Add SCI_GETUNDOSEQUENCE to determine whether an undo sequence is active and its

nesting depth.

15 files changed, 58 insertions, 1 deletions

diff --git a/call/ScintillaCall.cxx b/call/ScintillaCall.cxx
index 4cb1f19d4..d1732a463 100644
--- a/call/ScintillaCall.cxx
+++ b/call/ScintillaCall.cxx
@@ -799,6 +799,10 @@ void ScintillaCall::EndUndoAction() {
 	Call(Message::EndUndoAction);
 }
 
+int ScintillaCall::UndoSequence() {
+	return static_cast<int>(Call(Message::GetUndoSequence));
+}
+
 int ScintillaCall::UndoActions() {
 	return static_cast<int>(Call(Message::GetUndoActions));
 }
diff --git a/doc/ScintillaDoc.html b/doc/ScintillaDoc.html
index 0e0300d95..b9a5971b2 100644
--- a/doc/ScintillaDoc.html
+++ b/doc/ScintillaDoc.html
@@ -1936,6 +1936,7 @@ struct Sci_TextToFindFull {
      <a class="message" href="#SCI_GETUNDOCOLLECTION">SCI_GETUNDOCOLLECTION &rarr; bool</a><br />
      <a class="message" href="#SCI_BEGINUNDOACTION">SCI_BEGINUNDOACTION</a><br />
      <a class="message" href="#SCI_ENDUNDOACTION">SCI_ENDUNDOACTION</a><br />
+     <a class="message" href="#SCI_GETUNDOSEQUENCE">SCI_GETUNDOSEQUENCE &rarr; int</a><br />
      <a class="message" href="#SCI_ADDUNDOACTION">SCI_ADDUNDOACTION(int token, int flags)</a><br />
     </code>
 
@@ -1979,11 +1980,17 @@ struct Sci_TextToFindFull {
 
     <p><b id="SCI_BEGINUNDOACTION">SCI_BEGINUNDOACTION</b><br />
      <b id="SCI_ENDUNDOACTION">SCI_ENDUNDOACTION</b><br />
-     Send these two messages to Scintilla to mark the beginning and end of a set of operations that
+     Send these two messages to Scintilla to mark the beginning and end of a sequence of operations that
     you want to undo all as one operation but that you have to generate as several operations.
     Alternatively, you can use these to mark a set of operations that you do not want to have
     combined with the preceding or following operations if they are undone.</p>
 
+    <p><b id="SCI_GETUNDOSEQUENCE">SCI_GETUNDOSEQUENCE &rarr; int</b><br />
+     Determine if an undo sequence is active with a positive value indicating that a sequence is active and 0 that there is no current sequence.
+     The value returned is the nesting depth of the sequence, that is, the number of times <code>SCI_BEGINUNDOACTION</code>
+     was called without a correspnding <code>SCI_ENDUNDOACTION</code>.
+     A negative value indicates an error.</p>
+
     <p><b id="SCI_ADDUNDOACTION">SCI_ADDUNDOACTION(int token, int flags)</b><br />
      The container can add its own actions into the undo stack by calling
      <code>SCI_ADDUNDOACTION</code> and an <code>SCN_MODIFIED</code>
diff --git a/doc/ScintillaHistory.html b/doc/ScintillaHistory.html
index 520760784..3a820fb92 100644
--- a/doc/ScintillaHistory.html
+++ b/doc/ScintillaHistory.html
@@ -596,6 +596,9 @@
 	Add SCI_SETCOPYSEPARATOR for separator between parts of a multiple selection when copied to the clipboard.
 	<a href="https://sourceforge.net/p/scintilla/feature-requests/1530/">Feature #1530</a>.
 	</li>
+	<li>
+	Add SCI_GETUNDOSEQUENCE to determine whether an undo sequence is active and its nesting depth.
+	</li>
     </ul>
     <h3>
        <a href="https://www.scintilla.org/scintilla551.zip">Release 5.5.1</a>
diff --git a/include/Scintilla.h b/include/Scintilla.h
index 719b44afd..d97da016f 100644
--- a/include/Scintilla.h
+++ b/include/Scintilla.h
@@ -342,6 +342,7 @@ typedef sptr_t (*SciFnDirectStatus)(sptr_t ptr, unsigned int iMessage, uptr_t wP
 #define SCI_GETCHARACTERCATEGORYOPTIMIZATION 2721
 #define SCI_BEGINUNDOACTION 2078
 #define SCI_ENDUNDOACTION 2079
+#define SCI_GETUNDOSEQUENCE 2799
 #define SCI_GETUNDOACTIONS 2790
 #define SCI_SETUNDOSAVEPOINT 2791
 #define SCI_GETUNDOSAVEPOINT 2792
diff --git a/include/Scintilla.iface b/include/Scintilla.iface
index 195c87d37..c04d23a80 100644
--- a/include/Scintilla.iface
+++ b/include/Scintilla.iface
@@ -837,6 +837,9 @@ fun void BeginUndoAction=2078(,)
 # End a sequence of actions that is undone and redone as a unit.
 fun void EndUndoAction=2079(,)
 
