and counts must be in the exact same
     // state as when the stats were added. Hence, any modification to the Link
     // state should be preceded by a setStats(.., false).
-    fn setStats(entry: Map.Entry, add: bool) void {
-        if (entry.value_ptr.counted == add) return;
-        entry.value_ptr.counted = add;
+    fn setStats(l: *Link, add: bool) void {
+        if (l.pack.counted == add) return;
 
         var nlink: u31 = 0;
+        var inconsistent = false;
         var dirs = std.AutoHashMap(*Dir, u32).init(main.allocator);
         defer dirs.deinit();
-        var it = entry.key_ptr.*;
+        var it = l;
         while (true) {
-            if (it.entry.pack.counted) {
+            it.pack.counted = add;
             nlink += 1;
+            if (it.pack.nlink != l.pack.nlink) inconsistent = true;
             var parent: ?*Dir = it.parent;
             while (parent) |p| : (parent = p.parent) {
                 const de = dirs.getOrPut(p) catch unreachable;
                 if (de.found_existing) de.value_ptr.* += 1
                 else de.value_ptr.* = 1;
             }
-            }
             it = it.next;
-            if (it == entry.key_ptr.*)
+            if (it == l)
                 break;
         }
 
-        if (entry.value_ptr.nlink < nlink) entry.value_ptr.nlink = nlink
-        else nlink = entry.value_ptr.nlink;
+        // There's not many sensible things we can do when we encounter
+        // inconsistent nlink counts. Current approach is to use the number of
+        // times we've seen this link in our tree as fallback for when the
+        // nlink counts aren't matching. May want to add a warning of some
+        // sorts to the UI at some point.
+        if (!inconsistent and l.pack.nlink >= nlink) nlink = l.pack.nlink;
+
+        // XXX: We're also not testing for inconsistent entry sizes, instead
+        // using the given 'l' size for all Links. Might warrant a warning as
+        // well.
 
         var dir_iter = dirs.iterator();
         if (add) {
             while (dir_iter.next()) |de| {
-                de.key_ptr.*.entry.pack.blocks +|= entry.key_ptr.*.entry.pack.blocks;
-                de.key_ptr.*.entry.size        +|= entry.key_ptr.*.entry.size;
+                de.key_ptr.*.entry.pack.blocks +|= l.entry.pack.blocks;
+                de.key_ptr.*.entry.size        +|= l.entry.size;
                 if (de.value_ptr.* < nlink) {
-                    de.key_ptr.*.shared_blocks +|= entry.key_ptr.*.entry.pack.blocks;
-                    de.key_ptr.*.shared_size   +|= entry.key_ptr.*.entry.size;
+                    de.key_ptr.*.shared_blocks +|= l.entry.pack.blocks;
+                    de.key_ptr.*.shared_size   +|= l.entry.size;
                 }
             }
         } else {
             while (dir_iter.next()) |de| {
-                de.key_ptr.*.entry.pack.blocks -|= entry.key_ptr.*.entry.pack.blocks;
-                de.key_ptr.*.entry.size        -|= entry.key_ptr.*.entry.size;
+                de.key_ptr.*.entry.pack.blocks -|= l.entry.pack.blocks;
+                de.key_ptr.*.entry.size        -|= l.entry.size;
                 if (de.value_ptr.* < nlink) {
-                    de.key_ptr.*.shared_blocks -|= entry.key_ptr.*.entry.pack.blocks;
-                    de.key_ptr.*.shared_size   -|= entry.key_ptr.*.entry.size;
+                    de.key_ptr.*.shared_blocks -|= l.entry.pack.blocks;
+                    de.key_ptr.*.shared_size   -|= l.entry.size;
                 }
             }
         }
     }
 
+    // counters to track progress for addAllStats()
+    pub var add_total: usize = 0;
+    pub var add_done: usize = 0;
+
     pub fn addAllStats() void {
         if (uncounted_full) {
-            var it = map.iterator();
-            while (it.next()) |e| setStats(e, true);
+            add_total = map.count();
+            add_done = 0;
+            var it = map.keyIterator();
+            while (it.next()) |e| {
+                setStats(e.*, true);
+                add_done += 1;
+                if ((add_done & 65) == 0) main.handleEvent(false, false);
+            }
         } else {
-            var it = uncounted.iterator();
-            while (it.next()) |u| if (map.getEntry(u.key_ptr.*)) |e| setStats(e, true);
+            add_total = uncounted.count();
+            add_done = 0;
+            var it = uncounted.keyIterator();
+            while (it.next()) |u| {
+                if (map.getKey(u.*)) |e| setStats(e, true);
+                add_done += 1;
+                if ((add_done & 65) == 0) main.handleEvent(false, false);
+            }
         }
         uncounted_full = false;
         if (uncounted.count() > 0)
@@ -462,8 +505,9 @@ pub var root: *Dir = undefined;
 
 
 test "entry" {
-    var e = Entry.create(.file, false, "hello");
-    try std.testing.expectEqual(e.pack.etype, .file);
+    var e = Entry.create(std.testing.allocator, .reg, false, "hello");
+    defer e.destroy(std.testing.allocator);
+    try std.testing.expectEqual(e.pack.etype, .reg);
     try std.testing.expect(!e.pack.isext);
     try std.testing.expectEqualStrings(e.name(), "hello");
 }

