PuduLangHttpClient.Transport.Abort

type: module path: "@root/src/PuduLangHttpClient/Transport/Abort.pudu" fidelity: Active grammar: "[[grammar/pudu]]" depth_score: 0.6 depth_status: MODERATE tags: [module, leaf] aliases: [PuduLangHttpClient.Transport.Abort]

Purpose

A connection closed when its request is cancelled mid-exchange, so a read or write blocked on it wakes at once.

Interface

Signatures

export type Stage = Running | Finished | Aborted

export type Guard = { stage: Shared.Shared[Stage] }

export fn watch(link: &Wire.Link, token: &Cancel.Token) -> Guard

export fn finish(guard: &Guard) -> Bool

Linkage

• Requires: [[src/PuduLangHttpClient/Constants/Defaults]], [[src/PuduLangHttpClient/Transport/Wire]], [[src/PuduLangHttpClient/Utils/Shared]], the standard library.
• Consumed by: [[src/PuduLangHttpClient/Transport/Hop]].

Algorithm

1. watch starts a watcher that looks for an explicit cancellation every 10 ms while the exchange runs and closes the link when it finds one.
2. finish ends the exchange and answers whether the watcher aborted it.
3. The stage moves from running to finished or to aborted exactly once, under a lock.

Negative Logic (Prohibited Paths)

• Once finish answers, the watcher never touches the link again, so a connection returned to the pool is never closed by a stale watcher.
• A deadline is not the watcher's to act on: the socket operations already wait at most what remains of it.

Edge Cases

• A watcher outlives its exchange by at most one poll and then ends without acting.

Depth

DEPTH 0.6 (MODERATE). Tested by the suite mirroring this module under test/.

Grill Log

• Q: Why close the socket rather than poll it with short reads? A: On the runtime a receive that times out closes the connection, while closing a socket from another thread wakes a blocked receive at once; closing is the one interruption a blocked read honours. _Rejected:_ polling reads (they destroy the connection they poll).
• Q: Why a thread per exchange? A: Threads are lightweight on the runtime, and a loopback benchmark of 2000 keep-alive requests measured no difference with and without the watcher. _Rejected:_ one watcher thread per transport tracking every request (shared state on every request's path).

Referenced by

[[CHANGELOG]] · [[decisions/ADR-0004-deadline-cancellation]] · [[src/PuduLangHttpClient/Constants/Defaults]] · [[src/PuduLangHttpClient/Transport/Hop]] · [[src/PuduLangHttpClient/Transport/Wire]] · [[src/PuduLangHttpClient/Transport/_MOC]] · [[src/PuduLangHttpClient/Utils/Shared]]