Alien-uv

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libuv/src/unix/fsevents.c  view on Meta::CPAN

  uv__cf_loop_signal_type_t type;
};

struct uv__fsevents_event_s {
  QUEUE member;
  int events;
  char path[1];
};

struct uv__cf_loop_state_s {
  CFRunLoopRef loop;
  CFRunLoopSourceRef signal_source;
  int fsevent_need_reschedule;
  FSEventStreamRef fsevent_stream;
  uv_sem_t fsevent_sem;
  uv_mutex_t fsevent_mutex;
  void* fsevent_handles[2];
  unsigned int fsevent_handle_count;
};

/* Forward declarations */
static void uv__cf_loop_cb(void* arg);
static void* uv__cf_loop_runner(void* arg);
static int uv__cf_loop_signal(uv_loop_t* loop,
                              uv_fs_event_t* handle,
                              uv__cf_loop_signal_type_t type);

/* Lazy-loaded by uv__fsevents_global_init(). */
static CFArrayRef (*pCFArrayCreate)(CFAllocatorRef,
                                    const void**,
                                    CFIndex,
                                    const CFArrayCallBacks*);
static void (*pCFRelease)(CFTypeRef);
static void (*pCFRunLoopAddSource)(CFRunLoopRef,
                                   CFRunLoopSourceRef,
                                   CFStringRef);
static CFRunLoopRef (*pCFRunLoopGetCurrent)(void);
static void (*pCFRunLoopRemoveSource)(CFRunLoopRef,
                                      CFRunLoopSourceRef,
                                      CFStringRef);
static void (*pCFRunLoopRun)(void);
static CFRunLoopSourceRef (*pCFRunLoopSourceCreate)(CFAllocatorRef,
                                                    CFIndex,
                                                    CFRunLoopSourceContext*);
static void (*pCFRunLoopSourceSignal)(CFRunLoopSourceRef);
static void (*pCFRunLoopStop)(CFRunLoopRef);
static void (*pCFRunLoopWakeUp)(CFRunLoopRef);
static CFStringRef (*pCFStringCreateWithFileSystemRepresentation)(
    CFAllocatorRef,
    const char*);
static CFStringEncoding (*pCFStringGetSystemEncoding)(void);
static CFStringRef (*pkCFRunLoopDefaultMode);
static FSEventStreamRef (*pFSEventStreamCreate)(CFAllocatorRef,
                                                FSEventStreamCallback,
                                                FSEventStreamContext*,
                                                CFArrayRef,
                                                FSEventStreamEventId,
                                                CFTimeInterval,
                                                FSEventStreamCreateFlags);
static void (*pFSEventStreamFlushSync)(FSEventStreamRef);
static void (*pFSEventStreamInvalidate)(FSEventStreamRef);
static void (*pFSEventStreamRelease)(FSEventStreamRef);
static void (*pFSEventStreamScheduleWithRunLoop)(FSEventStreamRef,
                                                 CFRunLoopRef,
                                                 CFStringRef);
static Boolean (*pFSEventStreamStart)(FSEventStreamRef);
static void (*pFSEventStreamStop)(FSEventStreamRef);

#define UV__FSEVENTS_PROCESS(handle, block)                                   \
    do {                                                                      \
      QUEUE events;                                                           \
      QUEUE* q;                                                               \
      uv__fsevents_event_t* event;                                            \
      int err;                                                                \
      uv_mutex_lock(&(handle)->cf_mutex);                                     \
      /* Split-off all events and empty original queue */                     \
      QUEUE_MOVE(&(handle)->cf_events, &events);                              \
      /* Get error (if any) and zero original one */                          \
      err = (handle)->cf_error;                                               \
      (handle)->cf_error = 0;                                                 \
      uv_mutex_unlock(&(handle)->cf_mutex);                                   \
      /* Loop through events, deallocating each after processing */           \
      while (!QUEUE_EMPTY(&events)) {                                         \
        q = QUEUE_HEAD(&events);                                              \
        event = QUEUE_DATA(q, uv__fsevents_event_t, member);                  \
        QUEUE_REMOVE(q);                                                      \
        /* NOTE: Checking uv__is_active() is required here, because handle    \
         * callback may close handle and invoking it after it will lead to    \
         * incorrect behaviour */                                             \
        if (!uv__is_closing((handle)) && uv__is_active((handle)))             \
          block                                                               \
        /* Free allocated data */                                             \
        uv__free(event);                                                      \
      }                                                                       \
      if (err != 0 && !uv__is_closing((handle)) && uv__is_active((handle)))   \
        (handle)->cb((handle), NULL, 0, err);                                 \
    } while (0)


/* Runs in UV loop's thread, when there're events to report to handle */
static void uv__fsevents_cb(uv_async_t* cb) {
  uv_fs_event_t* handle;

  handle = cb->data;

