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// dbhelpers.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/>.
*/
/* db helpers are helper functions and classes that let us easily manipulate the local
database instance.
*/
#pragma once
#include "../stdafx.h"
#include "client.h"
#include "db.h"
namespace mongo {
class Cursor;
class CoveredIndexMatcher;
class CursorIterator {
public:
CursorIterator( auto_ptr<Cursor> c , BSONObj filter = BSONObj() );
BSONObj next();
bool hasNext();
private:
void _advance();
auto_ptr<Cursor> _cursor;
auto_ptr<CoveredIndexMatcher> _matcher;
BSONObj _o;
};
/**
all helpers assume locking is handled above them
*/
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 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, BSONObj query, BSONObj& result, bool requireIndex = false);
/**
* @param foundIndex if passed in will be set to 1 if ns and index found
* @return true if object found
*/
static bool findById(Client&, const char *ns, BSONObj query, BSONObj& result ,
bool * nsFound = 0 , bool * indexFound = 0 );
static auto_ptr<CursorIterator> find( const char *ns , BSONObj query = BSONObj() , bool requireIndex = false );
/* Get/put the first object from a collection. Generally only useful if the collection
only ever has a single object -- which is a "singleton collection".
You do not need to set the database before calling.
Returns: true if object exists.
*/
static bool getSingleton(const char *ns, BSONObj& result);
static void putSingleton(const char *ns, BSONObj obj);
/* 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_;
};
} // namespace mongo
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