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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/pull_node.h"
#include "mongo/db/matcher/copyable_match_expression.h"
#include "mongo/db/matcher/extensions_callback_disallow_extensions.h"
#include "mongo/db/query/collation/collator_interface.h"
namespace mongo {
/**
* The ObjectMatcher is used when the $pull condition is specified as an object and the first field
* of that object is not an operator (like $gt).
*/
class PullNode::ObjectMatcher : public PullNode::ElementMatcher {
public:
ObjectMatcher(BSONObj matchCondition, const CollatorInterface* collator)
: _matchExpr(
matchCondition, stdx::make_unique<ExtensionsCallbackDisallowExtensions>(), collator) {
}
std::unique_ptr<ElementMatcher> clone() const final {
return stdx::make_unique<ObjectMatcher>(*this);
}
bool match(mutablebson::ConstElement element) final {
if (element.getType() == mongo::Object) {
return _matchExpr->matchesBSON(element.getValueObject());
} else {
return false;
}
}
void setCollator(const CollatorInterface* collator) final {
_matchExpr.setCollator(collator);
}
private:
CopyableMatchExpression _matchExpr;
};
/**
* The WrappedObjectMatcher is used when the condition is a regex or an object with an operator as
* its first field (e.g., {$gt: ...}). It is possible that the element we want to compare is not an
* object, so we wrap it in an object before comparing it. We also wrap the MatchExpression in an
* empty object so that we are comparing the MatchCondition and the array element at the same level.
* This hack allows us to use a MatchExpression to check a BSONElement.
*/
class PullNode::WrappedObjectMatcher : public PullNode::ElementMatcher {
public:
WrappedObjectMatcher(BSONElement matchCondition, const CollatorInterface* collator)
: _matchExpr(matchCondition.wrap(""),
stdx::make_unique<ExtensionsCallbackDisallowExtensions>(),
collator) {}
std::unique_ptr<ElementMatcher> clone() const final {
return stdx::make_unique<WrappedObjectMatcher>(*this);
}
bool match(mutablebson::ConstElement element) final {
BSONObj candidate = element.getValue().wrap("");
return _matchExpr->matchesBSON(candidate);
}
void setCollator(const CollatorInterface* collator) final {
_matchExpr.setCollator(collator);
}
private:
CopyableMatchExpression _matchExpr;
};
/**
* The EqualityMatcher is used when the condition is a primitive value or an array value. We require
* an exact match.
*/
class PullNode::EqualityMatcher : public PullNode::ElementMatcher {
public:
EqualityMatcher(BSONElement modExpr, const CollatorInterface* collator)
: _modExpr(modExpr), _collator(collator) {}
std::unique_ptr<ElementMatcher> clone() const final {
return stdx::make_unique<EqualityMatcher>(*this);
}
bool match(mutablebson::ConstElement element) final {
return (element.compareWithBSONElement(_modExpr, _collator, false) == 0);
}
void setCollator(const CollatorInterface* collator) final {
_collator = collator;
}
private:
BSONElement _modExpr;
const CollatorInterface* _collator;
};
Status PullNode::init(BSONElement modExpr, const CollatorInterface* collator) {
invariant(modExpr.ok());
try {
if (modExpr.type() == mongo::Object &&
!MatchExpressionParser::parsePathAcceptingKeyword(
modExpr.embeddedObject().firstElement())) {
_matcher = stdx::make_unique<ObjectMatcher>(modExpr.embeddedObject(), collator);
} else if (modExpr.type() == mongo::Object || modExpr.type() == mongo::RegEx) {
_matcher = stdx::make_unique<WrappedObjectMatcher>(modExpr, collator);
} else {
_matcher = stdx::make_unique<EqualityMatcher>(modExpr, collator);
}
} catch (UserException& exception) {
return exception.toStatus();
}
return Status::OK();
}
void PullNode::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 (!pathToCreate->empty()) {
// There were path components we could not traverse. We treat this as a no-op, unless it
// would have been impossible to create those elements, which we check with
// checkViability().
UpdateLeafNode::checkViability(element, *pathToCreate, *pathTaken);
*noop = true;
return;
}
// This operation only applies to arrays
uassert(ErrorCodes::BadValue,
"Cannot apply $pull to a non-array value",
element.getType() == mongo::Array);
size_t numRemoved = 0;
auto cursor = element.leftChild();
while (cursor.ok()) {
// Make sure to get the next array element now, because if we remove the 'cursor' element,
// the rightSibling pointer will be invalidated.
auto nextElement = cursor.rightSibling();
if (_matcher->match(cursor)) {
invariantOK(cursor.remove());
numRemoved++;
}
cursor = nextElement;
}
if (numRemoved == 0) {
*noop = true;
return; // Skip the index check and logging steps.
}
// Determine if indexes are affected.
if (indexData && indexData->mightBeIndexed(pathTaken->dottedField())) {
*indexesAffected = true;
}
if (logBuilder) {
auto& doc = logBuilder->getDocument();
auto logElement = doc.makeElementArray(pathTaken->dottedField());
for (auto cursor = element.leftChild(); cursor.ok(); cursor = cursor.rightSibling()) {
dassert(cursor.hasValue());
auto copy = doc.makeElementWithNewFieldName(StringData(), cursor.getValue());
uassert(ErrorCodes::InternalError, "could not create copy element", copy.ok());
uassertStatusOK(logElement.pushBack(copy));
}
uassertStatusOK(logBuilder->addToSets(logElement));
}
}
} // namespace mongo
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