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/**
* Copyright (C) 2011 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/>.
*/
#include "pch.h"
#include "db/pipeline/document_source.h"
#include "db/jsobj.h"
#include "db/pipeline/expression.h"
#include "db/pipeline/value.h"
namespace mongo {
const char DocumentSourceFilter::filterName[] = "$filter";
DocumentSourceFilter::~DocumentSourceFilter() {
}
bool DocumentSourceFilter::coalesce(
const intrusive_ptr<DocumentSource> &pNextSource) {
/* we only know how to coalesce other filters */
DocumentSourceFilter *pDocFilter =
dynamic_cast<DocumentSourceFilter *>(pNextSource.get());
if (!pDocFilter)
return false;
/*
Two adjacent filters can be combined by creating a conjunction of
their predicates.
*/
intrusive_ptr<ExpressionNary> pAnd(ExpressionAnd::create());
pAnd->addOperand(pFilter);
pAnd->addOperand(pDocFilter->pFilter);
pFilter = pAnd;
return true;
}
void DocumentSourceFilter::optimize() {
pFilter = pFilter->optimize();
}
void DocumentSourceFilter::sourceToBson(BSONObjBuilder *pBuilder) const {
pFilter->addToBsonObj(pBuilder, filterName, 0);
}
bool DocumentSourceFilter::accept(
const intrusive_ptr<Document> &pDocument) const {
intrusive_ptr<const Value> pValue(pFilter->evaluate(pDocument));
return pValue->coerceToBool();
}
intrusive_ptr<DocumentSource> DocumentSourceFilter::createFromBson(
BSONElement *pBsonElement,
const intrusive_ptr<ExpressionContext> &pCtx) {
uassert(15946, "a document filter expression must be an object",
pBsonElement->type() == Object);
Expression::ObjectCtx oCtx(0);
intrusive_ptr<Expression> pExpression(
Expression::parseObject(pBsonElement, &oCtx));
intrusive_ptr<DocumentSourceFilter> pFilter(
DocumentSourceFilter::create(pExpression));
return pFilter;
}
intrusive_ptr<DocumentSourceFilter> DocumentSourceFilter::create(
const intrusive_ptr<Expression> &pFilter) {
intrusive_ptr<DocumentSourceFilter> pSource(
new DocumentSourceFilter(pFilter));
return pSource;
}
DocumentSourceFilter::DocumentSourceFilter(
const intrusive_ptr<Expression> &pTheFilter):
DocumentSourceFilterBase(),
pFilter(pTheFilter) {
}
void DocumentSourceFilter::toMatcherBson(BSONObjBuilder *pBuilder) const {
pFilter->toMatcherBson(pBuilder, 0);
}
}
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