C++ BSONElement::canonicalType方法代码示例

 int oldElemCompare(const BSONElement&l , const BSONElement& r) { 
     int lt = (int) l.canonicalType();
     int rt = (int) r.canonicalType();
     int x = lt - rt;
     if( x )
         return x;
     return oldCompareElementValues(l, r);
 }

bool ComparisonMatchExpression::matchesSingleElement(const BSONElement& e) const {

    if (e.canonicalType() != _rhs.canonicalType()) {
        // some special cases
        //  jstNULL and undefined are treated the same
        if (e.canonicalType() + _rhs.canonicalType() == 5) {
            return matchType() == EQ || matchType() == LTE || matchType() == GTE;
        }

        if (_rhs.type() == MaxKey || _rhs.type() == MinKey) {
            return matchType() != EQ;
        }

        return false;
    }

    // Special case handling for NaN. NaN is equal to NaN but
    // otherwise always compares to false.
    if (std::isnan(e.numberDouble()) || std::isnan(_rhs.numberDouble())) {
        bool bothNaN = std::isnan(e.numberDouble()) && std::isnan(_rhs.numberDouble());
        switch (matchType()) {
            case LT:
                return false;
            case LTE:
                return bothNaN;
            case EQ:
                return bothNaN;
            case GT:
                return false;
            case GTE:
                return bothNaN;
            default:
                // This is a comparison match expression, so it must be either
                // a $lt, $lte, $gt, $gte, or equality expression.
                fassertFailed(17448);
        }
    }

    int x = compareElementValues(e, _rhs, _collator);

    switch (matchType()) {
        case LT:
            return x < 0;
        case LTE:
            return x <= 0;
        case EQ:
            return x == 0;
        case GT:
            return x > 0;
        case GTE:
            return x >= 0;
        default:
            // This is a comparison match expression, so it must be either
            // a $lt, $lte, $gt, $gte, or equality expression.
            fassertFailed(16828);
    }
}

bool ComparisonMatchExpression::matchesSingleElement( const BSONElement& e ) const {
    //log() << "\t ComparisonMatchExpression e: " << e << " _rhs: " << _rhs << "\n"
    //<< toString() << std::endl;

    if ( e.canonicalType() != _rhs.canonicalType() ) {
        // some special cases
        //  jstNULL and undefined are treated the same
        if ( e.canonicalType() + _rhs.canonicalType() == 5 ) {
            return matchType() == EQ || matchType() == LTE || matchType() == GTE;
        }

        if ( _rhs.type() == MaxKey || _rhs.type() == MinKey ) {
            return matchType() != EQ;
        }

        return false;
    }

    if ( _rhs.type() == Array ) {
        if ( matchType() != EQ ) {
            return false;
        }
    }

    int x = compareElementValues( e, _rhs );

    //log() << "\t\t" << x << endl;

    switch ( matchType() ) {
    case LT:
        return x < 0;
    case LTE:
        return x <= 0;
    case EQ:
        return x == 0;
    case GT:
        return x > 0;
    case GTE:
        return x >= 0;
    default:
        throw 1;
    }
    throw 1;
}

 string Command::parseNsCollectionRequired(const string& dbname, const BSONObj& cmdObj) const {
     // Accepts both BSON String and Symbol for collection name per SERVER-16260
     // TODO(kangas) remove Symbol support in MongoDB 3.0 after Ruby driver audit
     BSONElement first = cmdObj.firstElement();
     uassert(17009,
             "no collection name specified",
             first.canonicalType() == canonicalizeBSONType(mongo::String)
             && first.valuestrsize() > 0);
     std::string coll = first.valuestr();
     return dbname + '.' + coll;
 }

string Command::parseNsFullyQualified(const string& dbname, const BSONObj& cmdObj) {
    BSONElement first = cmdObj.firstElement();
    uassert(ErrorCodes::BadValue,
            str::stream() << "collection name has invalid type " << typeName(first.type()),
            first.canonicalType() == canonicalizeBSONType(mongo::String));
    const NamespaceString nss(first.valueStringData());
    uassert(ErrorCodes::InvalidNamespace,
            str::stream() << "Invalid namespace specified '" << nss.ns() << "'",
            nss.isValid());
    return nss.ns();
}