  UV__FSEVENTS_PROCESS(handle, {
    handle->cb(handle, event->path[0] ? event->path : NULL, event->events, 0);
  });
}


/* Runs in CF thread, pushed event into handle's event list */
static void uv__fsevents_push_event(uv_fs_event_t* handle,
                                    QUEUE* events,
                                    int err) {
  assert(events != NULL || err != 0);
  uv_mutex_lock(&handle->cf_mutex);

  /* Concatenate two queues */
  if (events != NULL)
    QUEUE_ADD(&handle->cf_events, events);

libuv/src/unix/fsevents.c  view on Meta::CPAN

    }

    if (!QUEUE_EMPTY(&head))
      uv__fsevents_push_event(handle, &head, 0);
  }
  uv_mutex_unlock(&state->fsevent_mutex);
}


/* Runs in CF thread */
static int uv__fsevents_create_stream(uv_loop_t* loop, CFArrayRef paths) {
  uv__cf_loop_state_t* state;
  FSEventStreamContext ctx;
  FSEventStreamRef ref;
  CFAbsoluteTime latency;
  FSEventStreamCreateFlags flags;

  /* Initialize context */
  ctx.version = 0;
  ctx.info = loop;
  ctx.retain = NULL;
  ctx.release = NULL;
  ctx.copyDescription = NULL;

  latency = 0.05;

  /* Explanation of selected flags:
   * 1. NoDefer - without this flag, events that are happening continuously
   *    (i.e. each event is happening after time interval less than `latency`,
   *    counted from previous event), will be deferred and passed to callback
   *    once they'll either fill whole OS buffer, or when this continuous stream
   *    will stop (i.e. there'll be delay between events, bigger than
   *    `latency`).
   *    Specifying this flag will invoke callback after `latency` time passed
   *    since event.
   * 2. FileEvents - fire callback for file changes too (by default it is firing
   *    it only for directory changes).
   */
  flags = kFSEventStreamCreateFlagNoDefer | kFSEventStreamCreateFlagFileEvents;

  /*
   * NOTE: It might sound like a good idea to remember last seen StreamEventId,
   * but in reality one dir might have last StreamEventId less than, the other,
   * that is being watched now. Which will cause FSEventStream API to report
   * changes to files from the past.
   */
  ref = pFSEventStreamCreate(NULL,
                             &uv__fsevents_event_cb,
                             &ctx,
                             paths,
                             kFSEventStreamEventIdSinceNow,
                             latency,
                             flags);
  assert(ref != NULL);

  state = loop->cf_state;
  pFSEventStreamScheduleWithRunLoop(ref,
                                    state->loop,
                                    *pkCFRunLoopDefaultMode);
  if (!pFSEventStreamStart(ref)) {
    pFSEventStreamInvalidate(ref);
    pFSEventStreamRelease(ref);
    return UV_EMFILE;
  }

  state->fsevent_stream = ref;
  return 0;
}


/* Runs in CF thread */
static void uv__fsevents_destroy_stream(uv_loop_t* loop) {
  uv__cf_loop_state_t* state;

  state = loop->cf_state;

  if (state->fsevent_stream == NULL)
    return;

  /* Stop emitting events */
  pFSEventStreamStop(state->fsevent_stream);

  /* Release stream */
  pFSEventStreamInvalidate(state->fsevent_stream);
  pFSEventStreamRelease(state->fsevent_stream);
  state->fsevent_stream = NULL;
}


/* Runs in CF thread, when there're new fsevent handles to add to stream */
static void uv__fsevents_reschedule(uv_fs_event_t* handle,
                                    uv__cf_loop_signal_type_t type) {
  uv__cf_loop_state_t* state;
  QUEUE* q;
  uv_fs_event_t* curr;
  CFArrayRef cf_paths;
  CFStringRef* paths;
  unsigned int i;
  int err;
  unsigned int path_count;

  state = handle->loop->cf_state;
  paths = NULL;
  cf_paths = NULL;
  err = 0;
  /* NOTE: `i` is used in deallocation loop below */
  i = 0;

  /* Optimization to prevent O(n^2) time spent when starting to watch
   * many files simultaneously
   */
  uv_mutex_lock(&state->fsevent_mutex);
  if (state->fsevent_need_reschedule == 0) {
    uv_mutex_unlock(&state->fsevent_mutex);
    goto final;
  }
  state->fsevent_need_reschedule = 0;
  uv_mutex_unlock(&state->fsevent_mutex);

  /* Destroy previous FSEventStream */
  uv__fsevents_destroy_stream(handle->loop);

  /* Any failure below will be a memory failure */
  err = UV_ENOMEM;

