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/**
* Copyright (C) 2020-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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 <algorithm>
#include <boost/optional.hpp>
#include <iterator>
#include <memory>
#include <utility>
#include "mongo/db/cst/c_node_disambiguation.h"
#include "mongo/stdx/variant.h"
#include "mongo/util/visit_helper.h"
namespace mongo::c_node_disambiguation {
namespace {
enum class ProjectionType : char { inclusion, exclusion, inconsistent };
boost::optional<CNode> replaceCNode(const CNode& cst,
boost::optional<ProjectionType>& currentProjType) {
auto updateProjectionTypeCreateReplacement =
[&](auto&& isExclusion, auto&& makeExclusive, auto&& makeInclusive) {
auto seenProjType = isExclusion ? ProjectionType::exclusion : ProjectionType::inclusion;
if (!currentProjType)
currentProjType = seenProjType;
else if (*currentProjType != seenProjType)
currentProjType = ProjectionType::inconsistent;
return boost::make_optional(isExclusion ? makeExclusive() : makeInclusive());
};
// This is done without mutation so we can cancel the operation without side effects.
return stdx::visit(
visit_helper::Overloaded{
[&](const CNode::ObjectChildren& children) -> boost::optional<CNode> {
auto newChildren = CNode::ObjectChildren{};
for (auto&& [fieldname, fieldValue] : children)
if (!stdx::holds_alternative<UserFieldname>(fieldname))
return boost::none;
else if (auto newNode = replaceCNode(fieldValue, currentProjType); !newNode)
return boost::none;
else
newChildren.emplace_back(fieldname, *newNode);
return CNode{std::move(newChildren)};
},
[&](const UserInt& userInt) {
return updateProjectionTypeCreateReplacement(
userInt == UserInt{0},
[] { return CNode{KeyValue::intZeroKey}; },
[&] { return CNode{NonZeroKey{userInt}}; });
},
[&](const UserLong& userLong) {
return updateProjectionTypeCreateReplacement(
userLong == UserLong{0ll},
[] { return CNode{KeyValue::longZeroKey}; },
[&] { return CNode{NonZeroKey{userLong}}; });
},
[&](const UserDouble& userDouble) {
return updateProjectionTypeCreateReplacement(
userDouble == UserDouble{0.0},
[] { return CNode{KeyValue::doubleZeroKey}; },
[&] { return CNode{NonZeroKey{userDouble}}; });
},
[&](const UserDecimal& userDecimal) {
return updateProjectionTypeCreateReplacement(
userDecimal == UserDecimal{0.0},
[] { return CNode{KeyValue::decimalZeroKey}; },
[&] { return CNode{NonZeroKey{userDecimal}}; });
},
[&](const UserBoolean& userBoolean) {
return updateProjectionTypeCreateReplacement(
userBoolean == UserBoolean{false},
[] { return CNode{KeyValue::falseKey}; },
[] { return CNode{KeyValue::trueKey}; });
},
[&](auto &&) -> boost::optional<CNode> { return boost::none; }},
cst.payload);
}
} // namespace
CNode disambiguateCompoundProjection(CNode project) {
auto projectionType = boost::optional<ProjectionType>{};
auto cNode = replaceCNode(project, projectionType);
if (!cNode)
return project;
switch (*projectionType) {
case ProjectionType::inclusion:
return CNode{CompoundInclusionKey{std::make_unique<CNode>(*std::move(cNode))}};
case ProjectionType::exclusion:
return CNode{CompoundExclusionKey{std::make_unique<CNode>(*std::move(cNode))}};
case ProjectionType::inconsistent:
return CNode{CompoundInconsistentKey{std::make_unique<CNode>(*std::move(cNode))}};
}
MONGO_UNREACHABLE;
}
} // namespace mongo::c_node_disambiguation
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