From 3904be888928a2941c656c353ce3b062632e94da Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 29 Jul 2016 20:51:37 +0200
Subject: [PATCH] Ensure that we cancel any pending `textLayer` rendering
 operations when the viewer is closed (issue 7274)

---
 web/app.js                |  2 +-
 web/pdf_page_view.js      |  5 +++++
 web/text_layer_builder.js | 31 ++++++++++++++++++-------------
 3 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/web/app.js b/web/app.js
index 383972f1b..ff23341da 100644
--- a/web/app.js
+++ b/web/app.js
@@ -1641,7 +1641,7 @@ function webViewerTextLayerRendered(e) {
   }
 //#endif
 //#if (FIREFOX || MOZCENTRAL)
-  if (pageView.textLayer && pageView.textLayer.textDivs &&
+  if (pageView && pageView.textLayer && pageView.textLayer.textDivs &&
       pageView.textLayer.textDivs.length > 0 &&
       !PDFViewerApplication.supportsDocumentColors) {
     console.error(mozL10n.get('document_colors_not_allowed', null,
diff --git a/web/pdf_page_view.js b/web/pdf_page_view.js
index 5d4b4926b..4d1be7233 100644
--- a/web/pdf_page_view.js
+++ b/web/pdf_page_view.js
@@ -229,6 +229,11 @@ var PDFPageView = (function PDFPageViewClosure() {
       }
       this.renderingState = RenderingStates.INITIAL;
       this.resume = null;
+
+      if (this.textLayer) {
+        this.textLayer.cancel();
+        this.textLayer = null;
+      }
     },
 
     /**
diff --git a/web/text_layer_builder.js b/web/text_layer_builder.js
index 0a03a428a..65a337af0 100644
--- a/web/text_layer_builder.js
+++ b/web/text_layer_builder.js
@@ -18,8 +18,7 @@
 (function (root, factory) {
   if (typeof define === 'function' && define.amd) {
     define('pdfjs-web/text_layer_builder', ['exports', 'pdfjs-web/dom_events',
-        'pdfjs-web/pdfjs'],
-      factory);
+        'pdfjs-web/pdfjs'], factory);
   } else if (typeof exports !== 'undefined') {
     factory(exports, require('./dom_events.js'), require('./pdfjs.js'));
   } else {
@@ -52,8 +51,8 @@ var TextLayerBuilder = (function TextLayerBuilderClosure() {
   function TextLayerBuilder(options) {
     this.textLayerDiv = options.textLayerDiv;
     this.eventBus = options.eventBus || domEvents.getGlobalEventBus();
+    this.textContent = null;
     this.renderingDone = false;
-    this.divContentDone = false;
     this.pageIdx = options.pageIndex;
     this.pageNumber = this.pageIdx + 1;
     this.matches = [];
@@ -87,14 +86,10 @@ var TextLayerBuilder = (function TextLayerBuilderClosure() {
      *   for specified amount of ms.
      */
     render: function TextLayerBuilder_render(timeout) {
-      if (!this.divContentDone || this.renderingDone) {
+      if (!this.textContent || this.renderingDone) {
         return;
       }
-
-      if (this.textLayerRenderTask) {
-        this.textLayerRenderTask.cancel();
-        this.textLayerRenderTask = null;
-      }
+      this.cancel();
 
       this.textDivs = [];
       var textLayerFrag = document.createDocumentFragment();
@@ -111,17 +106,23 @@ var TextLayerBuilder = (function TextLayerBuilderClosure() {
         this._finishRendering();
         this.updateMatches();
       }.bind(this), function (reason) {
-        // canceled or failed to render text layer -- skipping errors
+        // cancelled or failed to render text layer -- skipping errors
       });
     },
 
-    setTextContent: function TextLayerBuilder_setTextContent(textContent) {
+    /**
+     * Cancels rendering of the text layer.
+     */
+    cancel: function TextLayerBuilder_cancel() {
       if (this.textLayerRenderTask) {
         this.textLayerRenderTask.cancel();
         this.textLayerRenderTask = null;
       }
+    },
+
+    setTextContent: function TextLayerBuilder_setTextContent(textContent) {
+      this.cancel();
       this.textContent = textContent;
-      this.divContentDone = true;
     },
 
     convertMatches: function TextLayerBuilder_convertMatches(matches,
@@ -324,6 +325,7 @@ var TextLayerBuilder = (function TextLayerBuilderClosure() {
       var div = this.textLayerDiv;
       var self = this;
       var expandDivsTimer = null;
+
       div.addEventListener('mousedown', function (e) {
         if (self.enhanceTextSelection && self.textLayerRenderTask) {
           self.textLayerRenderTask.expandTextDivs(true);
@@ -357,11 +359,14 @@ var TextLayerBuilder = (function TextLayerBuilderClosure() {
 //#endif
         end.classList.add('active');
       });
+
       div.addEventListener('mouseup', function (e) {
         if (self.enhanceTextSelection && self.textLayerRenderTask) {
 //#if !(MOZCENTRAL || FIREFOX)
           expandDivsTimer = setTimeout(function() {
-            self.textLayerRenderTask.expandTextDivs(false);
+            if (self.textLayerRenderTask) {
+              self.textLayerRenderTask.expandTextDivs(false);
+            }
             expandDivsTimer = null;
           }, EXPAND_DIVS_TIMEOUT);
 //#else