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/**
* 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/>.
*
* 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/db/repl/health.h"
#include "mongo/util/concurrency/mutex.h"
#include "mongo/util/log.h"
namespace mongo {
/**
* most operations on a ReplSet object should be done while locked. that
* logic implemented here.
*
* Order of locking: lock the replica set, then take a rwlock.
*/
class RSBase : boost::noncopyable {
private:
mongo::mutex m;
int _locked;
ThreadLocalValue<bool> _lockedByMe;
protected:
RSBase() : m("RSBase"), _locked(0) { }
~RSBase() {
// this can happen if we throw in the constructor; otherwise never happens. thus we
// logit as it is quite unusual.
log() << "replSet ~RSBase called" << rsLog;
}
public:
class lock {
RSBase& rsbase;
std::auto_ptr<scoped_lock> sl;
public:
lock(RSBase* b) : rsbase(*b) {
if( rsbase._lockedByMe.get() )
return; // recursive is ok...
sl.reset( new scoped_lock(rsbase.m) );
DEV verify(rsbase._locked == 0);
rsbase._locked++;
rsbase._lockedByMe.set(true);
}
~lock() {
if( sl.get() ) {
verify( rsbase._lockedByMe.get() );
DEV verify(rsbase._locked == 1);
rsbase._lockedByMe.set(false);
rsbase._locked--;
}
}
};
/* for asserts */
bool locked() const { return _locked != 0; }
/** if true, is locked, and was locked by this thread. note if false, it could be in the
* lock or not for another just for asserts & such so we can make the contracts clear on
* who locks what when. we don't use these locks that frequently, so the little bit of
* overhead is fine.
*/
bool lockedByMe() { return _lockedByMe.get(); }
};
} // namespace mongo
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