From b9b69bac339adad49bfc0cac94159b87697c94c7 Mon Sep 17 00:00:00 2001
From: Marco Bubke <marco.bubke@qt.io>
Date: Tue, 18 Jul 2017 17:37:08 +0200
Subject: [PATCH] TextEditor: Disconnect highlighting from text editor content
 changes

The syntax highligher is connected to the content changes of the text
editor which is not very useful if the diagnostics been provided by
an asynchronous mechanism. So we add a setter to disconnect the changes
from the syntax highlighter.

Change-Id: Ied4b5fe34000b13bafb1aa177b89befe6620d4d7
Reviewed-by: David Schulz <david.schulz@qt.io>
---
 src/plugins/texteditor/syntaxhighlighter.cpp | 27 ++++++++++++++------
 src/plugins/texteditor/syntaxhighlighter.h   |  2 ++
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/plugins/texteditor/syntaxhighlighter.cpp b/src/plugins/texteditor/syntaxhighlighter.cpp
index ebe2d9aaeb5..13bc6bba30e 100644
--- a/src/plugins/texteditor/syntaxhighlighter.cpp
+++ b/src/plugins/texteditor/syntaxhighlighter.cpp
@@ -43,11 +43,10 @@ namespace TextEditor {
 
 class SyntaxHighlighterPrivate
 {
-    SyntaxHighlighter *q_ptr;
+    SyntaxHighlighter *q_ptr = nullptr;
     Q_DECLARE_PUBLIC(SyntaxHighlighter)
 public:
-    inline SyntaxHighlighterPrivate()
-        : q_ptr(0), rehighlightPending(false), inReformatBlocks(false)
+    SyntaxHighlighterPrivate()
     {
         updateFormats(TextEditorSettings::fontSettings());
     }
@@ -70,12 +69,13 @@ public:
 
     QVector<QTextCharFormat> formatChanges;
     QTextBlock currentBlock;
-    bool rehighlightPending;
-    bool inReformatBlocks;
+    bool rehighlightPending = false;
+    bool inReformatBlocks = false;
     TextDocumentLayout::FoldValidator foldValidator;
     QVector<QTextCharFormat> formats;
     QVector<std::pair<int,TextStyle>> formatCategories;
     QTextCharFormat whitespaceFormat;
+    bool noAutomaticHighlighting = false;
 };
 
 static bool adjustRange(QTextLayout::FormatRange &range, int from, int charsRemoved, int charsAdded) {
@@ -315,9 +315,11 @@ void SyntaxHighlighter::setDocument(QTextDocument *doc)
     }
     d->doc = doc;
     if (d->doc) {
-        connect(d->doc, &QTextDocument::contentsChange, this, &SyntaxHighlighter::reformatBlocks);
-        d->rehighlightPending = true;
-        QTimer::singleShot(0, this, &SyntaxHighlighter::delayedRehighlight);
+        if (!d->noAutomaticHighlighting) {
+            connect(d->doc, &QTextDocument::contentsChange, this, &SyntaxHighlighter::reformatBlocks);
+            d->rehighlightPending = true;
+            QTimer::singleShot(0, this, &SyntaxHighlighter::delayedRehighlight);
+        }
         d->foldValidator.setup(qobject_cast<TextDocumentLayout *>(doc->documentLayout()));
     }
 }
@@ -764,6 +766,15 @@ void SyntaxHighlighter::setFontSettings(const FontSettings &fontSettings)
     Q_D(SyntaxHighlighter);
     d->updateFormats(fontSettings);
 }
+/*!
+    The syntax highlighter is not anymore reacting to the text document if \a noAutmatic is
+    \c true.
+*/
+void SyntaxHighlighter::setNoAutomaticHighlighting(bool noAutomatic)
+{
+    Q_D(SyntaxHighlighter);
+    d->noAutomaticHighlighting = noAutomatic;
+}
 
 /*!
     Creates text format categories for the text styles themselves, so the highlighter can
diff --git a/src/plugins/texteditor/syntaxhighlighter.h b/src/plugins/texteditor/syntaxhighlighter.h
index 56f526f04b1..629fe29b997 100644
--- a/src/plugins/texteditor/syntaxhighlighter.h
+++ b/src/plugins/texteditor/syntaxhighlighter.h
@@ -70,6 +70,8 @@ public:
     // Don't call in constructors of derived classes
     virtual void setFontSettings(const TextEditor::FontSettings &fontSettings);
 
+    void setNoAutomaticHighlighting(bool noAutomatic);
+
 public slots:
     void rehighlight();
     void rehighlightBlock(const QTextBlock &block);