gecko/ipc/glue/AsyncChannel.h
2012-05-21 12:12:37 +01:00

262 lines
8.3 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: sw=4 ts=4 et :
*/
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef ipc_glue_AsyncChannel_h
#define ipc_glue_AsyncChannel_h 1
#include "base/basictypes.h"
#include "base/message_loop.h"
#include "mozilla/Monitor.h"
#include "mozilla/ipc/Transport.h"
//-----------------------------------------------------------------------------
namespace mozilla {
namespace ipc {
struct HasResultCodes
{
enum Result {
MsgProcessed,
MsgDropped,
MsgNotKnown,
MsgNotAllowed,
MsgPayloadError,
MsgProcessingError,
MsgRouteError,
MsgValueError
};
};
class RefCountedMonitor : public Monitor
{
public:
RefCountedMonitor()
: Monitor("mozilla.ipc.AsyncChannel.mMonitor")
{}
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RefCountedMonitor)
};
class AsyncChannel : protected HasResultCodes
{
protected:
typedef mozilla::Monitor Monitor;
enum ChannelState {
ChannelClosed,
ChannelOpening,
ChannelConnected,
ChannelTimeout,
ChannelClosing,
ChannelError
};
public:
typedef IPC::Message Message;
typedef mozilla::ipc::Transport Transport;
class /*NS_INTERFACE_CLASS*/ AsyncListener: protected HasResultCodes
{
public:
virtual ~AsyncListener() { }
virtual void OnChannelClose() = 0;
virtual void OnChannelError() = 0;
virtual Result OnMessageReceived(const Message& aMessage) = 0;
virtual void OnProcessingError(Result aError) = 0;
virtual void OnChannelConnected(int32 peer_pid) {};
};
enum Side { Parent, Child, Unknown };
public:
//
// These methods are called on the "worker" thread
//
AsyncChannel(AsyncListener* aListener);
virtual ~AsyncChannel();
// "Open" from the perspective of the transport layer; the underlying
// socketpair/pipe should already be created.
//
// Returns true iff the transport layer was successfully connected,
// i.e., mChannelState == ChannelConnected.
bool Open(Transport* aTransport, MessageLoop* aIOLoop=0, Side aSide=Unknown);
// "Open" a connection to another thread in the same process.
//
// Returns true iff the transport layer was successfully connected,
// i.e., mChannelState == ChannelConnected.
//
// For more details on the process of opening a channel between
// threads, see the extended comment on this function
// in AsyncChannel.cpp.
bool Open(AsyncChannel *aTargetChan, MessageLoop *aTargetLoop, Side aSide);
// Close the underlying transport channel.
void Close();
// Asynchronously send a message to the other side of the channel
virtual bool Send(Message* msg);
// Asynchronously deliver a message back to this side of the
// channel
virtual bool Echo(Message* msg);
// Send OnChannelConnected notification to listeners.
void DispatchOnChannelConnected(int32 peer_pid);
//
// Each AsyncChannel is associated with either a ProcessLink or a
// ThreadLink via the field mLink. The type of link is determined
// by whether this AsyncChannel is communicating with another
// process or another thread. In the former case, file
// descriptors or a socket are used via the I/O queue. In the
// latter case, messages are enqueued directly onto the target
// thread's work queue.
//
class Link {
protected:
AsyncChannel *mChan;
public:
Link(AsyncChannel *aChan);
virtual ~Link();
// n.b.: These methods all require that the channel monitor is
// held when they are invoked.
virtual void EchoMessage(Message *msg) = 0;
virtual void SendMessage(Message *msg) = 0;
virtual void SendClose() = 0;
};
class ProcessLink : public Link, public Transport::Listener {
protected:
Transport* mTransport;
MessageLoop* mIOLoop; // thread where IO happens
Transport::Listener* mExistingListener; // channel's previous listener
void OnCloseChannel();
void OnChannelOpened();
void OnEchoMessage(Message* msg);
void AssertIOThread() const
{
NS_ABORT_IF_FALSE(mIOLoop == MessageLoop::current(),
"not on I/O thread!");
}
public:
ProcessLink(AsyncChannel *chan);
virtual ~ProcessLink();
void Open(Transport* aTransport, MessageLoop *aIOLoop, Side aSide);
// Run on the I/O thread, only when using inter-process link.
