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/**
* Copyright (C) 2014 MongoDB 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.
*/
#include "mongo/db/exec/keep_mutations.h"
#include "mongo/db/exec/filter.h"
namespace mongo {
// static
const char* KeepMutationsStage::kStageType = "KEEP_MUTATIONS";
KeepMutationsStage::KeepMutationsStage(const MatchExpression* filter,
WorkingSet* ws,
PlanStage* child)
: _workingSet(ws),
_child(child),
_filter(filter),
_doneReadingChild(false),
_doneReturningFlagged(false),
_commonStats(kStageType) { }
KeepMutationsStage::~KeepMutationsStage() { }
bool KeepMutationsStage::isEOF() {
return _doneReadingChild && _doneReturningFlagged;
}
PlanStage::StageState KeepMutationsStage::work(WorkingSetID* out) {
++_commonStats.works;
// If we've returned as many results as we're limited to, isEOF will be true.
if (isEOF()) { return PlanStage::IS_EOF; }
// Stream child results until the child is all done.
if (!_doneReadingChild) {
StageState status = _child->work(out);
// Child is still returning results. Pass them through.
if (PlanStage::IS_EOF != status) {
if (PlanStage::ADVANCED == status) {
++_commonStats.advanced;
}
else if (PlanStage::NEED_TIME == status) {
++_commonStats.needTime;
}
return status;
}
// Child is EOF. We want to stream flagged results if there are any.
_doneReadingChild = true;
_flaggedIterator = _workingSet->getFlagged().begin();
}
// We're streaming flagged results.
invariant(!_doneReturningFlagged);
if (_flaggedIterator == _workingSet->getFlagged().end()) {
_doneReturningFlagged = true;
return PlanStage::IS_EOF;
}
WorkingSetID idToTest = *_flaggedIterator;
_flaggedIterator++;
WorkingSetMember* member = _workingSet->get(idToTest);
if (Filter::passes(member, _filter)) {
*out = idToTest;
++_commonStats.advanced;
return PlanStage::ADVANCED;
}
else {
_workingSet->free(idToTest);
++_commonStats.needTime;
return PlanStage::NEED_TIME;
}
}
void KeepMutationsStage::prepareToYield() {
++_commonStats.yields;
_child->prepareToYield();
}
void KeepMutationsStage::recoverFromYield() {
++_commonStats.unyields;
_child->recoverFromYield();
}
void KeepMutationsStage::invalidate(const DiskLoc& dl, InvalidationType type) {
++_commonStats.invalidates;
_child->invalidate(dl, type);
}
PlanStageStats* KeepMutationsStage::getStats() {
_commonStats.isEOF = isEOF();
auto_ptr<PlanStageStats> ret(new PlanStageStats(_commonStats, STAGE_KEEP_MUTATIONS));
// Takes ownership of the object returned from _child->getStats().
ret->children.push_back(_child->getStats());
return ret.release();
}
} // namespace mongo
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