1/*
2 * Copyright (C) 2010 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#ifndef Task_h
32#define Task_h
33
34#include "webkit/support/webkit_support.h"
35#include <wtf/OwnPtr.h>
36#include <wtf/Vector.h>
37
38class TaskList;
39
40// WebTask represents a task which can run by postTask() or postDelayedTask().
41// it is named "WebTask", not "Task", to avoid conflist with base/task.h.
42class WebTask : public webkit_support::TaskAdaptor {
43public:
44    WebTask(TaskList*);
45    // The main code of this task.
46    // An implementation of run() should return immediately if cancel() was called.
47    virtual void run() = 0;
48    virtual void cancel() = 0;
49    virtual ~WebTask();
50
51private:
52    virtual void Run() { run(); }
53
54protected:
55    TaskList* m_taskList;
56};
57
58class TaskList {
59public:
60    TaskList() {}
61    ~TaskList() { revokeAll(); }
62    void registerTask(WebTask* task) { m_tasks.append(task); }
63    void unregisterTask(WebTask* task);
64    void revokeAll();
65private:
66    Vector<WebTask*> m_tasks;
67};
68
69// A task containing an object pointer of class T. Is is supposed that
70// runifValid() calls a member function of the object pointer.
71// Class T must have "TaskList* taskList()".
72template<class T> class MethodTask: public WebTask {
73public:
74    MethodTask(T* object): WebTask(object->taskList()), m_object(object) {}
75    virtual void run()
76    {
77        if (m_object)
78            runIfValid();
79    }
80    virtual void cancel()
81    {
82        m_object = 0;
83        m_taskList->unregisterTask(this);
84        m_taskList = 0;
85    }
86    virtual void runIfValid() = 0;
87protected:
88    T* m_object;
89};
90
91void postTask(WebTask* task);
92void postDelayedTask(WebTask* task, int64_t ms);
93
94#endif // Task_h
95