  /* Create list of all watched paths */
  uv_mutex_lock(&state->fsevent_mutex);
  path_count = state->fsevent_handle_count;
  if (path_count != 0) {
    paths = uv__malloc(sizeof(*paths) * path_count);
    if (paths == NULL) {
      uv_mutex_unlock(&state->fsevent_mutex);
      goto final;
    }

    q = &state->fsevent_handles;
    for (; i < path_count; i++) {
      q = QUEUE_NEXT(q);
      assert(q != &state->fsevent_handles);
      curr = QUEUE_DATA(q, uv_fs_event_t, cf_member);

      assert(curr->realpath != NULL);
      paths[i] =
          pCFStringCreateWithFileSystemRepresentation(NULL, curr->realpath);

libuv/src/unix/fsevents.c  view on Meta::CPAN

   */
  if (type == kUVCFLoopSignalClosing)
    uv_sem_post(&state->fsevent_sem);
}


static int uv__fsevents_global_init(void) {
  static pthread_mutex_t global_init_mutex = PTHREAD_MUTEX_INITIALIZER;
  static void* core_foundation_handle;
  static void* core_services_handle;
  int err;

  err = 0;
  pthread_mutex_lock(&global_init_mutex);
  if (core_foundation_handle != NULL)
    goto out;

  /* The libraries are never unloaded because we currently don't have a good
   * mechanism for keeping a reference count. It's unlikely to be an issue
   * but if it ever becomes one, we can turn the dynamic library handles into
   * per-event loop properties and have the dynamic linker keep track for us.
   */
  err = UV_ENOSYS;
  core_foundation_handle = dlopen("/System/Library/Frameworks/"
                                  "CoreFoundation.framework/"
                                  "Versions/A/CoreFoundation",
                                  RTLD_LAZY | RTLD_LOCAL);
  if (core_foundation_handle == NULL)
    goto out;

  core_services_handle = dlopen("/System/Library/Frameworks/"
                                "CoreServices.framework/"
                                "Versions/A/CoreServices",
                                RTLD_LAZY | RTLD_LOCAL);
  if (core_services_handle == NULL)
    goto out;

  err = UV_ENOENT;
#define V(handle, symbol)                                                     \
  do {                                                                        \
    *(void **)(&p ## symbol) = dlsym((handle), #symbol);                      \
    if (p ## symbol == NULL)                                                  \
      goto out;                                                               \
  }                                                                           \
  while (0)
  V(core_foundation_handle, CFArrayCreate);
  V(core_foundation_handle, CFRelease);
  V(core_foundation_handle, CFRunLoopAddSource);
  V(core_foundation_handle, CFRunLoopGetCurrent);
  V(core_foundation_handle, CFRunLoopRemoveSource);
  V(core_foundation_handle, CFRunLoopRun);
  V(core_foundation_handle, CFRunLoopSourceCreate);
  V(core_foundation_handle, CFRunLoopSourceSignal);
  V(core_foundation_handle, CFRunLoopStop);
  V(core_foundation_handle, CFRunLoopWakeUp);
  V(core_foundation_handle, CFStringCreateWithFileSystemRepresentation);
  V(core_foundation_handle, CFStringGetSystemEncoding);
  V(core_foundation_handle, kCFRunLoopDefaultMode);
  V(core_services_handle, FSEventStreamCreate);
  V(core_services_handle, FSEventStreamFlushSync);
  V(core_services_handle, FSEventStreamInvalidate);
  V(core_services_handle, FSEventStreamRelease);
  V(core_services_handle, FSEventStreamScheduleWithRunLoop);
  V(core_services_handle, FSEventStreamStart);
  V(core_services_handle, FSEventStreamStop);
#undef V
  err = 0;

out:
  if (err && core_services_handle != NULL) {
    dlclose(core_services_handle);
    core_services_handle = NULL;
  }

  if (err && core_foundation_handle != NULL) {
    dlclose(core_foundation_handle);
    core_foundation_handle = NULL;
  }

  pthread_mutex_unlock(&global_init_mutex);
  return err;
}


/* Runs in UV loop */
static int uv__fsevents_loop_init(uv_loop_t* loop) {
  CFRunLoopSourceContext ctx;
  uv__cf_loop_state_t* state;
  pthread_attr_t attr_storage;
  pthread_attr_t* attr;
  int err;

  if (loop->cf_state != NULL)
    return 0;

  err = uv__fsevents_global_init();
  if (err)
    return err;

  state = uv__calloc(1, sizeof(*state));
  if (state == NULL)
    return UV_ENOMEM;

  err = uv_mutex_init(&loop->cf_mutex);
  if (err)
    goto fail_mutex_init;

  err = uv_sem_init(&loop->cf_sem, 0);
  if (err)
    goto fail_sem_init;

  QUEUE_INIT(&loop->cf_signals);

  err = uv_sem_init(&state->fsevent_sem, 0);
  if (err)
    goto fail_fsevent_sem_init;

  err = uv_mutex_init(&state->fsevent_mutex);
  if (err)
    goto fail_fsevent_mutex_init;