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Diffstat (limited to 'chromium/v8/src/platform/semaphore.h')
-rw-r--r-- | chromium/v8/src/platform/semaphore.h | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/chromium/v8/src/platform/semaphore.h b/chromium/v8/src/platform/semaphore.h new file mode 100644 index 00000000000..2cfa1421117 --- /dev/null +++ b/chromium/v8/src/platform/semaphore.h @@ -0,0 +1,126 @@ +// Copyright 2013 the V8 project authors. All rights reserved. +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following +// disclaimer in the documentation and/or other materials provided +// with the distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived +// from this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#ifndef V8_PLATFORM_SEMAPHORE_H_ +#define V8_PLATFORM_SEMAPHORE_H_ + +#include "lazy-instance.h" +#if V8_OS_WIN +#include "win32-headers.h" +#endif + +#if V8_OS_MACOSX +#include <mach/semaphore.h> // NOLINT +#elif V8_OS_POSIX +#include <semaphore.h> // NOLINT +#endif + +namespace v8 { +namespace internal { + +// Forward declarations. +class TimeDelta; + +// ---------------------------------------------------------------------------- +// Semaphore +// +// A semaphore object is a synchronization object that maintains a count. The +// count is decremented each time a thread completes a wait for the semaphore +// object and incremented each time a thread signals the semaphore. When the +// count reaches zero, threads waiting for the semaphore blocks until the +// count becomes non-zero. + +class Semaphore V8_FINAL { + public: + explicit Semaphore(int count); + ~Semaphore(); + + // Increments the semaphore counter. + void Signal(); + + // Suspends the calling thread until the semaphore counter is non zero + // and then decrements the semaphore counter. + void Wait(); + + // Suspends the calling thread until the counter is non zero or the timeout + // time has passed. If timeout happens the return value is false and the + // counter is unchanged. Otherwise the semaphore counter is decremented and + // true is returned. + bool WaitFor(const TimeDelta& rel_time) V8_WARN_UNUSED_RESULT; + +#if V8_OS_MACOSX + typedef semaphore_t NativeHandle; +#elif V8_OS_POSIX + typedef sem_t NativeHandle; +#elif V8_OS_WIN + typedef HANDLE NativeHandle; +#endif + + NativeHandle& native_handle() { + return native_handle_; + } + const NativeHandle& native_handle() const { + return native_handle_; + } + + private: + NativeHandle native_handle_; + + DISALLOW_COPY_AND_ASSIGN(Semaphore); +}; + + +// POD Semaphore initialized lazily (i.e. the first time Pointer() is called). +// Usage: +// // The following semaphore starts at 0. +// static LazySemaphore<0>::type my_semaphore = LAZY_SEMAPHORE_INITIALIZER; +// +// void my_function() { +// // Do something with my_semaphore.Pointer(). +// } +// + +template <int N> +struct CreateSemaphoreTrait { + static Semaphore* Create() { + return new Semaphore(N); + } +}; + +template <int N> +struct LazySemaphore { + typedef typename LazyDynamicInstance< + Semaphore, + CreateSemaphoreTrait<N>, + ThreadSafeInitOnceTrait>::type type; +}; + +#define LAZY_SEMAPHORE_INITIALIZER LAZY_DYNAMIC_INSTANCE_INITIALIZER + +} } // namespace v8::internal + +#endif // V8_PLATFORM_SEMAPHORE_H_ |