file_watch + builtins + config: richer watch semantics, new builtins, config docs

1 files changed, 78 insertions, 4 deletions

diff --git a/src/macos.zig b/src/macos.zig
index 3c1458a3..38d2c961 100644
--- a/src/macos.zig
+++ b/src/macos.zig
@@ -172,6 +172,10 @@ const scene_frame_hz: u32 = 60;
 /// Keep the float-valued time and noise frame precise, then repeat after a
 /// little over an hour. None of the effects has state across this boundary.
 const scene_frame_wrap: u32 = 4096 * scene_frame_hz;
+/// FileWatcher.swift keys sources by an opaque u8. Pane ids occupy 0..15;
+/// the next value is the one process-global ThemeFile source.
+const theme_watch_pane: u8 = @intCast(pardes.MAX_PANES);
+const watch_slot_count = pardes.MAX_PANES + 1;
 
 // ---------------------------------------------------------------- state
 
@@ -201,9 +205,9 @@ const WatchedFile = struct {
 };
 
 const FileWatches = struct {
-    entries: [pardes.MAX_PANES]?WatchedFile = @splat(null),
-    generations: [pardes.MAX_PANES]u32 = @splat(0),
-    dirty: [pardes.MAX_PANES]bool = @splat(false),
+    entries: [watch_slot_count]?WatchedFile = @splat(null),
+    generations: [watch_slot_count]u32 = @splat(0),
+    dirty: [watch_slot_count]bool = @splat(false),
 
     fn nextGeneration(watches: *FileWatches, pane: u8) u32 {
         watches.generations[pane] +%= 1;
@@ -617,6 +621,7 @@ fn initCore(runtime: ?*const Runtime, cols_arg: u16, rows_arg: u16) !void {
         const found = user_config.load(io, config_arena.allocator(), env);
         opts.startup_config = found.bytes;
         opts.startup_config_path = found.path;
+        opts.config_dir = found.dir;
     }
 
     pardes.image.start(io, allocs.image);
@@ -729,6 +734,10 @@ export fn pardes_deinit() void {
         const generation = st.file_watches.stop(st.gpa, id);
         hostWatchFile(id, generation, null, 0);
     };
+    if (st.file_watches.entries[theme_watch_pane] != null) {
+        const generation = st.file_watches.stop(st.gpa, theme_watch_pane);
+        hostWatchFile(theme_watch_pane, generation, null, 0);
+    }
     // Every reader is joined here, before anything it touches is freed. The
     // runtime joins its tasks on exit, so a reader left parked in read(2) would
     // hang the process instead of the app quitting.
@@ -932,6 +941,57 @@ fn setFileWatch(st: *State, pane: u8, on: bool) void {
     _ = reloadWatchedFile(st, pane, false);
 }
 
