mirror of
https://github.com/sudosylabs/vnidrop.git
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cdricms
081b59815c
The Cancel button on an in-progress receive did nothing. CoreRepository funnelled every core call through one serial DispatchQueue, but `receive` is a blocking core call that occupies that queue for the whole transfer. The tapped `cancelTransfer` was enqueued behind the in-flight `receive` on the same serial queue, so it could never run until `receive` returned — which it never would, because it was waiting to be cancelled. A deadlock the button couldn't escape. The Rust core is explicitly designed for cancel to arrive from another thread mid-receive (VnidropCore.block_on uses a shared runtime handle for exactly this). Extracts the two-lane dispatch into a CoreDispatcher: a serial lane for ordered calls and a separate concurrent lane for interrupt-style calls, and routes cancel through the latter so the signal reaches the core and unblocks the receive. Adds CoreDispatcherTests, including a regression guard that an interrupt completes while the serial lane is blocked.
42 lines
1.8 KiB
Swift
42 lines
1.8 KiB
Swift
import Foundation
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/// Dispatch-queue labels for the core's serial and interrupt lanes.
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enum QueueLabel {
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static let core = "com.vnidrop.core"
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static let interrupt = "com.vnidrop.core.interrupt"
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}
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/// Two-lane dispatcher for blocking core calls.
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///
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/// `run` serializes calls on one queue so the core is driven from a single lane.
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/// `runInterrupt` uses a *separate* concurrent lane, so an interrupt-style call
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/// (cancel) can reach the core while a blocking call (`receive`) still occupies
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/// the serial lane. The core is internally synchronized and explicitly supports
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/// cancel arriving from another thread mid-receive (see VnidropCore.block_on);
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/// a single shared queue would deadlock it.
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final class CoreDispatcher: Sendable {
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private let serialQueue: DispatchQueue
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private let interruptQueue: DispatchQueue
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init(label: String = QueueLabel.core, interruptLabel: String = QueueLabel.interrupt) {
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serialQueue = DispatchQueue(label: label, qos: .userInitiated)
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interruptQueue = DispatchQueue(label: interruptLabel, qos: .userInitiated, attributes: .concurrent)
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}
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/// Runs a blocking core call on the serial lane and hops the result back.
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func run<T: Sendable>(_ block: @escaping @Sendable () throws -> T) async -> Result<T, Error> {
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await withCheckedContinuation { continuation in
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serialQueue.async { continuation.resume(returning: Result { try block() }) }
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}
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}
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/// Like `run`, but off the serial lane so it can interrupt a blocking call in
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/// flight there (e.g. cancel a `receive`). Only use for core calls that are
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/// safe to run concurrently with another core call.
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func runInterrupt<T: Sendable>(_ block: @escaping @Sendable () throws -> T) async -> Result<T, Error> {
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await withCheckedContinuation { continuation in
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interruptQueue.async { continuation.resume(returning: Result { try block() }) }
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}
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}
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}
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