src/sink.zig

@@ -0,0 +1,498 @@
+// SPDX-FileCopyrightText: Yorhel <projects@yorhel.nl>
+// SPDX-License-Identifier: MIT
+
+const std = @import("std");
+const main = @import("main.zig");
+const model = @import("model.zig");
+const mem_src = @import("mem_src.zig");
+const mem_sink = @import("mem_sink.zig");
+const json_export = @import("json_export.zig");
+const bin_export = @import("bin_export.zig");
+const ui = @import("ui.zig");
+const util = @import("util.zig");
+
+// Terminology note:
+// "source" is where scan results come from, these are scan.zig, mem_src.zig
+//   and json_import.zig.
+// "sink" is where scan results go to. This file provides a generic sink API
+//   for sources to use. The API forwards the results to specific sink
+//   implementations (mem_sink.zig or json_export.zig) and provides progress
+//   updates.
+
+// API for sources:
+//
+// Single-threaded:
+//
+//   createThreads(1)
+//   dir = createRoot(name, stat)
+//   dir.addSpecial(name, opt)
+//   dir.addFile(name, stat)
+//   sub = dir.addDir(name, stat)
+//     (no dir.stuff here)
+//     sub.addstuff();
+//     sub.unref();
+//   dir.unref();
+//   done()
+//
+// Multi-threaded interleaving:
+//
+//   createThreads(n)
+//   dir = createRoot(name, stat)
+//   dir.addSpecial(name, opt)
+//   dir.addFile(name, stat)
+//   sub = dir.addDir(...)
+//     sub.addstuff();
+//   sub2 = dir.addDir(..);
+//     sub.unref();
+//   dir.unref(); // <- no more direct descendants for x, but subdirs could still be active
+//     sub2.addStuff();
+//     sub2.unref(); // <- this is where 'dir' is really done.
+//   done()
+//
+// Rule:
+//   No concurrent method calls on a single Dir object, but objects may be passed between threads.
+
+
+// Concise stat struct for fields we're interested in, with the types used by the model.
+pub const Stat = struct {
+    etype: model.EType = .reg,
+    blocks: model.Blocks = 0,
+    size: u64 = 0,
+    dev: u64 = 0,
+    ino: u64 = 0,
+    nlink: u31 = 0,
+    ext: model.Ext = .{},
+};
+
+
+pub const Dir = struct {
+    refcnt: std.atomic.Value(usize) = std.atomic.Value(usize).init(1),
+    name: []const u8,
+    parent: ?*Dir,
+    out: Out,
+
+    const Out = union(enum) {
+        mem: mem_sink.Dir,
+        json: json_export.Dir,
+        bin: bin_export.Dir,
+    };
+
+    pub fn addSpecial(d: *Dir, t: *Thread, name: []const u8, sp: model.EType) void {
+        std.debug.assert(@intFromEnum(sp) < 0); // >=0 aren't "special"
+        _ = t.files_seen.fetchAdd(1, .monotonic);
+        switch (d.out) {
+            .mem => |*m| m.addSpecial(&t.sink.mem, name, sp),
+            .json => |*j| j.addSpecial(name, sp),
+            .bin => |*b| b.addSpecial(&t.sink.bin, name, sp),
+        }
+        if (sp == .err) {
+            global.last_error_lock.lock();
+            defer global.last_error_lock.unlock();
+            if (global.last_error) |p| main.allocator.free(p);
+            const p = d.path();
+            global.last_error = std.fs.path.joinZ(main.allocator, &.{ p, name }) catch unreachable;
+            main.allocator.free(p);
+        }
+    }
+
+    pub fn addStat(d: *Dir, t: *Thread, name: []const u8, stat: *const Stat) void {
+        _ = t.files_seen.fetchAdd(1, .monotonic);
+        _ = t.addBytes((stat.blocks *| 512) / @max(1, stat.nlink));
+        std.debug.assert(stat.etype != .dir);
+        switch (d.out) {
+            .mem => |*m| _ = m.addStat(&t.sink.mem, name, stat),
+            .json => |*j| j.addStat(name, stat),
+            .bin => |*b| b.addStat(&t.sink.bin, name, stat),
+        }
+    }
+
+    pub fn addDir(d: *Dir, t: *Thread, name: []const u8, stat: *const Stat) *Dir {
+        _ = t.files_seen.fetchAdd(1, .monotonic);
+        _ = t.addBytes(stat.blocks *| 512);
+        std.debug.assert(stat.etype == .dir);
+        std.debug.assert(d.out != .json or d.refcnt.load(.monotonic) == 1);
+
+        const s = main.allocator.create(Dir) catch unreachable;
+        s.* = .{
+            .name = main.allocator.dupe(u8, name) catch unreachable,
+            .parent = d,
+            .out = switch (d.out) {
+                .mem => |*m| .{ .mem = m.addDir(&t.sink.mem, name, stat) },
+                .json => |*j| .{ .json = j.addDir(name, stat) },
+                .bin => |*b| .{ .bin = b.addDir(stat) },
+            },
+        };
+        d.ref();
+        return s;
+    }
+
+    pub fn setReadError(d: *Dir, t: *Thread) void {
+        _ = t;
+        switch (d.out) {
+            .mem => |*m| m.setReadError(),
+            .json => |*j| j.setReadError(),
+            .bin => |*b| b.setReadError(),
+        }
+        global.last_error_lock.lock();
+        defer global.last_error_lock.unlock();
+        if (global.last_error) |p| main.allocator.free(p);
+        global.last_error = d.path();
+    }
+
+    fn path(d: *Dir) [:0]u8 {
+        var components: std.ArrayListUnmanaged([]const u8) = .empty;
+        defer components.deinit(main.allocator);
+        var it: ?*Dir = d;
+        while (it) |e| : (it = e.parent) components.append(main.allocator, e.name) catch unreachable;
+
+        var out: std.ArrayListUnmanaged(u8) = .empty;
+        var i: usize = components.items.len-1;
+        while (true) {
+            if (i != components.items.len-1 and !(out.items.len != 0 and out.items[out.items.len-1] == '/'))
+                out.append(main.allocator, '/') catch unreachable;
