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