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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2017 The Starwels developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef STARWELS_SYNC_H
#define STARWELS_SYNC_H
#include <threadsafety.h>
#include <condition_variable>
#include <thread>
#include <mutex>
////////////////////////////////////////////////
// //
// THE SIMPLE DEFINITION, EXCLUDING DEBUG CODE //
// //
////////////////////////////////////////////////
/*
CCriticalSection mutex;
std::recursive_mutex mutex;
LOCK(mutex);
std::unique_lock<std::recursive_mutex> criticalblock(mutex);
LOCK2(mutex1, mutex2);
std::unique_lock<std::recursive_mutex> criticalblock1(mutex1);
std::unique_lock<std::recursive_mutex> criticalblock2(mutex2);
TRY_LOCK(mutex, name);
std::unique_lock<std::recursive_mutex> name(mutex, std::try_to_lock_t);
ENTER_CRITICAL_SECTION(mutex); // no RAII
mutex.lock();
LEAVE_CRITICAL_SECTION(mutex); // no RAII
mutex.unlock();
*/
///////////////////////////////
// //
// THE ACTUAL IMPLEMENTATION //
// //
///////////////////////////////
/**
* Template mixin that adds -Wthread-safety locking
* annotations to a subset of the mutex API.
*/
template <typename PARENT>
class LOCKABLE AnnotatedMixin : public PARENT
{
public:
void lock() EXCLUSIVE_LOCK_FUNCTION()
{
PARENT::lock();
}
void unlock() UNLOCK_FUNCTION()
{
PARENT::unlock();
}
bool try_lock() EXCLUSIVE_TRYLOCK_FUNCTION(true)
{
return PARENT::try_lock();
}
};
#ifdef DEBUG_LOCKORDER
void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry = false);
void LeaveCritical();
std::string LocksHeld();
void AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs);
void AssertLockNotHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs);
void DeleteLock(void* cs);
#else
void static inline EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry = false) {}
void static inline LeaveCritical() {}
void static inline AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs) {}
void static inline AssertLockNotHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs) {}
void static inline DeleteLock(void* cs) {}
#endif
#define AssertLockHeld(cs) AssertLockHeldInternal(#cs, __FILE__, __LINE__, &cs)
#define AssertLockNotHeld(cs) AssertLockNotHeldInternal(#cs, __FILE__, __LINE__, &cs)
/**
* Wrapped mutex: supports recursive locking, but no waiting
* TODO: We should move away from using the recursive lock by default.
*/
class CCriticalSection : public AnnotatedMixin<std::recursive_mutex>
{
public:
~CCriticalSection() {
DeleteLock((void*)this);
}
};
/** Wrapped mutex: supports waiting but not recursive locking */
typedef AnnotatedMixin<std::mutex> CWaitableCriticalSection;
/** Just a typedef for std::condition_variable, can be wrapped later if desired */
typedef std::condition_variable CConditionVariable;
/** Just a typedef for std::unique_lock, can be wrapped later if desired */
typedef std::unique_lock<std::mutex> WaitableLock;
#ifdef DEBUG_LOCKCONTENTION
void PrintLockContention(const char* pszName, const char* pszFile, int nLine);
#endif
/** Wrapper around std::unique_lock<CCriticalSection> */
class SCOPED_LOCKABLE CCriticalBlock
{
private:
std::unique_lock<CCriticalSection> lock;
void Enter(const char* pszName, const char* pszFile, int nLine)
{
EnterCritical(pszName, pszFile, nLine, (void*)(lock.mutex()));
#ifdef DEBUG_LOCKCONTENTION
if (!lock.try_lock()) {
PrintLockContention(pszName, pszFile, nLine);
#endif
lock.lock();
#ifdef DEBUG_LOCKCONTENTION
}
#endif
}
bool TryEnter(const char* pszName, const char* pszFile, int nLine)
{
EnterCritical(pszName, pszFile, nLine, (void*)(lock.mutex()), true);
lock.try_lock();
if (!lock.owns_lock())
LeaveCritical();
return lock.owns_lock();
}
public:
CCriticalBlock(CCriticalSection& mutexIn, const char* pszName, const char* pszFile, int nLine, bool fTry = false) EXCLUSIVE_LOCK_FUNCTION(mutexIn) : lock(mutexIn, std::defer_lock)
{
if (fTry)
TryEnter(pszName, pszFile, nLine);
else
Enter(pszName, pszFile, nLine);
}
CCriticalBlock(CCriticalSection* pmutexIn, const char* pszName, const char* pszFile, int nLine, bool fTry = false) EXCLUSIVE_LOCK_FUNCTION(pmutexIn)
{
if (!pmutexIn) return;
lock = std::unique_lock<CCriticalSection>(*pmutexIn, std::defer_lock);
if (fTry)
TryEnter(pszName, pszFile, nLine);
else
Enter(pszName, pszFile, nLine);
}
~CCriticalBlock() UNLOCK_FUNCTION()
{
if (lock.owns_lock())
LeaveCritical();
}
operator bool()
{
return lock.owns_lock();
}
};
#define PASTE(x, y) x ## y
#define PASTE2(x, y) PASTE(x, y)
#define LOCK(cs) CCriticalBlock PASTE2(criticalblock, __COUNTER__)(cs, #cs, __FILE__, __LINE__)
#define LOCK2(cs1, cs2) CCriticalBlock criticalblock1(cs1, #cs1, __FILE__, __LINE__), criticalblock2(cs2, #cs2, __FILE__, __LINE__)
#define TRY_LOCK(cs, name) CCriticalBlock name(cs, #cs, __FILE__, __LINE__, true)
#define ENTER_CRITICAL_SECTION(cs) \
{ \
EnterCritical(#cs, __FILE__, __LINE__, (void*)(&cs)); \
(cs).lock(); \
}
#define LEAVE_CRITICAL_SECTION(cs) \
{ \
(cs).unlock(); \
LeaveCritical(); \
}
class CSemaphore
{
private:
std::condition_variable condition;
std::mutex mutex;
int value;
public:
explicit CSemaphore(int init) : value(init) {}
void wait()
{
std::unique_lock<std::mutex> lock(mutex);
condition.wait(lock, [&]() { return value >= 1; });
value--;
}
bool try_wait()
{
std::lock_guard<std::mutex> lock(mutex);
if (value < 1)
return false;
value--;
return true;
}
void post()
{
{
std::lock_guard<std::mutex> lock(mutex);
value++;
}
condition.notify_one();
}
};
/** RAII-style semaphore lock */
class CSemaphoreGrant
{
private:
CSemaphore* sem;
bool fHaveGrant;
public:
void Acquire()
{
if (fHaveGrant)
return;
sem->wait();
fHaveGrant = true;
}
void Release()
{
if (!fHaveGrant)
return;
sem->post();
fHaveGrant = false;
}
bool TryAcquire()
{
if (!fHaveGrant && sem->try_wait())
fHaveGrant = true;
return fHaveGrant;
}
void MoveTo(CSemaphoreGrant& grant)
{
grant.Release();
grant.sem = sem;
grant.fHaveGrant = fHaveGrant;
fHaveGrant = false;
}
CSemaphoreGrant() : sem(nullptr), fHaveGrant(false) {}
explicit CSemaphoreGrant(CSemaphore& sema, bool fTry = false) : sem(&sema), fHaveGrant(false)
{
if (fTry)
TryAcquire();
else
Acquire();
}
~CSemaphoreGrant()
{
Release();
}
operator bool() const
{
return fHaveGrant;
}
};
#endif // STARWELS_SYNC_H