feat: vendor permission system source

pi-permission-system/src/authority/authorizer-registry.ts

@@ -0,0 +1,69 @@
+/**
+ * Registry for named live-authority chain links (ADR 0007 §4).
+ *
+ * A downstream extension offers a named `Authorizer` link via
+ * `PermissionsService.registerAuthorizer`; this registry stores the link's
+ * `authorize` callback so composition can bind names to capabilities. One link
+ * per name; duplicate registration throws.
+ *
+ * Registration alone grants no authority — a link decides nothing until the
+ * operator names it in the `authorizerChain` config (the opt-in activation
+ * model). `AuthorizerSelection` owns that config-order resolution; this registry
+ * is storage only.
+ */
+
+import type { Authorizer } from "./authorizer";
+
+/**
+ * Read-only lookup used by chain composition (ISP — exposes only the read side,
+ * not the registration surface).
+ */
+export interface AuthorizerLookup {
+  get(name: string): Authorizer["authorize"] | undefined;
+}
+
+/**
+ * Registration side of the registry (ISP — exposes only the write surface,
+ * mirroring the read-only {@link AuthorizerLookup}).
+ */
+export interface AuthorizerRegistrar {
+  register(name: string, authorize: Authorizer["authorize"]): () => void;
+}
+
+/**
+ * Persistent registry mapping link names to their `authorize` callbacks.
+ *
+ * Owned by the extension factory (`index.ts`) so it survives across session
+ * activations. Exposed to sibling extensions via
+ * `PermissionsService.registerAuthorizer` and consulted by
+ * `AuthorizerSelection` during chain resolution.
+ */
+export class AuthorizerRegistry
+  implements AuthorizerLookup, AuthorizerRegistrar
+{
+  private readonly links = new Map<string, Authorizer["authorize"]>();
+
+  /**
+   * Register a link under `name`.
+   *
+   * Throws if a link is already registered for that name — keeps resolution
+   * deterministic (a pi-permission-system package priority). Returns a disposer
+   * that removes the link; the disposer is identity-guarded so a stale call
+   * cannot evict a later registration.
+   */
+  register(name: string, authorize: Authorizer["authorize"]): () => void {
+    if (this.links.has(name)) {
+      throw new Error(`An authorizer is already registered for '${name}'.`);
+    }
+    this.links.set(name, authorize);
+    return () => {
+      if (this.links.get(name) === authorize) {
+        this.links.delete(name);
+      }
+    };
+  }
+
+  get(name: string): Authorizer["authorize"] | undefined {
+    return this.links.get(name);
+  }
+}