1 /* 2 * Copyright 2015 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 // This file is not part of the public Skia API. 9 10 #ifndef SkSpinlock_DEFINED 11 #define SkSpinlock_DEFINED 12 13 #include "SkAtomics.h" 14 15 #define SK_DECLARE_STATIC_SPINLOCK(name) namespace {} static SkPODSpinlock name 16 17 // This class has no constructor and must be zero-initialized (the macro above does this). 18 struct SkPODSpinlock { acquireSkPODSpinlock19 void acquire() { 20 // To act as a mutex, we need an acquire barrier. 21 while(sk_atomic_exchange(&fLocked, true, sk_memory_order_acquire)) { /*spin*/ } 22 } releaseSkPODSpinlock23 void release() { 24 // To act as a mutex, we need a release barrier. 25 sk_atomic_store(&fLocked, false, sk_memory_order_release); 26 } 27 28 bool fLocked; 29 }; 30 31 // For non-global-static use cases, this is normally what you want. 32 class SkSpinlock : public SkPODSpinlock { 33 public: SkSpinlock()34 SkSpinlock() { this->release(); } 35 }; 36 37 #endif//SkSpinlock_DEFINED 38