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mongodb/util/background.h

73 lines
2.0 KiB
C++

/**
* 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,
* 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/>.
*/
#pragma once
namespace mongo {
/* object-orienty background thread dispatching.
subclass and define run()
It is ok to call go() more than once -- if the previous invocation
has finished. Thus one pattern of use is to embed a backgroundjob
in your object and reuse it (or same thing with inheritance).
*/
class BackgroundJob {
protected:
/* define this to do your work! */
virtual void run() = 0;
public:
enum State {
NotStarted,
Running,
Done
};
State getState() const {
return state;
}
bool running() const {
return state == Running;
}
bool deleteSelf; // delete self when Done?
BackgroundJob() {
deleteSelf = false;
state = NotStarted;
}
virtual ~BackgroundJob() { }
// start job. returns before it's finished.
BackgroundJob& go();
// wait for completion. this spins with sleep() so not terribly efficient.
// returns true if did not time out.
//
// note you can call wait() more than once if the first call times out.
bool wait(int msMax = 0);
private:
static BackgroundJob *grab;
static boost::mutex &mutex;
static void thr();
volatile State state;
};
} // namespace mongo