+            out.appendSlice(main.allocator, components.items[i]) catch unreachable;
+            if (i == 0) break;
+            i -= 1;
+        }
+        return out.toOwnedSliceSentinel(main.allocator, 0) catch unreachable;
+    }
+
+    fn ref(d: *Dir) void {
+        _ = d.refcnt.fetchAdd(1, .monotonic);
+    }
+
+    pub fn unref(d: *Dir, t: *Thread) void {
+        if (d.refcnt.fetchSub(1, .release) != 1) return;
+        _ = d.refcnt.load(.acquire);
+
+        switch (d.out) {
+            .mem => |*m| m.final(if (d.parent) |p| &p.out.mem else null),
+            .json => |*j| j.final(),
+            .bin => |*b| b.final(&t.sink.bin, d.name, if (d.parent) |p| &p.out.bin else null),
+        }
+
+        if (d.parent) |p| p.unref(t);
+        if (d.name.len > 0) main.allocator.free(d.name);
+        main.allocator.destroy(d);
+    }
+};
+
+
+pub const Thread = struct {
+    current_dir: ?*Dir = null,
+    lock: std.Thread.Mutex = .{},
+    // On 32-bit architectures, bytes_seen is protected by the above mutex instead.
+    bytes_seen: std.atomic.Value(u64) = std.atomic.Value(u64).init(0),
+    files_seen: std.atomic.Value(u32) = std.atomic.Value(u32).init(0),
+
+    sink: union {
+        mem: mem_sink.Thread,
+        json: void,
+        bin: bin_export.Thread,
+    } = .{.mem = .{}},
+
+    fn addBytes(t: *Thread, bytes: u64) void {
+        if (@bitSizeOf(usize) >= 64) _ = t.bytes_seen.fetchAdd(bytes, .monotonic)
+        else {
+            t.lock.lock();
+            defer t.lock.unlock();
+            t.bytes_seen.raw += bytes;
+        }
+    }
+
+    fn getBytes(t: *Thread) u64 {
+        if (@bitSizeOf(usize) >= 64) return t.bytes_seen.load(.monotonic)
+        else {
+            t.lock.lock();
+            defer t.lock.unlock();
+            return t.bytes_seen.raw;
+        }
+    }
+
+    pub fn setDir(t: *Thread, d: ?*Dir) void {
+        t.lock.lock();
+        defer t.lock.unlock();
+        t.current_dir = d;
+    }
+};
+
+
+pub const global = struct {
+    pub var state: enum { done, err, zeroing, hlcnt, running } = .running;
+    pub var threads: []Thread = undefined;
+    pub var sink: enum { json, mem, bin } = .mem;
+
+    pub var last_error: ?[:0]u8 = null;
+    var last_error_lock = std.Thread.Mutex{};
+    var need_confirm_quit = false;
+};
+
+
+// Must be the first thing to call from a source; initializes global state.
+pub fn createThreads(num: usize) []Thread {
+    // JSON export does not support multiple threads, scan into memory first.
+    if (global.sink == .json and num > 1) {
+        global.sink = .mem;
+        mem_sink.global.stats = false;
+    }
+
+    global.state = .running;
+    if (global.last_error) |p| main.allocator.free(p);
+    global.last_error = null;
+    global.threads = main.allocator.alloc(Thread, num) catch unreachable;
+    for (global.threads) |*t| t.* = .{
+        .sink = switch (global.sink) {
+            .mem  => .{ .mem  = .{} },
+            .json => .{ .json = {} },
+            .bin  => .{ .bin  = .{} },
+        },
+    };
+    return global.threads;
+}
+
+
+// Must be the last thing to call from a source.
+pub fn done() void {
+    switch (global.sink) {
+        .mem => mem_sink.done(),
+        .json => json_export.done(),
+        .bin => bin_export.done(global.threads),
+    }
+    global.state = .done;
+    main.allocator.free(global.threads);
+
+    // We scanned into memory, now we need to scan from memory to JSON
+    if (global.sink == .mem and !mem_sink.global.stats) {
+        global.sink = .json;
+        mem_src.run(model.root);
+    }
+
+    // Clear the screen when done.
+    if (main.config.scan_ui == .line) main.handleEvent(false, true);
+}
+
+
+pub fn createRoot(path: []const u8, stat: *const Stat) *Dir {
+    const d = main.allocator.create(Dir) catch unreachable;
+    d.* = .{
+        .name = main.allocator.dupe(u8, path) catch unreachable,
+        .parent = null,
+        .out = switch (global.sink) {
+            .mem => .{ .mem = mem_sink.createRoot(path, stat) },
+            .json => .{ .json = json_export.createRoot(path, stat) },
+            .bin => .{ .bin = bin_export.createRoot(stat, global.threads) },
+        },
+    };
+    return d;
+}
+
+
+fn drawConsole() void {
+    const st = struct {
+        var ansi: ?bool = null;
+        var lines_written: usize = 0;
+    };
+    const stderr = if (@hasDecl(std.io, "getStdErr")) std.io.getStdErr() else std.fs.File.stderr();
+    const ansi = st.ansi orelse blk: {
+        const t = stderr.supportsAnsiEscapeCodes();
+        st.ansi = t;
+        break :blk t;
+    };
+
+    var buf: [4096]u8 = undefined;
+    var strm = std.io.fixedBufferStream(buf[0..]);
+    var wr = strm.writer();
+    while (ansi and st.lines_written > 0) {
+        wr.writeAll("\x1b[1F\x1b[2K") catch {};
+        st.lines_written -= 1;
+    }
+
+    if (global.state == .hlcnt) {
+        wr.writeAll("Counting hardlinks...") catch {};
+        if (model.inodes.add_total > 0)
+            wr.print(" {} / {}", .{ model.inodes.add_done, model.inodes.add_total }) catch {};
+        wr.writeByte('\n') catch {};
+        st.lines_written += 1;
+
+    } else if (global.state == .running) {
+        var bytes: u64 = 0;
+        var files: u64 = 0;
+        for (global.threads) |*t| {
+            bytes +|= t.getBytes();
+            files += t.files_seen.load(.monotonic);
+        }
+        const r = ui.FmtSize.fmt(bytes);
