feat: convert file manager into a plugin

plugins/file-manager/src/backend/transfer-host-utils.ts

@@ -0,0 +1,59 @@
+import { networkInterfaces } from "os";
+import { normalizeSftpPath } from "./transfer-paths.js";
+
+let cachedLocalAddresses: Set<string> | null = null;
+
+export function normalizeHostAddress(host: string): string {
+  const trimmed = host.trim().toLowerCase();
+  if (trimmed.startsWith("[") && trimmed.endsWith("]")) {
+    return trimmed.slice(1, -1);
+  }
+  return trimmed.split(":")[0] ?? trimmed;
+}
+
+function getLocalAddresses(): Set<string> {
+  if (cachedLocalAddresses) return cachedLocalAddresses;
+
+  const addresses = new Set(["127.0.0.1", "::1", "localhost"]);
+  for (const ifaces of Object.values(networkInterfaces())) {
+    if (!ifaces) continue;
+    for (const iface of ifaces) {
+      if (!iface.internal && iface.family === "IPv4") {
+        addresses.add(iface.address.toLowerCase());
+      }
+    }
+  }
+  cachedLocalAddresses = addresses;
+  return addresses;
+}
+
+export function isLocalSshEndpoint(ip?: string): boolean {
+  if (!ip) return false;
+  const bare = normalizeHostAddress(ip);
+  if (bare === "localhost" || bare === "127.0.0.1" || bare === "::1") {
+    return true;
+  }
+  return getLocalAddresses().has(bare);
+}
+
+export function escapeShell(s: string): string {
+  return s.replace(/'/g, "'\"'\"'");
+}
+
+export function isRootOnlyPath(path: string): boolean {
+  const normalized = normalizeSftpPath(path);
+  return (
+    normalized === "/" ||
+    /^\/[A-Za-z]:$/.test(normalized) ||
+    /^[A-Za-z]:$/.test(normalized)
+  );
+}
+
+export function isPermissionError(err: Error): boolean {
+  const msg = err.message.toLowerCase();
+  return (
+    msg.includes("permission denied") ||
+    msg.includes("eacces") ||
+    msg.includes("access denied")
+  );
+}