| /* |
| * Copyright 2006 The Android Open Source Project |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef SkThread_DEFINED |
| #define SkThread_DEFINED |
| |
| #include "SkTypes.h" |
| |
| // SK_ATOMICS_PLATFORM_H must provide inline implementations for the following declarations. |
| |
| /** Atomically adds one to the int referenced by addr and returns the previous value. |
| * No additional memory barrier is required; this must act as a compiler barrier. |
| */ |
| static int32_t sk_atomic_inc(int32_t* addr); |
| |
| /** Atomically adds inc to the int referenced by addr and returns the previous value. |
| * No additional memory barrier is required; this must act as a compiler barrier. |
| */ |
| static int32_t sk_atomic_add(int32_t* addr, int32_t inc); |
| |
| /** Atomically subtracts one from the int referenced by addr and returns the previous value. |
| * This must act as a release (SL/S) memory barrier and as a compiler barrier. |
| */ |
| static int32_t sk_atomic_dec(int32_t* addr); |
| |
| /** Atomically adds one to the int referenced by addr iff the referenced int was not 0 |
| * and returns the previous value. |
| * No additional memory barrier is required; this must act as a compiler barrier. |
| */ |
| static int32_t sk_atomic_conditional_inc(int32_t* addr); |
| |
| /** Atomic compare and set. |
| * If *addr == before, set *addr to after and return true, otherwise return false. |
| * This must act as a release (SL/S) memory barrier and as a compiler barrier. |
| */ |
| static bool sk_atomic_cas(int32_t* addr, int32_t before, int32_t after); |
| |
| /** If sk_atomic_dec does not act as an acquire (L/SL) barrier, |
| * this must act as an acquire (L/SL) memory barrier and as a compiler barrier. |
| */ |
| static void sk_membar_acquire__after_atomic_dec(); |
| |
| /** If sk_atomic_conditional_inc does not act as an acquire (L/SL) barrier, |
| * this must act as an acquire (L/SL) memory barrier and as a compiler barrier. |
| */ |
| static void sk_membar_acquire__after_atomic_conditional_inc(); |
| |
| #include SK_ATOMICS_PLATFORM_H |
| |
| // This is POD and must be zero-initialized. |
| struct SkSpinlock { |
| void acquire() { |
| SkASSERT(shouldBeZero == 0); |
| // No memory barrier needed, but sk_atomic_cas gives us at least release anyway. |
| while (!sk_atomic_cas(&thisIsPrivate, 0, 1)) { |
| // spin |
| } |
| } |
| |
| void release() { |
| SkASSERT(shouldBeZero == 0); |
| // This requires a release memory barrier before storing, which sk_atomic_cas guarantees. |
| SkAssertResult(sk_atomic_cas(&thisIsPrivate, 1, 0)); |
| } |
| |
| int32_t thisIsPrivate; |
| SkDEBUGCODE(int32_t shouldBeZero;) |
| }; |
| |
| class SkAutoSpinlock : SkNoncopyable { |
| public: |
| explicit SkAutoSpinlock(SkSpinlock* lock) : fLock(lock) { fLock->acquire(); } |
| ~SkAutoSpinlock() { fLock->release(); } |
| private: |
| SkSpinlock* fLock; |
| }; |
| #define SkAutoSpinlock(...) SK_REQUIRE_LOCAL_VAR(SkAutoSpinlock) |
| |
| /** SK_MUTEX_PLATFORM_H must provide the following (or equivalent) declarations. |
| |
| class SkBaseMutex { |
| public: |
| void acquire(); |
| void release(); |
| }; |
| |
| class SkMutex : SkBaseMutex { |
| public: |
| SkMutex(); |
| ~SkMutex(); |
| }; |
| |
| #define SK_DECLARE_STATIC_MUTEX(name) static SkBaseMutex name = ... |
| #define SK_DECLARE_GLOBAL_MUTEX(name) SkBaseMutex name = ... |
| */ |
| |
| #include SK_MUTEX_PLATFORM_H |
| |
| |
| class SkAutoMutexAcquire : SkNoncopyable { |
| public: |
| explicit SkAutoMutexAcquire(SkBaseMutex& mutex) : fMutex(&mutex) { |
| SkASSERT(fMutex != NULL); |
| mutex.acquire(); |
| } |
| |
| explicit SkAutoMutexAcquire(SkBaseMutex* mutex) : fMutex(mutex) { |
| if (mutex) { |
| mutex->acquire(); |
| } |
| } |
| |
| /** If the mutex has not been released, release it now. */ |
| ~SkAutoMutexAcquire() { |
| if (fMutex) { |
| fMutex->release(); |
| } |
| } |
| |
| /** If the mutex has not been released, release it now. */ |
| void release() { |
| if (fMutex) { |
| fMutex->release(); |
| fMutex = NULL; |
| } |
| } |
| |
| private: |
| SkBaseMutex* fMutex; |
| }; |
| #define SkAutoMutexAcquire(...) SK_REQUIRE_LOCAL_VAR(SkAutoMutexAcquire) |
| |
| #endif |