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// @file task.h
/**
* Copyright (C) 2008 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,b
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects
* for all of the code used other than as permitted herein. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you do not
* wish to do so, delete this exception statement from your version. If you
* delete this exception statement from all source files in the program,
* then also delete it in the license file.
*/
#pragma once
#include "mongo/util/background.h"
namespace mongo {
namespace task {
/** abstraction around threads. simpler than BackgroundJob which is used behind the scenes.
allocate the Task dynamically. when the thread terminates, the Task object will delete itself.
*/
class Task : private BackgroundJob {
protected:
virtual void setUp(); // Override to perform any do-once work for the task.
virtual void doWork() = 0; // implement the task here.
virtual string name() const = 0; // name the thread
public:
Task();
/** for a repeating task, stop after current invocation ends. can be called by other threads
as long as the Task is still in scope.
*/
void halt();
private:
unsigned n, repeat;
friend void fork(Task* t);
friend void repeat(Task* t, unsigned millis);
virtual void run();
//virtual void ending() { }
void begin();
};
/** run once */
void fork(Task *t);
/** run doWork() over and over, with a pause between runs of millis */
void repeat(Task *t, unsigned millis);
/*** Example ***
inline void sample() {
class Sample : public Task {
public:
int result;
virtual void doWork() { result = 1234; }
Sample() : result(0) { }
};
shared_ptr<Sample> q( new Sample() );
fork(q);
cout << q->result << endl; // could print 1234 or 0.
}
*/
}
}
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