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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/update_array_node.h"
namespace mongo {
// static
std::unique_ptr<UpdateNode> UpdateArrayNode::createUpdateNodeByMerging(
const UpdateArrayNode& leftNode, const UpdateArrayNode& rightNode, FieldRef* pathTaken) {
invariant(&leftNode._arrayFilters == &rightNode._arrayFilters);
auto mergedNode = stdx::make_unique<UpdateArrayNode>(leftNode._arrayFilters);
const bool wrapFieldNameAsArrayFilterIdentifier = true;
mergedNode->_children = createUpdateNodeMapByMerging(
leftNode._children, rightNode._children, pathTaken, wrapFieldNameAsArrayFilterIdentifier);
return std::move(mergedNode);
}
UpdateNode::ApplyResult UpdateArrayNode::apply(ApplyParams applyParams) const {
if (!applyParams.pathToCreate->empty()) {
for (size_t i = 0; i < applyParams.pathToCreate->numParts(); ++i) {
applyParams.pathTaken->appendPart(applyParams.pathToCreate->getPart(i));
}
uasserted(ErrorCodes::BadValue,
str::stream() << "The path '" << applyParams.pathTaken->dottedField()
<< "' must exist in the document in order to apply array updates.");
}
uassert(ErrorCodes::BadValue,
str::stream() << "Cannot apply array updates to non-array element "
<< applyParams.element.toString(),
applyParams.element.getType() == BSONType::Array);
// Construct a map from the array index to the set of updates that should be applied to the
// array element at that index. We do not apply the updates yet because we need to know how many
// array elements will be updated in order to know whether to pass 'logBuilder' on to the
// UpdateNode children.
std::map<size_t, std::vector<UpdateNode*>> matchingElements;
size_t i = 0;
for (auto childElement = applyParams.element.leftChild(); childElement.ok();
childElement = childElement.rightSibling()) {
// 'childElement' will always be serialized because no updates have been performed on the
// array yet, and when we populate an upserted document with equality fields from the query,
// arrays can only be added in entirety.
invariant(childElement.hasValue());
auto arrayElement = childElement.getValue();
for (const auto& update : _children) {
if (update.first.empty()) {
// If the identifier is the empty string (e.g. came from 'a.$[].b'), the update
// should be applied to all array elements.
matchingElements[i].push_back(update.second.get());
} else {
auto filter = _arrayFilters.find(update.first);
invariant(filter != _arrayFilters.end());
if (filter->second->matchesBSONElement(arrayElement)) {
matchingElements[i].push_back(update.second.get());
}
}
}
++i;
}
// If at most one array element will be updated, pass 'logBuilder' to the UpdateNode child when
// applying it to that element.
const bool childrenShouldLogThemselves = matchingElements.size() <= 1;
// Keep track of which array elements were actually modified (non-noop updates) for logging
// purposes. We only need to keep track of one element, since if more than one element is
// modified, we log the whole array.
boost::optional<mutablebson::Element> modifiedElement;
size_t nModified = 0;
// Update array elements.
auto applyResult = ApplyResult::noopResult();
i = 0;
for (auto childElement = applyParams.element.leftChild(); childElement.ok();
childElement = childElement.rightSibling()) {
auto updates = matchingElements.find(i);
if (updates != matchingElements.end()) {
// Merge all of the updates for this array element.
invariant(updates->second.size() > 0);
auto mergedChild = updates->second[0];
FieldRefTempAppend tempAppend(*(applyParams.pathTaken), childElement.getFieldName());
for (size_t j = 1; j < updates->second.size(); ++j) {
// Use the cached merge result, if it is available.
const auto& cachedResult = _mergedChildrenCache[mergedChild][updates->second[j]];
if (cachedResult.get()) {
mergedChild = cachedResult.get();
continue;
}
// The cached merge result is not available, so perform the merge and cache the
// result.
_mergedChildrenCache[mergedChild][updates->second[j]] =
UpdateNode::createUpdateNodeByMerging(
*mergedChild, *updates->second[j], applyParams.pathTaken.get());
mergedChild = _mergedChildrenCache[mergedChild][updates->second[j]].get();
}
auto childApplyParams = applyParams;
childApplyParams.element = childElement;
if (!childrenShouldLogThemselves) {
childApplyParams.logBuilder = nullptr;
}
auto childApplyResult = mergedChild->apply(childApplyParams);
applyResult.indexesAffected =
applyResult.indexesAffected || childApplyResult.indexesAffected;
applyResult.noop = applyResult.noop && childApplyResult.noop;
if (!childApplyResult.noop) {
modifiedElement = childElement;
++nModified;
}
}
++i;
}
// If the child updates have not been logged, log the updated array elements.
if (!childrenShouldLogThemselves && applyParams.logBuilder) {
if (nModified > 1) {
// Log the entire array.
auto logElement = applyParams.logBuilder->getDocument().makeElementWithNewFieldName(
applyParams.pathTaken->dottedField(), applyParams.element);
invariant(logElement.ok());
uassertStatusOK(applyParams.logBuilder->addToSets(logElement));
} else if (nModified == 1) {
// Log the modified array element.
invariant(modifiedElement);
FieldRefTempAppend tempAppend(*(applyParams.pathTaken),
modifiedElement->getFieldName());
auto logElement = applyParams.logBuilder->getDocument().makeElementWithNewFieldName(
applyParams.pathTaken->dottedField(), *modifiedElement);
invariant(logElement.ok());
uassertStatusOK(applyParams.logBuilder->addToSets(logElement));
}
}
return applyResult;
}
UpdateNode* UpdateArrayNode::getChild(const std::string& field) const {
auto child = _children.find(field);
if (child == _children.end()) {
return nullptr;
}
return child->second.get();
}
void UpdateArrayNode::setChild(std::string field, std::unique_ptr<UpdateNode> child) {
invariant(_children.find(field) == _children.end());
_children[std::move(field)] = std::move(child);
}
} // namespace mongo
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