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/**
* Copyright (C) 2017 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/update/pop_node.h"
#include "mongo/db/matcher/expression_parser.h"
#include "mongo/db/update/path_support.h"
#include "mongo/util/stringutils.h"
namespace mongo {
Status PopNode::init(BSONElement modExpr, const CollatorInterface* collator) {
auto popVal = MatchExpressionParser::parseIntegerElementToLong(modExpr);
if (!popVal.isOK()) {
return popVal.getStatus();
}
if (popVal.getValue() != 1LL && popVal.getValue() != -1LL) {
return {ErrorCodes::FailedToParse,
str::stream() << "$pop expects 1 or -1, found: " << popVal.getValue()};
}
_popFromFront = (popVal.getValue() == -1LL);
return Status::OK();
}
void PopNode::apply(mutablebson::Element element,
FieldRef* pathToCreate,
FieldRef* pathTaken,
StringData matchedField,
bool fromReplication,
bool validateForStorage,
const FieldRefSet& immutablePaths,
const UpdateIndexData* indexData,
LogBuilder* logBuilder,
bool* indexesAffected,
bool* noop) const {
*indexesAffected = false;
*noop = false;
if (pathTaken->empty()) {
// No components of the path existed. The pop is treated as a no-op in this case.
*noop = true;
return;
}
if (!pathToCreate->empty()) {
// There were path components which we could not traverse. If 'element' is a nested object
// which does not contain 'pathToCreate', then this is a no-op (e.g. {$pop: {"a.b.c": 1}}
// for document {a: {b: {}}}).
//
// If the element is an array, but the numeric path does not exist, then this is also a
// no-op (e.g. {$pop: {"a.2.b": 1}} for document {a: [{b: 0}, {b: 1}]}).
//
// Otherwise, this the path contains a blocking leaf or array element, which is an error.
if (element.getType() == BSONType::Object) {
*noop = true;
return;
}
if (element.getType() == BSONType::Array &&
parseUnsignedBase10Integer(pathToCreate->getPart(0))) {
*noop = true;
return;
}
uasserted(ErrorCodes::PathNotViable,
str::stream() << "Cannot use the part (" << pathToCreate->getPart(0) << ") of ("
<< pathTaken->dottedField()
<< "."
<< pathToCreate->dottedField()
<< ") to traverse the element ({"
<< element.toString()
<< "})");
}
invariant(!pathTaken->empty());
invariant(pathToCreate->empty());
// The full path existed, but we must fail if the element at that path is not an array.
invariant(element.ok());
uassert(ErrorCodes::TypeMismatch,
str::stream() << "Path '" << pathTaken->dottedField()
<< "' contains an element of non-array type '"
<< typeName(element.getType())
<< "'",
element.getType() == BSONType::Array);
if (!element.hasChildren()) {
// The path exists and contains an array, but the array is empty.
*noop = true;
return;
}
if (indexData && indexData->mightBeIndexed(pathTaken->dottedField())) {
*indexesAffected = true;
}
auto elementToRemove = _popFromFront ? element.leftChild() : element.rightChild();
invariantOK(elementToRemove.remove());
// No need to validate for storage, since we cannot have increased the BSON depth or interfered
// with a DBRef.
// Ensure we are not changing any immutable paths.
for (auto immutablePath = immutablePaths.begin(); immutablePath != immutablePaths.end();
++immutablePath) {
uassert(ErrorCodes::ImmutableField,
str::stream() << "Performing a $pop on the path '" << pathTaken->dottedField()
<< "' would modify the immutable field '"
<< (*immutablePath)->dottedField()
<< "'",
pathTaken->commonPrefixSize(**immutablePath) <
std::min(pathTaken->numParts(), (*immutablePath)->numParts()));
}
if (logBuilder) {
uassertStatusOK(logBuilder->addToSetsWithNewFieldName(pathTaken->dottedField(), element));
}
}
} // namespace mongo
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