[LyX/master] Add a constructor of UndoGroupHelper that uses a CursorData parameter

[Jean-Marc Lasgouttes]

commit e7b1ee47eadc35b75862baf6127a5207412bcf36
Author: Jean-Marc Lasgouttes <lasgouttes at lyx.org>
Date:   Thu Jun 20 17:52:19 2024 +0200

    Add a constructor of UndoGroupHelper that uses a CursorData parameter
    
    This aloows to se the the `before' cursor of the undo group.
    
    Not used for now.
---
 src/Undo.cpp | 16 ++++++++++++++++
 src/Undo.h   |  6 ++++++
 2 files changed, 22 insertions(+)

diff --git a/src/Undo.cpp b/src/Undo.cpp
index 8dcffff32b..80dff34baa 100644
--- a/src/Undo.cpp
+++ b/src/Undo.cpp
@@ -704,6 +704,12 @@ UndoGroupHelper::UndoGroupHelper(Buffer * buf) : d(new UndoGroupHelper::Impl)
 }
 
 
+UndoGroupHelper::UndoGroupHelper(CursorData & cur) : d(new UndoGroupHelper::Impl)
+{
+	resetBuffer(cur);
+}
+
+
 UndoGroupHelper::~UndoGroupHelper()
 {
 	for (Buffer * buf : d->buffers_)
@@ -712,6 +718,7 @@ UndoGroupHelper::~UndoGroupHelper()
 	delete d;
 }
 
+
 void UndoGroupHelper::resetBuffer(Buffer * buf)
 {
 	if (buf && d->buffers_.count(buf) == 0) {
@@ -721,4 +728,13 @@ void UndoGroupHelper::resetBuffer(Buffer * buf)
 }
 
 
+void UndoGroupHelper::resetBuffer(CursorData & cur)
+{
+	if (!cur.empty() && d->buffers_.count(cur.buffer()) == 0) {
+		d->buffers_.insert(cur.buffer());
+		cur.buffer()->undo().beginUndoGroup(cur);
+	}
+}
+
+
 } // namespace lyx
diff --git a/src/Undo.h b/src/Undo.h
index b6d84569c5..32be7d2ede 100644
--- a/src/Undo.h
+++ b/src/Undo.h
@@ -140,12 +140,18 @@ class UndoGroupHelper {
 public:
 	// Begin a new undo group for buffer \c buf.
 	UndoGroupHelper(Buffer * buf);
+	// Begin an undo group for the buffer of \c cur with the the
+	// `before' cursor set to \c cur.
+	UndoGroupHelper(CursorData & cur);
 	// End all active undo groups.
 	~UndoGroupHelper();
 
 	// Begin if needed an undo group for buffer \c buf.
 	void resetBuffer(Buffer * buf);
 
+	// Begin if needed an undo group for the buffer of \c cur with the
+	// the `before' cursor set to \c cur.
+	void resetBuffer(CursorData & cur);
 private:
 	class Impl;
 	Impl * const d;