Implement JSON file import

Performance is looking great, but the code is rather ugly and
potentially buggy. Also doesn't handle hard links without an "nlink"
field yet.

Error handling of the import code is different from what I've been doing
until now. That's intentional, I'll change error handling of other
pieces to call ui.die() directly rather than propagating error enums.
The approach is less testable but conceptually simpler, it's perfectly
fine for a tiny application like ncdu.

.gitignore

 zig-cache/
+zig-out/
 ncdu.1
 *~
 *.swp

README.md

@@ -28,7 +28,6 @@ backported to the C version, depending on how viable a proper Zig release is.
 
 Missing features:
 
-- File import
 - Lots of informational UI windows
 - Directory refresh
 - File deletion

src/browser.zig

@@ -324,11 +324,13 @@ pub fn draw() !void {
     ui.addch('?');
     ui.style(.hd);
     ui.addstr(" for help");
-    if (main.config.read_only) {
+    if (main.config.imported) {
+        ui.move(0, saturateSub(ui.cols, 10));
+        ui.addstr("[imported]");
+    } else if (main.config.read_only) {
         ui.move(0, saturateSub(ui.cols, 10));
         ui.addstr("[readonly]");
     }
-    // TODO: [imported] indicator
 
     ui.style(.default);
     ui.move(1,0);
@@ -387,7 +389,7 @@ fn sortToggle(col: main.config.SortCol, default_order: main.config.SortOrder) vo
     sortDir();
 }
 
-pub fn key(ch: i32) !void {
+pub fn keyInput(ch: i32) !void {
     if (need_confirm_quit) {
         switch (ch) {
             'y', 'Y' => if (need_confirm_quit) ui.quit(),

src/main.zig

@@ -37,6 +37,7 @@ pub const config = struct {
     pub var sort_dirsfirst: bool = false;
 
     pub var read_only: bool = false;
+    pub var imported: bool = false;
     pub var can_shell: bool = true;
     pub var confirm_quit: bool = false;
 };
@@ -164,7 +165,6 @@ fn readExcludeFile(path: []const u8) !void {
 // TODO: Better error reporting
 pub fn main() !void {
     // Grab thousands_sep from the current C locale.
-    // (We can safely remove this when not linking against libc, it's a somewhat obscure feature)
     _ = c.setlocale(c.LC_ALL, "");
     if (c.localeconv()) |locale| {
         if (locale.*.thousands_sep) |sep| {
@@ -176,8 +176,8 @@ pub fn main() !void {
 
     var args = Args(std.process.ArgIteratorPosix).init(std.process.ArgIteratorPosix.init());
     var scan_dir: ?[]const u8 = null;
-    var import_file: ?[]const u8 = null;
-    var export_file: ?[]const u8 = null;
+    var import_file: ?[:0]const u8 = null;
+    var export_file: ?[:0]const u8 = null;
     var has_scan_ui = false;
     _ = args.next(); // program name
     while (args.next()) |opt| {
@@ -197,7 +197,9 @@ pub fn main() !void {
         else if(opt.is("-0")) { has_scan_ui = true; config.scan_ui = .none; }
         else if(opt.is("-1")) { has_scan_ui = true; config.scan_ui = .line; }
         else if(opt.is("-2")) { has_scan_ui = true; config.scan_ui = .full; }
+        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 = args.arg()
+        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 = args.arg()
         else if(opt.is("--si")) config.si = true
         else if(opt.is("-L") or opt.is("--follow-symlinks")) config.follow_symlinks = true
@@ -220,24 +222,28 @@ pub fn main() !void {
         ui.die("The --exclude-kernfs tag is currently only supported on Linux.\n", .{});
 
     const out_tty = std.io.getStdOut().isTty();
+    const in_tty = std.io.getStdIn().isTty();
     if (!has_scan_ui) {
         if (export_file) |f| {
             if (!out_tty or std.mem.eql(u8, f, "-")) config.scan_ui = .none
             else config.scan_ui = .line;
         }
     }
-    config.nc_tty = if (export_file) |f| std.mem.eql(u8, f, "-") else false;
+    if (!in_tty and import_file == null and export_file == null)
+        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);
 
     event_delay_timer = try std.time.Timer.start();
     defer ui.deinit();
+    state = .scan;
 
     var out_file = if (export_file) |f| (
         if (std.mem.eql(u8, f, "-")) std.io.getStdOut()
-        else try std.fs.cwd().createFile(f, .{})
+        else try std.fs.cwd().createFileZ(f, .{})
     ) else null;
 
-    state = .scan;
-    try scan.scanRoot(scan_dir orelse ".", out_file);
+    try if (import_file) |f| scan.importRoot(f, out_file)
+        else scan.scanRoot(scan_dir orelse ".", out_file);
     if (out_file != null) return;
 
     config.scan_ui = .full; // in case we're refreshing from the UI, always in full mode.
@@ -274,8 +280,8 @@ pub fn handleEvent(block: bool, force_draw: bool) !void {
         if (ch == 0) return;
         if (ch == -1) return handleEvent(firstblock, true);
         switch (state) {
-            .scan => try scan.key(ch),
-            .browse => try browser.key(ch),
+            .scan => try scan.keyInput(ch),
+            .browse => try browser.keyInput(ch),
         }
         firstblock = false;
     }

src/model.zig

@@ -196,10 +196,10 @@ pub const File = packed struct {
 };
 
 pub const Ext = packed struct {
-    mtime: u64,
-    uid: u32,
-    gid: u32,
-    mode: u16,
+    mtime: u64 = 0,
+    uid: u32 = 0,
+    gid: u32 = 0,
+    mode: u16 = 0,
 };
 
 comptime {

src/ui.zig

@@ -285,7 +285,6 @@ pub fn init() void {
         if (term == null) die("Error initializing ncurses.\n", .{});
         _ = c.set_term(term);
     } else {
-        if (!std.io.getStdIn().isTty()) die("Standard input is not a TTY. Did you mean to import a file using '-f -'?\n", .{});
         if (c.initscr() == null) die("Error initializing ncurses.\n", .{});
     }
     updateSize();