// Copyright (c) 2010 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 CHROME_BROWSER_GPU_PROCESS_HOST_H_
#define CHROME_BROWSER_GPU_PROCESS_HOST_H_

#include <queue>

#include "base/basictypes.h"
#include "base/scoped_ptr.h"
#include "chrome/browser/child_process_host.h"
#include "chrome/browser/renderer_host/resource_message_filter.h"

class ChildProcessLauncher;
class CommandBufferProxy;

class GpuProcessHost : public ChildProcessHost {
 public:
  // Getter for the singleton. This will return NULL on failure.
  static GpuProcessHost* Get();

  // Shutdown routine, which should only be called upon process
  // termination.
  static void Shutdown();

  virtual bool Send(IPC::Message* msg);

  // IPC::Channel::Listener implementation.
  virtual void OnMessageReceived(const IPC::Message& message);

  // Tells the GPU process to create a new channel for communication with a
  // renderer. Will asynchronously send message to object with given routing id
  // on completion.
  void EstablishGpuChannel(int renderer_id,
                           ResourceMessageFilter* filter);

  // Sends a reply message later when the next GpuHostMsg_SynchronizeReply comes
  // in.
  void Synchronize(IPC::Message* reply,
                   ResourceMessageFilter* filter);

 private:
  // Used to queue pending channel requests.
  struct ChannelRequest {
    explicit ChannelRequest(ResourceMessageFilter* filter)
        : filter(filter) {}
    // Used to send the reply message back to the renderer.
    scoped_refptr<ResourceMessageFilter> filter;
  };

  // Used to queue pending synchronization requests.
  struct SynchronizationRequest {
    SynchronizationRequest(IPC::Message* reply,
                           ResourceMessageFilter* filter)
        : reply(reply),
          filter(filter) {}
    // The delayed reply message which needs to be sent to the
    // renderer.
    IPC::Message* reply;

    // Used to send the reply message back to the renderer.
    scoped_refptr<ResourceMessageFilter> filter;
  };

  GpuProcessHost();
  virtual ~GpuProcessHost();

  bool EnsureInitialized();
  bool Init();

  void OnControlMessageReceived(const IPC::Message& message);

  // Message handlers.
  void OnChannelEstablished(const IPC::ChannelHandle& channel_handle);
  void OnSynchronizeReply();

  void ReplyToRenderer(const IPC::ChannelHandle& channel,
                       ResourceMessageFilter* filter);

  // Copies applicable command line switches from the given |browser_cmd| line
  // flags to the output |gpu_cmd| line flags. Not all switches will be
  // copied over.
  void PropagateBrowserCommandLineToGpu(const CommandLine& browser_cmd,
                                        CommandLine* gpu_cmd) const;

  // ResourceDispatcherHost::Receiver implementation:
  virtual URLRequestContext* GetRequestContext(
      uint32 request_id,
      const ViewHostMsg_Resource_Request& request_data);

  virtual bool CanShutdown();

  bool initialized_;
  bool initialized_successfully_;

  // These are the channel requests that we have already sent to
  // the GPU process, but haven't heard back about yet.
  std::queue<ChannelRequest> sent_requests_;

  // The pending synchronization requests we need to reply to.
  std::queue<SynchronizationRequest> queued_synchronization_replies_;

  DISALLOW_COPY_AND_ASSIGN(GpuProcessHost);
};

#endif  // CHROME_BROWSER_GPU_PROCESS_HOST_H_