bsonmisc.h

// @file bsonmisc.h

/*    Copyright 2009 10gen Inc.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

#pragma once

#include <memory>

#include "mongo/bson/bsonelement.h"
#include "mongo/client/export_macros.h"

namespace mongo {

int getGtLtOp(const BSONElement& e);

struct BSONElementCmpWithoutField {
    bool operator()(const BSONElement& l, const BSONElement& r) const {
        return l.woCompare(r, false) < 0;
    }
};

class BSONObjCmp {
public:
    BSONObjCmp(const BSONObj& order = BSONObj()) : _order(order) {}
    bool operator()(const BSONObj& l, const BSONObj& r) const {
        return l.woCompare(r, _order) < 0;
    }
    BSONObj order() const {
        return _order;
    }

private:
    BSONObj _order;
};

typedef std::set<BSONObj, BSONObjCmp> BSONObjSet;

enum FieldCompareResult {
    LEFT_SUBFIELD = -2,
    LEFT_BEFORE = -1,
    SAME = 0,
    RIGHT_BEFORE = 1,
    RIGHT_SUBFIELD = 2
};

#define BSON(x) ((::mongo::BSONObjBuilder(64) << x).obj())

#define BSON_ARRAY(x) ((::mongo::BSONArrayBuilder() << x).arr())

/* Utility class to auto assign object IDs.
   Example:
     std::cout << BSON( GENOID << "z" << 3 ); // { _id : ..., z : 3 }
*/
struct MONGO_CLIENT_API GENOIDLabeler {};
extern MONGO_CLIENT_API GENOIDLabeler GENOID;

/* Utility class to add a Date element with the current time
   Example:
     std::cout << BSON( "created" << DATENOW ); // { created : "2009-10-09 11:41:42" }
*/
struct MONGO_CLIENT_API DateNowLabeler {};
extern MONGO_CLIENT_API DateNowLabeler DATENOW;

/* Utility class to assign a NULL value to a given attribute
   Example:
     std::cout << BSON( "a" << BSONNULL ); // { a : null }
*/
struct MONGO_CLIENT_API NullLabeler {};
extern MONGO_CLIENT_API NullLabeler BSONNULL;

/* Utility class to assign an Undefined value to a given attribute
   Example:
     std::cout << BSON( "a" << BSONUndefined ); // { a : undefined }
*/
struct MONGO_CLIENT_API UndefinedLabeler {};
extern MONGO_CLIENT_API UndefinedLabeler BSONUndefined;

/* Utility class to add the minKey (minus infinity) to a given attribute
   Example:
     std::cout << BSON( "a" << MINKEY ); // { "a" : { "$minKey" : 1 } }
*/
struct MONGO_CLIENT_API MinKeyLabeler {};
extern MONGO_CLIENT_API MinKeyLabeler MINKEY;
struct MONGO_CLIENT_API MaxKeyLabeler {};
extern MONGO_CLIENT_API MaxKeyLabeler MAXKEY;

// Utility class to implement GT, GTE, etc as described above.
class Labeler {
public:
    struct Label {
        explicit Label(const char* l) : l_(l) {}
        const char* l_;
    };
    Labeler(const Label& l, BSONObjBuilderValueStream* s) : l_(l), s_(s) {}
    template <class T>
    BSONObjBuilder& operator<<(T value);

    /* the value of the element e is appended i.e. for
         "age" << GT << someElement
       one gets
         { age : { $gt : someElement's value } }
    */
    BSONObjBuilder& operator<<(const BSONElement& e);

private:
    const Label& l_;
    BSONObjBuilderValueStream* s_;
};

// Utility class to allow adding a string to BSON as a Symbol
struct BSONSymbol {
    explicit BSONSymbol(const StringData& sym) : symbol(sym) {}
    StringData symbol;
};

// Utility class to allow adding a string to BSON as Code
struct BSONCode {
    explicit BSONCode(const StringData& str) : code(str) {}
    StringData code;
};

// Utility class to allow adding CodeWScope to BSON
struct BSONCodeWScope {
    explicit BSONCodeWScope(const StringData& str, const BSONObj& obj) : code(str), scope(obj) {}
    StringData code;
    BSONObj scope;
};

// Utility class to allow adding a RegEx to BSON
struct BSONRegEx {
    explicit BSONRegEx(const StringData& pat, const StringData& f = "") : pattern(pat), flags(f) {}
    StringData pattern;
    StringData flags;
};

