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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.
*/
#pragma once
#include <memory>
#include "mongo/db/exec/requires_collection_stage.h"
#include "mongo/db/fts/fts_spec.h"
#include "mongo/db/matcher/expression.h"
#include "mongo/db/record_id.h"
namespace mongo {
using fts::FTSSpec;
class OperationContext;
/**
* A blocking stage that returns the set of WSMs with RecordIDs of all of the documents that contain
* the positive terms in the search query, as well as their scores.
*
* The WorkingSetMembers returned are fetched and in the LOC_AND_OBJ state.
*/
class TextOrStage final : public RequiresCollectionStage {
public:
/**
* Internal states.
*/
enum class State {
// 1. Initialize the _recordCursor.
kInit,
// 2. Read the terms/scores from the text index.
kReadingTerms,
// 3. Return results to our parent.
kReturningResults,
// 4. Finished.
kDone,
};
TextOrStage(OperationContext* opCtx,
const FTSSpec& ftsSpec,
WorkingSet* ws,
const MatchExpression* filter,
const Collection* collection);
void addChild(std::unique_ptr<PlanStage> child);
void addChildren(Children childrenToAdd);
bool isEOF() final;
StageState doWork(WorkingSetID* out) final;
void doDetachFromOperationContext() final;
void doReattachToOperationContext() final;
StageType stageType() const final {
return STAGE_TEXT_OR;
}
std::unique_ptr<PlanStageStats> getStats() final;
const SpecificStats* getSpecificStats() const final;
static const char* kStageType;
protected:
void doSaveStateRequiresCollection() final;
void doRestoreStateRequiresCollection() final;
private:
/**
* Worker for kInit. Initializes the _recordCursor member and handles the potential for
* getCursor() to throw WriteConflictException.
*/
StageState initStage(WorkingSetID* out);
/**
* Worker for kReadingTerms. Reads from the children, searching for the terms in the query and
* populates the score map.
*/
StageState readFromChildren(WorkingSetID* out);
/**
* Helper called from readFromChildren to update aggregate score with a newfound (term, score)
* pair for this document.
*/
StageState addTerm(WorkingSetID wsid, WorkingSetID* out);
/**
* Worker for kReturningResults. Returns a wsm with RecordID and Score.
*/
StageState returnResults(WorkingSetID* out);
// The index spec used to determine where to find the score.
FTSSpec _ftsSpec;
// Not owned by us.
WorkingSet* _ws;
// What state are we in? See the State enum above.
State _internalState = State::kInit;
// Which of _children are we calling work(...) on now?
size_t _currentChild = 0;
/**
* Temporary score data filled out by children.
* Maps from RecordID -> (aggregate score for doc, wsid).
* Map each buffered record id to this data.
*/
struct TextRecordData {
TextRecordData() : wsid(WorkingSet::INVALID_ID), score(0.0) {}
WorkingSetID wsid;
double score;
};
typedef stdx::unordered_map<RecordId, TextRecordData, RecordId::Hasher> ScoreMap;
ScoreMap _scores;
ScoreMap::const_iterator _scoreIterator;
TextOrStats _specificStats;
// Members needed only for using the TextMatchableDocument.
const MatchExpression* _filter;
WorkingSetID _idRetrying;
std::unique_ptr<SeekableRecordCursor> _recordCursor;
};
} // namespace mongo
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