wehub-resource-sync
36 lines
1.3 KiB
TypeScript
36 lines
1.3 KiB
TypeScript
import { AsyncLocalStorage } from 'node:async_hooks'
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/**
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* Process-local keyed lock for Desktop-owned context files.
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*
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* The Electron main process owns the application single-instance lock before
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* it activates profile writes. Every cooperative context writer must also use
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* this lock, so a read/check/publish transaction cannot be interleaved by a
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* second Desktop code path inside the owning process.
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*/
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export class DesktopContextLock {
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private readonly ownership = new AsyncLocalStorage<ReadonlySet<string>>()
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private readonly tails = new Map<string, Promise<void>>()
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async runExclusive<T>(key: string, operation: () => T | Promise<T>): Promise<T> {
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if (!key) throw new Error('Desktop context lock requires a non-empty key.')
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if (this.ownership.getStore()?.has(key)) {
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throw new Error('Desktop context lock cannot be re-entered for the same key.')
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}
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const previous = this.tails.get(key) ?? Promise.resolve()
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const queued = previous.catch(() => undefined).then(async () => {
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const held = new Set(this.ownership.getStore() ?? [])
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held.add(key)
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return this.ownership.run(held, operation)
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})
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const tail = queued.then(() => undefined, () => undefined)
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this.tails.set(key, tail)
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try {
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return await queued
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} finally {
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if (this.tails.get(key) === tail) this.tails.delete(key)
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}
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}
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}
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