lib: implement AbortSignal.any()

doc/api/globals.md

@@ -121,6 +121,18 @@ added:
 
 Returns a new `AbortSignal` which will be aborted in `delay` milliseconds.
 
+#### Static method: `AbortSignal.any(signals)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `signals` {Array} The `AbortSignal`s of which to compose a new `AbortSignal`.
+
+Returns a new `AbortSignal` which will be aborted if any of the provided
+signals are aborted. Its [`abortSignal.reason`][] will be set to whichever
+one of the `signals` caused it to be aborted.
+
 #### Event: `'abort'`
 
 <!-- YAML
@@ -1020,6 +1032,7 @@ A browser-compatible implementation of [`WritableStreamDefaultWriter`][].
 [`WritableStream`]: webstreams.md#class-writablestream
 [`__dirname`]: modules.md#__dirname
 [`__filename`]: modules.md#__filename
+[`abortSignal.reason`]: #abortSignal.reason
 [`buffer.atob()`]: buffer.md#bufferatobdata
 [`buffer.btoa()`]: buffer.md#bufferbtoadata
 [`clearImmediate`]: timers.md#clearimmediateimmediate

lib/internal/abort_controller.js

@@ -42,6 +42,7 @@ const {
 
 const {
   validateAbortSignal,
+  validateAbortSignalArray,
   validateObject,
   validateUint32,
 } = require('internal/validators');
@@ -54,6 +55,7 @@ const {
   clearTimeout,
   setTimeout,
 } = require('timers');
+const assert = require('internal/assert');
 
 const {
   messaging_deserialize_symbol: kDeserialize,
@@ -80,13 +82,16 @@ function lazyMakeTransferable(obj) {
 }
 
 const clearTimeoutRegistry = new SafeFinalizationRegistry(clearTimeout);
-const timeOutSignals = new SafeSet();
+const gcPersistentSignals = new SafeSet();
 
 const kAborted = Symbol('kAborted');
 const kReason = Symbol('kReason');
 const kCloneData = Symbol('kCloneData');
 const kTimeout = Symbol('kTimeout');
 const kMakeTransferable = Symbol('kMakeTransferable');
+const kComposite = Symbol('kComposite');
+const kSourceSignals = Symbol('kSourceSignals');
+const kDependantSignals = Symbol('kDependantSignals');
 
 function customInspect(self, obj, depth, options) {
   if (depth < 0)
@@ -116,7 +121,7 @@ function setWeakAbortSignalTimeout(weakRef, delay) {
   const timeout = setTimeout(() => {
     const signal = weakRef.deref();
     if (signal !== undefined) {
-      timeOutSignals.delete(signal);
+      gcPersistentSignals.delete(signal);
       abortSignal(
         signal,
         new DOMException(
@@ -185,25 +190,69 @@ class AbortSignal extends EventTarget {
     return signal;
   }
 
+  /**
+   * @param {AbortSignal[]} signals
+   * @returns {AbortSignal}
+   */
+  static any(signals) {
+    validateAbortSignalArray(signals, 'signals');
+    const resultSignal = createAbortSignal({ composite: true });
+    const resultSignalWeakRef = new WeakRef(resultSignal);
+    for (let i = 0; i < signals.length; i++) {
+      const signal = signals[i];
+      if (signal.aborted) {
+        abortSignal(resultSignal, signal.reason);
+        return resultSignal;
+      }
+      resultSignal[kSourceSignals] ??= new SafeSet();
+      signal[kDependantSignals] ??= new SafeSet();
+      if (!signal[kComposite]) {
+        resultSignal[kSourceSignals].add(new WeakRef(signal));
+        signal[kDependantSignals].add(resultSignalWeakRef);
+      } else {
+        if (!signal[kSourceSignals]) {
+          continue;
+        }
+        for (const sourceSignal of signal[kSourceSignals]) {
+          const sourceSignalRef = sourceSignal.deref();
+          if (!sourceSignalRef) {
+            continue;
+          }
+          assert(!sourceSignalRef.aborted);
+          assert(!sourceSignalRef[kComposite]);
+
+          if (resultSignal[kSourceSignals].has(sourceSignal)) {
+            continue;
+          }
+          resultSignal[kSourceSignals].add(sourceSignal);
+          sourceSignalRef[kDependantSignals].add(resultSignalWeakRef);
+        }
+      }
+    }
+    return resultSignal;
+  }
+
   [kNewListener](size, type, listener, once, capture, passive, weak) {
     super[kNewListener](size, type, listener, once, capture, passive, weak);
-    if (this[kTimeout] &&
+    const isTimeoutOrNonEmptyCompositeSignal = this[kTimeout] || (this[kComposite] && this[kSourceSignals]?.size);
+    if (isTimeoutOrNonEmptyCompositeSignal &&
         type === 'abort' &&
         !this.aborted &&
         !weak &&
         size === 1) {
-      // If this is a timeout signal, and we're adding a non-weak abort
+      // If this is a timeout signal, or a non-empty composite signal, and we're adding a non-weak abort
       // listener, then we don't want it to be gc'd while the listener
       // is attached and the timer still hasn't fired. So, we retain a
       // strong ref that is held for as long as the listener is registered.
-      timeOutSignals.add(this);
+      gcPersistentSignals.add(this);
     }
   }
 
