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/**
* Copyright (C) 2016 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/platform/basic.h"
#include "mongo/db/pipeline/parsed_add_fields.h"
#include <algorithm>
#include "mongo/db/pipeline/parsed_aggregation_projection.h"
namespace mongo {
namespace parsed_aggregation_projection {
std::unique_ptr<ParsedAddFields> ParsedAddFields::create(
const boost::intrusive_ptr<ExpressionContext>& expCtx, const BSONObj& spec) {
// Verify that we don't have conflicting field paths, etc.
Status status = ProjectionSpecValidator::validate(spec);
if (!status.isOK()) {
uasserted(status.location(),
str::stream() << "Invalid $addFields specification: " << status.reason());
}
std::unique_ptr<ParsedAddFields> parsedAddFields = stdx::make_unique<ParsedAddFields>(expCtx);
// Actually parse the specification.
parsedAddFields->parse(spec);
return parsedAddFields;
}
void ParsedAddFields::parse(const BSONObj& spec) {
for (auto elem : spec) {
auto fieldName = elem.fieldNameStringData();
if (elem.type() == BSONType::Object) {
// This is either an expression, or a nested specification.
if (parseObjectAsExpression(fieldName, elem.Obj(), _expCtx->variablesParseState)) {
// It was an expression.
} else {
// The field name might be a dotted path. If so, we need to keep adding children
// to our tree until we create a child that represents that path.
auto remainingPath = FieldPath(elem.fieldName());
auto child = _root.get();
while (remainingPath.getPathLength() > 1) {
child = child->addOrGetChild(remainingPath.getFieldName(0).toString());
remainingPath = remainingPath.tail();
}
// It is illegal to construct an empty FieldPath, so the above loop ends one
// iteration too soon. Add the last path here.
child = child->addOrGetChild(remainingPath.fullPath());
parseSubObject(elem.Obj(), _expCtx->variablesParseState, child);
}
} else {
// This is a literal or regular value.
_root->addComputedField(
FieldPath(elem.fieldName()),
Expression::parseOperand(_expCtx, elem, _expCtx->variablesParseState));
}
}
}
Document ParsedAddFields::applyProjection(Document inputDoc) const {
// The output doc is the same as the input doc, with the added fields.
MutableDocument output(inputDoc);
_root->addComputedFields(&output, inputDoc);
// Pass through the metadata.
output.copyMetaDataFrom(inputDoc);
return output.freeze();
}
bool ParsedAddFields::parseObjectAsExpression(StringData pathToObject,
const BSONObj& objSpec,
const VariablesParseState& variablesParseState) {
if (objSpec.firstElementFieldName()[0] == '$') {
// This is an expression like {$add: [...]}. We have already verified that it has only one
// field.
invariant(objSpec.nFields() == 1);
_root->addComputedField(pathToObject,
Expression::parseExpression(_expCtx, objSpec, variablesParseState));
return true;
}
return false;
}
void ParsedAddFields::parseSubObject(const BSONObj& subObj,
const VariablesParseState& variablesParseState,
InclusionNode* node) {
for (auto&& elem : subObj) {
invariant(elem.fieldName()[0] != '$');
// Dotted paths in a sub-object have already been detected and disallowed by the function
// ProjectionSpecValidator::validate().
invariant(elem.fieldNameStringData().find('.') == std::string::npos);
if (elem.type() == BSONType::Object) {
// This is either an expression, or a nested specification.
auto fieldName = elem.fieldNameStringData().toString();
if (!parseObjectAsExpression(
FieldPath::getFullyQualifiedPath(node->getPath(), fieldName),
elem.Obj(),
variablesParseState)) {
// It was a nested subobject
auto child = node->addOrGetChild(fieldName);
parseSubObject(elem.Obj(), variablesParseState, child);
}
} else {
// This is a literal or regular value.
node->addComputedField(FieldPath(elem.fieldName()),
Expression::parseOperand(_expCtx, elem, variablesParseState));
}
}
}
} // namespace parsed_aggregation_projection
} // namespace mongo
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