core: extract external directory validation to shared utility to reduce code duplication across tools

packages/opencode/src/tool/external-directory.ts

@@ -0,0 +1,33 @@
+import path from "path"
+import type { Tool } from "./tool"
+import { Filesystem } from "../util/filesystem"
+import { Instance } from "../project/instance"
+
+type Kind = "file" | "directory"
+
+type Options = {
+  bypass?: boolean
+  kind?: Kind
+}
+
+export async function assertExternalDirectory(ctx: Tool.Context, target?: string, options?: Options) {
+  if (!target) return
+
+  if (options?.bypass) return
+
+  if (Filesystem.contains(Instance.directory, target)) return
+
+  const kind = options?.kind ?? "file"
+  const parentDir = kind === "directory" ? target : path.dirname(target)
+  const glob = path.join(parentDir, "*")
+
+  await ctx.ask({
+    permission: "external_directory",
+    patterns: [glob],
+    always: [glob],
+    metadata: {
+      filepath: target,
+      parentDir,
+    },
+  })
+}