+        wr.print("{} files / {s}{s}\n", .{files, r.num(), r.unit}) catch {};
+        st.lines_written += 1;
+
+        for (global.threads, 0..) |*t, i| {
+            const dir = blk: {
+                t.lock.lock();
+                defer t.lock.unlock();
+                break :blk if (t.current_dir) |d| d.path() else null;
+            };
+            wr.print("  #{}: {s}\n", .{i+1, ui.shorten(ui.toUtf8(dir orelse "(waiting)"), 73)}) catch {};
+            st.lines_written += 1;
+            if (dir) |p| main.allocator.free(p);
+        }
+    }
+
+    stderr.writeAll(strm.getWritten()) catch {};
+}
+
+
+fn drawProgress() void {
+    const st = struct { var animation_pos: usize = 0; };
+
+    var bytes: u64 = 0;
+    var files: u64 = 0;
+    for (global.threads) |*t| {
+        bytes +|= t.getBytes();
+        files += t.files_seen.load(.monotonic);
+    }
+
+    ui.init();
+    const width = ui.cols -| 5;
+    const numthreads: u32 = @intCast(@min(global.threads.len, @max(1, ui.rows -| 10)));
+    const box = ui.Box.create(8 + numthreads, width, "Scanning...");
+    box.move(2, 2);
+    ui.addstr("Total items: ");
+    ui.addnum(.default, files);
+
+    if (width > 48) {
+        box.move(2, 30);
+        ui.addstr("size: ");
+        ui.addsize(.default, bytes);
+    }
+
+    for (0..numthreads) |i| {
+        box.move(3+@as(u32, @intCast(i)), 4);
+        const dir = blk: {
+            const t = &global.threads[i];
+            t.lock.lock();
+            defer t.lock.unlock();
+            break :blk if (t.current_dir) |d| d.path() else null;
+        };
+        ui.addstr(ui.shorten(ui.toUtf8(dir orelse "(waiting)"), width -| 6));
+        if (dir) |p| main.allocator.free(p);
+    }
+
+    blk: {
+        global.last_error_lock.lock();
+        defer global.last_error_lock.unlock();
+        const err = global.last_error orelse break :blk;
+        box.move(4 + numthreads, 2);
+        ui.style(.bold);
+        ui.addstr("Warning: ");
+        ui.style(.default);
+        ui.addstr("error scanning ");
+        ui.addstr(ui.shorten(ui.toUtf8(err), width -| 28));
+        box.move(5 + numthreads, 3);
+        ui.addstr("some directory sizes may not be correct.");
+    }
+
+    if (global.need_confirm_quit) {
+        box.move(6 + numthreads, width -| 20);
+        ui.addstr("Press ");
+        ui.style(.key);
+        ui.addch('y');
+        ui.style(.default);
+        ui.addstr(" to confirm");
+    } else {
+        box.move(6 + numthreads, width -| 18);
+        ui.addstr("Press ");
+        ui.style(.key);
+        ui.addch('q');
+        ui.style(.default);
+        ui.addstr(" to abort");
+    }
+
+    if (main.config.update_delay < std.time.ns_per_s and width > 40) {
+        const txt = "Scanning...";
+        st.animation_pos += 1;
+        if (st.animation_pos >= txt.len*2) st.animation_pos = 0;
+        if (st.animation_pos < txt.len) {
+            box.move(6 + numthreads, 2);
+            for (txt[0..st.animation_pos + 1]) |t| ui.addch(t);
+        } else {
+            var i: u32 = txt.len-1;
+            while (i > st.animation_pos-txt.len) : (i -= 1) {
+                box.move(6 + numthreads, 2+i);
+                ui.addch(txt[i]);
+            }
+        }
+    }
+}
+
+
+fn drawError() void {
+    const width = ui.cols -| 5;
+    const box = ui.Box.create(6, width, "Scan error");
+
+    box.move(2, 2);
+    ui.addstr("Unable to open directory:");
+    box.move(3, 4);
+    ui.addstr(ui.shorten(ui.toUtf8(global.last_error.?), width -| 10));
+
+    box.move(4, width -| 27);
+    ui.addstr("Press any key to continue");
+}
+
+
+fn drawMessage(msg: []const u8) void {
+    const width = ui.cols -| 5;
+    const box = ui.Box.create(4, width, "Scan error");
+    box.move(2, 2);
+    ui.addstr(msg);
+}
+
+
+pub fn draw() void {
+    switch (main.config.scan_ui.?) {
+        .none => {},
+        .line => drawConsole(),
+        .full => {
+            ui.init();
+            switch (global.state) {
+                .done => {},
+                .err => drawError(),
+                .zeroing => {
+                    const box = ui.Box.create(4, ui.cols -| 5, "Initializing");
+                    box.move(2, 2);
+                    ui.addstr("Clearing directory counts...");
+                },
+                .hlcnt => {
+                    const box = ui.Box.create(4, ui.cols -| 5, "Finalizing");
+                    box.move(2, 2);
+                    ui.addstr("Counting hardlinks... ");
+                    if (model.inodes.add_total > 0) {
+                        ui.addnum(.default, model.inodes.add_done);
+                        ui.addstr(" / ");
+                        ui.addnum(.default, model.inodes.add_total);
+                    }
+                },
+                .running => drawProgress(),
+            }
+        },
+    }
+}
+
+
+pub fn keyInput(ch: i32) void {
+    switch (global.state) {
+        .done => {},
+        .err => main.state = .browse,
+        .zeroing => {},
+        .hlcnt => {},
+        .running => {
+            switch (ch) {
+                'q' => {
+                    if (main.config.confirm_quit) global.need_confirm_quit = !global.need_confirm_quit
+                   else ui.quit();
+                },
+                'y', 'Y' => if (global.need_confirm_quit) ui.quit(),
+                else => global.need_confirm_quit = false,
+            }
+        },
+    }
+}