NamespaceString Command::parseNsCollectionRequired(const string& dbname,
                                                   const BSONObj& cmdObj) const {
    // Accepts both BSON String and Symbol for collection name per SERVER-16260
    // TODO(kangas) remove Symbol support in MongoDB 3.0 after Ruby driver audit
    BSONElement first = cmdObj.firstElement();
    uassert(40072,
            str::stream() << "collection name has invalid type " << typeName(first.type()),
            first.canonicalType() == canonicalizeBSONType(mongo::String));
    NamespaceString nss(dbname, first.valuestr());
    uassert(ErrorCodes::InvalidNamespace, "Not a valid namespace", nss.isValid());
    return nss;
}

 /* wo = "well ordered" */
 int BSONElement::woCompare( const BSONElement &e,
                             bool considerFieldName ) const {
     int lt = (int) canonicalType();
     int rt = (int) e.canonicalType();
     int x = lt - rt;
     if( x != 0 && (!isNumber() || !e.isNumber()) )
         return x;
     if ( considerFieldName ) {
         x = strcmp(fieldName(), e.fieldName());
         if ( x != 0 )
             return x;
     }
     x = compareElementValues(*this, e);
     return x;
 }

int BSONElement::woCompare(const BSONElement& elem,
                           ComparisonRulesSet rules,
                           const StringData::ComparatorInterface* comparator) const {
    if (type() != elem.type()) {
        int lt = (int)canonicalType();
        int rt = (int)elem.canonicalType();
        if (int diff = lt - rt)
            return diff;
    }
    if (rules & ComparisonRules::kConsiderFieldName) {
        if (int diff = fieldNameStringData().compare(elem.fieldNameStringData()))
            return diff;
    }
    return compareElements(*this, elem, rules, comparator);
}

bool InternalExprEqMatchExpression::matchesSingleElement(const BSONElement& elem,
                                                         MatchDetails* details) const {
    // We use NonLeafArrayBehavior::kMatchSubpath traversal in InternalExprEqMatchExpression. This
    // means matchesSinglElement() will be called when an array is found anywhere along the patch we
    // are matching against. When this occurs, we return 'true' and depend on the corresponding
    // ExprMatchExpression node to filter properly.
    if (elem.type() == BSONType::Array) {
        return true;
    }

    if (elem.canonicalType() != _rhs.canonicalType()) {
        return false;
    }

    auto comp = BSONElement::compareElements(
        elem, _rhs, BSONElement::ComparisonRules::kConsiderFieldName, _collator);
    return comp == 0;
}

    void BSONElementHasher::recursiveHash( Hasher* h ,
                                           const BSONElement& e ,
                                           bool includeFieldName ) {

        int canonicalType = e.canonicalType();
        h->addData( &canonicalType , sizeof( canonicalType ) );

        if ( includeFieldName ){
            h->addData( e.fieldName() , e.fieldNameSize() );
        }

        if ( !e.mayEncapsulate() ){
            //if there are no embedded objects (subobjects or arrays),
            //compute the hash, squashing numeric types to 64-bit ints
            if ( e.isNumber() ){
                long long int i = e.safeNumberLong(); //well-defined for troublesome doubles
                h->addData( &i , sizeof( i ) );
            }
            else {
                h->addData( e.value() , e.valuesize() );
            }
        }
        else {
            //else identify the subobject.
            //hash any preceding stuff (in the case of codeWscope)
            //then each sub-element
            //then finish with the EOO element.
            BSONObj b;
            if ( e.type() == CodeWScope ) {
                h->addData( e.codeWScopeCode() , e.codeWScopeCodeLen() );
                b = e.codeWScopeObject();
            }
            else {
                b = e.embeddedObject();
            }
            BSONObjIterator i(b);
            while( i.moreWithEOO() ) {
                BSONElement el = i.next();
                recursiveHash( h , el ,  true );
            }
        }
    }

void BSONComparatorInterfaceBase<T>::hashCombineBSONElement(
    size_t& hash,
    BSONElement elemToHash,
    bool considerFieldName,
    const StringData::ComparatorInterface* stringComparator) {
    boost::hash_combine(hash, elemToHash.canonicalType());

    const StringData fieldName = elemToHash.fieldNameStringData();
    if (considerFieldName && !fieldName.empty()) {
        SimpleStringDataComparator::kInstance.hash_combine(hash, fieldName);
    }

    switch (elemToHash.type()) {
        // Order of types is the same as in compareElementValues().

