From dcca4d075ac40d12272585578eae841896a069a3 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 12 Dec 2024 11:46:09 +0100
Subject: [PATCH] Polyfill `AbortSignal.any` in PDF.js `legacy` builds

With recent changes, in particular PR 19216, we're now relying on `AbortSignal.any` in a way that cannot just be skipped with pre-processor statements as done previously.
This is problematical since `AbortSignal.any` is fairly new functionality, see https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal/any_static#browser_compatibility, that's not available in all browsers that we support.

Instead it seems that we need to add a polyfill, however I unfortunately wasn't able to find one on NPM. In fact the only one I could find was https://gist.github.com/CNSeniorious000/9fc1a72e45358dd7c9e2f16e5d26df5c, which doesn't contain any licensing information.

*Note:* Given the use of pre-processor statements, this polfill will *not* be included in the Firefox PDF Viewer.
---
 src/shared/util.js | 64 ++++++++++++++++++++++++++++++++++++++++++++++
 web/app.js         |  8 ++----
 web/pdf_viewer.js  | 14 ++--------
 3 files changed, 68 insertions(+), 18 deletions(-)

diff --git a/src/shared/util.js b/src/shared/util.js
index e0f66716ab9ca..58b4bf9443abf 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -1125,6 +1125,70 @@ if (
   };
 }
 
+if (
+  typeof PDFJSDev !== "undefined" &&
+  !PDFJSDev.test("SKIP_BABEL") &&
+  typeof AbortSignal.any !== "function"
+) {
+  /**
+   * This polyfill is based on https://gist.github.com/CNSeniorious000/9fc1a72e45358dd7c9e2f16e5d26df5c
+   * which has no licensing information available.
+   *
+   * The following changes have been made:
+   *  - Removal of commented out code.
+   *  - Removal of test-only `count` variable and related code/logging.
+   *  - Renaming of variable in `clear` function, to avoid variable shadowing.
+   */
+  const registry = new FinalizationRegistry(callback => void callback());
+
+  AbortSignal.any = function polyfillAbortSignalAny(signals) {
+    const controller = new AbortController();
+    for (const signal of signals) {
+      if (signal.aborted) {
+        controller.abort(signal.reason);
+        return controller.signal;
+      }
+    }
+    const controllerRef = new WeakRef(controller);
+    /** @type {[WeakRef<AbortSignal>, (() => void)][]} */
+    const eventListenerPairs = [];
+    let followingCount = signals.length;
+
+    signals.forEach(signal => {
+      const signalRef = new WeakRef(signal);
+      function abort() {
+        controllerRef.deref()?.abort(signalRef.deref()?.reason);
+      }
+      signal.addEventListener("abort", abort);
+      eventListenerPairs.push([signalRef, abort]);
+      registry.register(signal, () => !--followingCount && clear(), signal);
+    });
+    function clear() {
+      eventListenerPairs.forEach(([signalRef, abort]) => {
+        const signal = signalRef.deref();
+        if (signal) {
+          signal.removeEventListener("abort", abort);
+          registry.unregister(signal);
+        }
+        const cntlr = controllerRef.deref();
+        if (cntlr) {
+          registry.unregister(cntlr.signal);
+          delete cntlr.signal.__controller;
+        }
+      });
+    }
+
+    const { signal } = controller;
+
+    registry.register(signal, clear, signal);
+    signal.addEventListener("abort", clear);
+
+    signal.__controller = controller;
+
+    return signal;
+  };
+}
+
 export {
   AbortException,
   AnnotationActionEventType,
diff --git a/web/app.js b/web/app.js
index d23a04f2cc5a2..2dc9e4503a39f 100644
--- a/web/app.js
+++ b/web/app.js
@@ -531,11 +531,7 @@ const PDFViewerApplication = {
     }
 
     if (appConfig.annotationEditorParams) {
-      if (
-        ((typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
-          typeof AbortSignal.any === "function") &&
-        annotationEditorMode !== AnnotationEditorType.DISABLE
-      ) {
+      if (annotationEditorMode !== AnnotationEditorType.DISABLE) {
         this.annotationEditorParams = new AnnotationEditorParams(
           appConfig.annotationEditorParams,
           eventBus
@@ -2046,7 +2042,7 @@ const PDFViewerApplication = {
 
     this._touchManager = new TouchManager({
       container: window,
-      isPinchingDisabled: () => this.pdfViewer.isInPresentationMode,
+      isPinchingDisabled: () => pdfViewer.isInPresentationMode,
       isPinchingStopped: () => this.overlayManager?.active,
       onPinching: this.touchPinchCallback.bind(this),
       onPinchEnd: this.touchPinchEndCallback.bind(this),
diff --git a/web/pdf_viewer.js b/web/pdf_viewer.js
index e968db3f14810..2b7f4323fa542 100644
--- a/web/pdf_viewer.js
+++ b/web/pdf_viewer.js
@@ -686,13 +686,7 @@ class PDFViewer {
           hiddenCapability.resolve();
         }
       },
-      {
-        signal:
-          (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
-          typeof AbortSignal.any === "function"
-            ? AbortSignal.any([signal, ac.signal])
-            : signal,
-      }
+      { signal: AbortSignal.any([signal, ac.signal]) }
     );
 
     await Promise.race([
@@ -889,11 +883,7 @@ class PDFViewer {
           viewer.before(element);
         }
 
-        if (
-          ((typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
-            typeof AbortSignal.any === "function") &&
-          annotationEditorMode !== AnnotationEditorType.DISABLE
-        ) {
+        if (annotationEditorMode !== AnnotationEditorType.DISABLE) {
           const mode = annotationEditorMode;
 
           if (pdfDocument.isPureXfa) {