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/*
* libjingle
* Copyright 2004--2006, Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef TALK_BASE_TASKRUNNER_H__
#define TALK_BASE_TASKRUNNER_H__
#include <vector>
#include "talk/base/basictypes.h"
#include "talk/base/sigslot.h"
#include "talk/base/taskparent.h"
namespace talk_base {
class Task;
const int64 kSecToMsec = 1000;
const int64 kMsecTo100ns = 10000;
const int64 kSecTo100ns = kSecToMsec * kMsecTo100ns;
class TaskRunner : public TaskParent, public sigslot::has_slots<> {
public:
TaskRunner();
virtual ~TaskRunner();
virtual void WakeTasks() = 0;
// Returns the current time in 100ns units. It is used for
// determining timeouts. The origin is not important, only
// the units and that rollover while the computer is running.
//
// On Windows, GetSystemTimeAsFileTime is the typical implementation.
virtual int64 CurrentTime() = 0 ;
void StartTask(Task *task);
void RunTasks();
void PollTasks();
void UpdateTaskTimeout(Task *task, int64 previous_task_timeout_time);
#ifdef _DEBUG
bool is_ok_to_delete(Task* task) {
return task == deleting_task_;
}
void IncrementAbortCount() {
++abort_count_;
}
void DecrementAbortCount() {
--abort_count_;
}
#endif
// Returns the next absolute time when a task times out
// OR "0" if there is no next timeout.
int64 next_task_timeout() const;
protected:
// The primary usage of this method is to know if
// a callback timer needs to be set-up or adjusted.
// This method will be called
// * when the next_task_timeout() becomes a smaller value OR
// * when next_task_timeout() has changed values and the previous
// value is in the past.
//
// If the next_task_timeout moves to the future, this method will *not*
// get called (because it subclass should check next_task_timeout()
// when its timer goes off up to see if it needs to set-up a new timer).
//
// Note that this maybe called conservatively. In that it may be
// called when no time change has happened.
virtual void OnTimeoutChange() {
// by default, do nothing.
}
private:
void InternalRunTasks(bool in_destructor);
void CheckForTimeoutChange(int64 previous_timeout_time);
std::vector<Task *> tasks_;
Task *next_timeout_task_;
bool tasks_running_;
#ifdef _DEBUG
int abort_count_;
Task* deleting_task_;
#endif
void RecalcNextTimeout(Task *exclude_task);
};
} // namespace talk_base
#endif // TASK_BASE_TASKRUNNER_H__
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