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// 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.
#include "ipc/ipc_sync_message_filter.h"
#include "base/bind.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/single_thread_task_runner.h"
#include "base/synchronization/waitable_event.h"
#include "base/thread_task_runner_handle.h"
#include "ipc/ipc_channel.h"
#include "ipc/ipc_sync_message.h"
namespace IPC {
bool SyncMessageFilter::Send(Message* message) {
if (!message->is_sync()) {
{
base::AutoLock auto_lock(lock_);
if (sender_ && is_channel_send_thread_safe_) {
sender_->Send(message);
return true;
} else if (!io_task_runner_.get()) {
pending_messages_.push_back(message);
return true;
}
}
io_task_runner_->PostTask(
FROM_HERE,
base::Bind(&SyncMessageFilter::SendOnIOThread, this, message));
return true;
}
base::WaitableEvent done_event(true, false);
PendingSyncMsg pending_message(
SyncMessage::GetMessageId(*message),
static_cast<SyncMessage*>(message)->GetReplyDeserializer(),
&done_event);
{
base::AutoLock auto_lock(lock_);
// Can't use this class on the main thread or else it can lead to deadlocks.
// Also by definition, can't use this on IO thread since we're blocking it.
if (base::ThreadTaskRunnerHandle::IsSet()) {
DCHECK(base::ThreadTaskRunnerHandle::Get() != listener_task_runner_);
DCHECK(base::ThreadTaskRunnerHandle::Get() != io_task_runner_);
}
pending_sync_messages_.insert(&pending_message);
if (io_task_runner_.get()) {
io_task_runner_->PostTask(
FROM_HERE,
base::Bind(&SyncMessageFilter::SendOnIOThread, this, message));
} else {
pending_messages_.push_back(message);
}
}
base::WaitableEvent* events[2] = { shutdown_event_, &done_event };
base::WaitableEvent::WaitMany(events, 2);
{
base::AutoLock auto_lock(lock_);
delete pending_message.deserializer;
pending_sync_messages_.erase(&pending_message);
}
return pending_message.send_result;
}
void SyncMessageFilter::OnFilterAdded(Sender* sender) {
std::vector<Message*> pending_messages;
{
base::AutoLock auto_lock(lock_);
sender_ = sender;
io_task_runner_ = base::ThreadTaskRunnerHandle::Get();
pending_messages_.release(&pending_messages);
}
for (auto* msg : pending_messages)
SendOnIOThread(msg);
}
void SyncMessageFilter::OnChannelError() {
base::AutoLock auto_lock(lock_);
sender_ = NULL;
SignalAllEvents();
}
void SyncMessageFilter::OnChannelClosing() {
base::AutoLock auto_lock(lock_);
sender_ = NULL;
SignalAllEvents();
}
bool SyncMessageFilter::OnMessageReceived(const Message& message) {
base::AutoLock auto_lock(lock_);
for (PendingSyncMessages::iterator iter = pending_sync_messages_.begin();
iter != pending_sync_messages_.end(); ++iter) {
if (SyncMessage::IsMessageReplyTo(message, (*iter)->id)) {
if (!message.is_reply_error()) {
(*iter)->send_result =
(*iter)->deserializer->SerializeOutputParameters(message);
}
(*iter)->done_event->Signal();
return true;
}
}
return false;
}
SyncMessageFilter::SyncMessageFilter(base::WaitableEvent* shutdown_event,
bool is_channel_send_thread_safe)
: sender_(NULL),
is_channel_send_thread_safe_(is_channel_send_thread_safe),
listener_task_runner_(base::ThreadTaskRunnerHandle::Get()),
shutdown_event_(shutdown_event) {
}
SyncMessageFilter::~SyncMessageFilter() {
}
void SyncMessageFilter::SendOnIOThread(Message* message) {
if (sender_) {
sender_->Send(message);
return;
}
if (message->is_sync()) {
// We don't know which thread sent it, but it doesn't matter, just signal
// them all.
base::AutoLock auto_lock(lock_);
SignalAllEvents();
}
delete message;
}
void SyncMessageFilter::SignalAllEvents() {
lock_.AssertAcquired();
for (PendingSyncMessages::iterator iter = pending_sync_messages_.begin();
iter != pending_sync_messages_.end(); ++iter) {
(*iter)->done_event->Signal();
}
}
} // namespace IPC
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