        case mongo::EOO:
        case mongo::Undefined:
        case mongo::jstNULL:
        case mongo::MaxKey:
        case mongo::MinKey:
            // These are valueless types
            break;

        case mongo::Bool:
            boost::hash_combine(hash, elemToHash.boolean());
            break;

        case mongo::bsonTimestamp:
            boost::hash_combine(hash, elemToHash.timestamp().asULL());
            break;

        case mongo::Date:
            boost::hash_combine(hash, elemToHash.date().asInt64());
            break;

        case mongo::NumberDecimal: {
            const Decimal128 dcml = elemToHash.numberDecimal();
            if (dcml.toAbs().isGreater(Decimal128(std::numeric_limits<double>::max(),
                                                  Decimal128::kRoundTo34Digits,
                                                  Decimal128::kRoundTowardZero)) &&
                !dcml.isInfinite() && !dcml.isNaN()) {
                // Normalize our decimal to force equivalent decimals
                // in the same cohort to hash to the same value
                Decimal128 dcmlNorm(dcml.normalize());
                boost::hash_combine(hash, dcmlNorm.getValue().low64);
                boost::hash_combine(hash, dcmlNorm.getValue().high64);
                break;
            }
            // Else, fall through and convert the decimal to a double and hash.
            // At this point the decimal fits into the range of doubles, is infinity, or is NaN,
            // which doubles have a cheaper representation for.
        }
        case mongo::NumberDouble:
        case mongo::NumberLong:
        case mongo::NumberInt: {
            // This converts all numbers to doubles, which ignores the low-order bits of
            // NumberLongs > 2**53 and precise decimal numbers without double representations,
            // but that is ok since the hash will still be the same for equal numbers and is
            // still likely to be different for different numbers. (Note: this issue only
            // applies for decimals when they are outside of the valid double range. See
            // the above case.)
            // SERVER-16851
            const double dbl = elemToHash.numberDouble();
            if (std::isnan(dbl)) {
                boost::hash_combine(hash, std::numeric_limits<double>::quiet_NaN());
            } else {
                boost::hash_combine(hash, dbl);
            }
            break;
        }

        case mongo::jstOID:
            elemToHash.__oid().hash_combine(hash);
            break;

        case mongo::String: {
            if (stringComparator) {
                stringComparator->hash_combine(hash, elemToHash.valueStringData());
            } else {
                SimpleStringDataComparator::kInstance.hash_combine(hash,
                                                                   elemToHash.valueStringData());
            }
            break;
        }

        case mongo::Code:
        case mongo::Symbol:
            SimpleStringDataComparator::kInstance.hash_combine(hash, elemToHash.valueStringData());
            break;

        case mongo::Object:
        case mongo::Array:
            hashCombineBSONObj(hash,
                               elemToHash.embeddedObject(),
                               true,  // considerFieldName
                               stringComparator);
            break;

        case mongo::DBRef:
        case mongo::BinData:
//.........这里部分代码省略.........

    /* must be same type when called, unless both sides are #s
    */
    int compareElementValues(const BSONElement& l, const BSONElement& r) {
        int f;
        double x;

