callback.hh revision 2665:a124942bacb8 
1/*
2 * Copyright (c) 2003-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Nathan Binkert
29 */
30
31#ifndef __CALLBACK_HH__
32#define __CALLBACK_HH__
33
34#include <list>
35
36/**
37 * Generic callback class.  This base class provides a virtual process
38 * function that gets called when the callback queue is processed.
39 */
40class Callback
41{
42  public:
43    /**
44     * virtualize the destructor to make sure that the correct one
45     * gets called.
46     */
47    virtual ~Callback() {}
48
49    /**
50     * virtual process function that is invoked when the callback
51     * queue is executed.
52     */
53    virtual void process() = 0;
54};
55
56class CallbackQueue
57{
58  protected:
59    /**
60     * Simple typedef for the data structure that stores all of the
61     * callbacks.
62     */
63    typedef std::list<Callback *> queue;
64
65    /**
66     * List of all callbacks.  To be called in fifo order.
67     */
68    queue callbacks;
69
70  public:
71    /**
72     * Add a callback to the end of the queue
73     * @param callback the callback to be added to the queue
74     */
75    void add(Callback *callback)
76    {
77        callbacks.push_back(callback);
78    }
79
80    /**
81     * Find out if there are any callbacks in the queue
82     */
83    bool empty() const { return callbacks.empty(); }
84
85    /**
86     * process all callbacks
87     */
88    void process()
89    {
90        queue::iterator i = callbacks.begin();
91        queue::iterator end = callbacks.end();
92
93        while (i != end) {
94            (*i)->process();
95            ++i;
96        }
97    }
98
99    /**
100     * clear the callback queue
101     */
102    void clear()
103    {
104        callbacks.clear();
105    }
106};
107
108/// Helper template class to turn a simple class member function into
109/// a callback.
110template <class T, void (T::* F)()>
111class MakeCallback : public Callback
112{
113  private:
114    T *object;
115
116  public:
117    MakeCallback(T *o)
118        : object(o)
119    { }
120
121    void process() { (object->*F)(); }
122};
123
124#endif // __CALLBACK_HH__
125