+# Is an undo sequence active?
+get int GetUndoSequence=2799(,)
+
 # How many undo actions are in the history?
 get int GetUndoActions=2790(,)
 
diff --git a/include/ScintillaCall.h b/include/ScintillaCall.h
index 6212a42cd..02c383883 100644
--- a/include/ScintillaCall.h
+++ b/include/ScintillaCall.h
@@ -245,6 +245,7 @@ public:
 	int CharacterCategoryOptimization();
 	void BeginUndoAction();
 	void EndUndoAction();
+	int UndoSequence();
 	int UndoActions();
 	void SetUndoSavePoint(int action);
 	int UndoSavePoint();
diff --git a/include/ScintillaMessages.h b/include/ScintillaMessages.h
index cac6d9d62..c511720c5 100644
--- a/include/ScintillaMessages.h
+++ b/include/ScintillaMessages.h
@@ -171,6 +171,7 @@ enum class Message {
 	GetCharacterCategoryOptimization = 2721,
 	BeginUndoAction = 2078,
 	EndUndoAction = 2079,
+	GetUndoSequence = 2799,
 	GetUndoActions = 2790,
 	SetUndoSavePoint = 2791,
 	GetUndoSavePoint = 2792,
diff --git a/src/CellBuffer.cxx b/src/CellBuffer.cxx
index b0b9d9c39..4985517e0 100644
--- a/src/CellBuffer.cxx
+++ b/src/CellBuffer.cxx
@@ -1070,6 +1070,10 @@ void CellBuffer::EndUndoAction() noexcept {
 	uh->EndUndoAction();
 }
 
+int CellBuffer::UndoSequenceDepth() const noexcept {
+	return uh->UndoSequenceDepth();
+}
+
 void CellBuffer::AddUndoAction(Sci::Position token, bool mayCoalesce) {
 	bool startSequence = false;
 	uh->AppendAction(ActionType::container, token, nullptr, 0, startSequence, mayCoalesce);
diff --git a/src/CellBuffer.h b/src/CellBuffer.h
index 3a72601a6..d5d9a0467 100644
--- a/src/CellBuffer.h
+++ b/src/CellBuffer.h
@@ -166,6 +166,7 @@ public:
 	bool IsCollectingUndo() const noexcept;
 	void BeginUndoAction(bool mayCoalesce=false) noexcept;
 	void EndUndoAction() noexcept;
+	int UndoSequenceDepth() const noexcept;
 	void AddUndoAction(Sci::Position token, bool mayCoalesce);
 	void DeleteUndoHistory() noexcept;
 
diff --git a/src/Document.cxx b/src/Document.cxx
index 3ae8964ba..88b876ebd 100644
--- a/src/Document.cxx
+++ b/src/Document.cxx
@@ -1543,6 +1543,10 @@ Sci::Position Document::Redo() {
 	return newPos;
 }
 
