From 2e044bf646890665767c049c69a4f22bb5c2cc65 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Tue, 19 Mar 2019 10:45:27 +0100
Subject: [PATCH] Prepare the `MOZCENTRAL` viewer for receiving zoom events
 from the browser UI (bug 786674, bug 1177385)

This lays the necessary foundation for handling zoom events originating within the browser itself, rather than in the viewer. Please note that this will also require a follow-up patch to `mozilla-central`, such that the viewer is actually notified when zooming occurs.
---
 web/app.js        | 21 +++++++++++++++++++--
 web/firefoxcom.js | 25 +++++++++++++++++++++++--
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/web/app.js b/web/app.js
index da99a55f2..feb06389c 100644
--- a/web/app.js
+++ b/web/app.js
@@ -431,6 +431,18 @@ let PDFViewerApplication = {
     this.pdfViewer.currentScaleValue = newScale;
   },
 
+  zoomReset(ignoreDuplicate = false) {
+    if (this.pdfViewer.isInPresentationMode) {
+      return;
+    } else if (ignoreDuplicate &&
+               this.pdfViewer.currentScaleValue === DEFAULT_SCALE_VALUE) {
+      // Avoid attempting to needlessly reset the zoom level *twice* in a row,
+      // when using the `Ctrl + 0` keyboard shortcut in `MOZCENTRAL` builds.
+      return;
+    }
+    this.pdfViewer.currentScaleValue = DEFAULT_SCALE_VALUE;
+  },
+
   get pagesCount() {
     return this.pdfDocument ? this.pdfDocument.numPages : 0;
   },
@@ -1343,6 +1355,7 @@ let PDFViewerApplication = {
     eventBus.on('previouspage', webViewerPreviousPage);
     eventBus.on('zoomin', webViewerZoomIn);
     eventBus.on('zoomout', webViewerZoomOut);
+    eventBus.on('zoomreset', webViewerZoomReset);
     eventBus.on('pagenumberchanged', webViewerPageNumberChanged);
     eventBus.on('scalechanged', webViewerScaleChanged);
     eventBus.on('rotatecw', webViewerRotateCw);
@@ -1417,6 +1430,7 @@ let PDFViewerApplication = {
     eventBus.off('previouspage', webViewerPreviousPage);
     eventBus.off('zoomin', webViewerZoomIn);
     eventBus.off('zoomout', webViewerZoomOut);
+    eventBus.off('zoomreset', webViewerZoomReset);
     eventBus.off('pagenumberchanged', webViewerPageNumberChanged);
     eventBus.off('scalechanged', webViewerScaleChanged);
     eventBus.off('rotatecw', webViewerRotateCw);
@@ -1940,6 +1954,9 @@ function webViewerZoomIn() {
 function webViewerZoomOut() {
   PDFViewerApplication.zoomOut();
 }
+function webViewerZoomReset(evt) {
+  PDFViewerApplication.zoomReset(evt && evt.ignoreDuplicate);
+}
 function webViewerPageNumberChanged(evt) {
   let pdfViewer = PDFViewerApplication.pdfViewer;
   // Note that for `<input type="number">` HTML elements, an empty string will
@@ -2189,9 +2206,9 @@ function webViewerKeyDown(evt) {
       case 96: // '0' on Numpad of Swedish keyboard
         if (!isViewerInPresentationMode) {
           // keeping it unhandled (to restore page zoom to 100%)
-          setTimeout(function () {
+          setTimeout(function() {
             // ... and resetting the scale after browser adjusts its scale
-            pdfViewer.currentScaleValue = DEFAULT_SCALE_VALUE;
+            PDFViewerApplication.zoomReset();
           });
           handled = false;
         }
diff --git a/web/firefoxcom.js b/web/firefoxcom.js
index e8432b75a..7039d8e45 100644
--- a/web/firefoxcom.js
+++ b/web/firefoxcom.js
@@ -171,7 +171,7 @@ class MozL10n {
     'findentirewordchange',
     'findbarclose',
   ];
-  let handleEvent = function({ type, detail, }) {
+  const handleEvent = function({ type, detail, }) {
     if (!PDFViewerApplication.initialized) {
       return;
     }
@@ -193,7 +193,28 @@ class MozL10n {
     });
   };
 
-  for (let event of events) {
+  for (const event of events) {
+    window.addEventListener(event, handleEvent);
+  }
+})();
+
+(function listenZoomEvents() {
+  const events = [
+    'zoomin',
+    'zoomout',
+    'zoomreset',
+  ];
+  const handleEvent = function({ type, detail, }) {
+    if (!PDFViewerApplication.initialized) {
+      return;
+    }
+    PDFViewerApplication.eventBus.dispatch(type, {
+      source: window,
+      ignoreDuplicate: (type === 'zoomreset' ? true : undefined),
+    });
+  };
+
+  for (const event of events) {
     window.addEventListener(event, handleEvent);
   }
 })();