Add FileSystemWatcher class to dart:io.

runtime/bin/file_system_watcher.cc

+// 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.
+
+#include "bin/file_system_watcher.h"
+
+#include "bin/builtin.h"
+#include "bin/dartutils.h"
+
+#include "include/dart_api.h"
+
+namespace dart {
+namespace bin {
+
+static const int kWatcherNativeField = 0;
+
+
+void SetWatcherIdNativeField(Dart_Handle watcher, intptr_t id) {
+  ThrowIfError(Dart_SetNativeInstanceField(watcher, kWatcherNativeField, id));
+}
+
+
+void GetWatcherIdNativeField(Dart_Handle watcher, intptr_t* id) {
+  ThrowIfError(Dart_GetNativeInstanceField(watcher, kWatcherNativeField, id));
+}
+
+
+void FUNCTION_NAME(FileSystemWatcher_WatchPath)(Dart_NativeArguments args) {
+  Dart_Handle watcher = Dart_GetNativeArgument(args, 0);
+  const char* path = DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
+  int events = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 2));
+  bool recursive = DartUtils::GetBooleanValue(Dart_GetNativeArgument(args, 3));
+  intptr_t id = FileSystemWatcher::WatchPath(path, events, recursive);
+  if (id == -1) {
+    Dart_PropagateError(DartUtils::NewDartOSError());
+  } else {
+    SetWatcherIdNativeField(watcher, id);
+  }
+  intptr_t socket_id = FileSystemWatcher::GetSocketId(id);
+  Dart_SetReturnValue(args, Dart_NewInteger(socket_id));
+}
+
+
+void FUNCTION_NAME(FileSystemWatcher_UnwatchPath)(Dart_NativeArguments args) {
+  Dart_Handle watcher = Dart_GetNativeArgument(args, 0);
+  intptr_t id;
+  GetWatcherIdNativeField(watcher, &id);
+  FileSystemWatcher::UnwatchPath(id);
+}
+
+
+void FUNCTION_NAME(FileSystemWatcher_ReadEvents)(Dart_NativeArguments args) {
+  Dart_Handle watcher = Dart_GetNativeArgument(args, 0);
+  intptr_t id;
+  GetWatcherIdNativeField(watcher, &id);
+  Dart_Handle handle = FileSystemWatcher::ReadEvents(id);
+  ThrowIfError(handle);
+  Dart_SetReturnValue(args, handle);
+}
+
+}  // namespace bin
+}  // namespace dart