   [kRemoveListener](size, type, listener, capture) {
     super[kRemoveListener](size, type, listener, capture);
-    if (this[kTimeout] && type === 'abort' && size === 0) {
-      timeOutSignals.delete(this);
+    const isTimeoutOrNonEmptyCompositeSignal = this[kTimeout] || (this[kComposite] && this[kSourceSignals]?.size);
+    if (isTimeoutOrNonEmptyCompositeSignal && type === 'abort' && size === 0) {
+      gcPersistentSignals.delete(this);
     }
   }
 
@@ -287,7 +336,8 @@ defineEventHandler(AbortSignal.prototype, 'abort');
  * @param {{
  *   aborted? : boolean,
  *   reason? : any,
- *   transferable? : boolean
+ *   transferable? : boolean,
+ *   composite? : boolean,
  * }} [init]
  * @returns {AbortSignal}
  */
@@ -296,11 +346,13 @@ function createAbortSignal(init = kEmptyObject) {
     aborted = false,
     reason = undefined,
     transferable = false,
+    composite = false,
   } = init;
   const signal = new EventTarget();
   ObjectSetPrototypeOf(signal, AbortSignal.prototype);
   signal[kAborted] = aborted;
   signal[kReason] = reason;
+  signal[kComposite] = composite;
   return transferable ? lazyMakeTransferable(signal) : signal;
 }
 
@@ -312,6 +364,11 @@ function abortSignal(signal, reason) {
     [kTrustEvent]: true,
   });
   signal.dispatchEvent(event);
+  signal[kDependantSignals]?.forEach((s) => {
+    const signalRef = s.deref();
+    if (!signalRef) return;
+    abortSignal(signalRef, reason);
+  });
 }
 
 class AbortController {

lib/internal/validators.js

@@ -324,6 +324,26 @@ function validateBooleanArray(value, name) {
   }
 }
 
+/**
+ * @callback validateAbortSignalArray
+ * @param {*} value
+ * @param {string} name
+ * @returns {asserts value is AbortSignal[]}
+ */
+
+/** @type {validateAbortSignalArray} */
+function validateAbortSignalArray(value, name) {
+  validateArray(value, name);
+  for (let i = 0; i < value.length; i++) {
+    const signal = value[i];
+    const indexedName = `${name}[${i}]`;
+    if (signal == null) {
+      throw new ERR_INVALID_ARG_TYPE(indexedName, 'AbortSignal', signal);
+    }
+    validateAbortSignal(signal, indexedName);
+  }
+}
+
 /**
  * @param {*} signal
  * @param {string} [name='signal']
@@ -534,6 +554,7 @@ module.exports = {
   validateArray,
   validateStringArray,
   validateBooleanArray,
+  validateAbortSignalArray,
   validateBoolean,
   validateBuffer,
   validateDictionary,

test/fixtures/wpt/README.md

@@ -12,7 +12,7 @@ Last update:
 
 - common: https://github.com/web-platform-tests/wpt/tree/dbd648158d/common
 - console: https://github.com/web-platform-tests/wpt/tree/767ae35464/console
-- dom/abort: https://github.com/web-platform-tests/wpt/tree/8fadb38120/dom/abort
+- dom/abort: https://github.com/web-platform-tests/wpt/tree/d1f1ecbd52/dom/abort
 - dom/events: https://github.com/web-platform-tests/wpt/tree/ab8999891c/dom/events
 - encoding: https://github.com/web-platform-tests/wpt/tree/0c1b9d1622/encoding
 - fetch/data-urls/resources: https://github.com/web-platform-tests/wpt/tree/7c79d998ff/fetch/data-urls/resources

test/fixtures/wpt/dom/abort/abort-signal-any.any.js

@@ -0,0 +1,4 @@
+// META: script=./resources/abort-signal-any-tests.js
+
+abortSignalAnySignalOnlyTests(AbortSignal);
+abortSignalAnyTests(AbortSignal, AbortController);