Mojo: WebSocket interface now reuses the DataPipe for subsequent sends or

mojo/services/public/cpp/network/web_socket_write_queue.h

+// Copyright 2014 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.
+
+#ifndef MOJO_SERVICES_PUBLIC_CPP_NETWORK_WEB_SOCKET_WRITE_QUEUE_H_
+#define MOJO_SERVICES_PUBLIC_CPP_NETWORK_WEB_SOCKET_WRITE_QUEUE_H_
+
+#include "base/callback.h"
+#include "base/memory/scoped_vector.h"
+#include "mojo/common/handle_watcher.h"
+#include "mojo/public/cpp/system/data_pipe.h"
+
+namespace mojo {
+
+// This class simplifies the handling of multiple Writes on a DataPipe. It
+// writes each chunk all at once (or waits until the pipe is ready before
+// writing), calling the callback when finished. Callbacks are owned by this
+// class, and are guaranteed not to be called after this class is destroyed.
+// See also: WebSocketReadQueue
+class WebSocketWriteQueue {
+ public:
+  WebSocketWriteQueue(DataPipeProducerHandle handle);
+  ~WebSocketWriteQueue();
+
+  void Write(const char* data,
+             uint32_t num_bytes,
+             base::Callback<void(const char*)> callback);
+
+ private:
+  struct Operation;
+
+  MojoResult TryToWrite();
+  void Wait();
+  void OnHandleReady(MojoResult result);
+
+  DataPipeProducerHandle handle_;
+  common::HandleWatcher handle_watcher_;
+  ScopedVector<Operation> queue_;
+  bool is_waiting_;
+};
+
+}  // namespace mojo
+
+#endif  // MOJO_SERVICES_PUBLIC_CPP_NETWORK_WEB_SOCKET_WRITE_QUEUE_H_