// These methods acquire the monitor and forward to the
// similarly named methods in AsyncChannel below
// (OnMessageReceivedFromLink(), etc)
NS_OVERRIDE virtual void OnMessageReceived(const Message& msg);
NS_OVERRIDE virtual void OnChannelConnected(int32 peer_pid);
NS_OVERRIDE virtual void OnChannelError();
NS_OVERRIDE virtual void EchoMessage(Message *msg);
NS_OVERRIDE virtual void SendMessage(Message *msg);
NS_OVERRIDE virtual void SendClose();
};
class ThreadLink : public Link {
protected:
AsyncChannel* mTargetChan;
public:
ThreadLink(AsyncChannel *aChan, AsyncChannel *aTargetChan);
virtual ~ThreadLink();
NS_OVERRIDE virtual void EchoMessage(Message *msg);
NS_OVERRIDE virtual void SendMessage(Message *msg);
NS_OVERRIDE virtual void SendClose();
};
protected:
// The "link" thread is either the I/O thread (ProcessLink) or the
// other actor's work thread (ThreadLink). In either case, it is
// NOT our worker thread.
void AssertLinkThread() const
{
NS_ABORT_IF_FALSE(mWorkerLoop != MessageLoop::current(),
"on worker thread but should not be!");
}
// Can be run on either thread
void AssertWorkerThread() const
{
NS_ABORT_IF_FALSE(mWorkerLoop == MessageLoop::current(),
"not on worker thread!");
}
bool Connected() const {
mMonitor->AssertCurrentThreadOwns();
return ChannelConnected == mChannelState;
}
// Return true if |msg| is a special message targeted at the IO
// thread, in which case it shouldn't be delivered to the worker.
virtual bool MaybeInterceptSpecialIOMessage(const Message& msg);
void ProcessGoodbyeMessage();
// Runs on the link thread. Invoked either from the I/O thread methods above
// or directly from the other actor if using a thread-based link.
//
// n.b.: mMonitor is always held when these methods are invoked.
// In the case of a ProcessLink, it is acquired by the ProcessLink.
// In the case of a ThreadLink, it is acquired by the other actor,
// which then invokes these methods directly.
virtual void OnMessageReceivedFromLink(const Message& msg);
virtual void OnChannelErrorFromLink();
void PostErrorNotifyTask();
// Run on the worker thread
void OnDispatchMessage(const Message& aMsg);
virtual bool OnSpecialMessage(uint16 id, const Message& msg);
void SendSpecialMessage(Message* msg) const;
// Tell the IO thread to close the channel and wait for it to ACK.
void SynchronouslyClose();
bool MaybeHandleError(Result code, const char* channelName);
void ReportConnectionError(const char* channelName) const;
// Run on the worker thread
void OnNotifyMaybeChannelError();
virtual bool ShouldDeferNotifyMaybeError() const {
return false;
}
void NotifyChannelClosed();
void NotifyMaybeChannelError();
void OnOpenAsSlave(AsyncChannel *aTargetChan, Side aSide);
void CommonThreadOpenInit(AsyncChannel *aTargetChan, Side aSide);
virtual void Clear();
AsyncListener* mListener;
ChannelState mChannelState;
nsRefPtr<RefCountedMonitor> mMonitor;
MessageLoop* mWorkerLoop; // thread where work is done
bool mChild; // am I the child or parent?
CancelableTask* mChannelErrorTask; // NotifyMaybeChannelError runnable
Link *mLink; // link to other thread/process
};
} // namespace ipc
} // namespace mozilla
#endif // ifndef ipc_glue_AsyncChannel_h