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73 lines
2.0 KiB
C++
73 lines
2.0 KiB
C++
// background.h
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/* Copyright 2009 10gen Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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namespace mongo {
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/* object-orienty background thread dispatching.
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subclass and define run()
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It is ok to call go() more than once -- if the previous invocation
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has finished. Thus one pattern of use is to embed a backgroundjob
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in your object and reuse it (or same thing with inheritance).
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*/
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class BackgroundJob {
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protected:
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/* define this to do your work! */
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virtual void run() = 0;
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public:
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enum State {
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NotStarted,
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Running,
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Done
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};
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State getState() const {
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return state;
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}
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bool running() const {
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return state == Running;
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}
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bool deleteSelf; // delete self when Done?
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BackgroundJob() {
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deleteSelf = false;
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state = NotStarted;
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}
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virtual ~BackgroundJob() { }
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// start job. returns before it's finished.
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BackgroundJob& go();
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// wait for completion. this spins with sleep() so not terribly efficient.
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// returns true if did not time out.
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//
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// note you can call wait() more than once if the first call times out.
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bool wait(int msMax = 0);
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private:
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static BackgroundJob *grab;
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static mongo::mutex mutex;
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static void thr();
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volatile State state;
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};
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} // namespace mongo
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