From 0cf093422878653e174d57c0c02ffe4880c6be7a Mon Sep 17 00:00:00 2001
From: Colomban Wendling <ban@herbesfolles.org>
Date: Tue, 21 Feb 2017 22:30:05 +0100
Subject: Bug [#1910]. GTK a11y: Speed up converting byte offsets to character
 offsets

Use a per-line cache to avoid re-computing the offset from the start of
the buffer each time. This dramatically speeds up multiple replacements
on large files.
---
 gtk/ScintillaGTKAccessible.cxx |  7 +++++++
 gtk/ScintillaGTKAccessible.h   | 16 +++++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/gtk/ScintillaGTKAccessible.cxx b/gtk/ScintillaGTKAccessible.cxx
index 948b19575..11966bf20 100644
--- a/gtk/ScintillaGTKAccessible.cxx
+++ b/gtk/ScintillaGTKAccessible.cxx
@@ -856,6 +856,13 @@ void ScintillaGTKAccessible::NotifyReadOnly() {
 void ScintillaGTKAccessible::Notify(GtkWidget *, gint, SCNotification *nt) {
 	switch (nt->nmhdr.code) {
 		case SCN_MODIFIED: {
+			if (nt->modificationType & (SC_MOD_INSERTTEXT | SC_MOD_DELETETEXT)) {
+				// invalidate character offset cache if applicable
+				const Position line = sci->pdoc->LineFromPosition(nt->position);
+				if (character_offsets.size() > static_cast<size_t>(line + 1)) {
+					character_offsets.resize(line + 1);
+				}
+			}
 			if (nt->modificationType & SC_MOD_INSERTTEXT) {
 				int startChar = CharacterOffsetFromByteOffset(nt->position);
 				int lengthChar = sci->pdoc->CountCharacters(nt->position, nt->position + nt->length);
diff --git a/gtk/ScintillaGTKAccessible.h b/gtk/ScintillaGTKAccessible.h
index fa9698417..88256e0ca 100644
--- a/gtk/ScintillaGTKAccessible.h
+++ b/gtk/ScintillaGTKAccessible.h
@@ -20,6 +20,9 @@ private:
 	GtkAccessible *accessible;
 	ScintillaGTK *sci;
 
+	// cache holding character offset for each line start, see CharacterOffsetFromByteOffset()
+	std::vector<Position> character_offsets;
+
 	// cached length of the deletion, in characters (see Notify())
 	int deletionLengthChar;
 	// local state for comparing
@@ -52,7 +55,18 @@ private:
 	}
 
 	int CharacterOffsetFromByteOffset(Position byteOffset) {
-		return sci->pdoc->CountCharacters(0, byteOffset);
+		const Position line = sci->pdoc->LineFromPosition(byteOffset);
+		if (character_offsets.size() <= static_cast<size_t>(line)) {
+			if (character_offsets.empty())
+				character_offsets.push_back(0);
+			for (Position i = character_offsets.size(); i <= line; i++) {
+				const Position start = sci->pdoc->LineStart(i - 1);
+				const Position end = sci->pdoc->LineStart(i);
+				character_offsets.push_back(character_offsets[i - 1] + sci->pdoc->CountCharacters(start, end));
+			}
+		}
+		const Position lineStart = sci->pdoc->LineStart(line);
+		return character_offsets[line] + sci->pdoc->CountCharacters(lineStart, byteOffset);
 	}
 
 	void CharacterRangeFromByteRange(Position startByte, Position endByte, int *startChar, int *endChar) {
-- 
cgit v1.2.3


From bc31bdeb3b5437171af42ef2921f9bb7080b3b64 Mon Sep 17 00:00:00 2001
From: Neil Hodgson <nyamatongwe@gmail.com>
Date: Fri, 3 Mar 2017 16:40:44 +1100
Subject: Change log.

---
 doc/ScintillaHistory.html | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/doc/ScintillaHistory.html b/doc/ScintillaHistory.html
index c63563c7f..ab03e7f3e 100644
--- a/doc/ScintillaHistory.html
+++ b/doc/ScintillaHistory.html
@@ -545,6 +545,11 @@
 	<a href="http://sourceforge.net/p/scintilla/bugs/1915/">Bug #1915</a>.
 	</li>
 	<li>
+	Improved speed of accessibility code on GTK+ by using additional memory
+	as a cache.
+	<a href="http://sourceforge.net/p/scintilla/bugs/1910/">Bug #1910</a>.
+	</li>
+	<li>
 	Fix crash in accessibility code on GTK+ &lt; 3.3.6 caused by previous bug fix.
 	<a href="http://sourceforge.net/p/scintilla/bugs/1907/">Bug #1907</a>.
 	</li>
-- 
cgit v1.2.3