1#![cfg(target_os = "macos")]
2
3use bitflags::bitflags;
4use fsevent_sys::{self as fs, core_foundation as cf};
5use parking_lot::Mutex;
6use std::{
7 convert::AsRef,
8 ffi::{c_void, CStr, OsStr},
9 os::unix::ffi::OsStrExt,
10 path::{Path, PathBuf},
11 ptr, slice,
12 sync::Arc,
13 time::Duration,
14};
15
16#[derive(Clone, Debug)]
17pub struct Event {
18 pub event_id: u64,
19 pub flags: StreamFlags,
20 pub path: PathBuf,
21}
22
23pub struct EventStream {
24 lifecycle: Arc<Mutex<Lifecycle>>,
25 state: Box<State>,
26}
27
28struct State {
29 latency: Duration,
30 paths: cf::CFMutableArrayRef,
31 callback: Option<Box<dyn FnMut(Vec<Event>) -> bool>>,
32 last_valid_event_id: Option<fs::FSEventStreamEventId>,
33 stream: fs::FSEventStreamRef,
34}
35
36impl Drop for State {
37 fn drop(&mut self) {
38 unsafe {
39 cf::CFRelease(self.paths);
40 fs::FSEventStreamStop(self.stream);
41 fs::FSEventStreamInvalidate(self.stream);
42 fs::FSEventStreamRelease(self.stream);
43 }
44 }
45}
46
47enum Lifecycle {
48 New,
49 Running(cf::CFRunLoopRef),
50 Stopped,
51}
52
53pub struct Handle(Arc<Mutex<Lifecycle>>);
54
55unsafe impl Send for EventStream {}
56unsafe impl Send for Lifecycle {}
57
58impl EventStream {
59 pub fn new(paths: &[&Path], latency: Duration) -> (Self, Handle) {
60 unsafe {
61 let cf_paths =
62 cf::CFArrayCreateMutable(cf::kCFAllocatorDefault, 0, &cf::kCFTypeArrayCallBacks);
63 assert!(!cf_paths.is_null());
64
65 for path in paths {
66 let path_bytes = path.as_os_str().as_bytes();
67 let cf_url = cf::CFURLCreateFromFileSystemRepresentation(
68 cf::kCFAllocatorDefault,
69 path_bytes.as_ptr() as *const i8,
70 path_bytes.len() as cf::CFIndex,
71 false,
72 );
73 let cf_path = cf::CFURLCopyFileSystemPath(cf_url, cf::kCFURLPOSIXPathStyle);
74 cf::CFArrayAppendValue(cf_paths, cf_path);
75 cf::CFRelease(cf_path);
76 cf::CFRelease(cf_url);
77 }
78
79 let mut state = Box::new(State {
80 latency,
81 paths: cf_paths,
82 callback: None,
83 last_valid_event_id: None,
84 stream: ptr::null_mut(),
85 });
86 let stream_context = fs::FSEventStreamContext {
87 version: 0,
88 info: state.as_ref() as *const _ as *mut c_void,
89 retain: None,
90 release: None,
91 copy_description: None,
92 };
93 let stream = fs::FSEventStreamCreate(
94 cf::kCFAllocatorDefault,
95 Self::trampoline,
96 &stream_context,
97 cf_paths,
98 FSEventsGetCurrentEventId(),
99 latency.as_secs_f64(),
100 fs::kFSEventStreamCreateFlagFileEvents
101 | fs::kFSEventStreamCreateFlagNoDefer
102 | fs::kFSEventStreamCreateFlagWatchRoot,
103 );
104 state.stream = stream;
105
106 let lifecycle = Arc::new(Mutex::new(Lifecycle::New));
107 (
108 EventStream {
109 lifecycle: lifecycle.clone(),
110 state,
111 },
112 Handle(lifecycle),
113 )
114 }
115 }
116
117 pub fn run<F>(mut self, f: F)
118 where
119 F: FnMut(Vec<Event>) -> bool + 'static,
120 {
121 self.state.callback = Some(Box::new(f));
122 unsafe {
123 let run_loop = cf::CFRunLoopGetCurrent();
124 {
125 let mut state = self.lifecycle.lock();
126 match *state {
127 Lifecycle::New => *state = Lifecycle::Running(run_loop),
128 Lifecycle::Running(_) => unreachable!(),
129 Lifecycle::Stopped => return,
130 }
131 }
132 fs::FSEventStreamScheduleWithRunLoop(
133 self.state.stream,
134 run_loop,
135 cf::kCFRunLoopDefaultMode,
136 );
137 fs::FSEventStreamStart(self.state.stream);
138 cf::CFRunLoopRun();
139 }
140 }
141
142 extern "C" fn trampoline(
143 stream_ref: fs::FSEventStreamRef,
144 info: *mut ::std::os::raw::c_void,
145 num: usize, // size_t numEvents
146 event_paths: *mut ::std::os::raw::c_void, // void *eventPaths
147 event_flags: *const ::std::os::raw::c_void, // const FSEventStreamEventFlags eventFlags[]
