batches support in Editor, used by IncrementalInserter and exec_string

Editor groups all modification together in one undo group when batching.
nested batches are supported.

src/editor.cc

@@ -23,7 +23,7 @@ private:
 
 Editor::Editor(Buffer& buffer)
     : m_buffer(buffer),
-      m_current_inserter(nullptr)
+      m_batch_level(0)
 {
     m_selections.push_back(SelectionList());
     selections().push_back(Selection(buffer.begin(), buffer.begin()));
@@ -31,7 +31,7 @@ Editor::Editor(Buffer& buffer)
 
 void Editor::erase()
 {
-    if (m_current_inserter == nullptr)
+    if (not is_in_batch())
     {
         scoped_undo_group undo_group(m_buffer);
         erase_noundo();
@@ -49,7 +49,7 @@ void Editor::erase_noundo()
 
 void Editor::insert(const String& string)
 {
-    if (m_current_inserter == nullptr)
+    if (not is_in_batch())
     {
         scoped_undo_group undo_group(m_buffer);
         insert_noundo(string);
@@ -66,7 +66,7 @@ void Editor::insert_noundo(const String& string)
 
 void Editor::append(const String& string)
 {
-    if (m_current_inserter == nullptr)
+    if (not is_in_batch())
     {
         scoped_undo_group undo_group(m_buffer);
         append_noundo(string);
@@ -83,7 +83,7 @@ void Editor::append_noundo(const String& string)
 
 void Editor::replace(const std::string& string)
 {
-    if (m_current_inserter == nullptr)
+    if (not is_in_batch())
     {
         scoped_undo_group undo_group(m_buffer);
         erase_noundo();
@@ -237,28 +237,32 @@ CandidateList Editor::complete_filterid(const std::string& prefix,
     return m_filters.complete_id<str_to_str>(prefix, cursor_pos);
 }
 
-void Editor::begin_incremental_insert(IncrementalInserter* inserter)
+void Editor::begin_batch()
 {
-    assert(not m_current_inserter);
-    m_current_inserter = inserter;
-    m_buffer.begin_undo_group();
+    ++m_batch_level;
 
-    on_begin_incremental_insert();
+    if (m_batch_level == 1)
+    {
+        m_buffer.begin_undo_group();
+        on_begin_batch();
+    }
 }
 
-void Editor::end_incremental_insert(IncrementalInserter* inserter)
+void Editor::end_batch()
 {
-    on_end_incremental_insert();
-
-    assert(m_current_inserter and m_current_inserter == inserter);
-    m_current_inserter = nullptr;
-    m_buffer.end_undo_group();
+    assert(m_batch_level > 0);
+    if (m_batch_level == 1)
+    {
+        on_end_batch();
+        m_buffer.end_undo_group();
+    }
+    --m_batch_level;
 }
 
 IncrementalInserter::IncrementalInserter(Editor& editor, Mode mode)
     : m_editor(editor)
 {
-    m_editor.begin_incremental_insert(this);
+    m_editor.begin_batch();
 
     if (mode == Mode::Change)
         editor.erase_noundo();
@@ -294,7 +298,7 @@ IncrementalInserter::IncrementalInserter(Editor& editor, Mode mode)
 IncrementalInserter::~IncrementalInserter()
 {
     move_cursors(BufferCoord(0, -1));
-    m_editor.end_incremental_insert(this);
+    m_editor.end_batch();
 }
 
 void IncrementalInserter::apply(Modification&& modification) const

src/editor.hh

@@ -55,7 +55,9 @@ public:
     CandidateList complete_filterid(const std::string& prefix,
                                     size_t cursor_pos = std::string::npos);
 
-    bool is_inserting() const { return m_current_inserter != nullptr; }
+    void begin_batch();
+    void end_batch();
+    bool is_in_batch() const { return m_batch_level != 0; }
 
 private:
     void erase_noundo();
@@ -67,12 +69,10 @@ private:
     void check_invariant() const;
 
     friend class IncrementalInserter;
-    IncrementalInserter* m_current_inserter;
+    int m_batch_level;
 
-    void begin_incremental_insert(IncrementalInserter* inserter);
-    void end_incremental_insert(IncrementalInserter* inserter);
-    virtual void on_begin_incremental_insert() {}
-    virtual void on_end_incremental_insert() {}
+    virtual void on_begin_batch() {}
+    virtual void on_end_batch() {}
 
 
     Buffer&                             m_buffer;

src/main.cc

@@ -1055,8 +1055,12 @@ void exec_string(const CommandParameters& params,
         return keys[pos++];
     };
 
-    Editor standalone_editor(context.buffer());
-    Editor& editor = context.has_window() ? context.window() : standalone_editor;
+    Editor batch_editor(context.buffer());
+    Editor& editor = context.has_window() ? static_cast<Editor&>(context.window())
+                                          : static_cast<Editor&>(batch_editor);
+
+    editor.begin_batch();
+    auto end_batch = on_scope_end([&]() { editor.end_batch(); });
 
     int count = 0;
     while(pos < keys.size())

src/window.cc

@@ -154,12 +154,12 @@ std::string Window::status_line() const
         oss << " [+]";
     oss << " -- " << cursor.line+1 << "," << cursor.column+1
         << " -- " << selections().size() << " sel -- ";
-    if (is_inserting())
+    if (is_in_batch())
         oss << "[Insert]";
     return oss.str();
 }
 
-void Window::on_end_incremental_insert()
+void Window::on_end_batch()
 {
     push_selections();
     hooks_manager().run_hook("InsertEnd", "", Context(*this));

src/window.hh

@@ -50,7 +50,7 @@ private:
     Window(Buffer& buffer);
     Window(const Window&) = delete;
 
-    void on_end_incremental_insert();
+    void on_end_batch();
 
     void scroll_to_keep_cursor_visible_ifn();