mongodb/db/update.h

// update.h

/**
 *    Copyright (C) 2008 10gen 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/>.
 */

#include "../pch.h"
#include "jsobj.h"
#include "../util/embedded_builder.h"
#include "matcher.h"

namespace mongo {

    class ModState;
    class ModSetState;

    /* Used for modifiers such as $inc, $set, $push, ... 
     * stores the info about a single operation
     * once created should never be modified
     */
    struct Mod {
        // See opFromStr below
        //        0    1    2     3         4     5          6    7      8       9       10    11
        enum Op { INC, SET, PUSH, PUSH_ALL, PULL, PULL_ALL , POP, UNSET, BITAND, BITOR , BIT , ADDTOSET  } op;
        
        static const char* modNames[];
        static unsigned modNamesNum;

        const char *fieldName;
        const char *shortFieldName;
        
        BSONElement elt; // x:5 note: this is the actual element from the updateobj
        boost::shared_ptr<Matcher> matcher;

        void init( Op o , BSONElement& e ){
            op = o;
            elt = e;
            if ( op == PULL && e.type() == Object )
                matcher.reset( new Matcher( e.embeddedObject() ) );
        }

        void setFieldName( const char * s ){
            fieldName = s;
            shortFieldName = strrchr( fieldName , '.' );
            if ( shortFieldName )
                shortFieldName++;
            else
                shortFieldName = fieldName;
        }
        
        /**
         * @param in incrememnts the actual value inside in
         */
        void incrementMe( BSONElement& in ) const {
            BSONElementManipulator manip( in );
            
            switch ( in.type() ){
            case NumberDouble:
                manip.setNumber( elt.numberDouble() + in.numberDouble() );
                break;
            case NumberLong:
                manip.setLong( elt.numberLong() + in.numberLong() );
                break;
            case NumberInt:
                manip.setInt( elt.numberInt() + in.numberInt() );
                break;
            default:
                assert(0);
            }
            
        }
        
        template< class Builder >
        void appendIncremented( Builder& bb , const BSONElement& in, ModState& ms ) const;
        
        bool operator<( const Mod &other ) const {
            return strcmp( fieldName, other.fieldName ) < 0;
        }
        
        bool arrayDep() const {
            switch (op){
            case PUSH:
            case PUSH_ALL:
            case POP:
                return true;
            default:
                return false;
            }
        }
        
        bool isIndexed( const set<string>& idxKeys ) const {
            // check if there is an index key that is a parent of mod
            for( const char *dot = strchr( fieldName, '.' ); dot; dot = strchr( dot + 1, '.' ) )
                if ( idxKeys.count( string( fieldName, dot - fieldName ) ) )
                    return true;
            string fullName = fieldName;
            // check if there is an index key equal to mod
            if ( idxKeys.count(fullName) )
                return true;
            // check if there is an index key that is a child of mod
            set< string >::const_iterator j = idxKeys.upper_bound( fullName );
            if ( j != idxKeys.end() && j->find( fullName ) == 0 && (*j)[fullName.size()] == '.' )
                return true;
            return false;
        }
        
        template< class Builder >
        void apply( Builder& b , BSONElement in , ModState& ms ) const;
        
        /**
         * @return true iff toMatch should be removed from the array
         */
        bool _pullElementMatch( BSONElement& toMatch ) const;

        void _checkForAppending( const BSONElement& e ) const {
            if ( e.type() == Object ){
                // this is a tiny bit slow, but rare and important
                // only when setting something TO an object, not setting something in an object
                // and it checks for { $set : { x : { 'a.b' : 1 } } } 
                // which is feel has been common
                uassert( 12527 , "not okForStorage" , e.embeddedObject().okForStorage() );
            }
        }
        
        bool isEach() const {
            if ( elt.type() != Object )
                return false;
            BSONElement e = elt.embeddedObject().firstElement();
            if ( e.type() != Array )
                return false;
            return strcmp( e.fieldName() , "$each" ) == 0;
        }

