48 lines
1 KiB
TypeScript
48 lines
1 KiB
TypeScript
import type { RelativePath } from "../persistence/database";
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const locked = new Set<RelativePath>();
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const waiters = new Map<RelativePath, (() => void)[]>();
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export function tryLockDocument(relativePath: RelativePath): boolean {
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if (locked.has(relativePath)) {
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return false;
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}
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locked.add(relativePath);
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return true;
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}
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export async function waitForDocumentLock(
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relativePath: RelativePath
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): Promise<void> {
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if (tryLockDocument(relativePath)) {
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return Promise.resolve();
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}
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return new Promise((resolve) => {
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let waiting = waiters.get(relativePath);
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if (!waiting) {
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waiting = [];
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waiters.set(relativePath, waiting);
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}
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waiting.push(resolve);
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});
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}
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export function unlockDocument(relativePath: RelativePath): void {
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if (!locked.has(relativePath)) {
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throw new Error(
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`Document ${relativePath} is not locked, cannot unlock`
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);
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}
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// Remove the first element to ensure FIFO unblocking order
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const nextWaiting = waiters.get(relativePath)?.shift();
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if (nextWaiting) {
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nextWaiting();
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} else {
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locked.delete(relativePath);
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}
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}
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