From aa255d832bd769d2814c5bffcce30d02ccd27208 Mon Sep 17 00:00:00 2001
From: mitchell <unknown>
Date: Sun, 31 Mar 2019 21:57:39 -0400
Subject: Backport Avoid hangs in idle styling modes caused by high-priority
 idle work styling.

Backport of changeset 7315:57ea0255c8aa, but without constexpr, as non-static
data members cannot be constexpr in C++11.
---
 src/Editor.cxx | 10 +++++++---
 src/Editor.h   |  3 +++
 2 files changed, 10 insertions(+), 3 deletions(-)

(limited to 'src')

diff --git a/src/Editor.cxx b/src/Editor.cxx
index f059a8243..94e1f6164 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -2659,12 +2659,16 @@ void Editor::NotifyModified(Document *, DocModification mh, void *) {
 			}
 
 			if (paintState == notPainting && !CanDeferToLastStep(mh)) {
-				QueueIdleWork(WorkNeeded::workStyle, pdoc->Length());
+				if (SynchronousStylingToVisible()) {
+					QueueIdleWork(WorkNeeded::workStyle, pdoc->Length());
+				}
 				Redraw();
 			}
 		} else {
 			if (paintState == notPainting && mh.length && !CanEliminate(mh)) {
-				QueueIdleWork(WorkNeeded::workStyle, mh.position + mh.length);
+				if (SynchronousStylingToVisible()) {
+					QueueIdleWork(WorkNeeded::workStyle, mh.position + mh.length);
+				}
 				InvalidateRange(mh.position, mh.position + mh.length);
 			}
 		}
@@ -5065,7 +5069,7 @@ void Editor::StyleToPositionInView(Sci::Position pos) {
 }
 
 Sci::Position Editor::PositionAfterMaxStyling(Sci::Position posMax, bool scrolling) const {
-	if ((idleStyling == SC_IDLESTYLING_NONE) || (idleStyling == SC_IDLESTYLING_AFTERVISIBLE)) {
+	if (SynchronousStylingToVisible()) {
 		// Both states do not limit styling
 		return posMax;
 	}
diff --git a/src/Editor.h b/src/Editor.h
index 29150276a..cbdd171cf 100644
--- a/src/Editor.h
+++ b/src/Editor.h
@@ -522,6 +522,9 @@ protected:	// ScintillaBase subclass needs access to much of Editor
 	Sci::Position PositionAfterMaxStyling(Sci::Position posMax, bool scrolling) const;
 	void StartIdleStyling(bool truncatedLastStyling);
 	void StyleAreaBounded(PRectangle rcArea, bool scrolling);
+	bool SynchronousStylingToVisible() const noexcept {
+		return (idleStyling == SC_IDLESTYLING_NONE) || (idleStyling == SC_IDLESTYLING_AFTERVISIBLE);
+	}
 	void IdleStyling();
 	virtual void IdleWork();
 	virtual void QueueIdleWork(WorkNeeded::workItems items, Sci::Position upTo=0);
-- 
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