/*!
 * \file CyclopsLock.h
 * \date 2018/07/18
 *
 * \author Lin, Chi
 * Contact: lin.chi@hzleaper.com
 *
 *
 * \note
*/

#ifndef __CyclopsLock_h_
#define __CyclopsLock_h_

// for backward compatibility of Cyclops
// to compile in visual studios doesn't fully support modern cpp

#include "CyclopsVersion.h"
#include <memory>

class CSImpl;

/*! \brief Wrapper of lock for compilers don't fully support modern cpp
*
* [Windows]
* For visual studio 2010 or older version, it's implemented via CRITICAL_SECTION
* For others, it equals to std::mutex
* [Unix]
* For gcc have no c++11 support, it's not implemented yet, as no requirement yet
* For others, it equals to std::mutex
*
* Example:
* \code{.cpp}
* mylock.lock();
* // balabala, the code you want to protect
* // ...
* mylock.unlock();
* \endcode
*
* Note: it's recommended in ANY cases to use CyclopsLockGuard instead of manually call lock/unlock yourself,
* since the designed work flow may be interrupted by some exceptions and you need to write unlock in every return branch.
* Unless you're 100% sure you want and need to manipulate the lock yourself, DO USE CyclopsLockGuard
*
*/
class CYCLOPS_UTILS_SPEC CyclopsLock
{
public:
	CyclopsLock();
	~CyclopsLock();

	/*! Acquire the lock */
	void lock();

	/*! Release the lock */
	void unlock();

	/*! Acquire the shared lock */
	void lock_shared();

	/*! Release the shared lock */
	void unlock_shared();

	/*! Whether this lock is exclusively locked */
	bool isLocked() const;

private:
	std::unique_ptr<CSImpl> mpCSImpl;
};

/*! \brief Lock guard for CyclopsLock
*
* It is used to ensure a lock is always released when leave the code block
* 
* Example:
* \code{.cpp}
* {
*     CyclopsLockGuard guard(&mylock);
*     // balabala, the code you want to protect
*     // ...
* } // the lock will be released when leave the block
* \endcode
*/
class CyclopsLockGuard
{
public:
	CyclopsLockGuard(CyclopsLock* pLock) {
		mpLock = pLock;
		mpLock->lock();
	}
	~CyclopsLockGuard() {
		mpLock->unlock();
	}

private:
	CyclopsLock* mpLock;
};

/*! \brief Shared lock guard for CyclopsLock
*
* It is used to ensure a shared lock is always released when leave the code block
*
* Example:
* \code{.cpp}
* {
*     CyclopsSharedLockGuard guard(&mylock);
*     // balabala, the code you want to protect
*     // ...
* } // the lock will be released when leave the block
* \endcode
*/
class CyclopsSharedLockGuard
{
public:
	CyclopsSharedLockGuard(CyclopsLock* pLock) {
		mpLock = pLock;
		mpLock->lock_shared();
	}
	~CyclopsSharedLockGuard() {
		mpLock->unlock_shared();
	}

private:
	CyclopsLock* mpLock;
};

#endif