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/**
* Copyright 2011 (c) 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/document.h"
#include "db/pipeline/expression.h"
#include "db/pipeline/value.h"
namespace mongo {
const char DocumentSourceProject::projectName[] = "$project";
DocumentSourceProject::~DocumentSourceProject() {
}
DocumentSourceProject::DocumentSourceProject():
excludeId(false),
pEO(ExpressionObject::create()) {
}
bool DocumentSourceProject::eof() {
return pSource->eof();
}
bool DocumentSourceProject::advance() {
return pSource->advance();
}
intrusive_ptr<Document> DocumentSourceProject::getCurrent() {
intrusive_ptr<Document> pInDocument(pSource->getCurrent());
/* create the result document */
const size_t sizeHint =
pEO->getSizeHint(pInDocument) + (excludeId ? 0 : 1);
intrusive_ptr<Document> pResultDocument(Document::create(sizeHint));
if (!excludeId) {
intrusive_ptr<const Value> pId(
pInDocument->getField(Document::idName));
pResultDocument->addField(Document::idName, pId);
}
/* use the ExpressionObject to create the base result */
pEO->addToDocument(pResultDocument, pInDocument);
return pResultDocument;
}
void DocumentSourceProject::optimize() {
intrusive_ptr<Expression> pE(pEO->optimize());
pEO = dynamic_pointer_cast<ExpressionObject>(pE);
}
void DocumentSourceProject::sourceToBson(BSONObjBuilder *pBuilder) const {
BSONObjBuilder insides;
if (excludeId)
insides.append(Document::idName, false);
pEO->documentToBson(&insides, 0);
pBuilder->append(projectName, insides.done());
}
intrusive_ptr<DocumentSourceProject> DocumentSourceProject::create() {
intrusive_ptr<DocumentSourceProject> pSource(
new DocumentSourceProject());
return pSource;
}
void DocumentSourceProject::addField(
const string &fieldName, const intrusive_ptr<Expression> &pExpression) {
uassert(15960,
"projection fields must be defined by non-empty expressions",
pExpression);
pEO->addField(fieldName, pExpression);
}
void DocumentSourceProject::includePath(const string &fieldPath) {
if (Document::idName.compare(fieldPath) == 0) {
uassert(15961, str::stream() << projectName <<
": _id cannot be included once it has been excluded",
!excludeId);
return;
}
pEO->includePath(fieldPath);
}
void DocumentSourceProject::excludePath(const string &fieldPath) {
if (Document::idName.compare(fieldPath) == 0) {
excludeId = true;
return;
}
pEO->excludePath(fieldPath);
}
intrusive_ptr<DocumentSource> DocumentSourceProject::createFromBson(
BSONElement *pBsonElement,
const intrusive_ptr<ExpressionContext> &pCtx) {
/* validate */
uassert(15969, str::stream() << projectName <<
" specification must be an object",
pBsonElement->type() == Object);
/* chain the projection onto the original source */
intrusive_ptr<DocumentSourceProject> pProject(
DocumentSourceProject::create());
/*
Pull out the $project object. This should just be a list of
field inclusion or exclusion specifications. Note you can't do
both, except for the case of _id.
*/
BSONObj projectObj(pBsonElement->Obj());
BSONObjIterator fieldIterator(projectObj);
Expression::ObjectCtx objectCtx(
Expression::ObjectCtx::DOCUMENT_OK);
while(fieldIterator.more()) {
BSONElement outFieldElement(fieldIterator.next());
string outFieldPath(outFieldElement.fieldName());
string inFieldName(outFieldPath);
BSONType specType = outFieldElement.type();
int fieldInclusion = -1;
switch(specType) {
case NumberDouble: {
double inclusion = outFieldElement.numberDouble();
fieldInclusion = static_cast<int>(inclusion);
goto IncludeExclude;
}
case NumberInt:
/* just a plain integer include/exclude specification */
fieldInclusion = outFieldElement.numberInt();
IncludeExclude:
uassert(15970, str::stream() <<
"field inclusion or exclusion specification for \"" <<
outFieldPath <<
"\" must be true, 1, false, or zero",
((fieldInclusion == 0) || (fieldInclusion == 1)));
if (fieldInclusion == 0)
pProject->excludePath(outFieldPath);
else
pProject->includePath(outFieldPath);
break;
case Bool:
/* just a plain boolean include/exclude specification */
fieldInclusion = (outFieldElement.Bool() ? 1 : 0);
goto IncludeExclude;
case String:
/* include a field, with rename */
fieldInclusion = 1;
inFieldName = outFieldElement.String();
pProject->addField(
outFieldPath,
ExpressionFieldPath::create(
Expression::removeFieldPrefix(inFieldName)));
break;
case Object: {
intrusive_ptr<Expression> pDocument(
Expression::parseObject(&outFieldElement, &objectCtx));
/* add The document expression to the projection */
pProject->addField(outFieldPath, pDocument);
break;
}
default:
uassert(15971, str::stream() <<
"invalid BSON type (" << specType <<
") for " << projectName <<
" field " << outFieldPath, false);
}
}
return pProject;
}
}
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