From b2152d983e3b20aed7f687ba1d9e916ae6065b24 Mon Sep 17 00:00:00 2001
From: Don Ho <don.h@free.fr>
Date: Sun, 26 Jan 2025 08:31:12 +0100
Subject: [PATCH] Optimize switching programming language performance for large
 files

Fix #16106, close #16109
---
 PowerEditor/src/Notepad_plus.cpp              | 48 ++++++++-----------
 .../ScintillaComponent/ScintillaEditView.cpp  | 28 +++++++++++
 .../ScintillaComponent/ScintillaEditView.h    |  1 +
 3 files changed, 49 insertions(+), 28 deletions(-)

diff --git a/PowerEditor/src/Notepad_plus.cpp b/PowerEditor/src/Notepad_plus.cpp
index e1e4ada7a..90b7c980d 100644
--- a/PowerEditor/src/Notepad_plus.cpp
+++ b/PowerEditor/src/Notepad_plus.cpp
@@ -3872,39 +3872,31 @@ BOOL Notepad_plus::processTabSwitchAccel(MSG* msg) const
 
 void Notepad_plus::setLanguage(LangType langType)
 {
-	//Add logic to prevent changing a language when a document is shared between two views
-	//If so, release one document
-	bool reset = false;
-	Document prev = 0;
 	unsigned long MODEVENTMASK_ON = NppParameters::getInstance().getScintillaModEventMask();
-	if (bothActive())
+
+	if (bothActive() && (_mainEditView.getCurrentBufferID() == _subEditView.getCurrentBufferID()))
 	{
-		if (_mainEditView.getCurrentBufferID() == _subEditView.getCurrentBufferID())
-		{
-			reset = true;
-			_subEditView.saveCurrentPos();
-			prev = _subEditView.execute(SCI_GETDOCPOINTER);
-			_subEditView.execute(SCI_SETMODEVENTMASK, MODEVENTMASK_OFF);
-			_subEditView.execute(SCI_SETDOCPOINTER, 0, 0);
-			_subEditView.execute(SCI_SETMODEVENTMASK, MODEVENTMASK_ON);
-		}
-	}
-	
-	if (reset)
-	{
-		_mainEditView.getCurrentBuffer()->setLangType(langType);
+		// Add logic to prevent changing a language when a document is shared between two views
+		// If so, release one document
+
+		_subEditView.saveCurrentPos();
+		Document subPrev = _subEditView.execute(SCI_GETDOCPOINTER);
+		_subEditView.execute(SCI_SETMODEVENTMASK, MODEVENTMASK_OFF);
+		_subEditView.execute(SCI_SETDOCPOINTER, 0, 0);
+		_subEditView.execute(SCI_SETMODEVENTMASK, MODEVENTMASK_ON);
+
+		_mainEditView.setLanguage(langType);
+
+		_subEditView.execute(SCI_SETMODEVENTMASK, MODEVENTMASK_OFF);
+		_subEditView.execute(SCI_SETDOCPOINTER, 0, subPrev);
+		_subEditView.execute(SCI_SETMODEVENTMASK, MODEVENTMASK_ON);
+		_subEditView.maintainStateForNpc();
+		_subEditView.setCRLF();
+		_subEditView.restoreCurrentPosPreStep();
 	}
 	else
 	{
-		_pEditView->getCurrentBuffer()->setLangType(langType);
-	}
-
-	if (reset)
-	{
-		_subEditView.execute(SCI_SETMODEVENTMASK, MODEVENTMASK_OFF);
-		_subEditView.execute(SCI_SETDOCPOINTER, 0, prev);
-		_subEditView.execute(SCI_SETMODEVENTMASK, MODEVENTMASK_ON);
-		_subEditView.restoreCurrentPosPreStep();
+		_pEditView->setLanguage(langType);
 	}
 }
 
diff --git a/PowerEditor/src/ScintillaComponent/ScintillaEditView.cpp b/PowerEditor/src/ScintillaComponent/ScintillaEditView.cpp
index 021532f53..bba5ad04e 100644
--- a/PowerEditor/src/ScintillaComponent/ScintillaEditView.cpp
+++ b/PowerEditor/src/ScintillaComponent/ScintillaEditView.cpp
@@ -1707,6 +1707,34 @@ void ScintillaEditView::setNpcAndCcUniEOL(long color)
 	redraw();
 }
 
+void ScintillaEditView::setLanguage(LangType langType)
+{
+	unsigned long MODEVENTMASK_ON = NppParameters::getInstance().getScintillaModEventMask();
+
+	if (_currentBuffer->getLastLangType() != -1)
+	{
+		saveCurrentPos();
+		Document prev = execute(SCI_GETDOCPOINTER);
+		execute(SCI_SETMODEVENTMASK, MODEVENTMASK_OFF);
+		execute(SCI_SETDOCPOINTER, 0, getBlankDocument());
+		execute(SCI_SETMODEVENTMASK, MODEVENTMASK_ON);
+
+		_currentBuffer->setLangType(langType);
+		
+		execute(SCI_SETMODEVENTMASK, MODEVENTMASK_OFF);
+		execute(SCI_SETDOCPOINTER, 0, prev);
+		execute(SCI_SETMODEVENTMASK, MODEVENTMASK_ON);
+
+		maintainStateForNpc();
+		setCRLF();
+		restoreCurrentPosPreStep();
+	}
+	else
+	{
+		_currentBuffer->setLangType(langType);
+	}
+}
+
 void ScintillaEditView::defineDocType(LangType typeDoc)
 {
 	StyleArray & stylers = NppParameters::getInstance().getMiscStylerArray();
diff --git a/PowerEditor/src/ScintillaComponent/ScintillaEditView.h b/PowerEditor/src/ScintillaComponent/ScintillaEditView.h
index 0b61c14da..580e1d0c7 100644
--- a/PowerEditor/src/ScintillaComponent/ScintillaEditView.h
+++ b/PowerEditor/src/ScintillaComponent/ScintillaEditView.h
@@ -845,6 +845,7 @@ public:
 			typeDoc == L_ASN1 || typeDoc == L_GDSCRIPT);
 	};
 
+	void setLanguage(LangType langType);
 	void defineDocType(LangType typeDoc);	//setup stylers for active document
 
 	void addCustomWordChars();