1 files changed, 123 insertions, 0 deletions
diff --git a/ext/web/03_abort_signal.js b/ext/web/03_abort_signal.js
new file mode 100644
index 000000000..d67bfef26
--- /dev/null
+++ b/ext/web/03_abort_signal.js
@@ -0,0 +1,123 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+"use strict";
+
+// @ts-check
+/// <reference path="../../core/internal.d.ts" />
+
+((window) => {
+  const webidl = window.__bootstrap.webidl;
+  const { setIsTrusted, defineEventHandler } = window.__bootstrap.event;
+  const {
+    Boolean,
+    Set,
+    SetPrototypeAdd,
+    SetPrototypeClear,
+    SetPrototypeDelete,
+    Symbol,
+    SymbolToStringTag,
+    TypeError,
+  } = window.__bootstrap.primordials;
+
+  const add = Symbol("add");
+  const signalAbort = Symbol("signalAbort");
+  const remove = Symbol("remove");
+
+  const illegalConstructorKey = Symbol("illegalConstructorKey");
+
+  class AbortSignal extends EventTarget {
+    #aborted = false;
+    #abortAlgorithms = new Set();
+
+    static abort() {
+      const signal = new AbortSignal(illegalConstructorKey);
+      signal[signalAbort]();
+      return signal;
+    }
+
+    [add](algorithm) {
+      SetPrototypeAdd(this.#abortAlgorithms, algorithm);
+    }
+
+    [signalAbort]() {
+      if (this.#aborted) {
+        return;
+      }
+      this.#aborted = true;
+      for (const algorithm of this.#abortAlgorithms) {
+        algorithm();
+      }
+      SetPrototypeClear(this.#abortAlgorithms);
+      const event = new Event("abort");
+      setIsTrusted(event, true);
+      this.dispatchEvent(event);
+    }
+
+    [remove](algorithm) {
+      SetPrototypeDelete(this.#abortAlgorithms, algorithm);
+    }
+
+    constructor(key = null) {
+      if (key != illegalConstructorKey) {
+        throw new TypeError("Illegal constructor.");
+      }
+      super();
+      this[webidl.brand] = webidl.brand;
+    }
+
+    get aborted() {
+      return Boolean(this.#aborted);
+    }
+
+    get [SymbolToStringTag]() {
+      return "AbortSignal";
+    }
+  }
+  defineEventHandler(AbortSignal.prototype, "abort");
+
+  webidl.configurePrototype(AbortSignal);
+
+  class AbortController {
+    #signal = new AbortSignal(illegalConstructorKey);
+
+    get signal() {
+      return this.#signal;
+    }
+
+    abort() {
+      this.#signal[signalAbort]();
+    }
+
+    get [SymbolToStringTag]() {
+      return "AbortController";
+    }
+  }
+
+  webidl.configurePrototype(AbortController);
+
+  webidl.converters["AbortSignal"] = webidl.createInterfaceConverter(
+    "AbortSignal",
+    AbortSignal,
+  );
+
+  function newSignal() {
+    return new AbortSignal(illegalConstructorKey);
+  }
+
+  function follow(followingSignal, parentSignal) {
+    if (parentSignal.aborted) {
+      followingSignal[signalAbort]();
+    } else {
+      parentSignal[add](() => followingSignal[signalAbort]());
+    }
+  }
+
+  window.AbortSignal = AbortSignal;
+  window.AbortController = AbortController;
+  window.__bootstrap.abortSignal = {
+    add,
+    signalAbort,
+    remove,
+    follow,
+    newSignal,
+  };
+})(this);