diff options
author | mtklein <mtklein@chromium.org> | 2015-03-30 08:13:33 -0700 |
---|---|---|
committer | Commit bot <commit-bot@chromium.org> | 2015-03-30 08:13:34 -0700 |
commit | 50ffd9921e6dc82cae8ef143e8cecfd8bcf900fb (patch) | |
tree | 56876ee2f54e95478ad143b177abc8f34843e3dd /include/core/SkSpinlock.h | |
parent | ff420217394e6e35e831b11e98b46202e37de23f (diff) |
Extract the spinlock from SkOnce as SkSpinlock.
This uses slightly newer APIs from SkAtomics.h to make it a bit more efficient.
No public API changes.
TBR=reed@google.com
BUG=skia:
Review URL: https://codereview.chromium.org/1039323002
Diffstat (limited to 'include/core/SkSpinlock.h')
-rw-r--r-- | include/core/SkSpinlock.h | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/include/core/SkSpinlock.h b/include/core/SkSpinlock.h new file mode 100644 index 0000000000..68a6ff7b12 --- /dev/null +++ b/include/core/SkSpinlock.h @@ -0,0 +1,37 @@ +/* + * Copyright 2015 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +// This file is not part of the public Skia API. + +#ifndef SkSpinlock_DEFINED +#define SkSpinlock_DEFINED + +#include "SkAtomics.h" + +#define SK_DECLARE_STATIC_SPINLOCK(name) namespace {} static SkPODSpinlock name + +// This class has no constructor and must be zero-initialized (the macro above does this). +struct SkPODSpinlock { + void acquire() { + // To act as a mutex, we need an acquire barrier. + while(sk_atomic_exchange(&fLocked, true, sk_memory_order_acquire)) { /*spin*/ } + } + void release() { + // To act as a mutex, we need a release barrier. + sk_atomic_store(&fLocked, false, sk_memory_order_release); + } + + bool fLocked; +}; + +// For non-global-static use cases, this is normally what you want. +class SkSpinlock : public SkPODSpinlock { +public: + SkSpinlock() { this->release(); } +}; + +#endif//SkSpinlock_DEFINED |