c0bd9f9fe5
Current strategy: everything from the top
Things to look at first are the manual changes:
- added tools/rewrite_includes.py
- removed -Idirectives from BUILD.gn
- various compile.sh simplifications
- tweak tools/embed_resources.py
- update gn/find_headers.py to write paths from the top
- update gn/gn_to_bp.py SkUserConfig.h layout
so that #include "include/config/SkUserConfig.h" always
gets the header we want.
No-Presubmit: true
Change-Id: I73a4b181654e0e38d229bc456c0d0854bae3363e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/209706
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
52 lines
1.7 KiB
C++
52 lines
1.7 KiB
C++
/*
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* Copyright 2013 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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#ifndef SkOnce_DEFINED
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#define SkOnce_DEFINED
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#include <atomic>
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#include <utility>
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#include "include/core/SkTypes.h"
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// SkOnce provides call-once guarantees for Skia, much like std::once_flag/std::call_once().
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//
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// There should be no particularly error-prone gotcha use cases when using SkOnce.
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// It works correctly as a class member, a local, a global, a function-scoped static, whatever.
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class SkOnce {
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public:
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constexpr SkOnce() = default;
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template <typename Fn, typename... Args>
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void operator()(Fn&& fn, Args&&... args) {
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auto state = fState.load(std::memory_order_acquire);
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if (state == Done) {
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return;
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}
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// If it looks like no one has started calling fn(), try to claim that job.
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if (state == NotStarted && fState.compare_exchange_strong(state, Claimed,
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std::memory_order_relaxed,
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std::memory_order_relaxed)) {
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// Great! We'll run fn() then notify the other threads by releasing Done into fState.
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fn(std::forward<Args>(args)...);
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return fState.store(Done, std::memory_order_release);
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}
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// Some other thread is calling fn().
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// We'll just spin here acquiring until it releases Done into fState.
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while (fState.load(std::memory_order_acquire) != Done) { /*spin*/ }
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}
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private:
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enum State : uint8_t { NotStarted, Claimed, Done};
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std::atomic<uint8_t> fState{NotStarted};
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};
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#endif // SkOnce_DEFINED
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