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<?php
/**
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
namespace Wikimedia\LightweightObjectStore;
/**
* Generic interface providing error code and quality-of-service constants for object stores
*
* @internal For use by BagOStuff and WANObjectCache
* @ingroup Cache
*/
interface StorageAwareness {
/** No storage medium error */
public const ERR_NONE = 0;
/** Storage medium failed to yield a complete response to an operation */
public const ERR_NO_RESPONSE = 1;
/** Storage medium could not be reached to establish a connection */
public const ERR_UNREACHABLE = 2;
/** Storage medium operation failed due to usage limitations or an I/O error */
public const ERR_UNEXPECTED = 3;
/** @deprecated Since 1.41; Emulation/fallback mode; see QOS_EMULATION_*; higher is better */
public const ATTR_EMULATION = 1;
/** Durability of writes; see QOS_DURABILITY_* (higher means stronger) */
public const ATTR_DURABILITY = 2;
/** Data is never saved to begin with (blackhole store) */
public const QOS_DURABILITY_NONE = 1;
/** Data is lost at the end of the current web request or CLI script */
public const QOS_DURABILITY_SCRIPT = 2;
/** Data is lost once the service storing the data restarts */
public const QOS_DURABILITY_SERVICE = 3;
/** Data is saved to disk and writes do not usually block on fsync() */
public const QOS_DURABILITY_DISK = 4;
/** Data is saved to disk and writes usually block on fsync(), like a standard RDBMS */
public const QOS_DURABILITY_RDBMS = 5;
/** Generic "unknown" value; useful for comparisons (always "good enough") */
public const QOS_UNKNOWN = INF;
}
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