dbhelpers.h

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/* @file dbhelpers.h

   db helpers are helper functions and classes that let us easily manipulate the local
   database instance in-proc.
*/

#pragma once

#include "../pch.h"
#include "client.h"
#include "db.h"

namespace mongo {

    const BSONObj reverseNaturalObj = BSON( "$natural" << -1 );

    class Cursor;
    class CoveredIndexMatcher;

    struct Helpers {

        /* ensure the specified index exists.

           @param keyPattern key pattern, e.g., { ts : 1 }
           @param name index name, e.g., "name_1"

           This method can be a little (not much) cpu-slow, so you may wish to use
             OCCASIONALLY ensureIndex(...);

           Note: use ensureHaveIdIndex() for the _id index: it is faster.
           Note: does nothing if collection does not yet exist.
        */
        static void ensureIndex(const char *ns, BSONObj keyPattern, bool unique, const char *name);

        /* fetch a single object from collection ns that matches query.
           set your db SavedContext first.

           @param query - the query to perform.  note this is the low level portion of query so "orderby : ..."
                          won't work.

           @param requireIndex if true, complain if no index for the query.  a way to guard against
           writing a slow query.

           @return true if object found
        */
        static bool findOne(const char *ns, const BSONObj &query, BSONObj& result, bool requireIndex = false);
        static DiskLoc findOne(const char *ns, const BSONObj &query, bool requireIndex);

        static bool findById(Client&, const char *ns, BSONObj query, BSONObj& result ,
                             bool * nsFound = 0 , bool * indexFound = 0 );

        /* uasserts if no _id index.
           @return null loc if not found */
        static DiskLoc findById(NamespaceDetails *d, BSONObj query);

        static bool getSingleton(const char *ns, BSONObj& result);
        static void putSingleton(const char *ns, BSONObj obj);
        static void putSingletonGod(const char *ns, BSONObj obj, bool logTheOp);
        static bool getFirst(const char *ns, BSONObj& result) { return getSingleton(ns, result); }
        static bool getLast(const char *ns, BSONObj& result); // get last object int he collection; e.g. {$natural : -1}

        static void upsert( const string& ns , const BSONObj& o );

        static bool isEmpty(const char *ns, bool doAuth=true);

        // TODO: this should be somewhere else probably
        static BSONObj toKeyFormat( const BSONObj& o , BSONObj& key );

        class RemoveCallback {
        public:
            virtual ~RemoveCallback() {}
            virtual void goingToDelete( const BSONObj& o ) = 0;
        };
        /* removeRange: operation is oplog'd */
        static long long removeRange( const string& ns , const BSONObj& min , const BSONObj& max , bool yield = false , bool maxInclusive = false , RemoveCallback * callback = 0 );

        /* Remove all objects from a collection.
        You do not need to set the database before calling.
        */
        static void emptyCollection(const char *ns);

    };

    class Database;

    // manage a set using collection backed storage
    class DbSet {
    public:
        DbSet( const string &name = "", const BSONObj &key = BSONObj() ) :
            name_( name ),
            key_( key.getOwned() ) {
        }
        ~DbSet();
        void reset( const string &name = "", const BSONObj &key = BSONObj() );
        bool get( const BSONObj &obj ) const;
        void set( const BSONObj &obj, bool val );
    private:
        string name_;
        BSONObj key_;
    };


    class RemoveSaver : public Helpers::RemoveCallback , boost::noncopyable {
    public:
        RemoveSaver( const string& type , const string& ns , const string& why);
        ~RemoveSaver();

        void goingToDelete( const BSONObj& o );

    private:
        path _root;
        path _file;
        ofstream* _out;

    };


} // namespace mongo

---

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