libcore/include/sirikata/core/queue/ThreadSafeQueueWithNotification.hpp

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/*  Sirikata Utilities -- Sirikata Synchronization Utilities
 *  ThreadSafeQueueWithNotification.hpp
 *
 *  Copyright (c) 2010, Ewen Cheslack-Postava
 *  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 Sirikata 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,
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _SIRIKATA_THREAD_SAFE_QUEUE_WITH_NOTIFICATION_HPP_
#define _SIRIKATA_THREAD_SAFE_QUEUE_WITH_NOTIFICATION_HPP_

#include "ThreadSafeQueue.hpp"

namespace Sirikata {

template <typename T>
class ThreadSafeQueueWithNotification {
  public:
    typedef std::tr1::function<void()> Notification;

    ThreadSafeQueueWithNotification(const Notification& cb)
            : mQueue(),
              mCallback(cb)
    {
    }

    ~ThreadSafeQueueWithNotification() {
    }

    void push(const T &value) {
        // We get the new size from the push, which is locked so we know exactly
        // how big the queue is immediately after the push, guaranteeing we
        // don't miss it going empty.
        int32 new_size = mQueue.push(value);
        if (new_size == 1)
            mCallback();
    }

    void pushMultiple(const std::deque<T> &values) {
        int32 nelements = values.size();
        int32 new_size = mQueue.pushMultiple(values);
        if (new_size == nelements)
            mCallback();
    }

    bool pop(T& ret) {
        return mQueue.pop(ret);
    }

    void blockingPop(T& retval) {
        mQueue.blockingPop(retval);
    }

    void swap(std::deque<T>& swapWith) {
        mQueue.swap(swapWith);
    }

    void popAll(std::deque<T> *popResults) {
        mQueue.popAll(popResults);
    }

    bool probablyEmpty() {
        return mQueue.probablyEmpty();
    }

    bool empty() {
        return probablyEmpty();
    }

    int32 size() {
        return mQueue.size();
    }

  private:
    // Disable default constructor -- if you're not specifying a callback you
    // shouldn't be using this class.
    ThreadSafeQueueWithNotification();
    // Disable assignment and copy
    ThreadSafeQueueWithNotification& operator=(const ThreadSafeQueueWithNotification& other);
    ThreadSafeQueueWithNotification(const ThreadSafeQueueWithNotification& other);

    ThreadSafeQueue<T> mQueue;
    Notification mCallback;
};

} // namespace Sirikata

#endif //_SIRIKATA_THREAD_SAFE_QUEUE_WITH_NOTIFICATION_HPP_