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// fts_element_iterator.h
/**
* Copyright (C) 2014 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.
*/
#pragma once
#include "mongo/bson/bsonobj.h"
#include "mongo/db/fts/fts_language.h"
#include "mongo/db/fts/fts_spec.h"
#include <map>
#include <stack>
#include <string>
namespace mongo {
namespace fts {
/**
* Encapsulates data fields returned by FTSElementIterator
*/
struct FTSIteratorValue {
FTSIteratorValue(const char* text, const FTSLanguage* language, double weight)
: _text(text), _language(language), _weight(weight), _valid(true) {}
FTSIteratorValue() : _text(NULL), _language(), _weight(0.0), _valid(false) {}
bool valid() const {
return _valid;
}
const char* _text;
const FTSLanguage* _language;
double _weight;
bool _valid;
};
/**
* Iterator pattern for walking through text-indexed fields of a
* BSON document.
*
* Example usage:
* FTSSpec spec( FTSSpec::fixSpec( indexSpec ) );
* FTSElementIterator it( spec, obj );
* while ( it.more() ) {
* FTSIteratorValue val = it.next();
* std::cout << val._text << '[' << val._language.str()
* << ',' << val._weight << ']' << std::endl;
* }
*
*/
class FTSElementIterator {
public:
/**
* Iterator constructor
*
* Note: Caller must ensure that the constructed FTSElementIterator
* does >not< outlive either spec or obj.
*
* @arg spec text index specifier
* @arg obj document that the iterator will traverse
*/
FTSElementIterator(const FTSSpec& spec, const BSONObj& obj);
/**
* Iterator interface: returns false iff there are no further text-indexable fields.
*/
bool more();
/**
* Iterator interface: advances to the next text-indexable field.
*/
FTSIteratorValue next();
/**
* Iterator frame needed for iterative implementation of
* recursive sub-documents.
*/
struct FTSIteratorFrame {
FTSIteratorFrame(const BSONObj& obj,
const FTSSpec& spec,
const FTSLanguage* parentLanguage,
const std::string& parentPath,
bool isArray)
: _it(obj),
_language(spec._getLanguageToUseV2(obj, parentLanguage)),
_parentPath(parentPath),
_isArray(isArray) {}
friend std::ostream& operator<<(std::ostream&, FTSIteratorFrame&);
BSONObjIterator _it;
const FTSLanguage* _language;
std::string _parentPath;
bool _isArray;
};
private:
/**
* Helper method:
* returns false iff all FTSIteratorFrames on _frameStack are exhausted.
*/
bool moreFrames();
/**
* Helper method:
* advances to the next text-indexable field, possibly pushing frames as
* needed for recursive sub-documents.
*/
FTSIteratorValue advance();
/**
* Stack used by iterative implementation of recursive sub-document traversal.
*/
std::stack<FTSIteratorFrame> _frameStack;
/**
* Current frame, not yet pushed to stack.
*/
FTSIteratorFrame _frame;
/**
* Constructor input parameter: text index specification.
*/
const FTSSpec& _spec;
/**
* Current iterator return value, computed by 'more()', returned by 'next()'.
*/
FTSIteratorValue _currentValue;
};
} // namespace fts
} // namespace mongo
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