From 1dd0c173e20ec011518d8277df6188a03a4cba63 Mon Sep 17 00:00:00 2001
From: Jan Odvarko <odvarko@gmail.com>
Date: Fri, 19 Oct 2018 14:21:23 +0000
Subject: [PATCH] Bug 1477252 - Check whether editor is destroyed before using
 it; review=nchevobbe r=nchevobbe

Differential Revision: https://phabricator.services.mozilla.com/D9251

--HG--
extra : moz-landing-system : lando
---
 .../netmonitor/src/components/SourceEditor.js       | 13 +++++++++++++
 devtools/client/sourceeditor/editor.js              |  4 ++++
 2 files changed, 17 insertions(+)

diff --git a/devtools/client/netmonitor/src/components/SourceEditor.js b/devtools/client/netmonitor/src/components/SourceEditor.js
index 566f6886535b..ebb757f29c62 100644
--- a/devtools/client/netmonitor/src/components/SourceEditor.js
+++ b/devtools/client/netmonitor/src/components/SourceEditor.js
@@ -38,11 +38,14 @@ class SourceEditor extends Component {
 
     // Delay to CodeMirror initialization content to prevent UI freezing
     this.editorTimeout = setTimeout(() => {
+      this.editorTimeout = null;
       this.editor.appendToLocalElement(this.refs.editorElement);
+
       // CodeMirror's setMode() (syntax highlight) is the performance bottleneck when
       // processing large content, so we enable it asynchronously within the setTimeout
       // to avoid UI blocking. (rendering source code -> drawing syntax highlight)
       this.editorSetModeTimeout = setTimeout(() => {
+        this.editorSetModeTimeout = null;
         this.editor.setMode(mode);
       });
     });
@@ -55,16 +58,26 @@ class SourceEditor extends Component {
   componentDidUpdate(prevProps) {
     const { mode, text } = this.props;
 
+    // Bail out if the editor has been destroyed in the meantime.
+    if (this.editor.isDestroyed()) {
+      return;
+    }
+
     if (prevProps.text !== text) {
       // Reset the existed 'mode' attribute in order to make setText() process faster
       // to prevent drawing unnecessary syntax highlight.
       this.editor.setMode(null);
       this.editor.setText(text);
 
+      if (this.editorSetModeTimeout) {
+        clearTimeout(this.editorSetModeTimeout);
+      }
+
       // CodeMirror's setMode() (syntax highlight) is the performance bottleneck when
       // processing large content, so we enable it asynchronously within the setTimeout
       // to avoid UI blocking. (rendering source code -> drawing syntax highlight)
       this.editorSetModeTimeout = setTimeout(() => {
+        this.editorSetModeTimeout = null;
         this.editor.setMode(mode);
       });
     }
diff --git a/devtools/client/sourceeditor/editor.js b/devtools/client/sourceeditor/editor.js
index 57a9e3f9e30d..3c7d4313765d 100644
--- a/devtools/client/sourceeditor/editor.js
+++ b/devtools/client/sourceeditor/editor.js
@@ -1331,6 +1331,10 @@ Editor.prototype = {
     });
   },
 
+  isDestroyed: function() {
+    return !editors.get(this);
+  },
+
   destroy: function() {
     this.container = null;
     this.config = null;