        switch ( l.type() ) {
        case EOO:
        case Undefined:
        case jstNULL:
        case MaxKey:
        case MinKey:
            f = l.canonicalType() - r.canonicalType();
            if ( f<0 ) return -1;
            return f==0 ? 0 : 1;
        case Bool:
            return *l.value() - *r.value();
        case Timestamp:
        case Date:
            if ( l.date() < r.date() )
                return -1;
            return l.date() == r.date() ? 0 : 1;
        case NumberLong:
            if( r.type() == NumberLong ) {
                long long L = l._numberLong();
                long long R = r._numberLong();
                if( L < R ) return -1;
                if( L == R ) return 0;
                return 1;
            }
            // else fall through
        case NumberInt:
        case NumberDouble: {
            double left = l.number();
            double right = r.number();
            bool lNan = !( left <= numeric_limits< double >::max() &&
                         left >= -numeric_limits< double >::max() );
            bool rNan = !( right <= numeric_limits< double >::max() &&
                         right >= -numeric_limits< double >::max() );
            if ( lNan ) {
                if ( rNan ) {
                    return 0;
                } else {
                    return -1;
                }
            } else if ( rNan ) {
                return 1;
            }
            x = left - right;
            if ( x < 0 ) return -1;
            return x == 0 ? 0 : 1;
            }
        case jstOID:
            return memcmp(l.value(), r.value(), 12);
        case Code:
        case Symbol:
        case String:
            /* todo: utf version */
            return strcmp(l.valuestr(), r.valuestr());
        case Object:
        case Array:
            return l.embeddedObject().woCompare( r.embeddedObject() );
        case DBRef: {
            int lsz = l.valuesize();
            int rsz = r.valuesize();
            if ( lsz - rsz != 0 ) return lsz - rsz;
            return memcmp(l.value(), r.value(), lsz);
        }
        case BinData: {
            int lsz = l.objsize(); // our bin data size in bytes, not including the subtype byte
            int rsz = r.objsize();
            if ( lsz - rsz != 0 ) return lsz - rsz;
            return memcmp(l.value()+4, r.value()+4, lsz+1);
        }
        case RegEx:
        {
            int c = strcmp(l.regex(), r.regex());
            if ( c )
                return c;
            return strcmp(l.regexFlags(), r.regexFlags());
        }
        case CodeWScope : {
            f = l.canonicalType() - r.canonicalType();
            if ( f )
                return f;
            f = strcmp( l.codeWScopeCode() , r.codeWScopeCode() );
            if ( f )
                return f;
            f = strcmp( l.codeWScopeScopeData() , r.codeWScopeScopeData() );
            if ( f )
                return f;
            return 0;
        }
        default:
            out() << "compareElementValues: bad type " << (int) l.type() << endl;
            assert(false);
        }
        return -1;
    }

int BSONElement::compareElements(const BSONElement& l,
                                 const BSONElement& r,
                                 ComparisonRulesSet rules,
                                 const StringData::ComparatorInterface* comparator) {
    switch (l.type()) {
        case BSONType::EOO:
        case BSONType::Undefined:  // EOO and Undefined are same canonicalType
        case BSONType::jstNULL:
        case BSONType::MaxKey:
        case BSONType::MinKey: {
            auto f = l.canonicalType() - r.canonicalType();
            if (f < 0)
                return -1;
            return f == 0 ? 0 : 1;
        }
        case BSONType::Bool:
            return *l.value() - *r.value();
        case BSONType::bsonTimestamp:
            // unsigned compare for timestamps - note they are not really dates but (ordinal +
            // time_t)
            if (l.timestamp() < r.timestamp())
                return -1;
            return l.timestamp() == r.timestamp() ? 0 : 1;
        case BSONType::Date:
            // Signed comparisons for Dates.
            {
                const Date_t a = l.Date();
                const Date_t b = r.Date();
                if (a < b)
                    return -1;
                return a == b ? 0 : 1;
            }

        case BSONType::NumberInt: {
            // All types can precisely represent all NumberInts, so it is safe to simply convert to
            // whatever rhs's type is.
            switch (r.type()) {
                case NumberInt:
                    return compareInts(l._numberInt(), r._numberInt());
                case NumberLong:
                    return compareLongs(l._numberInt(), r._numberLong());
                case NumberDouble:
                    return compareDoubles(l._numberInt(), r._numberDouble());
                case NumberDecimal:
                    return compareIntToDecimal(l._numberInt(), r._numberDecimal());
                default:
                    MONGO_UNREACHABLE;
            }
        }

