[Init] Initial commit - NetMesh terminal manager

application/state/sftp/sharedRemoteHostCache.ts

@@ -0,0 +1,94 @@
+import type { SftpFileEntry, SftpFilenameEncoding } from "../../../domain/models";
+
+export interface SharedRemoteHostCacheEntry {
+  path: string;
+  homeDir: string;
+  files: SftpFileEntry[];
+  filenameEncoding: SftpFilenameEncoding;
+  updatedAt: number;
+}
+
+const SHARED_REMOTE_HOST_CACHE_TTL_MS = 60_000;
+export const MAX_SHARED_REMOTE_HOST_CACHE_ENTRIES = 64;
+export const MAX_SHARED_REMOTE_HOST_CACHE_FILES = 20_000;
+
+const sharedRemoteHostCache = new Map<string, SharedRemoteHostCacheEntry>();
+
+const pruneSharedRemoteHostCache = (now: number): void => {
+  for (const [key, entry] of sharedRemoteHostCache) {
+    if (now - entry.updatedAt > SHARED_REMOTE_HOST_CACHE_TTL_MS) {
+      sharedRemoteHostCache.delete(key);
+    }
+  }
+
+  let totalFiles = 0;
+  for (const entry of sharedRemoteHostCache.values()) totalFiles += entry.files.length;
+  while (
+    sharedRemoteHostCache.size > 1
+    && (
+      sharedRemoteHostCache.size > MAX_SHARED_REMOTE_HOST_CACHE_ENTRIES
+      || totalFiles > MAX_SHARED_REMOTE_HOST_CACHE_FILES
+    )
+  ) {
+    const oldestKey = sharedRemoteHostCache.keys().next().value as string | undefined;
+    if (!oldestKey) break;
+    const oldest = sharedRemoteHostCache.get(oldestKey);
+    sharedRemoteHostCache.delete(oldestKey);
+    totalFiles -= oldest?.files.length ?? 0;
+  }
+};
+
+/**
+ * Build a cache key that includes connection details so that the same host ID
+ * with different session-time overrides (port, protocol) uses separate entries.
+ */
+export const buildCacheKey = (
+  hostId: string,
+  hostname?: string,
+  port?: number,
+  protocol?: string,
+  sftpSudo?: boolean,
+  username?: string,
+  sftpFileProtocol?: string,
+): string => {
+  const fileProto = sftpFileProtocol && sftpFileProtocol !== "auto" ? sftpFileProtocol : "";
+  return `${hostId}:${hostname ?? ''}:${port ?? ''}:${protocol ?? ''}:${sftpSudo ? 'sudo' : ''}:${username ?? ''}:${fileProto}`;
+};
+
+export const getSharedRemoteHostCache = (
+  cacheKey: string,
+): SharedRemoteHostCacheEntry | null => {
+  pruneSharedRemoteHostCache(Date.now());
+  const entry = sharedRemoteHostCache.get(cacheKey);
+  if (!entry) return null;
+  sharedRemoteHostCache.delete(cacheKey);
+  sharedRemoteHostCache.set(cacheKey, entry);
+  return entry;
+};
+
+export const setSharedRemoteHostCache = (
+  cacheKey: string,
+  entry: Omit<SharedRemoteHostCacheEntry, "updatedAt">,
+): void => {
+  const now = Date.now();
+  pruneSharedRemoteHostCache(now);
+  sharedRemoteHostCache.delete(cacheKey);
+  // Never exceed the advertised file-row budget with a single huge listing.
+  // Dropping it from cache preserves the full result for this read without
+  // retaining an unbounded array for the lifetime of the renderer.
+  if (entry.files.length > MAX_SHARED_REMOTE_HOST_CACHE_FILES) return;
+  sharedRemoteHostCache.set(cacheKey, {
+    ...entry,
+    updatedAt: now,
+  });
+  pruneSharedRemoteHostCache(now);
+};
+
+export const _resetSharedRemoteHostCacheForTests = (): void => {
+  sharedRemoteHostCache.clear();
+};
+
+export const _getSharedRemoteHostCacheStatsForTests = () => ({
+  entries: sharedRemoteHostCache.size,
+  files: [...sharedRemoteHostCache.values()].reduce((sum, entry) => sum + entry.files.length, 0),
+});