148 event_ids: *const ::std::os::raw::c_void, // const FSEventStreamEventId eventIds[]
149 ) {
150 unsafe {
151 let event_paths = event_paths as *const *const ::std::os::raw::c_char;
152 let e_ptr = event_flags as *mut u32;
153 let i_ptr = event_ids as *mut u64;
154 let state = (info as *mut State).as_mut().unwrap();
155 let callback = if let Some(callback) = state.callback.as_mut() {
156 callback
157 } else {
158 return;
159 };
160
161 let paths = slice::from_raw_parts(event_paths, num);
162 let flags = slice::from_raw_parts_mut(e_ptr, num);
163 let ids = slice::from_raw_parts_mut(i_ptr, num);
164 let mut stream_restarted = false;
165
166 // Sometimes FSEvents reports a "dropped" event, an indication that either the kernel
167 // or our code couldn't keep up with the sheer volume of file-system events that were
168 // generated. If we observed a valid event before this happens, we'll try to read the
169 // file-system journal by stopping the current stream and creating a new one starting at
170 // such event. Otherwise, we'll let invoke the callback with the dropped event, which
171 // will likely perform a re-scan of one of the root directories.
172 if flags
173 .iter()
174 .copied()
175 .filter_map(StreamFlags::from_bits)
176 .any(|flags| {
177 flags.contains(StreamFlags::USER_DROPPED)
178 || flags.contains(StreamFlags::KERNEL_DROPPED)
179 })
180 {
181 if let Some(last_valid_event_id) = state.last_valid_event_id.take() {
182 fs::FSEventStreamStop(state.stream);
183 fs::FSEventStreamInvalidate(state.stream);
184 fs::FSEventStreamRelease(state.stream);
185
186 let stream_context = fs::FSEventStreamContext {
187 version: 0,
188 info,
189 retain: None,
190 release: None,
191 copy_description: None,
192 };
193 let stream = fs::FSEventStreamCreate(
194 cf::kCFAllocatorDefault,
195 Self::trampoline,
196 &stream_context,
197 state.paths,
198 last_valid_event_id,
199 state.latency.as_secs_f64(),
200 fs::kFSEventStreamCreateFlagFileEvents
201 | fs::kFSEventStreamCreateFlagNoDefer
202 | fs::kFSEventStreamCreateFlagWatchRoot,
203 );
204
205 state.stream = stream;
206 fs::FSEventStreamScheduleWithRunLoop(
207 state.stream,
208 cf::CFRunLoopGetCurrent(),
209 cf::kCFRunLoopDefaultMode,
210 );
211 fs::FSEventStreamStart(state.stream);
212 stream_restarted = true;
213 }
214 }
215
216 if !stream_restarted {
217 let mut events = Vec::with_capacity(num);
218 for p in 0..num {
219 if let Some(flag) = StreamFlags::from_bits(flags[p]) {
220 if !flag.contains(StreamFlags::HISTORY_DONE) {
221 let path_c_str = CStr::from_ptr(paths[p]);
222 let path = PathBuf::from(OsStr::from_bytes(path_c_str.to_bytes()));
223 let event = Event {
224 event_id: ids[p],
225 flags: flag,
226 path,
227 };
228 state.last_valid_event_id = Some(event.event_id);
229 events.push(event);
230 }
231 } else {
232 debug_assert!(false, "unknown flag set for fs event: {}", flags[p]);
233 }
234 }
235
236 if !events.is_empty() && !callback(events) {
237 fs::FSEventStreamStop(stream_ref);
238 cf::CFRunLoopStop(cf::CFRunLoopGetCurrent());
239 }
240 }
241 }
242 }
243}
244
245impl Drop for Handle {
246 fn drop(&mut self) {
247 let mut state = self.0.lock();
248 if let Lifecycle::Running(run_loop) = *state {
249 unsafe {
250 cf::CFRunLoopStop(run_loop);
251 }
252 }
253 *state = Lifecycle::Stopped;
254 }
255}
256
257// Synchronize with
258// /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/FSEvents.framework/Versions/A/Headers/FSEvents.h
259bitflags! {
260 #[repr(C)]
261 pub struct StreamFlags: u32 {
262 const NONE = 0x00000000;
263 const MUST_SCAN_SUBDIRS = 0x00000001;
264 const USER_DROPPED = 0x00000002;
265 const KERNEL_DROPPED = 0x00000004;
266 const IDS_WRAPPED = 0x00000008;
