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/*
* Copyright (c) 2013, 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_LOCK_H_
#define SRC_COMPONENTS_INCLUDE_UTILS_LOCK_H_
#include <stdint.h>
#include <boost/thread/mutex.hpp>
#include <boost/thread/recursive_mutex.hpp>
#include "utils/atomic.h"
#include "utils/macro.h"
#include "utils/memory_barrier.h"
#include <iostream>
using boost::system::error_code;
namespace sync_primitives {
class SpinMutex {
public:
SpinMutex() : state_(0) {}
void Lock() {
// Comment below add exception for lint error
// Reason: FlexeLint doesn't know about compiler's built-in instructions
/*lint -e1055*/
if (atomic_post_set(&state_) == 0) {
return;
}
for (;;) {
sched_yield();
/*lint -e1055*/
if (state_ == 0 && atomic_post_set(&state_) == 0) {
return;
}
}
}
void Unlock() {
state_ = 0;
}
~SpinMutex() {}
private:
volatile unsigned int state_;
};
/* Abstract base class that allows AutoLock to handle both recursive and
* non-recursive locks
*/
class BaseLock {
public:
BaseLock() : lock_taken_(0) {}
// Ackquire the lock. Must be called only once on a thread.
// Please consider using AutoLock to capture it.
virtual void Acquire() = 0;
// Release the lock. Must be called only once on a thread after lock.
// was acquired. Please consider using AutoLock to automatically release
// the lock
virtual void Release() = 0;
// Try if lock can be captured and lock it if it was possible.
// If it captured, lock must be manually released calling to Release
// when protected resource access was finished.
// @returns wether lock was captured.
virtual bool Try() = 0;
protected:
/**
* @brief Basic debugging aid, a flag that signals wether this lock is
* currently taken
* Allows detection of abandoned and recursively captured mutexes
*/
uint32_t lock_taken_;
// Ensures safety in locking
virtual void AssertTakenAndMarkFree() = 0;
virtual void AssertFreeAndMarkTaken() = 0;
friend class ConditionalVariable;
};
/*
* Platform-indepenednt NON-RECURSIVE lock (mutex) wrapper
*/
class Lock : public BaseLock {
public:
Lock();
~Lock();
virtual void Acquire();
virtual void Release();
virtual bool Try();
private:
virtual void AssertTakenAndMarkFree();
virtual void AssertFreeAndMarkTaken();
boost::mutex mutex_;
DISALLOW_COPY_AND_ASSIGN(Lock);
friend class ConditionalVariable;
};
/*
* Platform-indepenednt RECURSIVE lock (mutex) wrapper
*/
class RecursiveLock : public BaseLock {
public:
RecursiveLock();
~RecursiveLock();
virtual void Acquire();
virtual void Release();
virtual bool Try();
private:
virtual void AssertTakenAndMarkFree();
virtual void AssertFreeAndMarkTaken();
boost::recursive_mutex mutex_;
DISALLOW_COPY_AND_ASSIGN(RecursiveLock);
friend class ConditionalVariable;
};
// This class is used to automatically acquire and release the a lock
class AutoLock {
public:
explicit AutoLock(BaseLock& lock) : lock_(lock) {
std::cerr << "lock is at " << &lock << std::endl;
lock_.Acquire();
}
~AutoLock() {
lock_.Release();
}
private:
BaseLock& GetLock() {
return lock_;
}
BaseLock& lock_;
private:
friend class AutoUnlock;
friend class ConditionalVariable;
DISALLOW_COPY_AND_ASSIGN(AutoLock);
};
/* Please use AutoLock to ackquire and (automatically) release it
* It eases balancing of multple lock taking/releasing and makes it
* Impossible to forget to release the lock:
* ...
* ConcurentlyAccessedData data_;
* sync_primitives::Lock data_lock_;
* ...
* {
* sync_primitives::AutoLock auto_lock(data_lock_);
* data_.ReadOrWriteData();
* } // lock is automatically released here
*/
// This class is used to temporarly unlock autolocked lock
class AutoUnlock {
public:
explicit AutoUnlock(BaseLock& lock) : lock_(lock) {
lock_.Release();
}
explicit AutoUnlock(AutoLock& lock) : lock_(lock.GetLock()) {
lock_.Release();
}
~AutoUnlock() {
lock_.Acquire();
}
private:
BaseLock& lock_;
private:
DISALLOW_COPY_AND_ASSIGN(AutoUnlock);
};
} // namespace sync_primitives
#endif // SRC_COMPONENTS_INCLUDE_UTILS_LOCK_H_
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