src/ui.zig

@@ -6,26 +6,18 @@
 const std = @import("std");
 const main = @import("main.zig");
 const util = @import("util.zig");
-
-pub const c = @cImport({
-    @cDefine("_XOPEN_SOURCE", "1");
-    @cInclude("stdio.h");
-    @cInclude("string.h");
-    @cInclude("curses.h");
-    @cInclude("time.h");
-    @cInclude("wchar.h");
-    @cInclude("locale.h");
-});
+const c = @import("c.zig").c;
 
 pub var inited: bool = false;
+pub var main_thread: std.Thread.Id = undefined;
+pub var oom_threads = std.atomic.Value(usize).init(0);
 
 pub var rows: u32 = undefined;
 pub var cols: u32 = undefined;
 
 pub fn die(comptime fmt: []const u8, args: anytype) noreturn {
     deinit();
-    const stderr = std.io.getStdErr();
-    stderr.writer().print(fmt, args) catch {};
+    std.debug.print(fmt, args);
     std.process.exit(1);
 }
 
@@ -34,6 +26,8 @@ pub fn quit() noreturn {
     std.process.exit(0);
 }
 
+const sleep = if (@hasDecl(std.time, "sleep")) std.time.sleep else std.Thread.sleep;
+
 // Should be called when malloc fails. Will show a message to the user, wait
 // for a second and return to give it another try.
 // Glitch: this function may be called while we're in the process of drawing
@@ -44,13 +38,19 @@ pub fn quit() noreturn {
 // no clue if ncurses will consistently report OOM, but we're not handling that
 // right now.
 pub fn oom() void {
+    @branchHint(.cold);
+    if (main_thread == std.Thread.getCurrentId()) {
         const haveui = inited;
         deinit();
-    const stderr = std.io.getStdErr();
-    stderr.writeAll("\x1b7\x1b[JOut of memory, trying again in 1 second. Hit Ctrl-C to abort.\x1b8") catch {};
-    std.time.sleep(std.time.ns_per_s);
+        std.debug.print("\x1b7\x1b[JOut of memory, trying again in 1 second. Hit Ctrl-C to abort.\x1b8", .{});
+        sleep(std.time.ns_per_s);
         if (haveui)
             init();
+    } else {
+        _ = oom_threads.fetchAdd(1, .monotonic);
+        sleep(std.time.ns_per_s);
+        _ = oom_threads.fetchSub(1, .monotonic);
+    }
 }
 
 // Dumb strerror() alternative for Zig file I/O, not complete.
@@ -75,11 +75,12 @@ pub fn errorString(e: anyerror) [:0]const u8 {
         error.ReadOnlyFilesystem => "Read-only filesystem",
         error.SymlinkLoop => "Symlink loop",
         error.SystemFdQuotaExceeded => "System file descriptor limit exceeded",
+        error.EndOfStream => "Unexpected end of file",
         else => @errorName(e),
     };
 }
 
-var to_utf8_buf = std.ArrayList(u8).init(main.allocator);
+var to_utf8_buf: std.ArrayListUnmanaged(u8) = .empty;
 
 fn toUtf8BadChar(ch: u8) bool {
     return switch (ch) {
@@ -106,19 +107,19 @@ pub fn toUtf8(in: [:0]const u8) [:0]const u8 {
         if (std.unicode.utf8ByteSequenceLength(in[i])) |cp_len| {
             if (!toUtf8BadChar(in[i]) and i + cp_len <= in.len) {
                 if (std.unicode.utf8Decode(in[i .. i + cp_len])) |_| {
-                    to_utf8_buf.appendSlice(in[i .. i + cp_len]) catch unreachable;
+                    to_utf8_buf.appendSlice(main.allocator, in[i .. i + cp_len]) catch unreachable;
                     i += cp_len;
                     continue;
                 } else |_| {}
             }
         } else |_| {}
-        to_utf8_buf.writer().print("\\x{X:0>2}", .{in[i]}) catch unreachable;
+        to_utf8_buf.writer(main.allocator).print("\\x{X:0>2}", .{in[i]}) catch unreachable;
         i += 1;
     }
-    return util.arrayListBufZ(&to_utf8_buf);
+    return util.arrayListBufZ(&to_utf8_buf, main.allocator);
 }
 
-var shorten_buf = std.ArrayList(u8).init(main.allocator);
+var shorten_buf: std.ArrayListUnmanaged(u8) = .empty;
 
 // Shorten the given string to fit in the given number of columns.
 // If the string is too long, only the prefix and suffix will be printed, with '...' in between.
@@ -149,8 +150,8 @@ pub fn shorten(in: [:0]const u8, max_width: u32) [:0] const u8 {
     if (total_width <= max_width) return in;
 
     shorten_buf.shrinkRetainingCapacity(0);
-    shorten_buf.appendSlice(in[0..prefix_end]) catch unreachable;
-    shorten_buf.appendSlice("...") catch unreachable;
+    shorten_buf.appendSlice(main.allocator, in[0..prefix_end]) catch unreachable;
+    shorten_buf.appendSlice(main.allocator, "...") catch unreachable;
 