+int Document::UndoSequenceDepth() const noexcept {
+	return cb.UndoSequenceDepth();
+}
+
 void Document::DelChar(Sci::Position pos) {
 	DeleteChars(pos, LenChar(pos));
 }
diff --git a/src/Document.h b/src/Document.h
index efb1ae6d6..fa1c3fe42 100644
--- a/src/Document.h
+++ b/src/Document.h
@@ -397,6 +397,7 @@ public:
 	bool IsCollectingUndo() const noexcept { return cb.IsCollectingUndo(); }
 	void BeginUndoAction(bool coalesceWithPrior=false) noexcept { cb.BeginUndoAction(coalesceWithPrior); }
 	void EndUndoAction() noexcept { cb.EndUndoAction(); }
+	int UndoSequenceDepth() const noexcept;
 	void AddUndoAction(Sci::Position token, bool mayCoalesce) { cb.AddUndoAction(token, mayCoalesce); }
 	void SetSavePoint();
 	bool IsSavePoint() const noexcept { return cb.IsSavePoint(); }
diff --git a/src/Editor.cxx b/src/Editor.cxx
index 390c83898..0561b42f8 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -6636,6 +6636,9 @@ sptr_t Editor::WndProc(Message iMessage, uptr_t wParam, sptr_t lParam) {
 		pdoc->EndUndoAction();
 		return 0;
 
+	case Message::GetUndoSequence:
+		return pdoc->UndoSequenceDepth();
+
 	case Message::GetUndoActions:
 		return pdoc->UndoActions();
 
diff --git a/src/UndoHistory.cxx b/src/UndoHistory.cxx
index c4b241103..c0d7ba5f2 100644
--- a/src/UndoHistory.cxx
+++ b/src/UndoHistory.cxx
@@ -350,6 +350,10 @@ void UndoHistory::EndUndoAction() noexcept {
 	}
 }
 
+int UndoHistory::UndoSequenceDepth() const noexcept {
+	return undoSequenceDepth;
+}
+
 void UndoHistory::DropUndoSequence() noexcept {
 	undoSequenceDepth = 0;
 }
diff --git a/src/UndoHistory.h b/src/UndoHistory.h
index 8cde395ae..be639c541 100644
--- a/src/UndoHistory.h
+++ b/src/UndoHistory.h
@@ -101,6 +101,7 @@ public:
 
 	void BeginUndoAction(bool mayCoalesce=false) noexcept;
 	void EndUndoAction() noexcept;
+	int UndoSequenceDepth() const noexcept;
 	void DropUndoSequence() noexcept;
 	void DeleteUndoHistory() noexcept;
 
diff --git a/test/simpleTests.py b/test/simpleTests.py
index 1ca5b76cb..ce67edfde 100644
--- a/test/simpleTests.py
+++ b/test/simpleTests.py
@@ -221,6 +221,25 @@ class TestSimple(unittest.TestCase):
 		self.assertEqual(self.ed.CanRedo(), 0)
 		self.assertEqual(self.ed.CanUndo(), 1)
 
+	def testUndoSequence(self):
+		data = b"xy"
+		self.assertEqual(self.ed.UndoSequence, 0)
+		self.ed.InsertText(0, data)
+		self.assertEqual(self.ed.UndoSequence, 0)
+		# Check that actions between BeginUndoAction and EndUndoAction are undone together
+		self.ed.BeginUndoAction()
+		self.assertEqual(self.ed.UndoSequence, 1)
+		self.ed.InsertText(0, data)
+		self.ed.InsertText(1, data)
+		# xxyyxy
+		self.assertEqual(self.ed.Length, 6)
+		self.ed.EndUndoAction()
+		self.assertEqual(self.ed.UndoSequence, 0)
+		self.ed.Undo()
+		# xy as 2 inserts removed
+		self.assertEqual(self.ed.Length, 2)
+		self.assertEqual(self.ed.UndoSequence, 0)
+
 	def testUndoSavePoint(self):
 		data = b"xy"
 		self.assertEqual(self.ed.Modify, 0)