// Utility class to allow adding binary data to BSON
struct BSONBinData {
    BSONBinData(const void* d, int l, BinDataType t) : data(d), length(l), type(t) {}
    const void* data;
    int length;
    BinDataType type;
};

// Utility class to allow adding deprecated DBRef type to BSON
struct BSONDBRef {
    BSONDBRef(const StringData& nameSpace, const OID& o) : ns(nameSpace), oid(o) {}
    StringData ns;
    OID oid;
};

extern MONGO_CLIENT_API Labeler::Label GT;
extern MONGO_CLIENT_API Labeler::Label GTE;
extern MONGO_CLIENT_API Labeler::Label LT;
extern MONGO_CLIENT_API Labeler::Label LTE;
extern MONGO_CLIENT_API Labeler::Label NE;
extern MONGO_CLIENT_API Labeler::Label NIN;
extern MONGO_CLIENT_API Labeler::Label BSIZE;


// $or helper: OR(BSON("x" << GT << 7), BSON("y" << LT << 6));
// becomes   : {$or: [{x: {$gt: 7}}, {y: {$lt: 6}}]}
inline BSONObj OR(const BSONObj& a, const BSONObj& b);
inline BSONObj OR(const BSONObj& a, const BSONObj& b, const BSONObj& c);
inline BSONObj OR(const BSONObj& a, const BSONObj& b, const BSONObj& c, const BSONObj& d);
inline BSONObj OR(
    const BSONObj& a, const BSONObj& b, const BSONObj& c, const BSONObj& d, const BSONObj& e);
inline BSONObj OR(const BSONObj& a,
                  const BSONObj& b,
                  const BSONObj& c,
                  const BSONObj& d,
                  const BSONObj& e,
                  const BSONObj& f);
// definitions in bsonobjbuilder.h b/c of incomplete types

// Utility class to implement BSON( key << val ) as described above.
class MONGO_CLIENT_API BSONObjBuilderValueStream : public boost::noncopyable {
public:
    friend class Labeler;
    BSONObjBuilderValueStream(BSONObjBuilder* builder);

    BSONObjBuilder& operator<<(const BSONElement& e);

    template <class T>
    BSONObjBuilder& operator<<(T value);

    BSONObjBuilder& operator<<(const DateNowLabeler& id);

    BSONObjBuilder& operator<<(const NullLabeler& id);
    BSONObjBuilder& operator<<(const UndefinedLabeler& id);

    BSONObjBuilder& operator<<(const MinKeyLabeler& id);
    BSONObjBuilder& operator<<(const MaxKeyLabeler& id);

    Labeler operator<<(const Labeler::Label& l);

    void endField(const StringData& nextFieldName = StringData());
    bool subobjStarted() const {
        return _fieldName != 0;
    }

    // The following methods provide API compatibility with BSONArrayBuilder
    BufBuilder& subobjStart();
    BufBuilder& subarrayStart();

    // This method should only be called from inside of implementations of
    // BSONObjBuilder& operator<<(BSONObjBuilderValueStream&, SOME_TYPE)
    // to provide the return value.
    BSONObjBuilder& builder() {
        return *_builder;
    }

private:
    StringData _fieldName;
    BSONObjBuilder* _builder;

    bool haveSubobj() const {
        return _subobj.get() != 0;
    }
    BSONObjBuilder* subobj();
    std::auto_ptr<BSONObjBuilder> _subobj;
};

class BSONSizeTracker {
public:
    BSONSizeTracker() {
        _pos = 0;
        for (int i = 0; i < SIZE; i++)
            _sizes[i] = 512;  // this is the default, so just be consistent
    }

    ~BSONSizeTracker() {}

    void got(int size) {
        _sizes[_pos] = size;
        _pos = (_pos + 1) % SIZE;  // thread safe at least on certain compilers
    }

    int getSize() const {
        int x = 16;  // sane min
        for (int i = 0; i < SIZE; i++) {
            if (_sizes[i] > x)
                x = _sizes[i];
        }
        return x;
    }

private:
    enum { SIZE = 10 };
    int _pos;
    int _sizes[SIZE];
};

// considers order
bool fieldsMatch(const BSONObj& lhs, const BSONObj& rhs);
}