From a91dc12519faa84ebf1287e240418488dbfc138d Mon Sep 17 00:00:00 2001
From: Roy Qu <royqh1979@gmail.com>
Date: Sat, 18 Feb 2023 07:09:19 +0800
Subject: [PATCH] - enhancement: Reduce flicker when editing big files.

---
 NEWS.md                             |  1 +
 RedPandaIDE/editor.cpp              | 30 ++++++++++++++++++++---------
 RedPandaIDE/editor.h                |  2 ++
 libs/qsynedit/qsynedit/document.cpp |  6 +++---
 4 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 2451000e..2ef119ff 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -37,6 +37,7 @@ Red Panda C++ Version 2.12
   - enhancement: Show "..." instead of "...}" when folding #if/#endif
   - enhancement: Correctly handle high-precision mouse wheel / touchpad in editors.
   - enhancement: Greatly reduce time to open/edit big files.
+  - enhancement: Reduce flicker when editing big files.
 
 Red Panda C++ Version 2.11
 
diff --git a/RedPandaIDE/editor.cpp b/RedPandaIDE/editor.cpp
index 3ad109e3..1b3db7e5 100644
--- a/RedPandaIDE/editor.cpp
+++ b/RedPandaIDE/editor.cpp
@@ -1125,12 +1125,18 @@ void Editor::onPreparePaintHighlightToken(int line, int aChar, const QString &to
     //        qDebug()<<s;
     //        PStatement statement = mParser->findStatementOf(mFilename,
     //          s , p.Line);
-            QStringList expression = getExpressionAtPosition(p);
-            PStatement statement = parser()->findStatementOf(
-                        filename(),
-                        expression,
-                        p.line);
-            StatementKind kind = getKindOfStatement(statement);
+            StatementKind kind;
+            if (mParser->parsing()){
+                kind=mIdentCache.value(QString("%1 %2").arg(aChar).arg(token),StatementKind::skUnknown);
+            } else {
+                QStringList expression = getExpressionAtPosition(p);
+                PStatement statement = parser()->findStatementOf(
+                            filename(),
+                            expression,
+                            p.line);
+                kind = getKindOfStatement(statement);
+                mIdentCache.insert(QString("%1 %2").arg(aChar).arg(token),kind);
+            }
             if (kind == StatementKind::skUnknown) {
                 QSynedit::BufferCoord pBeginPos,pEndPos;
                 QString s= getWordAtPosition(this,p, pBeginPos,pEndPos, WordPurpose::wpInformation);
@@ -1356,7 +1362,7 @@ void Editor::showEvent(QShowEvent */*event*/)
         connect(mParser.get(),
                 &CppParser::onEndParsing,
                 this,
-                &QSynedit::QSynEdit::invalidate);
+                &Editor::onEndParsing);
         reparse(false);
     }
     if (mParentPageControl) {
@@ -1399,7 +1405,7 @@ void Editor::hideEvent(QHideEvent */*event*/)
         disconnect(mParser.get(),
                 &CppParser::onEndParsing,
                 this,
-                &QSynedit::QSynEdit::invalidate);
+                &Editor::onEndParsing);
     }
     pMainWindow->updateForEncodingInfo(nullptr);
     pMainWindow->updateStatusbarForLineCol(nullptr);
@@ -1973,6 +1979,12 @@ void Editor::onTooltipTimer()
     }
 }
 
+void Editor::onEndParsing()
+{
+    mIdentCache.clear();
+    invalidate();
+}
+
 void Editor::resolveAutoDetectEncodingOption()
 {
     if (mEncodingOption==ENCODING_AUTO_DETECT) {
@@ -4341,7 +4353,7 @@ void Editor::setProject(Project *pProject)
                     connect(mParser.get(),
                             &CppParser::onEndParsing,
                             this,
-                            &QSynedit::QSynEdit::invalidate);
+                            &Editor::onEndParsing);
                 } else {
                     invalidate();
                 }
diff --git a/RedPandaIDE/editor.h b/RedPandaIDE/editor.h
index d416ebc6..c6501174 100644
--- a/RedPandaIDE/editor.h
+++ b/RedPandaIDE/editor.h
@@ -237,6 +237,7 @@ private slots:
     void onFunctionTipsTimer();
     void onAutoBackupTimer();
     void onTooltipTimer();
+    void onEndParsing();
 
 private:
     void resolveAutoDetectEncodingOption();
@@ -348,6 +349,7 @@ private:
     QTimer mTooltipTimer;
     int mHoverModifiedLine;
     int mWheelAccumulatedDelta;
+    QMap<QString,StatementKind> mIdentCache;
 
     static QHash<ParserLanguage,std::weak_ptr<CppParser>> mSharedParsers;
 
diff --git a/libs/qsynedit/qsynedit/document.cpp b/libs/qsynedit/qsynedit/document.cpp
index bfb65e7b..cddc8553 100644
--- a/libs/qsynedit/qsynedit/document.cpp
+++ b/libs/qsynedit/qsynedit/document.cpp
@@ -260,12 +260,12 @@ void Document::setContents(const QStringList &text)
 QStringList Document::contents()
 {
     QMutexLocker locker(&mMutex);
-    QStringList Result;
+    QStringList result;
     DocumentLines list = mLines;
     foreach (const PDocumentLine& line, list) {
-        Result.append(line->lineText);
+        result.append(line->lineText);
     }
-    return Result;
+    return result;
 }
 
 void Document::beginUpdate()