minor optimization: don't mark contents as dirty if nothing was changed

Merge-request: 481
Reviewed-by: Thorbjørn Lindeijer <thorbjorn.lindeijer@nokia.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/src/gui/text/qsyntaxhighlighter.cpp b/src/gui/text/qsyntaxhighlighter.cpp
index d3db2a1..28af5bb 100644
--- a/src/gui/text/qsyntaxhighlighter.cpp
+++ b/src/gui/text/qsyntaxhighlighter.cpp
@@ -95,6 +95,8 @@ public:
 
 void QSyntaxHighlighterPrivate::applyFormatChanges()
 {
+    bool formatsChanged = false;
+
     QTextLayout *layout = currentBlock.layout();
 
     QList<QTextLayout::FormatRange> ranges = layout->additionalFormats();
@@ -110,6 +112,7 @@ void QSyntaxHighlighterPrivate::applyFormatChanges()
                 ++it;
             } else {
                 it = ranges.erase(it);
+                formatsChanged = true;
             }
         }
     }
@@ -147,6 +150,7 @@ void QSyntaxHighlighterPrivate::applyFormatChanges()
         }
 
         ranges << r;
+        formatsChanged = true;
         r.start = -1;
     }
 
@@ -161,9 +165,13 @@ void QSyntaxHighlighterPrivate::applyFormatChanges()
         }
 
         ranges << r;
+        formatsChanged = true;
     }
 
-    layout->setAdditionalFormats(ranges);
+    if (formatsChanged) {
+        layout->setAdditionalFormats(ranges);
+        doc->markContentsDirty(currentBlock.position(), currentBlock.length());
+    }
 }
 
 void QSyntaxHighlighterPrivate::_q_reformatBlocks(int from, int charsRemoved, int charsAdded)
@@ -214,8 +222,6 @@ void QSyntaxHighlighterPrivate::reformatBlock(const QTextBlock &block)
     q->highlightBlock(block.text());
     applyFormatChanges();
 
-    doc->markContentsDirty(block.position(), block.length());
-
     currentBlock = QTextBlock();
 }