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// Copyright (c) 2006-2008 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_COMMON_IPC_CHANNEL_H_
#define CHROME_COMMON_IPC_CHANNEL_H_
#include <queue>
#include "base/message_loop.h"
#include "chrome/common/ipc_message.h"
namespace IPC {
//------------------------------------------------------------------------------
class Channel : public MessageLoopForIO::IOHandler,
public Message::Sender {
// Security tests need access to the pipe handle.
friend class ChannelTest;
public:
// Implemented by consumers of a Channel to receive messages.
class Listener {
public:
virtual ~Listener() {}
// Called when a message is received.
virtual void OnMessageReceived(const Message& message) = 0;
// Called when the channel is connected and we have received the internal
// Hello message from the peer.
virtual void OnChannelConnected(int32 peer_pid) {}
// Called when an error is detected that causes the channel to close.
// This method is not called when a channel is closed normally.
virtual void OnChannelError() {}
};
enum Mode {
MODE_SERVER,
MODE_CLIENT
};
// The maximum message size in bytes. Attempting to receive a
// message of this size or bigger results in a channel error.
enum {
kMaximumMessageSize = 256 * 1024 * 1024
};
// Initialize a Channel.
//
// |channel_id| identifies the communication Channel.
// |mode| specifies whether this Channel is to operate in server mode or
// client mode. In server mode, the Channel is responsible for setting up the
// IPC object, whereas in client mode, the Channel merely connects to the
// already established IPC object.
// |listener| receives a callback on the current thread for each newly
// received message.
//
Channel(const std::wstring& channel_id, Mode mode, Listener* listener);
~Channel() { Close(); }
// Connect the pipe. On the server side, this will initiate
// waiting for connections. On the client, it attempts to
// connect to a pre-existing pipe. Note, calling Connect()
// will not block the calling thread and may complete
// asynchronously.
bool Connect();
// Close this Channel explicitly. May be called multiple times.
void Close();
// Modify the Channel's listener.
void set_listener(Listener* listener) { listener_ = listener; }
// Send a message over the Channel to the listener on the other end.
//
// |message| must be allocated using operator new. This object will be
// deleted once the contents of the Message have been sent.
//
// FIXME bug 551500: the channel does not notice failures, so if the
// renderer crashes, it will silently succeed, leaking the parameter.
// At least the leak will be fixed by...
//
virtual bool Send(Message* message);
// Process any pending incoming and outgoing messages. Wait for at most
// max_wait_msec for pending messages if there are none. Returns true if
// there were no pending messages or if pending messages were successfully
// processed. Returns false if there are pending messages that cannot be
// processed for some reason (e.g., because ProcessIncomingMessages would be
// re-entered).
// TODO(darin): Need a better way of dealing with the recursion problem.
bool ProcessPendingMessages(DWORD max_wait_msec);
private:
const std::wstring PipeName(const std::wstring& channel_id) const;
bool CreatePipe(const std::wstring& channel_id, Mode mode);
bool ProcessConnection();
bool ProcessIncomingMessages(OVERLAPPED* context, DWORD bytes_read);
bool ProcessOutgoingMessages(OVERLAPPED* context, DWORD bytes_written);
// MessageLoop::IOHandler implementation.
virtual void OnIOCompleted(OVERLAPPED* context, DWORD bytes_transfered,
DWORD error);
private:
enum {
BUF_SIZE = 4096
};
struct State {
State();
~State();
OVERLAPPED overlapped;
bool is_pending;
};
State input_state_;
State output_state_;
HANDLE pipe_;
Listener* listener_;
// Messages to be sent are queued here.
std::queue<Message*> output_queue_;
// We read from the pipe into this buffer
char input_buf_[BUF_SIZE];
// Large messages that span multiple pipe buffers, get built-up using
// this buffer.
std::string input_overflow_buf_;
// 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_;
ScopedRunnableMethodFactory<Channel> factory_;
// The Hello message is internal to the Channel class. It is sent
// by the peer when the channel is connected. The message contains
// just the process id (pid). The message has a special routing_id
// (MSG_ROUTING_NONE) and type (HELLO_MESSAGE_TYPE).
enum {
HELLO_MESSAGE_TYPE = MAXWORD // Maximum value of message type (WORD),
// to avoid conflicting with normal
// message types, which are enumeration
// constants starting from 0.
};
};
}
#endif // CHROME_COMMON_IPC_CHANNEL_H_
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