        case BSONType::NumberLong: {
            switch (r.type()) {
                case NumberLong:
                    return compareLongs(l._numberLong(), r._numberLong());
                case NumberInt:
                    return compareLongs(l._numberLong(), r._numberInt());
                case NumberDouble:
                    return compareLongToDouble(l._numberLong(), r._numberDouble());
                case NumberDecimal:
                    return compareLongToDecimal(l._numberLong(), r._numberDecimal());
                default:
                    MONGO_UNREACHABLE;
            }
        }

        case BSONType::NumberDouble: {
            switch (r.type()) {
                case NumberDouble:
                    return compareDoubles(l._numberDouble(), r._numberDouble());
                case NumberInt:
                    return compareDoubles(l._numberDouble(), r._numberInt());
                case NumberLong:
                    return compareDoubleToLong(l._numberDouble(), r._numberLong());
                case NumberDecimal:
                    return compareDoubleToDecimal(l._numberDouble(), r._numberDecimal());
                default:
                    MONGO_UNREACHABLE;
            }
        }

        case BSONType::NumberDecimal: {
            switch (r.type()) {
                case NumberDecimal:
                    return compareDecimals(l._numberDecimal(), r._numberDecimal());
                case NumberInt:
                    return compareDecimalToInt(l._numberDecimal(), r._numberInt());
                case NumberLong:
                    return compareDecimalToLong(l._numberDecimal(), r._numberLong());
                case NumberDouble:
                    return compareDecimalToDouble(l._numberDecimal(), r._numberDouble());
                default:
                    MONGO_UNREACHABLE;
            }
        }

        case BSONType::jstOID:
            return memcmp(l.value(), r.value(), OID::kOIDSize);
        case BSONType::Code:
            return compareElementStringValues(l, r);
        case BSONType::Symbol:
//.........这里部分代码省略.........

bool ComparisonMatchExpression::matchesSingleElement(const BSONElement& e,
                                                     MatchDetails* details) const {
    if (e.canonicalType() != _rhs.canonicalType()) {
        // We can't call 'compareElements' on elements of different canonical types.  Usually
        // elements with different canonical types should never match any comparison, but there are
        // a few exceptions, handled here.

        // jstNULL and undefined are treated the same
        if (e.canonicalType() + _rhs.canonicalType() == 5) {
            return matchType() == EQ || matchType() == LTE || matchType() == GTE;
        }
        if (_rhs.type() == MaxKey || _rhs.type() == MinKey) {
            switch (matchType()) {
                // LT and LTE need no distinction here because the two elements that we are
                // comparing do not even have the same canonical type and are thus not equal
                // (i.e.the case where we compare MinKey against MinKey would not reach this switch
                // statement at all).  The same reasoning follows for the lack of distinction
                // between GTE and GT.
                case LT:
                case LTE:
                    return _rhs.type() == MaxKey;
                case EQ:
                    return false;
                case GT:
                case GTE:
                    return _rhs.type() == MinKey;
                default:
                    // This is a comparison match expression, so it must be either
                    // a $lt, $lte, $gt, $gte, or equality expression.
                    MONGO_UNREACHABLE;
            }
        }
        return false;
    }

    // Special case handling for NaN. NaN is equal to NaN but
    // otherwise always compares to false.
    if (std::isnan(e.numberDouble()) || std::isnan(_rhs.numberDouble())) {
        bool bothNaN = std::isnan(e.numberDouble()) && std::isnan(_rhs.numberDouble());
        switch (matchType()) {
            case LT:
                return false;
            case LTE:
                return bothNaN;
            case EQ:
                return bothNaN;
            case GT:
                return false;
            case GTE:
                return bothNaN;
            default:
                // This is a comparison match expression, so it must be either
                // a $lt, $lte, $gt, $gte, or equality expression.
                fassertFailed(17448);
        }
    }

    int x = BSONElement::compareElements(
        e, _rhs, BSONElement::ComparisonRules::kConsiderFieldName, _collator);
    switch (matchType()) {
        case LT:
            return x < 0;
        case LTE:
            return x <= 0;
        case EQ:
            return x == 0;
        case GT:
            return x > 0;
        case GTE:
            return x >= 0;
        default:
            // This is a comparison match expression, so it must be either
            // a $lt, $lte, $gt, $gte, or equality expression.
            fassertFailed(16828);
    }
}