From b8dacf1df7f8c45f50c59044d135700bdb676f67 Mon Sep 17 00:00:00 2001
From: Wang Guan <momocraft@gmail.com>
Date: Sat, 6 Apr 2024 23:03:46 +0900
Subject: [PATCH] rename lease.ts

---
 src/concurrency/lazy-thenable.ts       |  8 ++++++--
 src/concurrency/lease.ts               |  8 ++++++++
 src/concurrency/lockable.ts            |  0
 src/concurrency/locks/lockable.spec.ts |  3 ---
 src/concurrency/locks/lockable.ts      | 11 -----------
 src/concurrency/resource-pool.ts       | 14 +++++++++-----
 6 files changed, 23 insertions(+), 21 deletions(-)
 create mode 100644 src/concurrency/lease.ts
 create mode 100644 src/concurrency/lockable.ts
 delete mode 100644 src/concurrency/locks/lockable.spec.ts
 delete mode 100644 src/concurrency/locks/lockable.ts

diff --git a/src/concurrency/lazy-thenable.ts b/src/concurrency/lazy-thenable.ts
index 633c7e8..d12cdfa 100644
--- a/src/concurrency/lazy-thenable.ts
+++ b/src/concurrency/lazy-thenable.ts
@@ -1,11 +1,15 @@
-export function lazyThenable<T>(action: () => PromiseLike<T>): PromiseLike<T> {
+/**
+ * create a lazy, at-most-once PromiseLike from async function
+ * @param io
+ */
+export function lazyThenable<T>(io: () => PromiseLike<T>): PromiseLike<T> {
   let r: null | Promise<T> = null;
   return {
     then<TResult1, TResult2 = never>(
       onfulfilled?: ((value: T) => PromiseLike<TResult1> | TResult1) | undefined | null,
       onrejected?: ((reason: any) => PromiseLike<TResult2> | TResult2) | undefined | null,
     ): PromiseLike<TResult1 | TResult2> {
-      return (r ??= Promise.resolve(action())).then(onfulfilled, onrejected);
+      return (r ??= Promise.resolve(io())).then(onfulfilled, onrejected);
     },
   };
 }
diff --git a/src/concurrency/lease.ts b/src/concurrency/lease.ts
new file mode 100644
index 0000000..03e994a
--- /dev/null
+++ b/src/concurrency/lease.ts
@@ -0,0 +1,8 @@
+/**
+ * An acquired lock or resource
+ */
+export interface Lease<T> {
+  value: T;
+  dispose(): PromiseLike<void>;
+  [Symbol.asyncDispose](): PromiseLike<void>;
+}
diff --git a/src/concurrency/lockable.ts b/src/concurrency/lockable.ts
new file mode 100644
index 0000000..e69de29
diff --git a/src/concurrency/locks/lockable.spec.ts b/src/concurrency/locks/lockable.spec.ts
deleted file mode 100644
index 9739d84..0000000
--- a/src/concurrency/locks/lockable.spec.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-describe('ResourcePool lock', () => {
-  it.todo('');
-});
diff --git a/src/concurrency/locks/lockable.ts b/src/concurrency/locks/lockable.ts
deleted file mode 100644
index da8c236..0000000
--- a/src/concurrency/locks/lockable.ts
+++ /dev/null
@@ -1,11 +0,0 @@
-import { ResourcePool } from '../resource-pool';
-
-export class LockableError extends Error {
-  static A = class L2 extends LockableError {};
-}
-
-export interface Lease<T> {
-  value: T;
-  // close(): Promise<void>;
-  [Symbol.asyncDispose](): Promise<void>;
-}
diff --git a/src/concurrency/resource-pool.ts b/src/concurrency/resource-pool.ts
index e0fc940..60a41e7 100644
--- a/src/concurrency/resource-pool.ts
+++ b/src/concurrency/resource-pool.ts
@@ -5,7 +5,7 @@
  * - NOT supported: replace / refresh / timeout of tasks
  */
 import { wait } from './timing';
-import { Lease } from './locks/lockable';
+import { Lease } from './lease';
 import { lazyThenable } from './lazy-thenable';
 
 export class ResourcePool<T> {
@@ -41,7 +41,7 @@ export class ResourcePool<T> {
 
   async use<R>(task: (res: T) => R): Promise<Awaited<R>> {
     await using lease = await this.borrow();
-    return await task(lease.value);
+    return /* must not omit 'await' here */ await task(lease.value);
   }
 
   tryUse<R>(task: (res: T | null) => R): R | Promise<Awaited<R>> {
@@ -85,7 +85,8 @@ export class ResourcePool<T> {
     }
   }
 
-  async borrow(timeout?: number): Promise<Lease<T>> {
+  async borrow(): Promise<Lease<T>> {
+    // TODO: implement timeout
     const v = await this._borrow();
 
     // console.log('borrowed', v);
@@ -97,8 +98,11 @@ export class ResourcePool<T> {
 
     return {
       value: v,
-      [Symbol.asyncDispose]: async () => {
-        await _return;
+      dispose(): PromiseLike<void> {
+        return _return;
+      },
+      [Symbol.asyncDispose]() {
+        return _return;
       },
     };
   }