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// index.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/>.
*/
#pragma once
#include "mongo/pch.h"
#include <vector>
#include "mongo/db/diskloc.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/key.h"
#include "mongo/db/storage/namespace.h"
namespace mongo {
/* Details about a particular index. There is one of these effectively for each object in
system.namespaces (although this also includes the head pointer, which is not in that
collection).
** MemoryMapped Record ** (i.e., this is on disk data)
*/
class IndexDetails {
public:
/**
* btree head disk location
* TODO We should make this variable private, since btree operations
* may change its value and we don't want clients to rely on an old
* value. If we create a btree class, we can provide a btree object
* to clients instead of 'head'.
*/
DiskLoc head;
/* Location of index info object. Format:
{ name:"nameofindex", ns:"parentnsname", key: {keypattobject}
[, unique: <bool>, background: <bool>, v:<version>]
}
This object is in the system.indexes collection. Note that since we
have a pointer to the object here, the object in system.indexes MUST NEVER MOVE.
*/
DiskLoc info;
/* extract key value from the query object
e.g., if key() == { x : 1 },
{ x : 70, y : 3 } -> { x : 70 }
*/
BSONObj getKeyFromQuery(const BSONObj& query) const {
BSONObj k = keyPattern();
BSONObj res = query.extractFieldsUnDotted(k);
return res;
}
/* get the key pattern for this object.
e.g., { lastname:1, firstname:1 }
*/
BSONObj keyPattern() const {
return info.obj().getObjectField("key");
}
/**
* @return offset into keyPattern for key
-1 if doesn't exist
*/
int keyPatternOffset( const string& key ) const;
bool inKeyPattern( const string& key ) const { return keyPatternOffset( key ) >= 0; }
/* true if the specified key is in the index */
bool hasKey(const BSONObj& key);
// returns name of this index's storage area (database.collection.$index)
string indexNamespace() const {
return indexNamespaceFromObj(info.obj());
}
// returns the name of an index's storage area (database.collection.$index) from a BSONObj
static string indexNamespaceFromObj(const BSONObj& io) {
string s;
s.reserve(Namespace::MaxNsLen);
s = io.getStringField("ns");
verify( !s.empty() );
s += ".$";
s += io.getStringField("name");
return s;
}
string indexName() const { // e.g. "ts_1"
BSONObj io = info.obj();
return io.getStringField("name");
}
static bool isIdIndexPattern( const BSONObj &pattern ) {
BSONObjIterator i(pattern);
BSONElement e = i.next();
//_id index must have form exactly {_id : 1} or {_id : -1}.
//Allows an index of form {_id : "hashed"} to exist but
//do not consider it to be the primary _id index
if(! ( strcmp(e.fieldName(), "_id") == 0
&& (e.numberInt() == 1 || e.numberInt() == -1)))
return false;
return i.next().eoo();
}
/* returns true if this is the _id index. */
bool isIdIndex() const {
return isIdIndexPattern( keyPattern() );
}
/* gets not our namespace name (indexNamespace for that),
but the collection we index, its name.
*/
string parentNS() const {
BSONObj io = info.obj();
return io.getStringField("ns");
}
static int versionForIndexObj( const BSONObj &obj ) {
BSONElement e = obj["v"];
if( e.type() == NumberInt )
return e._numberInt();
// should normally be an int. this is for backward compatibility
int v = e.numberInt();
uassert(14802, "index v field should be Integer type", v == 0);
return v;
}
int version() const {
return versionForIndexObj( info.obj() );
}
/** @return true if index has unique constraint */
bool unique() const {
BSONObj io = info.obj();
return io["unique"].trueValue() ||
/* temp: can we juse make unique:true always be there for _id and get rid of this? */
isIdIndex();
}
/** return true if dropDups was set when building index (if any duplicates, dropdups drops the duplicating objects) */
bool dropDups() const {
return info.obj().getBoolField( "dropDups" );
}
/** delete this index. does NOT clean up the system catalog
(system.indexes or system.namespaces) -- only NamespaceIndex.
*/
void kill_idx();
string toString() const {
return info.obj().toString();
}
/** @return true if supported. supported means we can use the index, including adding new keys.
it may not mean we can build the index version in question: we may not maintain building
of indexes in old formats in the future.
*/
static bool isASupportedIndexVersionNumber(int v) { return (v&1)==v; } // v == 0 || v == 1
};
class NamespaceDetails;
// changedId should be initialized to false
// @return how many things were deleted
int assureSysIndexesEmptied(const char *ns, IndexDetails *exceptForIdIndex);
int removeFromSysIndexes(const char *ns, const char *idxName);
/**
* Prepare to build an index. Does not actually build it (except for a special _id case).
* - We validate that the params are good
* - That the index does not already exist
* - Creates the source collection if it DNE
*
* example of 'io':
* { ns : 'test.foo', name : 'z', key : { z : 1 } }
*
* @throws DBException
*
* @param mayInterrupt - When true, killop may interrupt the function call.
* @param sourceNS - source NS we are indexing
* @param sourceCollection - its details ptr
* @return true if ok to continue. when false we stop/fail silently (index already exists)
*/
bool prepareToBuildIndex(const BSONObj& io,
bool mayInterrupt,
bool god,
string& sourceNS,
NamespaceDetails*& sourceCollection,
BSONObj& fixedIndexObject);
} // namespace mongo
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