Tools/DumpRenderTree/chromium/TestRunner/public/WebTask.h

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 * Copyright (C) 2010 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
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#ifndef WebTask_h
#define WebTask_h

#include "WebTestCommon.h"
#include <vector>

namespace WebTestRunner {

class WebTaskList;

// WebTask represents a task which can run by WebTestDelegate::postTask() or
// WebTestDelegate::postDelayedTask().
class WEBTESTRUNNER_EXPORT WebTask {
public:
    explicit WebTask(WebTaskList*);
    virtual ~WebTask();

    // The main code of this task.
    // An implementation of run() should return immediately if cancel() was called.
    virtual void run() = 0;
    virtual void cancel() = 0;

protected:
    WebTaskList* m_taskList;
};

class WEBTESTRUNNER_EXPORT WebTaskList {
public:
    WebTaskList();
    ~WebTaskList();
    void registerTask(WebTask*);
    void unregisterTask(WebTask*);
    void revokeAll();

private:
    std::vector<WebTask*> m_tasks;
};

// A task containing an object pointer of class T. Derived classes should
// override runIfValid() which in turn can safely invoke methods on the
// m_object. The Class T must have "WebTaskList* taskList()".
template<class T>
class WebMethodTask : public WebTask {
public:
    explicit WebMethodTask(T* object)
        : WebTask(object->taskList())
        , m_object(object)
    {
    }

    virtual ~WebMethodTask() { }

    virtual void run()
    {
        if (m_object)
            runIfValid();
    }

    virtual void cancel()
    {
        m_object = 0;
        m_taskList->unregisterTask(this);
        m_taskList = 0;
    }

    virtual void runIfValid() = 0;

protected:
    T* m_object;
};

}

#endif // WebTask_h