skia2/include/private/SkMutex.h

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/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkMutex_DEFINED
#define SkMutex_DEFINED
#include "../private/SkSemaphore.h"
#include "../private/SkThreadID.h"
#include "SkTypes.h"
#define SK_DECLARE_STATIC_MUTEX(name) static SkBaseMutex name;
class SkBaseMutex {
public:
constexpr SkBaseMutex() = default;
void acquire() {
fSemaphore.wait();
SkDEBUGCODE(fOwner = SkGetThreadID();)
}
void release() {
this->assertHeld();
SkDEBUGCODE(fOwner = kIllegalThreadID;)
fSemaphore.signal();
}
void assertHeld() {
SkASSERT(fOwner == SkGetThreadID());
}
protected:
SkBaseSemaphore fSemaphore{1};
SkDEBUGCODE(SkThreadID fOwner{kIllegalThreadID};)
};
class SkMutex : public SkBaseMutex {
public:
using SkBaseMutex::SkBaseMutex;
~SkMutex() { fSemaphore.cleanup(); }
};
class SkAutoMutexAcquire {
public:
template <typename T>
SkAutoMutexAcquire(T* mutex) : fMutex(mutex) {
if (mutex) {
mutex->acquire();
}
fRelease = [](void* mutex) { ((T*)mutex)->release(); };
}
template <typename T>
SkAutoMutexAcquire(T& mutex) : SkAutoMutexAcquire(&mutex) {}
~SkAutoMutexAcquire() { this->release(); }
void release() {
if (fMutex) {
fRelease(fMutex);
}
fMutex = nullptr;
}
private:
void* fMutex;
void (*fRelease)(void*);
};
#define SkAutoMutexAcquire(...) SK_REQUIRE_LOCAL_VAR(SkAutoMutexAcquire)
// SkAutoExclusive is a lighter weight version of SkAutoMutexAcquire.
// It assumes that there is a valid mutex, obviating the null check.
class SkAutoExclusive {
public:
template <typename T>
SkAutoExclusive(T& mutex) : fMutex(&mutex) {
mutex.acquire();
fRelease = [](void* mutex) { ((T*)mutex)->release(); };
}
~SkAutoExclusive() { fRelease(fMutex); }
private:
void* fMutex;
void (*fRelease)(void*);
};
#define SkAutoExclusive(...) SK_REQUIRE_LOCAL_VAR(SkAutoExclusive)
#endif//SkMutex_DEFINED