        BSONObj getEach() const {
            return elt.embeddedObjectUserCheck().firstElement().embeddedObjectUserCheck();
        }
        
        void parseEach( BSONElementSet& s ) const {
            BSONObjIterator i(getEach());
            while ( i.more() ){
                s.insert( i.next() );
            }
        }
        
    };

    /**
     * stores a set of Mods
     * once created, should never be changed
     */
    class ModSet : boost::noncopyable {
        typedef map<string,Mod> ModHolder;
        ModHolder _mods;
        int _isIndexed;
        bool _hasDynamicArray;

        static void extractFields( map< string, BSONElement > &fields, const BSONElement &top, const string &base );
        
        FieldCompareResult compare( const ModHolder::iterator &m, map< string, BSONElement >::iterator &p, const map< string, BSONElement >::iterator &pEnd ) const {
            bool mDone = ( m == _mods.end() );
            bool pDone = ( p == pEnd );
            assert( ! mDone );
            assert( ! pDone );
            if ( mDone && pDone )
                return SAME;
            // If one iterator is done we want to read from the other one, so say the other one is lower.
            if ( mDone )
                return RIGHT_BEFORE;
            if ( pDone )
                return LEFT_BEFORE;

            return compareDottedFieldNames( m->first, p->first.c_str() );
        }
        
        bool mayAddEmbedded( map< string, BSONElement > &existing, string right ) {
            for( string left = EmbeddedBuilder::splitDot( right );
                 left.length() > 0 && left[ left.length() - 1 ] != '.';
                 left += "." + EmbeddedBuilder::splitDot( right ) ) {
                if ( existing.count( left ) > 0 && existing[ left ].type() != Object )
                    return false;
                if ( haveModForField( left.c_str() ) )
                    return false;
            }
            return true;
        }
        static Mod::Op opFromStr( const char *fn ) {
            assert( fn[0] == '$' );
            switch( fn[1] ){
            case 'i': {
                if ( fn[2] == 'n' && fn[3] == 'c' && fn[4] == 0 )
                    return Mod::INC;
                break;
            }
            case 's': {
                if ( fn[2] == 'e' && fn[3] == 't' && fn[4] == 0 )
                    return Mod::SET;
                break;
            }
            case 'p': {
                if ( fn[2] == 'u' ){
                    if ( fn[3] == 's' && fn[4] == 'h' ){
                        if ( fn[5] == 0 )
                            return Mod::PUSH;
                        if ( fn[5] == 'A' && fn[6] == 'l' && fn[7] == 'l' && fn[8] == 0 )
                            return Mod::PUSH_ALL;
                    }
                    else if ( fn[3] == 'l' && fn[4] == 'l' ){
                        if ( fn[5] == 0 )
                            return Mod::PULL;
                        if ( fn[5] == 'A' && fn[6] == 'l' && fn[7] == 'l' && fn[8] == 0 )
                            return Mod::PULL_ALL;
                    }
                }
                else if ( fn[2] == 'o' && fn[3] == 'p' && fn[4] == 0 )
                    return Mod::POP;
                break;
            }
            case 'u': {
                if ( fn[2] == 'n' && fn[3] == 's' && fn[4] == 'e' && fn[5] == 't' && fn[6] == 0 )
                    return Mod::UNSET;
                break;
            }
            case 'b': {
                if ( fn[2] == 'i' && fn[3] == 't' ){
                    if ( fn[4] == 0 )
                        return Mod::BIT;
                    if ( fn[4] == 'a' && fn[5] == 'n' && fn[6] == 'd' && fn[7] == 0 )
                        return Mod::BITAND;
                    if ( fn[4] == 'o' && fn[5] == 'r' && fn[6] == 0 )
                        return Mod::BITOR;
                }
                break;
            }
            case 'a': {
                if ( fn[2] == 'd' && fn[3] == 'd' ){
                    // add
                    if ( fn[4] == 'T' && fn[5] == 'o' && fn[6] == 'S' && fn[7] == 'e' && fn[8] == 't' && fn[9] == 0 )
                        return Mod::ADDTOSET;
                    
