// Copyright (c) 2012 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 IPC_IPC_CHANNEL_WIN_H_
#define IPC_IPC_CHANNEL_WIN_H_

#include "ipc/ipc_channel.h"

#include <queue>
#include <string>

#include "base/memory/scoped_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/message_loop/message_loop.h"
#include "base/win/scoped_handle.h"
#include "ipc/ipc_channel_reader.h"

namespace base {
class ThreadChecker;
}

namespace IPC {

class ChannelWin : public Channel,
                   public internal::ChannelReader,
                   public base::MessageLoopForIO::IOHandler {
 public:
  // Mirror methods of Channel, see ipc_channel.h for description.
  ChannelWin(const IPC::ChannelHandle &channel_handle, Mode mode,
             Listener* listener);
  ~ChannelWin() override;

  // Channel implementation
  bool Connect() override;
  void Close() override;
  bool Send(Message* message) override;
  base::ProcessId GetPeerPID() const override;
  base::ProcessId GetSelfPID() const override;

  static bool IsNamedServerInitialized(const std::string& channel_id);


 private:
  // ChannelReader implementation.
  ReadState ReadData(char* buffer, int buffer_len, int* bytes_read) override;
  bool WillDispatchInputMessage(Message* msg) override;
  bool DidEmptyInputBuffers() override;
  void HandleInternalMessage(const Message& msg) override;

  static const base::string16 PipeName(const std::string& channel_id,
                                       int32* secret);
  bool CreatePipe(const IPC::ChannelHandle &channel_handle, Mode mode);

  bool ProcessConnection();
  bool ProcessOutgoingMessages(base::MessageLoopForIO::IOContext* context,
                               DWORD bytes_written);

  // MessageLoop::IOHandler implementation.
  void OnIOCompleted(base::MessageLoopForIO::IOContext* context,
                     DWORD bytes_transfered,
                     DWORD error) override;

 private:
  struct State {
    explicit State(ChannelWin* channel);
    ~State();
    base::MessageLoopForIO::IOContext context;
    bool is_pending;
  };

  State input_state_;
  State output_state_;

  base::win::ScopedHandle pipe_;

  base::ProcessId peer_pid_;

  // Messages to be sent are queued here.
  std::queue<Message*> output_queue_;

  // In server-mode, we have to wait for the client to connect before we
  // can begin reading.  We make use of the input_state_ when performing
  // the connect operation in overlapped mode.
  bool waiting_connect_;

  // This flag is set when processing incoming messages.  It is used to
  // avoid recursing through ProcessIncomingMessages, which could cause
  // problems.  TODO(darin): make this unnecessary
  bool processing_incoming_;

  // Determines if we should validate a client's secret on connection.
  bool validate_client_;

  // Tracks the lifetime of this object, for debugging purposes.
  uint32 debug_flags_;

  // This is a unique per-channel value used to authenticate the client end of
  // a connection. If the value is non-zero, the client passes it in the hello
  // and the host validates. (We don't send the zero value fto preserve IPC
  // compatability with existing clients that don't validate the channel.)
  int32 client_secret_;

  scoped_ptr<base::ThreadChecker> thread_check_;
  base::WeakPtrFactory<ChannelWin> weak_factory_;

  DISALLOW_COPY_AND_ASSIGN(ChannelWin);
};

}  // namespace IPC

#endif  // IPC_IPC_CHANNEL_WIN_H_