| // 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_CONDITION_VARIABLE_H_ |
| #define V8_PLATFORM_CONDITION_VARIABLE_H_ |
| |
| #include "platform/mutex.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // Forward declarations. |
| class ConditionVariableEvent; |
| class TimeDelta; |
| |
| // ----------------------------------------------------------------------------- |
| // ConditionVariable |
| // |
| // This class is a synchronization primitive that can be used to block a thread, |
| // or multiple threads at the same time, until: |
| // - a notification is received from another thread, |
| // - a timeout expires, or |
| // - a spurious wakeup occurs |
| // Any thread that intends to wait on a ConditionVariable has to acquire a lock |
| // on a Mutex first. The |Wait()| and |WaitFor()| operations atomically release |
| // the mutex and suspend the execution of the calling thread. When the condition |
| // variable is notified, the thread is awakened, and the mutex is reacquired. |
| |
| class ConditionVariable V8_FINAL { |
| public: |
| ConditionVariable(); |
| ~ConditionVariable(); |
| |
| // If any threads are waiting on this condition variable, calling |
| // |NotifyOne()| unblocks one of the waiting threads. |
| void NotifyOne(); |
| |
| // Unblocks all threads currently waiting for this condition variable. |
| void NotifyAll(); |
| |
| // |Wait()| causes the calling thread to block until the condition variable is |
| // notified or a spurious wakeup occurs. Atomically releases the mutex, blocks |
| // the current executing thread, and adds it to the list of threads waiting on |
| // this condition variable. The thread will be unblocked when |NotifyAll()| or |
| // |NotifyOne()| is executed. It may also be unblocked spuriously. When |
| // unblocked, regardless of the reason, the lock on the mutex is reacquired |
| // and |Wait()| exits. |
| void Wait(Mutex* mutex); |
| |
| // Atomically releases the mutex, blocks the current executing thread, and |
| // adds it to the list of threads waiting on this condition variable. The |
| // thread will be unblocked when |NotifyAll()| or |NotifyOne()| is executed, |
| // or when the relative timeout |rel_time| expires. It may also be unblocked |
| // spuriously. When unblocked, regardless of the reason, the lock on the mutex |
| // is reacquired and |WaitFor()| exits. Returns true if the condition variable |
| // was notified prior to the timeout. |
| bool WaitFor(Mutex* mutex, const TimeDelta& rel_time) V8_WARN_UNUSED_RESULT; |
| |
| // The implementation-defined native handle type. |
| #if V8_OS_POSIX |
| typedef pthread_cond_t NativeHandle; |
| #elif V8_OS_WIN |
| struct Event; |
| class NativeHandle V8_FINAL { |
| public: |
| NativeHandle() : waitlist_(NULL), freelist_(NULL) {} |
| ~NativeHandle(); |
| |
| Event* Pre() V8_WARN_UNUSED_RESULT; |
| void Post(Event* event, bool result); |
| |
| Mutex* mutex() { return &mutex_; } |
| Event* waitlist() { return waitlist_; } |
| |
| private: |
| Event* waitlist_; |
| Event* freelist_; |
| Mutex mutex_; |
| |
| DISALLOW_COPY_AND_ASSIGN(NativeHandle); |
| }; |
| #endif |
| |
| NativeHandle& native_handle() V8_WARN_UNUSED_RESULT { |
| return native_handle_; |
| } |
| const NativeHandle& native_handle() const V8_WARN_UNUSED_RESULT { |
| return native_handle_; |
| } |
| |
| private: |
| NativeHandle native_handle_; |
| |
| DISALLOW_COPY_AND_ASSIGN(ConditionVariable); |
| }; |
| |
| |
| // POD ConditionVariable initialized lazily (i.e. the first time Pointer() is |
| // called). |
| // Usage: |
| // static LazyConditionVariable my_condvar = |
| // LAZY_CONDITION_VARIABLE_INITIALIZER; |
| // |
| // void my_function() { |
| // LockGuard<Mutex> lock_guard(&my_mutex); |
| // my_condvar.Pointer()->Wait(&my_mutex); |
| // } |
| typedef LazyStaticInstance<ConditionVariable, |
| DefaultConstructTrait<ConditionVariable>, |
| ThreadSafeInitOnceTrait>::type LazyConditionVariable; |
| |
| #define LAZY_CONDITION_VARIABLE_INITIALIZER LAZY_STATIC_INSTANCE_INITIALIZER |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_PLATFORM_CONDITION_VARIABLE_H_ |