                }
            }
            default: break;
            }
            uassert( 10161 ,  "Invalid modifier specified " + string( fn ), false );
            return Mod::INC;
        }
        
        ModSet(){}

    public:
        
        ModSet( const BSONObj &from , 
            const set<string>& idxKeys = set<string>(),
            const set<string>* backgroundKeys = 0
            );

        // TODO: this is inefficient - should probably just handle when iterating
        ModSet * fixDynamicArray( const char * elemMatchKey ) const;

        bool hasDynamicArray() const { return _hasDynamicArray; }

        /**
         * creates a ModSetState suitable for operation on obj
         * doesn't change or modify this ModSet or any underying Mod
         */
        auto_ptr<ModSetState> prepare( const BSONObj& obj ) const;
        
        /**
         * given a query pattern, builds an object suitable for an upsert
         * will take the query spec and combine all $ operators
         */
        BSONObj createNewFromQuery( const BSONObj& query );

        /**
         *
         */
        int isIndexed() const {
            return _isIndexed;
        }

        unsigned size() const { return _mods.size(); }

        bool haveModForField( const char *fieldName ) const {
            return _mods.find( fieldName ) != _mods.end();
        }

        bool haveConflictingMod( const string& fieldName ){
            size_t idx = fieldName.find( '.' );
            if ( idx == string::npos )
                idx = fieldName.size();
            
            ModHolder::const_iterator start = _mods.lower_bound(fieldName.substr(0,idx));
            for ( ; start != _mods.end(); start++ ){
                FieldCompareResult r = compareDottedFieldNames( fieldName , start->first );
                switch ( r ){
                case LEFT_SUBFIELD: return true;
                case LEFT_BEFORE: return false;
                case SAME: return true;
                case RIGHT_BEFORE: return false;
                case RIGHT_SUBFIELD: return true;
                }
            }
            return false;

            
        }
        
    };

    /**
     * stores any information about a single Mod operating on a single Object
     */
    class ModState {
    public:
        const Mod * m;
        BSONElement old;
        
        const char * fixedOpName;
        BSONElement * fixed;
        int pushStartSize;
        
        BSONType incType;
        int incint;
        double incdouble;
        long long inclong;
        
        ModState(){
            fixedOpName = 0;
            fixed = 0;
            pushStartSize = -1;
            incType = EOO;
        }
           
        Mod::Op op() const {
            return m->op;
        }

        const char * fieldName() const {
            return m->fieldName;
        }
        
        bool needOpLogRewrite() const {
            if ( fixed || fixedOpName || incType )
                return true;
            
            switch( op() ){
            case Mod::BIT:
            case Mod::BITAND:
            case Mod::BITOR:
                // TODO: should we convert this to $set?
                return false;
            default:
                return false;
            }
        }
        
        void appendForOpLog( BSONObjBuilder& b ) const {
            if ( incType ){
                BSONObjBuilder bb( b.subobjStart( "$set" ) );
                appendIncValue( bb );
                bb.done();
                return;
            }
            
            const char * name = fixedOpName ? fixedOpName : Mod::modNames[op()];

            BSONObjBuilder bb( b.subobjStart( name ) );
            if ( fixed )
                bb.appendAs( *fixed , m->fieldName );
            else
                bb.appendAs( m->elt , m->fieldName );
            bb.done();
        }

        template< class Builder >
        void apply( Builder& b , BSONElement in ){
            m->apply( b , in , *this );
        }
        
        template< class Builder >
        void appendIncValue( Builder& b ) const {
            switch ( incType ){
            case NumberDouble:
                b.append( m->shortFieldName , incdouble ); break;
            case NumberLong:
                b.append( m->shortFieldName , inclong ); break;
            case NumberInt:
                b.append( m->shortFieldName , incint ); break;
            default:
                assert(0);
            }
        }
    };
    
