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74 lines
2.1 KiB
C++
74 lines
2.1 KiB
C++
// synchronization.h
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/* Copyright 2010 10gen Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <boost/thread/condition.hpp>
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#include "mutex.h"
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namespace mongo {
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/*
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* A class to establish a synchronization point between two threads. One thread is the waiter and one is
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* the notifier. After the notification event, both proceed normally.
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*
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* This class is thread-safe.
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*/
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class Notification {
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public:
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Notification();
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~Notification();
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/*
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* Blocks until the method 'notifyOne()' is called.
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*/
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void waitToBeNotified();
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/*
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* Notifies the waiter of '*this' that it can proceed. Can only be called once.
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*/
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void notifyOne();
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private:
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mongo::mutex _mutex; // protects state below
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bool _notified; // was notifyOne() issued?
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boost::condition _condition; // cond over _notified being true
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};
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/** establishes a synchronization point between threads. N threads are waits and one is notifier.
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threadsafe.
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*/
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class NotifyAll : boost::noncopyable {
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public:
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NotifyAll();
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/** awaits the next notifyAll() call by another thread. notifications that precede this
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call are ignored -- we are looking for a fresh event.
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*/
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void wait();
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/** may be called multiple times. notifies all waiters */
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void notifyAll();
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private:
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mongo::mutex _mutex;
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unsigned long long _counter;
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boost::condition _condition;
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};
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} // namespace mongo
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