// 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_