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 38 class 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. 42 class WebTask : public webkit_support::TaskAdaptor { 43 public: 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 51 private: Run()52 virtual void Run() { run(); } 53 54 protected: 55 TaskList* m_taskList; 56 }; 57 58 class TaskList { 59 public: TaskList()60 TaskList() {} ~TaskList()61 ~TaskList() { revokeAll(); } registerTask(WebTask * task)62 void registerTask(WebTask* task) { m_tasks.append(task); } 63 void unregisterTask(WebTask* task); 64 void revokeAll(); 65 private: 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()". 72 template<class T> class MethodTask: public WebTask { 73 public: MethodTask(T * object)74 MethodTask(T* object): WebTask(object->taskList()), m_object(object) {} run()75 virtual void run() 76 { 77 if (m_object) 78 runIfValid(); 79 } cancel()80 virtual void cancel() 81 { 82 m_object = 0; 83 m_taskList->unregisterTask(this); 84 m_taskList = 0; 85 } 86 virtual void runIfValid() = 0; 87 protected: 88 T* m_object; 89 }; 90 91 void postTask(WebTask* task); 92 void postDelayedTask(WebTask* task, int64_t ms); 93 94 #endif // Task_h 95