     var start_width: u32 = prefix_width;
     var start_len: u32 = prefix_end;
@@ -162,11 +163,11 @@ pub fn shorten(in: [:0]const u8, max_width: u32) [:0] const u8 {
         start_width += cp_width;
         start_len += cp_len;
         if (total_width - start_width <= max_width - prefix_width - 3) {
-            shorten_buf.appendSlice(in[start_len..]) catch unreachable;
+            shorten_buf.appendSlice(main.allocator, in[start_len..]) catch unreachable;
             break;
         }
     }
-    return util.arrayListBufZ(&shorten_buf);
+    return util.arrayListBufZ(&shorten_buf, main.allocator);
 }
 
 fn shortenTest(in: [:0]const u8, max_width: u32, out: [:0]const u8) !void {
@@ -287,7 +288,7 @@ pub const Style = lbl: {
         };
     }
     break :lbl @Type(.{
-        .Enum = .{
+        .@"enum" = .{
             .tag_type = u8,
             .fields = &fields,
             .decls = &[_]std.builtin.Type.Declaration{},
@@ -334,8 +335,7 @@ fn updateSize() void {
 fn clearScr() void {
     // Send a "clear from cursor to end of screen" instruction, to clear a
     // potential line left behind from scanning in -1 mode.
-    const stderr = std.io.getStdErr();
-    stderr.writeAll("\x1b[J") catch {};
+    std.debug.print("\x1b[J", .{});
 }
 
 pub fn init() void {
@@ -405,39 +405,86 @@ pub fn addch(ch: c.chtype) void {
 //   unit = " XB" or " XiB"
 // Concatenated, these take 8 columns in SI mode or 9 otherwise.
 pub const FmtSize = struct {
-    buf: [8:0]u8,
+    buf: [5:0]u8,
     unit: [:0]const u8,
 
-    pub fn fmt(v: u64) @This() {
-        var r: @This() = undefined;
-        var f: f32 = @floatFromInt(v);
-        if (main.config.si) {
-            if(f < 1000.0)    { r.unit = "  B"; }
-            else if(f < 1e6)  { r.unit = " KB"; f /= 1e3;  }
-            else if(f < 1e9)  { r.unit = " MB"; f /= 1e6;  }
-            else if(f < 1e12) { r.unit = " GB"; f /= 1e9;  }
-            else if(f < 1e15) { r.unit = " TB"; f /= 1e12; }
-            else if(f < 1e18) { r.unit = " PB"; f /= 1e15; }
-            else              { r.unit = " EB"; f /= 1e18; }
-        }
-        else {
-            if(f < 1000.0)       { r.unit = "   B"; }
-            else if(f < 1023e3)  { r.unit = " KiB"; f /= 1024.0; }
-            else if(f < 1023e6)  { r.unit = " MiB"; f /= 1048576.0; }
-            else if(f < 1023e9)  { r.unit = " GiB"; f /= 1073741824.0; }
-            else if(f < 1023e12) { r.unit = " TiB"; f /= 1099511627776.0; }
-            else if(f < 1023e15) { r.unit = " PiB"; f /= 1125899906842624.0; }
-            else                 { r.unit = " EiB"; f /= 1152921504606846976.0; }
-        }
-        _ = std.fmt.bufPrintZ(&r.buf, "{d:>5.1}", .{f}) catch unreachable;
-        return r;
+    fn init(u: [:0]const u8, n: u64, mul: u64, div: u64) FmtSize {
+        return .{
+            .unit = u,
+            .buf = util.fmt5dec(@intCast( ((n*mul) +| (div / 2)) / div )),
+        };
     }
 
-    pub fn num(self: *const @This()) [:0]const u8 {
-        return std.mem.sliceTo(&self.buf, 0);
+    pub fn fmt(v: u64) FmtSize {
+        if (main.config.si) {
+            if      (v < 1000)                    { return FmtSize.init("  B", v, 10, 1); }
+            else if (v < 999_950)                 { return FmtSize.init(" kB", v, 1, 100); }
+            else if (v < 999_950_000)             { return FmtSize.init(" MB", v, 1, 100_000); }
+            else if (v < 999_950_000_000)         { return FmtSize.init(" GB", v, 1, 100_000_000); }
+            else if (v < 999_950_000_000_000)     { return FmtSize.init(" TB", v, 1, 100_000_000_000); }
+            else if (v < 999_950_000_000_000_000) { return FmtSize.init(" PB", v, 1, 100_000_000_000_000); }
+            else                                  { return FmtSize.init(" EB", v, 1, 100_000_000_000_000_000); }
+        } else {
+            // Cutoff values are obtained by calculating 999.949999999999999999999999 * div with an infinite-precision calculator.
+            // (Admittedly, this precision is silly)
+            if (v < 1000)                     { return FmtSize.init("   B", v, 10, 1); }
+            else if (v < 1023949)             { return FmtSize.init(" KiB", v, 10, 1<<10); }
+            else if (v < 1048523572)          { return FmtSize.init(" MiB", v, 10, 1<<20); }
+            else if (v < 1073688136909)       { return FmtSize.init(" GiB", v, 10, 1<<30); }
+            else if (v < 1099456652194612)    { return FmtSize.init(" TiB", v, 10, 1<<40); }
+            else if (v < 1125843611847281869) { return FmtSize.init(" PiB", v, 10, 1<<50); }
+            else                              { return FmtSize.init(" EiB", v, 1, (1<<60)/10); }
+        }
+    }
+
+    pub fn num(self: *const FmtSize) [:0]const u8 {
+        return &self.buf;
+    }
+
+    fn testEql(self: FmtSize, exp: []const u8) !void {
+        var buf: [10]u8 = undefined;
+        try std.testing.expectEqualStrings(exp, try std.fmt.bufPrint(&buf, "{s}{s}", .{ self.num(), self.unit }));
     }
 };
 
