From 7619caa2b3df64afc252a640b98f118299d35433 Mon Sep 17 00:00:00 2001
From: Robert Sesek <rsesek@google.com>
Date: Fri, 20 Mar 2015 12:49:37 -0400
Subject: [PATCH] Initial checkin of basic FSEvent watcher.

---
 fseventw.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 fseventw.c

diff --git a/fseventw.c b/fseventw.c
new file mode 100644
index 0000000..7f8ea3e
--- /dev/null
+++ b/fseventw.c
@@ -0,0 +1,84 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <CoreServices/CoreServices.h>
+#include <dispatch/dispatch.h>
+#include <stdio.h>
+
+void EventStreamCallback(ConstFSEventStreamRef event_stream,
+                         void* callback_info,
+                         size_t num_events,
+                         void* event_paths_void,
+                         const FSEventStreamEventFlags event_flags[],
+                         const FSEventStreamEventId event_ids[]) {
+  dispatch_queue_t log_queue = callback_info;
+  const char** event_paths = event_paths_void;
+
+  for (size_t i = 0; i < num_events; ++i) {
+    const FSEventStreamEventFlags flags = event_flags[i];
+    const FSEventStreamEventId ids = event_ids[i];
+
+    char* path = strdup(event_paths[i]);
+
+    dispatch_async(log_queue, ^{
+        printf("event %llx %x at %s\n", ids, flags, path);
+        free(path);
+    });
+  }
+}
+
+int main() {
+  dispatch_queue_t log_queue = dispatch_queue_create("com.google.fseventw.logq", DISPATCH_QUEUE_SERIAL);
+  dispatch_queue_t event_queue = dispatch_queue_create("com.google.fseventw.eventq", DISPATCH_QUEUE_CONCURRENT);
+
+  const CFStringRef kPath = CFSTR("/");
+  const void* paths_to_watch_c[] = { kPath };
+  CFArrayRef paths_to_watch = CFArrayCreate(NULL, paths_to_watch_c, 1, &kCFTypeArrayCallBacks);
+
+  FSEventStreamContext context = {
+    .version = 0,
+    .info = log_queue,
+    .retain = (const void* (*)(const void*))&dispatch_retain,
+    .release = (void (*)(const void*))&dispatch_release,
+    .copyDescription = NULL
+  };
+  FSEventStreamRef event_stream =
+      FSEventStreamCreate(NULL,
+                          &EventStreamCallback,
+                          &context,
+                          paths_to_watch,
+                          kFSEventStreamEventIdSinceNow,
+                          1,
+                          kFSEventStreamCreateFlagFileEvents);
+
+  CFRelease(paths_to_watch);
+
+  FSEventStreamSetDispatchQueue(event_stream, event_queue);
+
+  if (!FSEventStreamStart(event_stream)) {
+    fprintf(stderr, "Failed to start FSEventStream\n");
+    return EXIT_FAILURE;
+  }
+
+  dispatch_main();
+
+  FSEventStreamStop(event_stream);
+  FSEventStreamSetDispatchQueue(event_stream, NULL);
+  FSEventStreamRelease(event_stream);
+
+  dispatch_release(event_queue);
+  dispatch_barrier_sync(log_queue, ^{
+      dispatch_release(log_queue);
+  });
+}
-- 
2.43.5