Module lock 

Directory lock facade for queue and daemon coordination.

Responsibilities:

• Expose lock acquisition, owner metadata, stale-lock handling, and PID liveness helpers.
• Keep concurrency-critical concerns split into focused submodules.

Not handled here:

• Queue mutation or config validation.
• Cross-machine or distributed locking.

Invariants/assumptions:

• Callers hold DirLock for the full critical section.
• The lock directory path is stable for the resource being protected.
• The task label remains reserved for shared supervisor/task lock semantics.

Structs

DirLock

Held directory lock guard.

LockOwner

Lock owner metadata parsed from the owner file.

Enums

PidLiveness

Tri-state PID liveness result.

Constants

TASK_OWNER_PREFIX

Functions

acquire_dir_lock

is_supervising_process

is_task_owner_file

pid_is_running

pid_liveness

queue_lock_dir

read_lock_owner