gecko/ipc/glue/AsyncChannel.cpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: sw=4 ts=4 et :
*/
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Plugin App.
*
* The Initial Developer of the Original Code is
* Chris Jones <jones.chris.g@gmail.com>
* Portions created by the Initial Developer are Copyright (C) 2009
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "mozilla/ipc/AsyncChannel.h"
#include "mozilla/ipc/BrowserProcessSubThread.h"
#include "mozilla/ipc/ProtocolUtils.h"
#include "nsDebug.h"
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#include "nsTraceRefcnt.h"
#include "nsXULAppAPI.h"
using mozilla::MutexAutoLock;
template<>
struct RunnableMethodTraits<mozilla::ipc::AsyncChannel>
{
static void RetainCallee(mozilla::ipc::AsyncChannel* obj) { }
static void ReleaseCallee(mozilla::ipc::AsyncChannel* obj) { }
};
// We rely on invariants about the lifetime of the transport:
//
// - outlives this AsyncChannel
// - deleted on the IO thread
//
// These invariants allow us to send messages directly through the
// transport without having to worry about orphaned Send() tasks on
// the IO thread touching AsyncChannel memory after it's been deleted
// on the worker thread. We also don't need to refcount the
// Transport, because whatever task triggers its deletion only runs on
// the IO thread, and only runs after this AsyncChannel is done with
// the Transport.
template<>
struct RunnableMethodTraits<mozilla::ipc::AsyncChannel::Transport>
{
static void RetainCallee(mozilla::ipc::AsyncChannel::Transport* obj) { }
static void ReleaseCallee(mozilla::ipc::AsyncChannel::Transport* obj) { }
};
namespace {
// This is an async message
class GoodbyeMessage : public IPC::Message
{
public:
enum { ID = GOODBYE_MESSAGE_TYPE };
GoodbyeMessage() :
IPC::Message(MSG_ROUTING_NONE, ID, PRIORITY_NORMAL)
{
}
// XXX not much point in implementing this; maybe could help with
// debugging?
static bool Read(const Message* msg)
{
return true;
}
void Log(const std::string& aPrefix,
FILE* aOutf) const
{
fputs("(special `Goodbye' message)", aOutf);
}
};
} // namespace <anon>
namespace mozilla {
namespace ipc {
AsyncChannel::AsyncChannel(AsyncListener* aListener)
: mTransport(0),
mListener(aListener),
mChannelState(ChannelClosed),
mMutex("mozilla.ipc.AsyncChannel.mMutex"),
mCvar(mMutex, "mozilla.ipc.AsyncChannel.mCvar"),
mIOLoop(),
mWorkerLoop(),
mChild(false),
mChannelErrorTask(NULL),
mExistingListener(NULL)
{
MOZ_COUNT_CTOR(AsyncChannel);
}
AsyncChannel::~AsyncChannel()
{
MOZ_COUNT_DTOR(AsyncChannel);
Clear();
}
bool
AsyncChannel::Open(Transport* aTransport, MessageLoop* aIOLoop)
{
NS_PRECONDITION(!mTransport, "Open() called > once");
NS_PRECONDITION(aTransport, "need transport layer");
// FIXME need to check for valid channel
mTransport = aTransport;
mExistingListener = mTransport->set_listener(this);
// FIXME figure out whether we're in parent or child, grab IO loop
// appropriately
bool needOpen = true;
if(!aIOLoop) {
// parent
needOpen = false;
aIOLoop = XRE_GetIOMessageLoop();
// FIXME assuming that the parent waits for the OnConnected event.
// FIXME see GeckoChildProcessHost.cpp. bad assumption!
mChannelState = ChannelConnected;
}
mChild = needOpen;
mIOLoop = aIOLoop;
mWorkerLoop = MessageLoop::current();
NS_ASSERTION(mIOLoop, "need an IO loop");
NS_ASSERTION(mWorkerLoop, "need a worker loop");
if (needOpen) { // child process
MutexAutoLock lock(mMutex);
mIOLoop->PostTask(FROM_HERE,
NewRunnableMethod(this,
&AsyncChannel::OnChannelOpened));
// FIXME/cjones: handle errors
while (mChannelState != ChannelConnected) {
mCvar.Wait();
}
}
return true;
}
void
AsyncChannel::Close()
{
AssertWorkerThread();
{
MutexAutoLock lock(mMutex);
if (ChannelError == mChannelState ||
ChannelTimeout == mChannelState) {
// See bug 538586: if the listener gets deleted while the
// IO thread's NotifyChannelError event is still enqueued
// and subsequently deletes us, then the error event will
// also be deleted and the listener will never be notified
// of the channel error.
