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/**
* Copyright (C) 2015 MongoDB 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 <map>
#include <string>
#include "mongo/base/disallow_copying.h"
#include "mongo/stdx/mutex.h"
namespace mongo {
class CatalogManager;
class DBConfig;
template <typename T>
class StatusWith;
/**
* This is the root of the "read-only" hierarchy of cached catalog metadata. It is read only
* in the sense that it only reads from the persistent store, but never writes to it. Instead
* writes happen thorugh the CatalogManager and the cache hierarchy needs to be invalidated.
*/
class CatalogCache {
MONGO_DISALLOW_COPYING(CatalogCache);
public:
explicit CatalogCache(CatalogManager* catalogManager);
/**
* Retrieves the cached metadata for the specified database. The returned value is still
* owned by the cache and it should not be cached elsewhere, but instead only used as a
* local variable. The reason for this is so that if the cache gets invalidated, the caller
* does not miss getting the most up-to-date value.
*
* @param dbname The name of the database (must not contain dots, etc).
* @return The database if it exists, NULL otherwise.
*/
StatusWith<std::shared_ptr<DBConfig>> getDatabase(const std::string& dbName);
/**
* Removes the database information for the specified name from the cache, so that the
* next time getDatabase is called, it will be reloaded.
*/
void invalidate(const std::string& dbName);
/**
* Purges all cached database information, which will cause the data to be reloaded again.
*/
void invalidateAll();
private:
typedef std::map<std::string, std::shared_ptr<DBConfig>> ShardedDatabasesMap;
// Reference to the catalog manager. Not owned.
CatalogManager* const _catalogManager;
// Databases catalog map and mutex to protect it
stdx::mutex _mutex;
ShardedDatabasesMap _databases;
};
} // namespace mongo
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