+test "fmtsize" {
+    main.config.si = true;
+    try FmtSize.fmt(            0).testEql("  0.0  B");
+    try FmtSize.fmt(          999).testEql("999.0  B");
+    try FmtSize.fmt(         1000).testEql("  1.0 kB");
+    try FmtSize.fmt(         1049).testEql("  1.0 kB");
+    try FmtSize.fmt(         1050).testEql("  1.1 kB");
+    try FmtSize.fmt(      999_899).testEql("999.9 kB");
+    try FmtSize.fmt(      999_949).testEql("999.9 kB");
+    try FmtSize.fmt(      999_950).testEql("  1.0 MB");
+    try FmtSize.fmt(     1000_000).testEql("  1.0 MB");
+    try FmtSize.fmt(  999_850_009).testEql("999.9 MB");
+    try FmtSize.fmt(  999_899_999).testEql("999.9 MB");
+    try FmtSize.fmt(  999_900_000).testEql("999.9 MB");
+    try FmtSize.fmt(  999_949_999).testEql("999.9 MB");
+    try FmtSize.fmt(  999_950_000).testEql("  1.0 GB");
+    try FmtSize.fmt(  999_999_999).testEql("  1.0 GB");
+    try FmtSize.fmt(std.math.maxInt(u64)).testEql(" 18.4 EB");
+
+    main.config.si = false;
+    try FmtSize.fmt(                  0).testEql("  0.0   B");
+    try FmtSize.fmt(                999).testEql("999.0   B");
+    try FmtSize.fmt(               1000).testEql("  1.0 KiB");
+    try FmtSize.fmt(               1024).testEql("  1.0 KiB");
+    try FmtSize.fmt(             102400).testEql("100.0 KiB");
+    try FmtSize.fmt(            1023898).testEql("999.9 KiB");
+    try FmtSize.fmt(            1023949).testEql("  1.0 MiB");
+    try FmtSize.fmt(         1048523571).testEql("999.9 MiB");
+    try FmtSize.fmt(         1048523572).testEql("  1.0 GiB");
+    try FmtSize.fmt(      1073688136908).testEql("999.9 GiB");
+    try FmtSize.fmt(      1073688136909).testEql("  1.0 TiB");
+    try FmtSize.fmt(   1099456652194611).testEql("999.9 TiB");
+    try FmtSize.fmt(   1099456652194612).testEql("  1.0 PiB");
+    try FmtSize.fmt(1125843611847281868).testEql("999.9 PiB");
+    try FmtSize.fmt(1125843611847281869).testEql("  1.0 EiB");
+    try FmtSize.fmt(std.math.maxInt(u64)).testEql(" 16.0 EiB");
+}
+
 // Print a formatted human-readable size string onto the given background.
 pub fn addsize(bg: Bg, v: u64) void {
     const r = FmtSize.fmt(v);
@@ -586,7 +633,7 @@ pub fn getch(block: bool) i32 {
         }
         if (ch == c.ERR) {
             if (!block) return 0;
-            std.time.sleep(10*std.time.ns_per_ms);
+            sleep(10*std.time.ns_per_ms);
             continue;
         }
         return ch;
@@ -594,3 +641,50 @@ pub fn getch(block: bool) i32 {
     die("Error reading keyboard input, assuming TTY has been lost.\n(Potentially nonsensical error message: {s})\n",
         .{ c.strerror(@intFromEnum(std.posix.errno(-1))) });
 }
+
+fn waitInput() void {
+    if (@hasDecl(std.io, "getStdIn")) {
+        std.io.getStdIn().reader().skipUntilDelimiterOrEof('\n') catch unreachable;
+    } else {
+        var buf: [512]u8 = undefined;
+        var rd = std.fs.File.stdin().reader(&buf);
+        _ = rd.interface.discardDelimiterExclusive('\n') catch unreachable;
+    }
+}
+
+pub fn runCmd(cmd: []const []const u8, cwd: ?[]const u8, env: *std.process.EnvMap, reporterr: bool) void {
+    deinit();
+    defer init();
+
+    // NCDU_LEVEL can only count to 9, keeps the implementation simple.
+    if (env.get("NCDU_LEVEL")) |l|
+        env.put("NCDU_LEVEL", if (l.len == 0) "1" else switch (l[0]) {
+            '0'...'8' => |d| &[1] u8{d+1},
+            '9' => "9",
+            else => "1"
+        }) catch unreachable
+    else
+        env.put("NCDU_LEVEL", "1") catch unreachable;
+
+    var child = std.process.Child.init(cmd, main.allocator);
+    child.cwd = cwd;
+    child.env_map = env;
+
+    const term = child.spawnAndWait() catch |e| blk: {
+        std.debug.print("Error running command: {s}\n\nPress enter to continue.\n", .{ ui.errorString(e) });
+        waitInput();
+        break :blk std.process.Child.Term{ .Exited = 0 };
+    };
+
+    const n = switch (term) {
+        .Exited  => "error",
+        .Signal  => "signal",
+        .Stopped => "stopped",
+        .Unknown => "unknown",
+    };
+    const v = switch (term) { inline else => |v| v };
+    if (term != .Exited or (reporterr and v != 0)) {
+        std.debug.print("\nCommand returned with {s} code {}.\nPress enter to continue.\n", .{ n, v });
+        waitInput();
+    }
+}

src/util.zig

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: MIT
 
 const std = @import("std");
+const c = @import("c.zig").c;
 
 // Cast any integer type to the target type, clamping the value to the supported maximum if necessary.
 pub fn castClamp(comptime T: type, x: anytype) T {
@@ -17,8 +18,8 @@ pub fn castClamp(comptime T: type, x: anytype) T {
 