267 const HISTORY_DONE = 0x00000010;
268 const ROOT_CHANGED = 0x00000020;
269 const MOUNT = 0x00000040;
270 const UNMOUNT = 0x00000080;
271 const ITEM_CREATED = 0x00000100;
272 const ITEM_REMOVED = 0x00000200;
273 const INODE_META_MOD = 0x00000400;
274 const ITEM_RENAMED = 0x00000800;
275 const ITEM_MODIFIED = 0x00001000;
276 const FINDER_INFO_MOD = 0x00002000;
277 const ITEM_CHANGE_OWNER = 0x00004000;
278 const ITEM_XATTR_MOD = 0x00008000;
279 const IS_FILE = 0x00010000;
280 const IS_DIR = 0x00020000;
281 const IS_SYMLINK = 0x00040000;
282 const OWN_EVENT = 0x00080000;
283 const IS_HARDLINK = 0x00100000;
284 const IS_LAST_HARDLINK = 0x00200000;
285 const ITEM_CLONED = 0x400000;
286 }
287}
288
289impl std::fmt::Display for StreamFlags {
290 fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
291 if self.contains(StreamFlags::MUST_SCAN_SUBDIRS) {
292 let _d = write!(f, "MUST_SCAN_SUBDIRS ");
293 }
294 if self.contains(StreamFlags::USER_DROPPED) {
295 let _d = write!(f, "USER_DROPPED ");
296 }
297 if self.contains(StreamFlags::KERNEL_DROPPED) {
298 let _d = write!(f, "KERNEL_DROPPED ");
299 }
300 if self.contains(StreamFlags::IDS_WRAPPED) {
301 let _d = write!(f, "IDS_WRAPPED ");
302 }
303 if self.contains(StreamFlags::HISTORY_DONE) {
304 let _d = write!(f, "HISTORY_DONE ");
305 }
306 if self.contains(StreamFlags::ROOT_CHANGED) {
307 let _d = write!(f, "ROOT_CHANGED ");
308 }
309 if self.contains(StreamFlags::MOUNT) {
310 let _d = write!(f, "MOUNT ");
311 }
312 if self.contains(StreamFlags::UNMOUNT) {
313 let _d = write!(f, "UNMOUNT ");
314 }
315 if self.contains(StreamFlags::ITEM_CREATED) {
316 let _d = write!(f, "ITEM_CREATED ");
317 }
318 if self.contains(StreamFlags::ITEM_REMOVED) {
319 let _d = write!(f, "ITEM_REMOVED ");
320 }
321 if self.contains(StreamFlags::INODE_META_MOD) {
322 let _d = write!(f, "INODE_META_MOD ");
323 }
324 if self.contains(StreamFlags::ITEM_RENAMED) {
325 let _d = write!(f, "ITEM_RENAMED ");
326 }
327 if self.contains(StreamFlags::ITEM_MODIFIED) {
328 let _d = write!(f, "ITEM_MODIFIED ");
329 }
330 if self.contains(StreamFlags::FINDER_INFO_MOD) {
331 let _d = write!(f, "FINDER_INFO_MOD ");
332 }
333 if self.contains(StreamFlags::ITEM_CHANGE_OWNER) {
334 let _d = write!(f, "ITEM_CHANGE_OWNER ");
335 }
336 if self.contains(StreamFlags::ITEM_XATTR_MOD) {
337 let _d = write!(f, "ITEM_XATTR_MOD ");
338 }
339 if self.contains(StreamFlags::IS_FILE) {
340 let _d = write!(f, "IS_FILE ");
341 }
342 if self.contains(StreamFlags::IS_DIR) {
343 let _d = write!(f, "IS_DIR ");
344 }
345 if self.contains(StreamFlags::IS_SYMLINK) {
346 let _d = write!(f, "IS_SYMLINK ");
347 }
348 if self.contains(StreamFlags::OWN_EVENT) {
349 let _d = write!(f, "OWN_EVENT ");
350 }
351 if self.contains(StreamFlags::IS_LAST_HARDLINK) {
352 let _d = write!(f, "IS_LAST_HARDLINK ");
353 }
354 if self.contains(StreamFlags::IS_HARDLINK) {
355 let _d = write!(f, "IS_HARDLINK ");
356 }
357 if self.contains(StreamFlags::ITEM_CLONED) {
358 let _d = write!(f, "ITEM_CLONED ");
359 }
360 write!(f, "")
361 }
362}
363
364#[link(name = "CoreServices", kind = "framework")]
365extern "C" {
366 pub fn FSEventsGetCurrentEventId() -> u64;
367}
368
369#[cfg(test)]
370mod tests {
371 use super::*;
372 use std::{fs, sync::mpsc, thread, time::Duration};
373
374 #[test]
375 fn test_event_stream_simple() {
376 for _ in 0..3 {
377 let dir = tempfile::Builder::new()
378 .prefix("test-event-stream")
379 .tempdir()
380 .unwrap();
381 let path = dir.path().canonicalize().unwrap();
382 for i in 0..10 {
383 fs::write(path.join(format!("existing-file-{}", i)), "").unwrap();
384 }
385 flush_historical_events();
386
