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/*
* Copyright (c) 2014, Ford Motor Company
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following
* disclaimer in the documentation and/or other materials provided with the
* distribution.
*
* Neither the name of the Ford Motor Company nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef SRC_COMPONENTS_INCLUDE_UTILS_THREADS_MESSAGE_LOOP_THREAD_H_
#define SRC_COMPONENTS_INCLUDE_UTILS_THREADS_MESSAGE_LOOP_THREAD_H_
#include <string>
#include <queue>
#include "utils/logger.h"
#include "utils/macro.h"
#include "utils/message_queue.h"
#include "utils/threads/thread.h"
#include "utils/lock.h"
namespace threads {
using ::utils::MessageQueue;
/**
* \class MessageLoopThread
* \brief Handles a thread which sole purpose is to pump messages pushed
* to it's queue. To handle messages someone, Handler must be implemented and
* passed to MessageLoopThread constructor.
*/
template <class Q>
class MessageLoopThread {
public:
typedef Q Queue;
typedef typename Queue::value_type Message;
/*
* Handler interface. It is called from a thread that is
* owned by MessageLoopThread so make sure is only accesses
* thread-safe data
*/
struct Handler {
/*
* Method called by MessageLoopThread to process single message
* from it's queue. After calling this method message is discarded.
*/
// TODO (AKozoriz) : change to const reference (APPLINK-20235)
virtual void Handle(const Message message) = 0;
virtual ~Handler() {}
};
/*
* Constructs new MessageLoopThread. Must be named to aid debugging.
*/
MessageLoopThread(const std::string& name,
Handler* handler,
const ThreadOptions& thread_opts = ThreadOptions());
~MessageLoopThread();
// Places a message to the therad's queue. Thread-safe.
void PostMessage(const Message& message);
// Process already posted messages and stop thread processing. Thread-safe.
void Shutdown();
// Added for utils/test/auto_trace_test.cc
size_t GetMessageQueueSize() const;
/*
* Wait until message queue will be empty
*/
void WaitDumpQueue();
private:
/*
* Implementation of ThreadDelegate that actually pumps the queue and is
* able to correctly shut it down
*/
class LoopThreadDelegate : public threads::ThreadDelegate {
public:
LoopThreadDelegate(MessageQueue<Message, Queue>* message_queue,
Handler* handler);
// threads::ThreadDelegate overrides
virtual void threadMain() OVERRIDE;
virtual void exitThreadMain() OVERRIDE;
private:
// Handle all messages that are in the queue until it is empty
void DrainQue();
// Handler that processes messages
Handler& handler_;
// Message queue that is actually owned by MessageLoopThread
MessageQueue<Message, Queue>& message_queue_;
};
private:
MessageQueue<Message, Queue> message_queue_;
LoopThreadDelegate* thread_delegate_;
threads::Thread* thread_;
};
///////// Implementation
template <class Q>
size_t MessageLoopThread<Q>::GetMessageQueueSize() const {
return message_queue_.size();
}
template <class Q>
MessageLoopThread<Q>::MessageLoopThread(const std::string& name,
Handler* handler,
const ThreadOptions& thread_opts)
: thread_delegate_(new LoopThreadDelegate(&message_queue_, handler))
, thread_(threads::CreateThread(name.c_str(), thread_delegate_)) {
const bool started = thread_->start(thread_opts);
if (!started) {
CREATE_LOGGERPTR_LOCAL(logger_, "Utils")
LOG4CXX_ERROR(logger_, "Failed to start thread " << name);
}
}
template <class Q>
MessageLoopThread<Q>::~MessageLoopThread() {
Shutdown();
delete thread_delegate_;
threads::DeleteThread(thread_);
}
template <class Q>
void MessageLoopThread<Q>::PostMessage(const Message& message) {
message_queue_.push(message);
}
template <class Q>
void MessageLoopThread<Q>::Shutdown() {
thread_->join();
}
template <class Q>
void MessageLoopThread<Q>::WaitDumpQueue() {
message_queue_.WaitUntilEmpty();
}
//////////
template <class Q>
MessageLoopThread<Q>::LoopThreadDelegate::LoopThreadDelegate(
MessageQueue<Message, Queue>* message_queue, Handler* handler)
: handler_(*handler), message_queue_(*message_queue) {
DCHECK(handler != NULL);
DCHECK(message_queue != NULL);
}
template <class Q>
void MessageLoopThread<Q>::LoopThreadDelegate::threadMain() {
CREATE_LOGGERPTR_LOCAL(logger_, "Utils")
LOG4CXX_AUTO_TRACE(logger_);
while (!message_queue_.IsShuttingDown()) {
DrainQue();
message_queue_.wait();
}
// Process leftover messages
DrainQue();
}
template <class Q>
void MessageLoopThread<Q>::LoopThreadDelegate::exitThreadMain() {
message_queue_.Shutdown();
}
template <class Q>
void MessageLoopThread<Q>::LoopThreadDelegate::DrainQue() {
while (!message_queue_.empty()) {
Message msg;
if (message_queue_.pop(msg)) {
handler_.Handle(msg);
}
}
}
} // namespace threads
#endif // SRC_COMPONENTS_INCLUDE_UTILS_THREADS_MESSAGE_LOOP_THREAD_H_
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