callback.hh

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/*
 * Copyright (c) 2003-2005 The Regents of The University of Michigan
 * 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 the copyright holders 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,
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __BASE_CALLBACK_HH__
#define __BASE_CALLBACK_HH__

#include <list>
#include <string>

class Callback
{
  protected:
    friend class CallbackQueue;
    virtual void autoDestruct() {}

  public:
    virtual ~Callback() {}

    virtual void process() = 0;
};

template <class T, void (T::* F)()>
class MakeCallback : public Callback
{
  protected:
    T *object;
    const bool autoDestroy;

    void autoDestruct() { if (autoDestroy) delete this; }

  public:
    MakeCallback(T *o, bool auto_destroy = false)
        : object(o), autoDestroy(auto_destroy)
    { }

    MakeCallback(T &o, bool auto_destroy = false)
        : object(&o), autoDestroy(auto_destroy)
    { }

    void process() { (object->*F)(); }
};

class CallbackQueue
{
  protected:
    typedef std::list<Callback *> queue;

    queue callbacks;

  public:
    ~CallbackQueue();
    std::string name() const { return "CallbackQueue"; }

    void
    add(Callback *callback)
    {
        callbacks.push_back(callback);
    }

    template <class T, void (T::* F)()>
    void
    add(T *obj)
    {
        add(new MakeCallback<T, F>(obj, true));
    }

    template <class T, void (T::* F)()>
    void
    add(T &obj)
    {
        add(new MakeCallback<T, F>(&obj, true));
    }

    bool empty() const { return callbacks.empty(); }

    void
    process()
    {
        queue::iterator i = callbacks.begin();
        queue::iterator end = callbacks.end();

        while (i != end) {
            (*i)->process();
            ++i;
        }
    }

    void
    clear()
    {
        callbacks.clear();
    }
};

#endif // __BASE_CALLBACK_HH__