72
return [];
73
}
75
>
const key = workingDirectory.toString();
76
>
const now = Date.now();
77
>
const existing = this._cache.get(key);
78
>
let shared: Promise<readonly URI[]>;
79
if (existing && existing.expiresAt > now) {
80
shared = existing.promise;
82
>
shared = this._enumerate(workingDirectory);
83
>
const entry: ICacheEntry = { promise: shared, expiresAt: now + CACHE_TTL_MS };
84
>
this._cache.set(key, entry);
85
>
// If enumeration fails, drop the cache entry so the next caller retries.
86
>
shared.catch(() => {
87
if (this._cache.get(key) === entry) {
88
this._cache.delete(key);
89
}
91
>
}
92
>
93
>
// Race the shared enumeration against the caller's cancellation
94
>
// token. Only the caller's promise rejects on cancellation; the
95
>
// shared enumeration runs to completion so concurrent callers (and
96
>
// future cache hits within the TTL) still see the result.
97
>
if (token.isCancellationRequested) {
98
throw new CancellationError();
99
}
101
return shared;
102
}