    /**
     * this is used to hold state, meta data while applying a ModSet to a BSONObj
     * the goal is to make ModSet const so its re-usable
     */
    class ModSetState : boost::noncopyable {
        struct FieldCmp {
            bool operator()( const string &l, const string &r ) const {
                return lexNumCmp( l.c_str(), r.c_str() ) < 0;
            }
        };
        typedef map<string,ModState,FieldCmp> ModStateHolder;
        const BSONObj& _obj;
        ModStateHolder _mods;
        bool _inPlacePossible;
        
        ModSetState( const BSONObj& obj ) 
            : _obj( obj ) , _inPlacePossible(true){
        }
        
        /**
         * @return if in place is still possible
         */
        bool amIInPlacePossible( bool inPlacePossible ){
            if ( ! inPlacePossible )
                _inPlacePossible = false;
            return _inPlacePossible;
        }

        template< class Builder >
        void createNewFromMods( const string& root , Builder& b , const BSONObj &obj );

        template< class Builder >
        void _appendNewFromMods( const string& root , ModState& m , Builder& b , set<string>& onedownseen );
        
        template< class Builder >
        void appendNewFromMod( ModState& ms , Builder& b ){
            //const Mod& m = *(ms.m); // HACK
            Mod& m = *((Mod*)(ms.m)); // HACK
                
            switch ( m.op ){
                    
            case Mod::PUSH: 
            case Mod::ADDTOSET: { 
                if ( m.isEach() ){
                    b.appendArray( m.shortFieldName , m.getEach() );
                }
                else {
                    BSONObjBuilder arr( b.subarrayStart( m.shortFieldName ) );
                    arr.appendAs( m.elt, "0" );
                    arr.done();
                }
                break;
            } 
                
            case Mod::PUSH_ALL: {
                b.appendAs( m.elt, m.shortFieldName );
                break;
            } 
                
            case Mod::UNSET:
            case Mod::PULL:
            case Mod::PULL_ALL:
                // no-op b/c unset/pull of nothing does nothing
                break;
                
            case Mod::INC:
                ms.fixedOpName = "$set";
            case Mod::SET: {
                m._checkForAppending( m.elt );
                b.appendAs( m.elt, m.shortFieldName );
                break;
            }
            default: 
                stringstream ss;
                ss << "unknown mod in appendNewFromMod: " << m.op;
                throw UserException( 9015, ss.str() );
            }
         
        }

    public:
        
        bool canApplyInPlace() const {
            return _inPlacePossible;
        }
        
        /**
         * modified underlying _obj
         */
        void applyModsInPlace();

        BSONObj createNewFromMods();

        // re-writing for oplog

        bool needOpLogRewrite() const {
            for ( ModStateHolder::const_iterator i = _mods.begin(); i != _mods.end(); i++ )
                if ( i->second.needOpLogRewrite() )
                    return true;
            return false;            
        }
        
        BSONObj getOpLogRewrite() const {
            BSONObjBuilder b;
            for ( ModStateHolder::const_iterator i = _mods.begin(); i != _mods.end(); i++ )
                i->second.appendForOpLog( b );
            return b.obj();
        }

        bool haveArrayDepMod() const {
            for ( ModStateHolder::const_iterator i = _mods.begin(); i != _mods.end(); i++ )
                if ( i->second.m->arrayDep() )
                    return true;
            return false;
        }

        void appendSizeSpecForArrayDepMods( BSONObjBuilder &b ) const {
            for ( ModStateHolder::const_iterator i = _mods.begin(); i != _mods.end(); i++ ) {
                const ModState& m = i->second;
                if ( m.m->arrayDep() ){
                    if ( m.pushStartSize == -1 )
                        b.appendNull( m.fieldName() );
                    else
                        b << m.fieldName() << BSON( "$size" << m.pushStartSize );
                }
            }
        }


        friend class ModSet;
    };
    
}