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/**
* Copyright (C) 2018-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 "mongo/platform/basic.h"
#include "mongo/base/exact_cast.h"
#include "mongo/db/query/projection_ast_path_tracking_visitor.h"
#include "mongo/db/query/query_planner_common.h"
#include "mongo/db/query/query_solution.h"
#include "mongo/db/query/stage_types.h"
#include "mongo/db/query/tree_walker.h"
#include "mongo/logv2/log.h"
#include "mongo/logv2/redaction.h"
#include "mongo/util/assert_util.h"
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kQuery
namespace mongo {
bool QueryPlannerCommon::scanDirectionsEqual(QuerySolutionNode* node, int direction) {
StageType type = node->getType();
boost::optional<int> scanDir;
if (STAGE_IXSCAN == type) {
IndexScanNode* isn = static_cast<IndexScanNode*>(node);
scanDir = isn->direction;
} else if (STAGE_DISTINCT_SCAN == type) {
DistinctNode* dn = static_cast<DistinctNode*>(node);
scanDir = dn->direction;
} else if (STAGE_COLLSCAN == type) {
CollectionScanNode* collScan = static_cast<CollectionScanNode*>(node);
scanDir = collScan->direction;
} else {
// We shouldn't encounter a sort stage.
invariant(!isSortStageType(type));
}
// If we found something with a direction, and the direction doesn't match, we return false.
if (scanDir && scanDir != direction) {
return false;
}
for (size_t i = 0; i < node->children.size(); ++i) {
if (!scanDirectionsEqual(node->children[i].get(), direction)) {
return false;
}
}
return true;
}
void QueryPlannerCommon::reverseScans(QuerySolutionNode* node, bool reverseCollScans) {
StageType type = node->getType();
if (STAGE_IXSCAN == type) {
IndexScanNode* isn = static_cast<IndexScanNode*>(node);
isn->direction *= -1;
isn->bounds = isn->bounds.reverse();
invariant(isn->bounds.isValidFor(isn->index.keyPattern, isn->direction),
str::stream() << "Invalid bounds: "
<< redact(isn->bounds.toString(isn->index.collator != nullptr)));
// TODO: we can just negate every value in the already computed properties.
isn->computeProperties();
} else if (STAGE_DISTINCT_SCAN == type) {
DistinctNode* dn = static_cast<DistinctNode*>(node);
dn->direction *= -1;
dn->bounds = dn->bounds.reverse();
invariant(dn->bounds.isValidFor(dn->index.keyPattern, dn->direction),
str::stream() << "Invalid bounds: "
<< redact(dn->bounds.toString(dn->index.collator != nullptr)));
dn->computeProperties();
} else if (STAGE_SORT_MERGE == type) {
// reverse direction of comparison for merge
MergeSortNode* msn = static_cast<MergeSortNode*>(node);
msn->sort = reverseSortObj(msn->sort);
} else if (reverseCollScans && STAGE_COLLSCAN == type) {
CollectionScanNode* collScan = static_cast<CollectionScanNode*>(node);
collScan->direction *= -1;
} else {
// Reversing scans is done in order to determine whether or not we need to add an explicit
// SORT stage. There shouldn't already be one present in the plan.
invariant(!isSortStageType(type));
}
for (size_t i = 0; i < node->children.size(); ++i) {
reverseScans(node->children[i].get(), reverseCollScans);
}
}
namespace {
struct MetaFieldData {
std::vector<FieldPath> metaPaths;
};
using MetaFieldVisitorContext = projection_ast::PathTrackingVisitorContext<MetaFieldData>;
/**
* Visitor which produces a list of paths where $meta expressions are.
*/
class MetaFieldVisitor final : public projection_ast::ProjectionASTConstVisitor {
public:
MetaFieldVisitor(MetaFieldVisitorContext* context) : _context(context) {}
void visit(const projection_ast::ExpressionASTNode* node) final {
const auto* metaExpr = exact_pointer_cast<const ExpressionMeta*>(node->expressionRaw());
if (!metaExpr || metaExpr->getMetaType() != DocumentMetadataFields::MetaType::kSortKey) {
return;
}
_context->data().metaPaths.push_back(_context->fullPath());
}
void visit(const projection_ast::ProjectionPositionalASTNode* node) final {}
void visit(const projection_ast::ProjectionSliceASTNode* node) final {}
void visit(const projection_ast::ProjectionElemMatchASTNode* node) final {}
void visit(const projection_ast::BooleanConstantASTNode* node) final {}
void visit(const projection_ast::ProjectionPathASTNode* node) final {}
void visit(const projection_ast::MatchExpressionASTNode* node) final {}
private:
MetaFieldVisitorContext* _context;
};
} // namespace
std::vector<FieldPath> QueryPlannerCommon::extractSortKeyMetaFieldsFromProjection(
const projection_ast::Projection& proj) {
MetaFieldVisitorContext ctx;
MetaFieldVisitor visitor(&ctx);
projection_ast::PathTrackingConstWalker<MetaFieldData> walker{&ctx, {&visitor}, {}};
tree_walker::walk<true, projection_ast::ASTNode>(proj.root(), &walker);
return std::move(ctx.data().metaPaths);
}
} // namespace mongo
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