From 9efc1784b20f77a93227a15d065d069b2e420482 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Wed, 23 Sep 2020 14:29:21 +0200
Subject: [PATCH] Remove the `PDFPageView.error` property, and simply include
 Errors in the "pagerendered" event instead

The way that rendering errors are handled in `PDFPageView` is *very* old, and predates e.g. the introduction of the `EventBus` by several years.
Hence we should be able to simplify things a bit here, by including the Error (when it exists) in the "pagerendered" event and thus avoid having to reach into `PDFPageView` for it.
---
 web/app.js                |  9 ++++-----
 web/pdf_page_view.js      | 11 +++++++----
 web/pdf_thumbnail_view.js |  2 +-
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/web/app.js b/web/app.js
index 6fd9d6d9f..885edab51 100644
--- a/web/app.js
+++ b/web/app.js
@@ -2126,8 +2126,7 @@ function webViewerResetPermissions() {
   appConfig.viewerContainer.classList.remove(ENABLE_PERMISSIONS_CLASS);
 }
 
-function webViewerPageRendered(evt) {
-  const pageNumber = evt.pageNumber;
+function webViewerPageRendered({ pageNumber, timestamp, error }) {
   const pageIndex = pageNumber - 1;
   const pageView = PDFViewerApplication.pdfViewer.getPageView(pageIndex);
 
@@ -2155,7 +2154,7 @@ function webViewerPageRendered(evt) {
     Stats.add(pageNumber, pageView.stats);
   }
 
-  if (pageView.error) {
+  if (error) {
     PDFViewerApplication.l10n
       .get(
         "rendering_error",
@@ -2163,13 +2162,13 @@ function webViewerPageRendered(evt) {
         "An error occurred while rendering the page."
       )
       .then(msg => {
-        PDFViewerApplication.error(msg, pageView.error);
+        PDFViewerApplication.error(msg, error);
       });
   }
 
   PDFViewerApplication.externalServices.reportTelemetry({
     type: "pageInfo",
-    timestamp: evt.timestamp,
+    timestamp,
   });
   // It is a good time to report stream and font types.
   PDFViewerApplication.pdfDocument.getStats().then(function (stats) {
diff --git a/web/pdf_page_view.js b/web/pdf_page_view.js
index 31e54ff0a..90f780df3 100644
--- a/web/pdf_page_view.js
+++ b/web/pdf_page_view.js
@@ -114,7 +114,7 @@ class PDFPageView {
     this.paintedViewportMap = new WeakMap();
     this.renderingState = RenderingStates.INITIAL;
     this.resume = null;
-    this.error = null;
+    this._renderError = null;
 
     this.annotationLayer = null;
     this.textLayer = null;
@@ -265,6 +265,7 @@ class PDFPageView {
         pageNumber: this.id,
         cssTransform: true,
         timestamp: performance.now(),
+        error: this._renderError,
       });
       return;
     }
@@ -293,6 +294,7 @@ class PDFPageView {
           pageNumber: this.id,
           cssTransform: true,
           timestamp: performance.now(),
+          error: this._renderError,
         });
         return;
       }
@@ -500,7 +502,7 @@ class PDFPageView {
       };
     }
 
-    const finishPaintTask = async error => {
+    const finishPaintTask = async (error = null) => {
       // The paintTask may have been replaced by a new one, so only remove
       // the reference to the paintTask if it matches the one that is
       // triggering this callback.
@@ -509,9 +511,10 @@ class PDFPageView {
       }
 
       if (error instanceof RenderingCancelledException) {
-        this.error = null;
+        this._renderError = null;
         return;
       }
+      this._renderError = error;
 
       this.renderingState = RenderingStates.FINISHED;
 
@@ -521,7 +524,6 @@ class PDFPageView {
       }
       this._resetZoomLayer(/* removeFromDOM = */ true);
 
-      this.error = error;
       this.stats = pdfPage.stats;
 
       this.eventBus.dispatch("pagerendered", {
@@ -529,6 +531,7 @@ class PDFPageView {
         pageNumber: this.id,
         cssTransform: false,
         timestamp: performance.now(),
+        error: this._renderError,
       });
 
       if (error) {
diff --git a/web/pdf_thumbnail_view.js b/web/pdf_thumbnail_view.js
index 685bf53b6..dddd931b5 100644
--- a/web/pdf_thumbnail_view.js
+++ b/web/pdf_thumbnail_view.js
@@ -317,7 +317,7 @@ class PDFThumbnailView {
     this.renderingState = RenderingStates.RUNNING;
 
     const renderCapability = createPromiseCapability();
-    const finishRenderTask = error => {
+    const finishRenderTask = (error = null) => {
       // The renderTask may have been replaced by a new one, so only remove
       // the reference to the renderTask if it matches the one that is
       // triggering this callback.