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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 | 27x 56x 56x 56x 7x 7x 56x 56x 56x 56x 56x 56x 56x 56x 56x 56x 56x 56x 56x 56x 55x | const uniqueCounterScopes = new WeakMap<object, Promise<void>>()
async function runEnsureUniqueCounterValue<T>({
initialValue,
isTaken,
reserve,
nextValue,
}: {
initialValue: T
isTaken: (candidate: T) => Promise<boolean> | boolean
reserve: (candidate: T) => void
nextValue: (counter: number) => T
}): Promise<T> {
let candidate = initialValue
let counter = 1
while (await isTaken(candidate)) {
candidate = nextValue(counter)
counter += 1
}
reserve(candidate)
return candidate
}
export async function ensureUniqueCounterValue<T>({
initialValue,
isTaken,
reserve,
nextValue,
scope,
}: {
initialValue: T
isTaken: (candidate: T) => Promise<boolean> | boolean
reserve: (candidate: T) => void
nextValue: (counter: number) => T
scope?: object
}): Promise<T> {
Iif (scope == null) {
return await runEnsureUniqueCounterValue({
initialValue,
isTaken,
reserve,
nextValue,
})
}
const previous = uniqueCounterScopes.get(scope) ?? Promise.resolve()
let releaseScope: (() => void) | undefined
const pendingScope = new Promise<void>((resolve) => {
releaseScope = resolve
})
const currentScope = previous
.catch(() => undefined)
.then(async () => {
await pendingScope
})
uniqueCounterScopes.set(scope, currentScope)
await previous.catch(() => undefined)
try {
return await runEnsureUniqueCounterValue({
initialValue,
isTaken,
reserve,
nextValue,
})
} finally {
releaseScope?.()
if (uniqueCounterScopes.get(scope) === currentScope) {
uniqueCounterScopes.delete(scope)
}
}
}
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