FilePathWatcher::Watch() - Listen for sub directory changes.

base/files/file_path_watcher.h

Index: base/files/file_path_watcher.h
diff --git a/base/files/file_path_watcher.h b/base/files/file_path_watcher.h
index 367be9435e9c952b7865b8f0aab3f479eeb6963e..76f000e10f01f9563501a38bd2c5415512279464 100644
--- a/base/files/file_path_watcher.h
+++ b/base/files/file_path_watcher.h
@@ -59,6 +59,7 @@ class BASE_EXPORT FilePathWatcher {
 
     // Start watching for the given |path| and notify |delegate| about changes.
     virtual bool Watch(const FilePath& path,
+                       bool recursive,
                        Delegate* delegate) WARN_UNUSED_RESULT = 0;
 
     // Stop watching. This is called from FilePathWatcher's dtor in order to
@@ -119,9 +120,13 @@ class BASE_EXPORT FilePathWatcher {
       WARN_UNUSED_RESULT;
 
   // Invokes |callback| whenever updates to |path| are detected. This should be
-  // called at most once, and from a MessageLoop of TYPE_IO. The callback will
-  // be invoked on the same loop. Returns true on success.
-  bool Watch(const FilePath& path, const Callback& callback);
+  // called at most once, and from a MessageLoop of TYPE_IO. Set |recursive| to
+  // true, to watch |path| and its children. The callback will be invoked on
+  // the same loop. Returns true on success.
+  //
+  // NOTE: Recursive watch is not supported on all platforms. Watch() will

[Lei Zhang, 2012/12/03 21:44:39]

Does it work on network shared on Windows? This may not be just per-platform.

[kmadhusu, 2012/12/03 22:54:57]

On Windows, notifications may not be returned when calling
FindFirstChangeNotification for a remote file system. (Ref:
http://msdn.microsoft.com/en-us/library/windows/desktop/aa364417(v=vs.85).aspx).
This note is very specific for a recursive_watch functionality. On windows, we
support recursive_watch but if the Windows API fails it will return false. Do
you want me to add all these details here?

[Lei Zhang, 2012/12/03 23:16:20]

No, we should go into such details here, but I'm concerned this statement as
written makes readers think it's supported for all paths on a supported
platform.

[kmadhusu, 2012/12/04 00:06:36]

Rephrased the comment. Let me know your comments.

+  // return false on those platforms that don't support it.
+  bool Watch(const FilePath& path, bool recursive, const Callback& callback);
 
  private:
   scoped_refptr<PlatformDelegate> impl_;