A lock's one job: only one client may hold a named resource at a time. Everyone else has to wait. Start with the core of it, an owner map.
acquire(name, client_id): grab the lock. Return True if it was free (now held by client_id), False if someone else already holds it.release(name, client_id): let go. Only the current owner may release it: return True if released, False otherwise.class LockManager:
def __init__(self):
self._owner = {} # name -> client_id
def acquire(self, name, client_id):
"""Return True if the lock was free and is now held by client_id."""
# TODO: look up name in the self._owner map. When no one holds it,
# record client_id as the new owner and answer True.
# When another client already holds it, change nothing and answer False.
pass
def release(self, name, client_id):
"""Only the owner may release. Return True if released."""
# TODO: compare the owner stored for name in self._owner with client_id.
# Only on a match, drop that entry and answer True.
# No holder, or a different holder, answers False and changes nothing.
pass
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A lock's one job: only one client may hold a named resource at a time. Everyone else has to wait. Start with the core of it, an owner map.
acquire(name, client_id): grab the lock. Return True if it was free (now held by client_id), False if someone else already holds it.release(name, client_id): let go. Only the current owner may release it: return True if released, False otherwise.Press Run Tests or ⌘↩ to check your solution.