[Init] Initial commit - NetMesh terminal manager

electron/preload/sessionTombstones.cjs

@@ -0,0 +1,59 @@
+"use strict";
+
+const DEFAULT_SESSION_TOMBSTONE_TTL_MS = 5 * 60_000;
+const DEFAULT_MAX_SESSION_TOMBSTONES = 4096;
+
+class SessionTombstones {
+  constructor(options = {}) {
+    this.maxEntries = options.maxEntries ?? DEFAULT_MAX_SESSION_TOMBSTONES;
+    this.ttlMs = options.ttlMs ?? DEFAULT_SESSION_TOMBSTONE_TTL_MS;
+    this.now = options.now ?? (() => Date.now());
+    this.entries = new Map();
+  }
+
+  prune() {
+    const now = this.now();
+    for (const [sessionId, closedAt] of this.entries) {
+      if (now - closedAt < this.ttlMs) break;
+      this.entries.delete(sessionId);
+    }
+    while (this.entries.size > this.maxEntries) {
+      const oldest = this.entries.keys().next().value;
+      if (oldest === undefined) break;
+      this.entries.delete(oldest);
+    }
+  }
+
+  add(sessionId) {
+    if (!sessionId) return this;
+    this.entries.delete(sessionId);
+    this.entries.set(sessionId, this.now());
+    this.prune();
+    return this;
+  }
+
+  delete(sessionId) {
+    return this.entries.delete(sessionId);
+  }
+
+  has(sessionId) {
+    this.prune();
+    return this.entries.has(sessionId);
+  }
+
+  get size() {
+    this.prune();
+    return this.entries.size;
+  }
+
+  [Symbol.iterator]() {
+    this.prune();
+    return this.entries.keys();
+  }
+}
+
+module.exports = {
+  DEFAULT_SESSION_TOMBSTONE_TTL_MS,
+  DEFAULT_MAX_SESSION_TOMBSTONES,
+  SessionTombstones,
+};