Add DirectoryWatcher implementation for Mac.

base/directory_watcher_mac.cc

+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/directory_watcher.h"
+
+#include <CoreServices/CoreServices.h>
+
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/message_loop.h"
+#include "base/scoped_cftyperef.h"
+
+namespace {
+
+const CFAbsoluteTime kEventLatencySeconds = 0.3;
+
+class DirectoryWatcherImpl : public DirectoryWatcher::PlatformDelegate {
+ public:
+  DirectoryWatcherImpl() {}
+  ~DirectoryWatcherImpl() {
+    if (!path_.value().empty()) {
+      FSEventStreamStop(fsevent_stream_);
+      FSEventStreamInvalidate(fsevent_stream_);
+      FSEventStreamRelease(fsevent_stream_);
+    }
+  }
+
+  virtual bool Watch(const FilePath& path, DirectoryWatcher::Delegate* delegate,
+                     bool recursive);
+
+  void OnFSEventsCallback(const FilePath& event_path) {
+    DCHECK(!path_.value().empty());
+    if (!recursive_) {
+      FilePath absolute_event_path = event_path;
+      if (!file_util::AbsolutePath(&absolute_event_path))
+        return;
+      if (absolute_event_path != path_)
+        return;
+    }
+    delegate_->OnDirectoryChanged(path_);
+  }
+
+ private:
+  // Delegate to notify upon changes.
+  DirectoryWatcher::Delegate* delegate_;
+
+  // Path we're watching (passed to delegate).
+  FilePath path_;
+
+  // Indicates recursive watch.
+  bool recursive_;
+
+  // Backend stream we receive event callbacks from (strong reference).
+  FSEventStreamRef fsevent_stream_;
+
+  DISALLOW_COPY_AND_ASSIGN(DirectoryWatcherImpl);
+};
+
+void FSEventsCallback(ConstFSEventStreamRef stream,
+                      void* event_watcher, size_t num_events,
+                      void* event_paths, const FSEventStreamEventFlags flags[],
+                      const FSEventStreamEventId event_ids[]) {
+  char** paths = reinterpret_cast<char**>(event_paths);
+  DirectoryWatcherImpl* watcher =
+      reinterpret_cast<DirectoryWatcherImpl*> (event_watcher);
+  for (size_t i = 0; i < num_events; i++) {
+    watcher->OnFSEventsCallback(FilePath(paths[i]));
+  }
+}
+
+bool DirectoryWatcherImpl::Watch(const FilePath& path,
+                                 DirectoryWatcher::Delegate* delegate,
+                                 bool recursive) {
+  DCHECK(path_.value().empty());  // Can only watch one path.
+
+  DCHECK(MessageLoop::current()->type() == MessageLoop::TYPE_UI);
+
+  if (!file_util::PathExists(path))
+    return false;
+
+  path_ = path;
+  if (!file_util::AbsolutePath(&path_)) {
+    path_ = FilePath();  // Make sure we're marked as not-in-use.
+    return false;
+  }
+  delegate_ = delegate;
+  recursive_ = recursive;
+
+  scoped_cftyperef<CFStringRef> cf_path(CFStringCreateWithCString(
+      NULL, path.value().c_str(), kCFStringEncodingMacHFS));
+  CFStringRef path_for_array = cf_path.get();
+  scoped_cftyperef<CFArrayRef> watched_paths(CFArrayCreate(
+      NULL, reinterpret_cast<const void**>(&path_for_array), 1,
+      &kCFTypeArrayCallBacks));
+
+  FSEventStreamContext context;
+  context.version = 0;
+  context.info = this;
+  context.retain = NULL;
+  context.release = NULL;
+  context.copyDescription = NULL;
+
+  fsevent_stream_ = FSEventStreamCreate(NULL, &FSEventsCallback, &context,
+                                        watched_paths,
+                                        kFSEventStreamEventIdSinceNow,
+                                        kEventLatencySeconds,
+                                        kFSEventStreamCreateFlagNone);
+  FSEventStreamScheduleWithRunLoop(fsevent_stream_, CFRunLoopGetCurrent(),
+                                   kCFRunLoopDefaultMode);
+  FSEventStreamStart(fsevent_stream_);
+
+  return true;
+}
+
+}  // namespace
+
+DirectoryWatcher::DirectoryWatcher() {
+  impl_ = new DirectoryWatcherImpl();
+}