Module Async_extra.Sequencer_table.Make

Parameters

Key : Core.Hashable

Signature

type ('state, 'job_tag) t

Every Key.t in the table has an associated state, which each job running on that key gets access to. Jobs maybe have an associated job_tag which is provided purely to assist debugging, as the tag is included in the sexp serialization of t.

include sig ... end
val sexp_of_t : ('state ‑> Sexplib.Sexp.t) ‑> ('job_tag ‑> Sexplib.Sexp.t) ‑> ('state, 'job_tag) t ‑> Sexplib.Sexp.t
val create : unit ‑> (_, _) t
val enqueue : ('state, 'job_tag) t ‑> key:Key.t ‑> ?tag:'job_tag ‑> ('state option ‑> 'b Import.Deferred.t) ‑> 'b Import.Deferred.t

enqueue t ~key f enqueues f for key. f will be called with the state of key when invoked.

Invariant 1: it is guaranteed that f will not be called immediately.

Invariant 2: if f raises, then the exception will be raised to the monitor in effect when enqueue was called. Subsequent jobs for key will proceed.

Invariant 3: to avoid race, there are no deferred operations between finding the state and calling f with the state found. Otherwise, the user would need to consider the race that the state passed to f might have been changed by set_state.

val set_state : ('state, _) t ‑> key:Key.t ‑> 'state option ‑> unit

set_state t key state_opt sets the state for key immediately. The state will be kept internally until set to None

val find_state : ('state, _) t ‑> Key.t ‑> 'state option
val num_unfinished_jobs : (_, _) t ‑> Key.t ‑> int

num_unfinished_jobs t key returns the number of jobs for key including including pending and running.

val mem : (_, _) t ‑> Key.t ‑> bool

mem t key returns true if there is state or an pending/running job

val fold : ('state, _) t ‑> init:'b ‑> f:('b ‑> key:Key.t ‑> 'state option ‑> 'b) ‑> 'b

Fold over keys with states or pending/running jobs. It's safe to mutate (enqueue or set_state) when folding

val prior_jobs_done : (_, _) t ‑> unit Import.Deferred.t

The result is determined when all jobs enqueued before this are finished. The implementation adds a new job to every key currently with at least one running job attached, so it will affect num_unfinished_jobs