if (mListener) {
MutexAutoUnlock unlock(mMutex);
NotifyMaybeChannelError();
}
return;
}
if (ChannelConnected != mChannelState)
// XXX be strict about this until there's a compelling reason
// to relax
NS_RUNTIMEABORT("Close() called on closed channel!");
AssertWorkerThread();
// notify the other side that we're about to close our socket
SendSpecialMessage(new GoodbyeMessage());
SynchronouslyClose();
}
NotifyChannelClosed();
}
void
AsyncChannel::SynchronouslyClose()
{
AssertWorkerThread();
mMutex.AssertCurrentThreadOwns();
mIOLoop->PostTask(
FROM_HERE, NewRunnableMethod(this, &AsyncChannel::OnCloseChannel));
while (ChannelClosed != mChannelState)
mCvar.Wait();
}
bool
AsyncChannel::Send(Message* msg)
{
AssertWorkerThread();
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mMutex.AssertNotCurrentThreadOwns();
NS_ABORT_IF_FALSE(MSG_ROUTING_NONE != msg->routing_id(), "need a route");
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{
MutexAutoLock lock(mMutex);
if (!Connected()) {
ReportConnectionError("AsyncChannel");
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return false;
}
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SendThroughTransport(msg);
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}
return true;
}
void
AsyncChannel::OnDispatchMessage(const Message& msg)
{
AssertWorkerThread();
NS_ASSERTION(!msg.is_reply(), "can't process replies here");
NS_ASSERTION(!(msg.is_sync() || msg.is_rpc()), "async dispatch only");
if (MSG_ROUTING_NONE == msg.routing_id()) {
if (!OnSpecialMessage(msg.type(), msg))
// XXX real error handling
NS_RUNTIMEABORT("unhandled special message!");
return;
}
// it's OK to dispatch messages if the channel is closed/error'd,
// since we don't have a reply to send back
(void)MaybeHandleError(mListener->OnMessageReceived(msg), "AsyncChannel");
}
bool
AsyncChannel::OnSpecialMessage(uint16 id, const Message& msg)
{
return false;
}
void
AsyncChannel::SendSpecialMessage(Message* msg) const
{
AssertWorkerThread();
SendThroughTransport(msg);
}
void
AsyncChannel::SendThroughTransport(Message* msg) const
{
AssertWorkerThread();
mIOLoop->PostTask(
FROM_HERE,
NewRunnableMethod(mTransport, &Transport::Send, msg));
}
void
AsyncChannel::OnNotifyMaybeChannelError()
{
AssertWorkerThread();
mMutex.AssertNotCurrentThreadOwns();
// OnChannelError holds mMutex when it posts this task and this
// task cannot be allowed to run until OnChannelError has
// exited. We enforce that order by grabbing the mutex here which
// should only continue once OnChannelError has completed.
{
MutexAutoLock lock(mMutex);
// nothing to do here
}
if (ShouldDeferNotifyMaybeError()) {
mChannelErrorTask =
NewRunnableMethod(this, &AsyncChannel::OnNotifyMaybeChannelError);
// 10 ms delay is completely arbitrary
mWorkerLoop->PostDelayedTask(FROM_HERE, mChannelErrorTask, 10);
return;
}
NotifyMaybeChannelError();
}
void
AsyncChannel::NotifyChannelClosed()
{
mMutex.AssertNotCurrentThreadOwns();
if (ChannelClosed != mChannelState)
NS_RUNTIMEABORT("channel should have been closed!");
// OK, the IO thread just closed the channel normally. Let the
// listener know about it.
mListener->OnChannelClose();
Clear();
}
void
AsyncChannel::NotifyMaybeChannelError()
{
mMutex.AssertNotCurrentThreadOwns();
// TODO sort out Close() on this side racing with Close() on the
// other side
if (ChannelClosing == mChannelState) {
// the channel closed, but we received a "Goodbye" message
// warning us about it. no worries
mChannelState = ChannelClosed;
NotifyChannelClosed();
return;
}
// Oops, error! Let the listener know about it.
