Add FileSystemWatcher class to dart:io.

runtime/bin/file_system_watcher.h

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef BIN_FILE_SYSTEM_WATCHER_H_
+#define BIN_FILE_SYSTEM_WATCHER_H_
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <sys/types.h>
+
+#include "bin/builtin.h"
+#include "bin/dartutils.h"
+
+
+namespace dart {
+namespace bin {
+
+class FileSystemWatcher {
+ public:
+  enum EventType {
+    kCreate = 1 << 0,
+    kModifyContent = 1 << 1,
+    kDelete = 1 << 2,
+    kMove = 1 << 3,
+    kModefyAttribute = 1 << 4
+  };
+
+  struct Event {
+    intptr_t path_id;
+    int event;
+    const char* filename;
+    int link;
+  };
+
+  static intptr_t WatchPath(const char* path, int events, bool recursive);
+  static void UnwatchPath(intptr_t id);
+  static intptr_t GetSocketId(intptr_t id);
+  static Dart_Handle ReadEvents(intptr_t id);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FileSystemWatcher);
+};
+
+}  // namespace bin
+}  // namespace dart
+
+#endif  // BIN_FILE_SYSTEM_WATCHER_H_
+