[feat] fs.watch

[cirospaciari]

No description provided.

[github-actions]

❌ @cirospaciari 9 files with test failures on linux-x64:

• test/bundler/bundler_browser.test.ts
• test/bundler/esbuild/default.test.ts
• test/bundler/esbuild/importstar.test.ts
• test/cli/install/bunx.test.ts
• test/js/bun/util/inspect.test.js
• test/js/bun/websocket/websocket-server.test.ts
• test/js/third_party/napi_create_external/napi-create-external.test.ts
• test/js/third_party/prisma/prisma.test.ts
• test/js/web/websocket/websocket.test.js

View test output

^{#42f1b6d40b33a952ac17a12bb17ee1aec007e152}

[github-actions]

❌ @cirospaciari 8 files with test failures on linux-x64-baseline:

• test/bundler/bundler_browser.test.ts
• test/bundler/esbuild/default.test.ts
• test/bundler/esbuild/importstar.test.ts
• test/cli/install/bunx.test.ts
• test/js/bun/util/inspect.test.js
• test/js/bun/websocket/websocket-server.test.ts
• test/js/third_party/prisma/prisma.test.ts
• test/js/web/websocket/websocket.test.js

View test output

^{#42f1b6d40b33a952ac17a12bb17ee1aec007e152}

[github-actions]

❌ @cirospaciari 12 files with test failures on bun-darwin-x64-baseline:

• test/bundler/bundler_browser.test.ts
• test/bundler/esbuild/default.test.ts
• test/bundler/esbuild/importstar.test.ts
• test/cli/install/bunx.test.ts
• test/js/bun/spawn/spawn-streaming-stdin.test.ts
• test/js/bun/sqlite/sqlite.test.js
• test/js/bun/util/inspect.test.js
• test/js/bun/util/sleepSync.test.ts
• test/js/bun/websocket/websocket-server.test.ts
• test/js/web/timers/setInterval.test.js
• test/js/web/timers/setTimeout.test.js
• test/js/web/websocket/websocket.test.js

View test output

^{#42f1b6d40b33a952ac17a12bb17ee1aec007e152}

[github-actions]

❌ @cirospaciari 10 files with test failures on bun-darwin-aarch64:

• test/bundler/bundler_browser.test.ts
• test/bundler/esbuild/default.test.ts
• test/bundler/esbuild/importstar.test.ts
• test/cli/install/bunx.test.ts
• test/js/bun/net/socket.test.ts
• test/js/bun/test/test-test.test.ts
• test/js/bun/util/inspect.test.js
• test/js/bun/websocket/websocket-server.test.ts
• test/js/web/fetch/fetch-leak.test.js
• test/js/web/websocket/websocket.test.js

View test output

^{#42f1b6d40b33a952ac17a12bb17ee1aec007e152}

[github-actions]

✅ prettier errors have been resolved. Thank you.

^{#42f1b6d40b33a952ac17a12bb17ee1aec007e152}

[cirospaciari]

@Jarred-Sumner

Today once initialized we never deinit this loop, but we can deinit it when no watchers are active

bun/src/bun.js/node/fs_events.zig

Lines 541 to 563 in a448078

	fn deinit(this: *FSEventsLoop) void {
	// signal close and wait
	this.enqueueTaskConcurrent(Task.New(FSEventsLoop, FSEventsLoop._stop).init(this));
	this.thread.join();
	const CF = CoreFoundation.get();
	CF.Release(this.signal_source);
	this.signal_source = null;
	this.sem.deinit();
	this.mutex.deinit();
	if (this.watcher_count > 0) {
	while (this.watchers.popOrNull()) |watcher| {
	if (watcher) |w| {
	// unlink watcher
	w.loop = null;
	}
	}
	}
	this.watchers.deinitWithAllocator(bun.default_allocator);
	bun.default_allocator.destroy(this);

This implementation is also using babylist to keep track of active stuff and we reuse free slots, not the optimal way but should be fine when using 1-100 watchers

bun/src/bun.js/node/fs_events.zig

Lines 501 to 508 in a448078

	var watchers = this.watchers.slice();
	for (watchers, 0..) |w, i| {
	if (w == null) {
	watchers[i] = watcher;
	this.watcher_count += 1;
	break;
	}
	}

This is the main logic

bun/src/bun.js/node/fs_events.zig

Lines 355 to 406 in a448078

	for (loop.watchers.slice()) |watcher| {
	if (watcher) |handle| {
	for (paths, 0..) |path_ptr, i| {
	var flags = event_flags[i];
	var path = path_ptr[0..bun.len(path_ptr)];
	// Filter out paths that are outside handle's request
	if (path.len < handle.path.len or !bun.strings.startsWith(path, handle.path)) {
	continue;
	}
	const is_file = (flags & kFSEventStreamEventFlagItemIsDir) == 0;
	// Remove common prefix, unless the watched folder is "/"
	if (!(handle.path.len == 1 and handle.path[0] == '/')) {
	path = path[handle.path.len..];
	// Ignore events with path equal to directory itself
	if (path.len <= 1 and is_file) {
	continue;
	}
	if (path.len == 0) {
	// Since we're using fsevents to watch the file itself, path == handle.path, and we now need to get the basename of the file back
	while (path.len > 0) {
	if (bun.strings.startsWithChar(path, '/')) {
	path = path[1..];
	break;
	} else {
	path = path[1..];
	}
	}
	// Created and Removed seem to be always set, but don't make sense
	flags &= ~kFSEventsRenamed;
	} else {
	// Skip forward slash
	path = path[1..];
	}
	}
	// Do not emit events from subdirectories (without option set)
	if (path.len == 0 or (bun.strings.containsChar(path, '/') and !handle.recursive)) {
	continue;
	}
	var is_rename = true;
	if ((flags & kFSEventsRenamed) == 0) {
	if ((flags & kFSEventsModified) != 0 or is_file) {
	is_rename = false;
	}
	}
	handle.callback(handle.ctx, path, is_file, is_rename);

and we use 1 thread for all watchers and just filter by path like uv does, watcher.zig is using 1 thread per watcher and maybe we can refactor it to do the same as fs_events, relative path logic is also much simpler on fs_events loop.

[Jarred-Sumner]

🎉