62a69c26b3
There is no API change. TBR=reed@google.com BUG=skia: Review URL: https://codereview.chromium.org/1368333004
45 lines
1.2 KiB
C++
45 lines
1.2 KiB
C++
/*
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* Copyright 2015 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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// This file is not part of the public Skia API.
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#ifndef SkSpinlock_DEFINED
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#define SkSpinlock_DEFINED
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#include "../private/SkAtomics.h"
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#define SK_DECLARE_STATIC_SPINLOCK(name) namespace {} static SkPODSpinlock name
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// This class has no constructor and must be zero-initialized (the macro above does this).
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class SK_API SkPODSpinlock {
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public:
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void acquire() {
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// To act as a mutex, we need an acquire barrier if we take the lock.
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if (sk_atomic_exchange(&fLocked, true, sk_memory_order_acquire)) {
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// Lock was contended. Fall back to an out-of-line spin loop.
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this->contendedAcquire();
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}
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}
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void release() {
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// To act as a mutex, we need a release barrier.
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sk_atomic_store(&fLocked, false, sk_memory_order_release);
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}
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private:
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void contendedAcquire();
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bool fLocked;
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};
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// For non-global-static use cases, this is normally what you want.
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class SkSpinlock : public SkPODSpinlock {
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public:
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SkSpinlock() { this->release(); }
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};
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#endif//SkSpinlock_DEFINED
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