mChannelState = ChannelError;
mListener->OnChannelError();
Clear();
}
void
AsyncChannel::Clear()
{
mListener = 0;
mIOLoop = 0;
mWorkerLoop = 0;
if (mTransport) {
mTransport->set_listener(0);
// we only hold a weak ref to the transport, which is "owned"
// by GeckoChildProcess/GeckoThread
mTransport = 0;
}
if (mChannelErrorTask) {
mChannelErrorTask->Cancel();
mChannelErrorTask = NULL;
}
}
static void
PrintErrorMessage(bool isChild, const char* channelName, const char* msg)
{
#ifdef DEBUG
fprintf(stderr, "\n###!!! [%s][%s] Error: %s\n\n",
isChild ? "Child" : "Parent", channelName, msg);
#endif
}
bool
AsyncChannel::MaybeHandleError(Result code, const char* channelName)
{
if (MsgProcessed == code)
return true;
const char* errorMsg;
switch (code) {
case MsgNotKnown:
errorMsg = "Unknown message: not processed";
break;
case MsgNotAllowed:
errorMsg = "Message not allowed: cannot be sent/recvd in this state";
break;
case MsgPayloadError:
errorMsg = "Payload error: message could not be deserialized";
break;
case MsgProcessingError:
errorMsg = "Processing error: message was deserialized, but the handler returned false (indicating failure)";
break;
case MsgRouteError:
errorMsg = "Route error: message sent to unknown actor ID";
break;
case MsgValueError:
errorMsg = "Value error: message was deserialized, but contained an illegal value";
break;
default:
NS_RUNTIMEABORT("unknown Result code");
return false;
}
PrintErrorMessage(mChild, channelName, errorMsg);
mListener->OnProcessingError(code);
return false;
}
void
AsyncChannel::ReportConnectionError(const char* channelName) const
{
const char* errorMsg;
switch (mChannelState) {
case ChannelClosed:
errorMsg = "Closed channel: cannot send/recv";
break;
case ChannelOpening:
errorMsg = "Opening channel: not yet ready for send/recv";
break;
case ChannelTimeout:
errorMsg = "Channel timeout: cannot send/recv";
break;
case ChannelClosing:
errorMsg = "Channel closing: too late to send/recv, messages will be lost";
break;
case ChannelError:
errorMsg = "Channel error: cannot send/recv";
break;
default:
NS_RUNTIMEABORT("unreached");
}
PrintErrorMessage(mChild, channelName, errorMsg);
mListener->OnProcessingError(MsgDropped);
}
//
// The methods below run in the context of the IO thread
//
void
AsyncChannel::OnMessageReceived(const Message& msg)
{
AssertIOThread();
NS_ASSERTION(mChannelState != ChannelError, "Shouldn't get here!");
MutexAutoLock lock(mMutex);
if (!MaybeInterceptSpecialIOMessage(msg))
// wake up the worker, there's work to do
mWorkerLoop->PostTask(
FROM_HERE,
NewRunnableMethod(this, &AsyncChannel::OnDispatchMessage, msg));
}
void
AsyncChannel::OnChannelOpened()
{
AssertIOThread();
mChannelState = ChannelOpening;
/*assert*/mTransport->Connect();
}
void
AsyncChannel::DispatchOnChannelConnected(int32 peer_pid)
{
AssertWorkerThread();
if (mListener)
mListener->OnChannelConnected(peer_pid);
}
void
AsyncChannel::OnChannelConnected(int32 peer_pid)
{
AssertIOThread();
{
MutexAutoLock lock(mMutex);
mChannelState = ChannelConnected;
mCvar.Notify();
}
if(mExistingListener)
mExistingListener->OnChannelConnected(peer_pid);
mWorkerLoop->PostTask(FROM_HERE, NewRunnableMethod(this,
&AsyncChannel::DispatchOnChannelConnected,
peer_pid));
}
void
AsyncChannel::OnChannelError()
{
AssertIOThread();
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MutexAutoLock lock(mMutex);
if (ChannelClosing != mChannelState)
mChannelState = ChannelError;
PostErrorNotifyTask();
}
void
AsyncChannel::PostErrorNotifyTask()
{
AssertIOThread();
mMutex.AssertCurrentThreadOwns();
NS_ASSERTION(!mChannelErrorTask, "OnChannelError called twice?");
// This must be the last code that runs on this thread!
mChannelErrorTask =
NewRunnableMethod(this, &AsyncChannel::OnNotifyMaybeChannelError);
mWorkerLoop->PostTask(FROM_HERE, mChannelErrorTask);
}
void
AsyncChannel::OnCloseChannel()
{
AssertIOThread();
mTransport->Close();
MutexAutoLock lock(mMutex);
mChannelState = ChannelClosed;
mCvar.Notify();
}
bool
AsyncChannel::MaybeInterceptSpecialIOMessage(const Message& msg)
{
AssertIOThread();
mMutex.AssertCurrentThreadOwns();
if (MSG_ROUTING_NONE == msg.routing_id()
&& GOODBYE_MESSAGE_TYPE == msg.type()) {
ProcessGoodbyeMessage();
return true;
}
return false;
}
void
AsyncChannel::ProcessGoodbyeMessage()
{
AssertIOThread();
mMutex.AssertCurrentThreadOwns();
// TODO sort out Close() on this side racing with Close() on the
// other side
mChannelState = ChannelClosing;
printf("NOTE: %s process received `Goodbye', closing down\n",
mChild ? "child" : "parent");
}
} // namespace ipc
} // namespace mozilla