Files
clawdbot/apps/macos/Sources/Clawdbot/CanvasFileWatcher.swift
2026-01-04 14:38:51 +00:00

95 lines
2.9 KiB
Swift

import CoreServices
import Foundation
final class CanvasFileWatcher: @unchecked Sendable {
private let url: URL
private let queue: DispatchQueue
private var stream: FSEventStreamRef?
private var pending = false
private let onChange: () -> Void
init(url: URL, onChange: @escaping () -> Void) {
self.url = url
self.queue = DispatchQueue(label: "com.clawdbot.canvaswatcher")
self.onChange = onChange
}
deinit {
self.stop()
}
func start() {
guard self.stream == nil else { return }
let retainedSelf = Unmanaged.passRetained(self)
var context = FSEventStreamContext(
version: 0,
info: retainedSelf.toOpaque(),
retain: nil,
release: { pointer in
guard let pointer else { return }
Unmanaged<CanvasFileWatcher>.fromOpaque(pointer).release()
},
copyDescription: nil)
let paths = [self.url.path] as CFArray
let flags = FSEventStreamCreateFlags(
kFSEventStreamCreateFlagFileEvents |
kFSEventStreamCreateFlagUseCFTypes |
kFSEventStreamCreateFlagNoDefer)
guard let stream = FSEventStreamCreate(
kCFAllocatorDefault,
Self.callback,
&context,
paths,
FSEventStreamEventId(kFSEventStreamEventIdSinceNow),
0.05,
flags)
else {
retainedSelf.release()
return
}
self.stream = stream
FSEventStreamSetDispatchQueue(stream, self.queue)
if FSEventStreamStart(stream) == false {
self.stream = nil
FSEventStreamSetDispatchQueue(stream, nil)
FSEventStreamInvalidate(stream)
FSEventStreamRelease(stream)
}
}
func stop() {
guard let stream = self.stream else { return }
self.stream = nil
FSEventStreamStop(stream)
FSEventStreamSetDispatchQueue(stream, nil)
FSEventStreamInvalidate(stream)
FSEventStreamRelease(stream)
}
}
extension CanvasFileWatcher {
private static let callback: FSEventStreamCallback = { _, info, numEvents, _, eventFlags, _ in
guard let info else { return }
let watcher = Unmanaged<CanvasFileWatcher>.fromOpaque(info).takeUnretainedValue()
watcher.handleEvents(numEvents: numEvents, eventFlags: eventFlags)
}
private func handleEvents(numEvents: Int, eventFlags: UnsafePointer<FSEventStreamEventFlags>?) {
guard numEvents > 0 else { return }
guard eventFlags != nil else { return }
// Coalesce rapid changes (common during builds/atomic saves).
if self.pending { return }
self.pending = true
self.queue.asyncAfter(deadline: .now() + 0.12) { [weak self] in
guard let self else { return }
self.pending = false
self.onChange()
}
}
}