Check the cache to see if the input exists in it. If it exists, returns true
. A hex encoding of its hash is available by calling final
.
This function will also acquire an exclusive lock to the manifest file. This means that a process holding a Manifest will block any other process attempting to acquire the lock. If want_shared_lock
is true
, a cache hit guarantees the manifest file to be locked in shared mode, and a cache miss guarantees the manifest file to be locked in exclusive mode.
The lock on the manifest file is released when deinit
is called. As another option, one may call toOwnedLock
to obtain a smaller object which can represent the lock. deinit
is safe to call whether or not toOwnedLock
has been called.