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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_exclusion_projection.h"
#include "mongo/db/pipeline/document.h"
#include "mongo/db/pipeline/field_path.h"
#include "mongo/db/pipeline/value.h"
#include "mongo/stdx/memory.h"
namespace mongo {
namespace parsed_aggregation_projection {
//
// ExclusionNode.
//
ExclusionNode::ExclusionNode(std::string pathToNode) : _pathToNode(std::move(pathToNode)) {}
Document ExclusionNode::serialize() const {
MutableDocument output;
for (auto&& excludedField : _excludedFields) {
output.addField(excludedField, Value(false));
}
for (auto&& childPair : _children) {
output.addField(childPair.first, Value(childPair.second->serialize()));
}
return output.freeze();
}
void ExclusionNode::excludePath(FieldPath path) {
if (path.getPathLength() == 1) {
_excludedFields.insert(path.fullPath());
return;
}
addOrGetChild(path.getFieldName(0))->excludePath(path.tail());
}
Document ExclusionNode::applyProjection(Document input) const {
MutableDocument output(input);
for (auto&& field : _excludedFields) {
output.remove(field);
}
for (auto&& childPair : _children) {
output[childPair.first] = childPair.second->applyProjectionToValue(input[childPair.first]);
}
return output.freeze();
}
ExclusionNode* ExclusionNode::addOrGetChild(FieldPath fieldPath) {
invariant(fieldPath.getPathLength() == 1);
auto child = getChild(fieldPath.fullPath());
return child ? child : addChild(fieldPath.fullPath());
}
ExclusionNode* ExclusionNode::getChild(std::string field) const {
auto it = _children.find(field);
return it == _children.end() ? nullptr : it->second.get();
}
ExclusionNode* ExclusionNode::addChild(std::string field) {
auto pathToChild = _pathToNode.empty() ? field : _pathToNode + "." + field;
auto emplacedPair = _children.emplace(
std::make_pair(std::move(field), stdx::make_unique<ExclusionNode>(pathToChild)));
// emplacedPair is a pair<iterator position, bool inserted>.
invariant(emplacedPair.second);
return emplacedPair.first->second.get();
}
Value ExclusionNode::applyProjectionToValue(Value val) const {
switch (val.getType()) {
case BSONType::Object:
return Value(applyProjection(val.getDocument()));
case BSONType::Array: {
// Apply exclusion to each element of the array. Note that numeric paths aren't treated
// specially, and we will always apply the projection to each element in the array.
//
// For example, applying the projection {"a.1": 0} to the document
// {a: [{b: 0, "1": 0}, {b: 1, "1": 1}]} will not result in {a: [{b: 0, "1": 0}]}, but
// instead will result in {a: [{b: 0}, {b: 1}]}.
std::vector<Value> values = val.getArray();
for (auto it = values.begin(); it != values.end(); it++) {
*it = applyProjectionToValue(*it);
}
return Value(std::move(values));
}
default:
return val;
}
}
void ExclusionNode::addModifiedPaths(std::set<std::string>* modifiedPaths) const {
for (auto&& excludedField : _excludedFields) {
modifiedPaths->insert(FieldPath::getFullyQualifiedPath(_pathToNode, excludedField));
}
for (auto&& childPair : _children) {
childPair.second->addModifiedPaths(modifiedPaths);
}
}
//
// ParsedExclusionProjection.
//
Document ParsedExclusionProjection::serialize(
boost::optional<ExplainOptions::Verbosity> explain) const {
return _root->serialize();
}
Document ParsedExclusionProjection::applyProjection(Document inputDoc) const {
return _root->applyProjection(inputDoc);
}
void ParsedExclusionProjection::parse(const BSONObj& spec, ExclusionNode* node, size_t depth) {
for (auto elem : spec) {
const auto fieldName = elem.fieldNameStringData().toString();
// A $ should have been detected in ParsedAggregationProjection's parsing before we get
// here.
invariant(fieldName[0] != '$');
switch (elem.type()) {
case BSONType::Bool:
case BSONType::NumberInt:
case BSONType::NumberLong:
case BSONType::NumberDouble:
case BSONType::NumberDecimal: {
// We have already verified this is an exclusion projection.
invariant(!elem.trueValue());
node->excludePath(FieldPath(fieldName));
break;
}
case BSONType::Object: {
// This object represents a nested projection specification, like the sub-object in
// {a: {b: 0, c: 0}} or {"a.b": {c: 0}}.
ExclusionNode* child;
if (elem.fieldNameStringData().find('.') == std::string::npos) {
child = node->addOrGetChild(fieldName);
} else {
// A dotted field is not allowed in a sub-object, and should have been detected
// in ParsedAggregationProjection's parsing before we get here.
invariant(depth == 0);
// We need to keep adding children to our tree until we create a child that
// represents this dotted path.
child = node;
auto fullPath = FieldPath(fieldName);
while (fullPath.getPathLength() > 1) {
child = child->addOrGetChild(fullPath.getFieldName(0));
fullPath = fullPath.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(fullPath.fullPath());
}
parse(elem.Obj(), child, depth + 1);
break;
}
default: { MONGO_UNREACHABLE; }
}
}
}
} // namespace parsed_aggregation_projection
} // namespace mongo
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