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/**
* 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/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <memory>
#include <boost/filesystem/path.hpp>
#include "mongo/db/db.h"
#include "mongo/db/record_id.h"
namespace mongo {
class Collection;
class Cursor;
class OperationContext;
struct KeyRange;
struct WriteConcernOptions;
/**
* db helpers are helper functions and classes that let us easily manipulate the local
* database instance in-proc.
*
* all helpers assume locking is handled above them
*/
struct Helpers {
class RemoveSaver;
/* 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: does nothing if collection does not yet exist.
*/
static void ensureIndex(OperationContext* txn,
Collection* collection,
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, assert if no index for the query. a way to guard against
writing a slow query.
@return true if object found
*/
static bool findOne(OperationContext* txn,
Collection* collection,
const BSONObj& query,
BSONObj& result,
bool requireIndex = false);
static RecordId findOne(OperationContext* txn,
Collection* collection,
const BSONObj& query,
bool requireIndex);
/**
* @param foundIndex if passed in will be set to 1 if ns and index found
* @return true if object found
*/
static bool findById(OperationContext* txn,
Database* db,
const char* ns,
BSONObj query,
BSONObj& result,
bool* nsFound = 0,
bool* indexFound = 0);
/* TODO: should this move into Collection?
* uasserts if no _id index.
* @return null loc if not found */
static RecordId findById(OperationContext* txn, Collection* collection, const BSONObj& query);
/**
* Get the first object generated from a forward natural-order scan on "ns". Callers do not
* have to lock "ns".
*
* Returns true if there is such an object. An owned copy of the object is placed into the
* out-argument "result".
*
* Returns false if there is no such object.
*/
static bool getSingleton(OperationContext* txn, const char* ns, BSONObj& result);
/**
* Same as getSingleton, but with a reverse natural-order scan on "ns".
*/
static bool getLast(OperationContext* txn, const char* ns, BSONObj& result);
/**
* Performs an upsert of "obj" into the collection "ns", with an empty update predicate.
* Callers must have "ns" locked.
*/
static void putSingleton(OperationContext* txn, const char* ns, BSONObj obj);
/**
* you have to lock
* you do not have to have Context set
* o has to have an _id field or will assert
*/
static void upsert(OperationContext* txn,
const std::string& ns,
const BSONObj& o,
bool fromMigrate = false);
// TODO: this should be somewhere else probably
/* Takes object o, and returns a new object with the
* same field elements but the names stripped out.
* Example:
* o = {a : 5 , b : 6} --> {"" : 5, "" : 6}
*/
static BSONObj toKeyFormat(const BSONObj& o);
/* Takes object o, and infers an ascending keyPattern with the same fields as o
* Example:
* o = {a : 5 , b : 6} --> {a : 1 , b : 1 }
*/
static BSONObj inferKeyPattern(const BSONObj& o);
/**
* Takes a namespace range, specified by a min and max and qualified by an index pattern,
* and removes all the documents in that range found by iterating
* over the given index. Caller is responsible for insuring that min/max are
* compatible with the given keyPattern (e.g min={a:100} is compatible with
* keyPattern={a:1,b:1} since it can be extended to {a:100,b:minKey}, but
* min={b:100} is not compatible).
*
* Caller must hold a write lock on 'ns'
*
* Returns -1 when no usable index exists
*
* Does oplog the individual document deletions.
* // TODO: Refactor this mechanism, it is growing too large
*/
static long long removeRange(OperationContext* txn,
const KeyRange& range,
bool maxInclusive,
const WriteConcernOptions& secondaryThrottle,
RemoveSaver* callback = NULL,
bool fromMigrate = false,
bool onlyRemoveOrphanedDocs = false);
// TODO: This will supersede Chunk::MaxObjectsPerChunk
static const long long kMaxDocsPerChunk;
/**
* Get sorted disklocs that belong to a range of a namespace defined over an index
* key pattern (KeyRange).
*
* @param chunk range of a namespace over an index key pattern.
* @param maxChunkSizeBytes max number of bytes that we will retrieve locs for, if the
* range is estimated larger (from avg doc stats) we will stop recording locs.
* @param locs set to record locs in
* @param estChunkSizeBytes chunk size estimated from doc count and avg doc size
* @param chunkTooBig whether the chunk was estimated larger than our maxChunkSizeBytes
* @param errmsg filled with textual description of error if this call return false
*
* @return NamespaceNotFound if the namespace doesn't exist
* @return IndexNotFound if the index pattern doesn't match any indexes
* @return InvalidLength if the estimated size exceeds maxChunkSizeBytes
*/
static Status getLocsInRange(OperationContext* txn,
const KeyRange& range,
long long maxChunkSizeBytes,
std::set<RecordId>* locs,
long long* numDocs,
long long* estChunkSizeBytes);
/**
* Remove all documents from a collection.
* You do not need to set the database before calling.
* Does not oplog the operation.
*/
static void emptyCollection(OperationContext* txn, const char* ns);
/**
* for saving deleted bson objects to a flat file
*/
class RemoveSaver {
MONGO_DISALLOW_COPYING(RemoveSaver);
public:
RemoveSaver(const std::string& type, const std::string& ns, const std::string& why);
/**
* Writes document to file. File is created lazily before writing the first document.
* Returns error status if the file could not be created or if there were errors writing
* to the file.
*/
Status goingToDelete(const BSONObj& o);
private:
boost::filesystem::path _root;
boost::filesystem::path _file;
std::unique_ptr<std::ostream> _out;
};
};
} // namespace mongo
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