 // Cast any integer type to the target type, truncating if necessary.
 pub fn castTruncate(comptime T: type, x: anytype) T {
-    const Ti = @typeInfo(T).Int;
-    const Xi = @typeInfo(@TypeOf(x)).Int;
+    const Ti = @typeInfo(T).int;
+    const Xi = @typeInfo(@TypeOf(x)).int;
     const nx: std.meta.Int(Ti.signedness, Xi.bits) = @bitCast(x);
     return if (Xi.bits > Ti.bits) @truncate(nx) else nx;
 }
@@ -31,12 +32,43 @@ pub fn blocksToSize(b: u64) u64 {
 // Ensure the given arraylist buffer gets zero-terminated and returns a slice
 // into the buffer. The returned buffer is invalidated whenever the arraylist
 // is freed or written to.
-pub fn arrayListBufZ(buf: *std.ArrayList(u8)) [:0]const u8 {
-    buf.append(0) catch unreachable;
+pub fn arrayListBufZ(buf: *std.ArrayListUnmanaged(u8), alloc: std.mem.Allocator) [:0]const u8 {
+    buf.append(alloc, 0) catch unreachable;
     defer buf.items.len -= 1;
     return buf.items[0..buf.items.len-1:0];
 }
 
+// Format an integer as right-aligned '###.#'.
+// Pretty much equivalent to:
+//   std.fmt.bufPrintZ(.., "{d:>5.1}", @floatFromInt(n)/10.0);
+// Except this function doesn't pull in large float formatting tables.
+pub fn fmt5dec(n: u14) [5:0]u8 {
+    std.debug.assert(n <= 9999);
+    var buf: [5:0]u8 = "  0.0".*;
+    var v = n;
+    buf[4] += @intCast(v % 10);
+    v /= 10;
+    buf[2] += @intCast(v % 10);
+    v /= 10;
+    if (v == 0) return buf;
+    buf[1] = '0' + @as(u8, @intCast(v % 10));
+    v /= 10;
+    if (v == 0) return buf;
+    buf[0] = '0' + @as(u8, @intCast(v));
+    return buf;
+}
+
+test "fmt5dec" {
+    const eq = std.testing.expectEqualStrings;
+    try eq("  0.0", &fmt5dec(0));
+    try eq("  0.5", &fmt5dec(5));
+    try eq("  9.5", &fmt5dec(95));
+    try eq(" 12.5", &fmt5dec(125));
+    try eq("123.9", &fmt5dec(1239));
+    try eq("999.9", &fmt5dec(9999));
+}
+
+
 // Straightforward Zig port of strnatcmp() from https://github.com/sourcefrog/natsort/
 // (Requiring nul-terminated strings is ugly, but we've got them anyway and it does simplify the code)
 pub fn strnatcmp(a: [:0]const u8, b: [:0]const u8) std.math.Order {
@@ -139,3 +171,79 @@ test "strnatcmp" {
         for (i+1..w.len) |j| try eq(strnatcmp(w[i], w[j]), .lt);
     }
 }
+
+
+pub fn expanduser(path: []const u8, alloc: std.mem.Allocator) ![:0]u8 {
+    if (path.len == 0 or path[0] != '~') return alloc.dupeZ(u8, path);
+
+    const len = std.mem.indexOfScalar(u8, path, '/') orelse path.len;
+    const home_raw = blk: {
+        const pwd = pwd: {
+            if (len == 1) {
+                if (std.posix.getenvZ("HOME")) |p| break :blk p;
+                break :pwd c.getpwuid(c.getuid());
+            } else {
+                const name = try alloc.dupeZ(u8, path[1..len]);
+                defer alloc.free(name);
+                break :pwd c.getpwnam(name.ptr);
+            }
+        };
+        if (pwd != null)
+            if (@as(*c.struct_passwd, pwd).pw_dir) |p|
+                break :blk std.mem.span(p);
+        return alloc.dupeZ(u8, path);
+    };
+    const home = std.mem.trimRight(u8, home_raw, "/");
+
+    if (home.len == 0 and path.len == len) return alloc.dupeZ(u8, "/");
+    return try std.mem.concatWithSentinel(alloc, u8, &.{ home, path[len..] }, 0);
+}
+
+
+// Silly abstraction to read a file one line at a time. Only exists to help
+// with supporting both Zig 0.14 and 0.15, can be removed once 0.14 support is
+// dropped.
+pub const LineReader = if (@hasDecl(std.io, "bufferedReader")) struct {
+    rd: std.io.BufferedReader(4096, std.fs.File.Reader),
+    fbs: std.io.FixedBufferStream([]u8),
+
+    pub fn init(f: std.fs.File, buf: []u8) @This() {
+        return .{
+            .rd = std.io.bufferedReader(f.reader()),
+            .fbs = std.io.fixedBufferStream(buf),
+        };
+    }
+
+    pub fn read(s: *@This()) !?[]u8 {
+        s.fbs.reset();
+        s.rd.reader().streamUntilDelimiter(s.fbs.writer(), '\n', s.fbs.buffer.len) catch |err| switch (err) {
+            error.EndOfStream => if (s.fbs.getPos() catch unreachable == 0) return null,
+            else => |e| return e,
+        };
+        return s.fbs.getWritten();
+    }
+
+} else struct {
+    rd: std.fs.File.Reader,
+
+    pub fn init(f: std.fs.File, buf: []u8) @This() {
+        return .{ .rd = f.readerStreaming(buf) };
+    }
+
+    pub fn read(s: *@This()) !?[]u8 {
+        // Can't use takeDelimiter() because that's not available in 0.15.1,
+        // Can't use takeDelimiterExclusive() because that changed behavior in 0.15.2.
+        const r = &s.rd.interface;
+        const result = r.peekDelimiterInclusive('\n') catch |err| switch (err) {
+            error.EndOfStream => {
+                const remaining = r.buffer[r.seek..r.end];
+                if (remaining.len == 0) return null;
+                r.toss(remaining.len);
+                return remaining;
+            },
+            else => |e| return e,
+        };
+        r.toss(result.len);
+        return result[0 .. result.len - 1];
+    }
+};