indexkey.h

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// index_key.h

#pragma once

#include "../pch.h"
#include "diskloc.h"
#include "jsobj.h"
#include <map>

namespace mongo {

    class Cursor;
    class IndexSpec;
    class IndexType; // TODO: this name sucks
    class IndexPlugin;
    class IndexDetails;

    enum IndexSuitability { USELESS = 0 , HELPFUL = 1 , OPTIMAL = 2 };

    class IndexType : boost::noncopyable {
    public:
        IndexType( const IndexPlugin * plugin , const IndexSpec * spec );
        virtual ~IndexType();

        virtual void getKeys( const BSONObj &obj, BSONObjSetDefaultOrder &keys ) const = 0;
        virtual shared_ptr<Cursor> newCursor( const BSONObj& query , const BSONObj& order , int numWanted ) const = 0;

        virtual BSONObj fixKey( const BSONObj& in ) { return in; }

        virtual int compare( const BSONObj& l , const BSONObj& r ) const;

        const IndexPlugin * getPlugin() const { return _plugin; }

        const BSONObj& keyPattern() const;

        virtual IndexSuitability suitability( const BSONObj& query , const BSONObj& order ) const ;

        virtual bool scanAndOrderRequired( const BSONObj& query , const BSONObj& order ) const ;

    protected:
        const IndexPlugin * _plugin;
        const IndexSpec * _spec;
    };

    class IndexPlugin : boost::noncopyable {
    public:
        IndexPlugin( const string& name );
        virtual ~IndexPlugin() {}

        virtual IndexType* generate( const IndexSpec * spec ) const = 0;

        string getName() const { return _name; }

        virtual BSONObj adjustIndexSpec( const BSONObj& spec ) const { return spec; }

        // ------- static below -------

        static IndexPlugin* get( const string& name ) {
            if ( ! _plugins )
                return 0;
            map<string,IndexPlugin*>::iterator i = _plugins->find( name );
            if ( i == _plugins->end() )
                return 0;
            return i->second;
        }

        static string findPluginName( const BSONObj& keyPattern );

    private:
        string _name;
        static map<string,IndexPlugin*> * _plugins;
    };

    /* precomputed details about an index, used for inserting keys on updates
       stored/cached in NamespaceDetailsTransient, or can be used standalone
       */
    class IndexSpec {
    public:
        BSONObj keyPattern; // e.g., { name : 1 }
        BSONObj info; // this is the same as IndexDetails::info.obj()

        IndexSpec()
            : _details(0) , _finishedInit(false) {
        }

        IndexSpec( const BSONObj& k , const BSONObj& m = BSONObj() )
            : keyPattern(k) , info(m) , _details(0) , _finishedInit(false) {
            _init();
        }

        IndexSpec( const DiskLoc& loc ) {
            reset( loc );
        }

        void reset( const DiskLoc& loc );
        void reset( const IndexDetails * details );

        void getKeys( const BSONObj &obj, BSONObjSetDefaultOrder &keys ) const;

        BSONElement missingField() const { return _nullElt; }

        string getTypeName() const {
            if ( _indexType.get() )
                return _indexType->getPlugin()->getName();
            return "";
        }

        IndexType* getType() const {
            return _indexType.get();
        }

        const IndexDetails * getDetails() const {
            return _details;
        }

        IndexSuitability suitability( const BSONObj& query , const BSONObj& order ) const ;

    protected:

        IndexSuitability _suitability( const BSONObj& query , const BSONObj& order ) const ;

        void _getKeys( vector<const char*> fieldNames , vector<BSONElement> fixed , const BSONObj &obj, BSONObjSetDefaultOrder &keys ) const;

        BSONSizeTracker _sizeTracker;

        vector<const char*> _fieldNames;
        vector<BSONElement> _fixed;

        BSONObj _nullKey; // a full key with all fields null

        BSONObj _nullObj; // only used for _nullElt
        BSONElement _nullElt; // jstNull

        int _nFields; // number of fields in the index
        bool _sparse; // if the index is sparse

        shared_ptr<IndexType> _indexType;

        const IndexDetails * _details;

        void _init();

    public:
        bool _finishedInit;

        friend class IndexType;
    };


} // namespace mongo

---

mongodb
Author(s): Nate Koenig
autogenerated on Fri Jan 11 12:15:18 2013