+fn setThemeFileWatch(st: *State, request_generation: u32, on: bool, animate: bool) void {
+    const stopped = st.file_watches.stop(st.gpa, theme_watch_pane);
+    hostWatchFile(theme_watch_pane, stopped, null, 0);
+    if (!on) return;
+    const request = st.core.themeFileRequest(request_generation) orelse return;
+    const bytes = look.readFile(st.gpa, request.path) catch |err| {
+        st.core.failThemeFile(request_generation, err);
+        return;
+    };
+    defer st.gpa.free(bytes);
+    if (!st.core.loadThemeFile(request_generation, bytes, animate)) return;
+    const callback_generation = st.file_watches.replace(
+        st.gpa,
+        theme_watch_pane,
+        request.path,
+        request_generation,
+        .{ .text = std.hash.Wyhash.hash(0, bytes) },
+    ) catch return;
+    const watched = st.file_watches.entries[theme_watch_pane].?;
+    hostWatchFile(theme_watch_pane, callback_generation, watched.path.ptr, watched.path.len);
+    // Read-before-watch has the same rename-over gap as document panes. One
+    // immediate reconciliation after Swift activates the source closes it.
+    _ = reloadWatchedTheme(st, false);
+}
+
+fn reloadWatchedTheme(st: *State, announce: bool) bool {
+    const watched = if (st.file_watches.entries[theme_watch_pane]) |*entry| entry else return false;
+    const request = st.core.themeFileRequest(watched.serial) orelse return false;
+    if (!std.mem.eql(u8, watched.path, request.path)) return false;
+    const bytes = look.readFile(st.gpa, watched.path) catch |err| {
+        st.core.failThemeFile(watched.serial, err);
+        return false;
+    };
+    defer st.gpa.free(bytes);
+    const hash = std.hash.Wyhash.hash(0, bytes);
+    switch (watched.generation_on_disk) {
+        .text => |accepted| if (accepted == hash) return false,
+        .pdf => unreachable,
+    }
+    if (!st.core.loadThemeFile(watched.serial, bytes, true)) return false;
+    const live = if (st.file_watches.entries[theme_watch_pane]) |*entry| entry else return false;
+    if (live.serial != watched.serial) return false;
+    live.generation_on_disk = .{ .text = hash };
+    live.retries_left = 0;
+    if (announce) {
+        var mbuf: [256]u8 = undefined;
+        st.core.setMessage(request.pane, message.stamp(&mbuf, "reloaded theme", request.path));
+    }
+    return true;
+}
+
 /// Read and apply on the main thread. Swift only says that this path or its
 /// parent changed. Text hashes an exact bounded snapshot; PDFs may be much
 /// larger than that bound and MuPDF reopens the path itself, so they compare a
@@ -1027,7 +1087,7 @@ fn reloadWatchedFile(st: *State, pane: u8, announce: bool) bool {
 /// IO and state mutation stay in pardes_tick with pty/nested messages.
 export fn pardes_watch_changed(pane: u8, generation: u32) void {
     const st = &(state orelse return);
-    if (pane >= pardes.MAX_PANES) return;
+    if (pane >= watch_slot_count) return;
     if (st.file_watches.notify(pane, generation)) wake(st);
 }
 
@@ -1083,6 +1143,9 @@ export fn pardes_tick() bool {
         if (!st.file_watches.takeDirty(id)) continue;
         if (reloadWatchedFile(st, id, true)) changed = true;
     }
+    if (st.file_watches.takeDirty(theme_watch_pane)) {
+        if (reloadWatchedTheme(st, true)) changed = true;
+    }
     refreshCwds(st);
     if (drainEffects(st, true)) changed = true;
     return changed;
@@ -1748,6 +1811,16 @@ fn drainEffects(st: *State, threads_ok: bool) bool {
                 _ = libc.close(fd);
                 core.setLastDump(path);
             },
+            .dump_themes => |request| {
+                const config_dir = core.opts.config_dir orelse continue;
+                const out_dir = user_config.dumpThemes(st.io, st.gpa, config_dir, pardes.themes) catch |err| {
+                    core.reportError(request.pane, "dump themes", err);
+                    continue;
+                };
+                defer st.gpa.free(out_dir);
+                var mbuf: [256]u8 = undefined;
+                core.setMessage(request.pane, message.stamp(&mbuf, "dumped themes", out_dir));
+            },
             .set_clipboard => {
                 const cb = st.runtime.set_clipboard orelse continue;
                 const y = core.yank orelse continue;
@@ -1771,6 +1844,7 @@ fn drainEffects(st: *State, threads_ok: bool) bool {
             // dot-Tab for the rest of the session does nothing at all.
             .lsp => |q| core.update(.{ .lsp_resp = .{ .id = q.id, .rows = "" } }),
             .watch => |watch| setFileWatch(st, watch.pane, watch.on),
+            .theme_file => |request| setThemeFileWatch(st, request.generation, request.on, threads_ok),
             .pipe => {},
             .quit => {},
         }