From 9e8d4f92df67dd8d4c8d4097035aaf6279fe84ba Mon Sep 17 00:00:00 2001
From: "evanm@google.com"
 <evanm@google.com@0039d316-1c4b-4281-b951-d872f2087c98>
Date: Fri, 17 Oct 2008 02:45:56 +0000
Subject: Add a DirectoryWatcher class, allowing objects to be notified
 whenever a directory's contents change.

Review URL: http://codereview.chromium.org/6377

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@3504 0039d316-1c4b-4281-b951-d872f2087c98
---
 base/directory_watcher_win.cc | 86 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 base/directory_watcher_win.cc

(limited to 'base/directory_watcher_win.cc')

diff --git a/base/directory_watcher_win.cc b/base/directory_watcher_win.cc
new file mode 100644
index 0000000..cdaec39
--- /dev/null
+++ b/base/directory_watcher_win.cc
@@ -0,0 +1,86 @@
+// Copyright (c) 2006-2008 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 "base/file_path.h"
+#include "base/object_watcher.h"
+
+// Private implementation class implementing the behavior of DirectoryWatcher.
+class DirectoryWatcher::Impl : public base::RefCounted<DirectoryWatcher::Impl>,
+                               public base::ObjectWatcher::Delegate {
+ public:
+  Impl(DirectoryWatcher::Delegate* delegate)
+      : delegate_(delegate), handle_(INVALID_HANDLE_VALUE) {}
+  ~Impl();
+
+  // Register interest in any changes in |path|.
+  // Returns false on error.
+  bool Watch(const FilePath& path);
+
+  // Callback from MessageLoopForIO.
+  virtual void OnObjectSignaled(HANDLE object);
+
+ private:
+  // Delegate to notify upon changes.
+  DirectoryWatcher::Delegate* delegate_;
+  // Path we're watching (passed to delegate).
+  FilePath path_;
+  // Handle for FindFirstChangeNotification.
+  HANDLE handle_;
+  // ObjectWatcher to watch handle_ for events.
+  base::ObjectWatcher watcher_;
+};
+
+DirectoryWatcher::Impl::~Impl() {
+  if (handle_ != INVALID_HANDLE_VALUE) {
+    watcher_.StopWatching();
+    FindCloseChangeNotification(handle_);
+  }
+}
+
+bool DirectoryWatcher::Impl::Watch(const FilePath& path) {
+  DCHECK(path_.value().empty());  // Can only watch one path.
+
+  handle_ = FindFirstChangeNotification(
+      path.value().c_str(),
+      FALSE,  // Don't watch subtree.
+      FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_SIZE |
+      FILE_NOTIFY_CHANGE_LAST_WRITE);
+  if (handle_ == INVALID_HANDLE_VALUE) {
+    NOTREACHED();
+    return false;
+  }
+
+  path_ = path;
+  watcher_.StartWatching(handle_, this);
+
+  return true;
+}
+
+void DirectoryWatcher::Impl::OnObjectSignaled(HANDLE object) {
+  DCHECK(object == handle_);
+  // Make sure we stay alive through the body of this function.
+  scoped_refptr<DirectoryWatcher::Impl> keep_alive(this);
+
+  delegate_->OnDirectoryChanged(path_);
+
+  // Register for more notifications on file change.
+  BOOL ok = FindNextChangeNotification(object);
+  DCHECK(ok);
+  watcher_.StartWatching(object, this);
+}
+
+DirectoryWatcher::DirectoryWatcher() {
+}
+
+DirectoryWatcher::~DirectoryWatcher() {
+  // Declared in .cc file for access to ~DirectoryWatcher::Impl.
+}
+
+bool DirectoryWatcher::Watch(const FilePath& path,
+                             Delegate* delegate) {
+  impl_ = new DirectoryWatcher::Impl(delegate);
+  return impl_->Watch(path);
+}
-- 
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