387 let (tx, rx) = mpsc::channel();
388 let (stream, handle) = EventStream::new(&[&path], Duration::from_millis(50));
389 thread::spawn(move || stream.run(move |events| tx.send(events.to_vec()).is_ok()));
390
391 fs::write(path.join("new-file"), "").unwrap();
392 let events = rx.recv_timeout(Duration::from_secs(2)).unwrap();
393 let event = events.last().unwrap();
394 assert_eq!(event.path, path.join("new-file"));
395 assert!(event.flags.contains(StreamFlags::ITEM_CREATED));
396
397 fs::remove_file(path.join("existing-file-5")).unwrap();
398 let events = rx.recv_timeout(Duration::from_secs(2)).unwrap();
399 let event = events.last().unwrap();
400 assert_eq!(event.path, path.join("existing-file-5"));
401 assert!(event.flags.contains(StreamFlags::ITEM_REMOVED));
402 drop(handle);
403 }
404 }
405
406 #[test]
407 fn test_event_stream_delayed_start() {
408 for _ in 0..3 {
409 let dir = tempfile::Builder::new()
410 .prefix("test-event-stream")
411 .tempdir()
412 .unwrap();
413 let path = dir.path().canonicalize().unwrap();
414 for i in 0..10 {
415 fs::write(path.join(format!("existing-file-{}", i)), "").unwrap();
416 }
417 flush_historical_events();
418
419 let (tx, rx) = mpsc::channel();
420 let (stream, handle) = EventStream::new(&[&path], Duration::from_millis(50));
421
422 // Delay the call to `run` in order to make sure we don't miss any events that occur
423 // between creating the `EventStream` and calling `run`.
424 thread::spawn(move || {
425 thread::sleep(Duration::from_millis(100));
426 stream.run(move |events| tx.send(events.to_vec()).is_ok())
427 });
428
429 fs::write(path.join("new-file"), "").unwrap();
430 let events = rx.recv_timeout(Duration::from_secs(2)).unwrap();
431 let event = events.last().unwrap();
432 assert_eq!(event.path, path.join("new-file"));
433 assert!(event.flags.contains(StreamFlags::ITEM_CREATED));
434
435 fs::remove_file(path.join("existing-file-5")).unwrap();
436 let events = rx.recv_timeout(Duration::from_secs(2)).unwrap();
437 let event = events.last().unwrap();
438 assert_eq!(event.path, path.join("existing-file-5"));
439 assert!(event.flags.contains(StreamFlags::ITEM_REMOVED));
440 drop(handle);
441 }
442 }
443
444 #[test]
445 fn test_event_stream_shutdown_by_dropping_handle() {
446 let dir = tempfile::Builder::new()
447 .prefix("test-event-stream")
448 .tempdir()
449 .unwrap();
450 let path = dir.path().canonicalize().unwrap();
451 flush_historical_events();
452
453 let (tx, rx) = mpsc::channel();
454 let (stream, handle) = EventStream::new(&[&path], Duration::from_millis(50));
455 thread::spawn(move || {
456 stream.run({
457 let tx = tx.clone();
458 move |_| {
459 tx.send("running").unwrap();
460 true
461 }
462 });
463 tx.send("stopped").unwrap();
464 });
465
466 fs::write(path.join("new-file"), "").unwrap();
467 assert_eq!(rx.recv_timeout(Duration::from_secs(2)).unwrap(), "running");
468
469 // Dropping the handle causes `EventStream::run` to return.
470 drop(handle);
471 assert_eq!(rx.recv_timeout(Duration::from_secs(2)).unwrap(), "stopped");
472 }
473
474 #[test]
475 fn test_event_stream_shutdown_before_run() {
476 let dir = tempfile::Builder::new()
477 .prefix("test-event-stream")
478 .tempdir()
479 .unwrap();
480 let path = dir.path().canonicalize().unwrap();
481
482 let (stream, handle) = EventStream::new(&[&path], Duration::from_millis(50));
483 drop(handle);
484
485 // This returns immediately because the handle was already dropped.
486 stream.run(|_| true);
487 }
488
489 fn flush_historical_events() {
490 let duration = if std::env::var("CI").is_ok() {
491 Duration::from_secs(2)
492 } else {
493 Duration::from_millis(500)
494 };
495 thread::sleep(duration);
496 }
497}