Interface for the persistence layer of LocalisationCache.
The persistence layer is two-level hierarchical cache. The first level is the language, the second level is the item or subitem.
Since the data for a whole language is rebuilt in one operation, it needs to have a fast and atomic method for deleting or replacing all of the current data for a given language. The interface reflects this bulk update operation. Callers writing to the cache must first call startWrite(), then will call set() a couple of thousand times, then will call finishWrite() to commit the operation. When finishWrite() is called, the cache is expected to delete all data previously stored for that language.
The values stored are PHP variables suitable for serialize(). Implementations of LCStore are responsible for serializing and unserializing.
Definition at line 38 of file LCStore.php.