From 2b53602d3c798b68db4ce986546d3434b986096a Mon Sep 17 00:00:00 2001
From: Benjamin Gruenbaum <benjamingr@gmail.com>
Date: Fri, 6 Aug 2021 20:21:29 +0300
Subject: [PATCH] feat: support AbortSignal in writeFile (#11568)

---
 cli/dts/lib.deno.ns.d.ts          |  6 ++++++
 cli/tests/unit/write_file_test.ts | 36 +++++++++++++++++++++++++++++++
 runtime/js/40_write_file.js       | 10 ++++++++-
 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/cli/dts/lib.deno.ns.d.ts b/cli/dts/lib.deno.ns.d.ts
index b0c56591bb..8aa478f12f 100644
--- a/cli/dts/lib.deno.ns.d.ts
+++ b/cli/dts/lib.deno.ns.d.ts
@@ -1714,6 +1714,12 @@ declare namespace Deno {
     create?: boolean;
     /** Permissions always applied to file. */
     mode?: number;
+    /**
+     * An abort signal to allow cancellation of the file write operation.
+     * If the signal becomes aborted the writeFile operation will be stopped
+     * and the promise returned will be rejected with an AbortError.
+     */
+    signal?: AbortSignal;
   }
 
   /** Synchronously write `data` to the given `path`, by default creating a new
diff --git a/cli/tests/unit/write_file_test.ts b/cli/tests/unit/write_file_test.ts
index 4c4cecf430..c4c4377080 100644
--- a/cli/tests/unit/write_file_test.ts
+++ b/cli/tests/unit/write_file_test.ts
@@ -239,3 +239,39 @@ unitTest(
     assertEquals("Hello", actual);
   },
 );
+
+unitTest(
+  { perms: { read: true, write: true } },
+  async function writeFileAbortSignal(): Promise<void> {
+    const ac = new AbortController();
+    const enc = new TextEncoder();
+    const data = enc.encode("Hello");
+    const filename = Deno.makeTempDirSync() + "/test.txt";
+    queueMicrotask(() => ac.abort());
+    try {
+      await Deno.writeFile(filename, data, { signal: ac.signal });
+    } catch (e) {
+      assertEquals(e.name, "AbortError");
+    }
+    const stat = Deno.statSync(filename);
+    assertEquals(stat.size, 0);
+  },
+);
+
+unitTest(
+  { perms: { read: true, write: true } },
+  async function writeFileAbortSignalPreAborted(): Promise<void> {
+    const ac = new AbortController();
+    ac.abort();
+    const enc = new TextEncoder();
+    const data = enc.encode("Hello");
+    const filename = Deno.makeTempDirSync() + "/test.txt";
+    try {
+      await Deno.writeFile(filename, data, { signal: ac.signal });
+    } catch (e) {
+      assertEquals(e.name, "AbortError");
+    }
+    const stat = Deno.statSync(filename);
+    assertEquals(stat.size, 0);
+  },
+);
diff --git a/runtime/js/40_write_file.js b/runtime/js/40_write_file.js
index def9f6fee4..6ced4e0669 100644
--- a/runtime/js/40_write_file.js
+++ b/runtime/js/40_write_file.js
@@ -13,6 +13,9 @@
     data,
     options = {},
   ) {
+    if (options?.signal?.aborted) {
+      throw new DOMException("The write operation was aborted.", "AbortError");
+    }
     if (options.create !== undefined) {
       const create = !!options.create;
       if (!create) {
@@ -68,12 +71,17 @@
       await chmod(path, options.mode);
     }
 
+    const signal = options?.signal ?? null;
     let nwritten = 0;
-    while (nwritten < data.length) {
+    while (!signal?.aborted && nwritten < data.length) {
       nwritten += await file.write(TypedArrayPrototypeSubarray(data, nwritten));
     }
 
     file.close();
+
+    if (signal?.aborted) {
+      throw new DOMException("The write operation was aborted.", "AbortError");
+    }
   }
 
   function writeTextFileSync(