interface StoreInterface

interface StoreInterface {
    
    /**
     * Locates a cached Response for the Request provided.
     */
    public function lookup(Request $request) : ?Response;
    
    /**
     * Writes a cache entry to the store for the given Request and Response.
     *
     * Existing entries are read and any that match the response are removed. This
     * method calls write with the new list of cache entries.
     *
     * @return string The key under which the response is stored
     */
    public function write(Request $request, Response $response) : string;
    
    /**
     * Invalidates all cache entries that match the request.
     */
    public function invalidate(Request $request) : void;
    
    /**
     * Locks the cache for a given Request.
     *
     * @return bool|string true if the lock is acquired, the path to the current lock otherwise
     */
    public function lock(Request $request) : bool|string;
    
    /**
     * Releases the lock for the given Request.
     *
     * @return bool False if the lock file does not exist or cannot be unlocked, true otherwise
     */
    public function unlock(Request $request) : bool;
    
    /**
     * Returns whether or not a lock exists.
     *
     * @return bool true if lock exists, false otherwise
     */
    public function isLocked(Request $request) : bool;
    
    /**
     * Purges data for the given URL.
     *
     * @return bool true if the URL exists and has been purged, false otherwise
     */
    public function purge(string $url) : bool;
    
    /**
     * Cleanups storage.
     */
    public function cleanup() : void;

}