make display buffers and highlighters handle better longer than display lines

still work in progress, I think the whole display system will in fact need
a rewrite.

src/display_buffer.cc

@@ -95,10 +95,20 @@ DisplayBuffer::DisplayBuffer()
 {
 }
 
-DisplayBuffer::iterator DisplayBuffer::insert(iterator where, const DisplayAtom& atom)
+DisplayBuffer::iterator DisplayBuffer::append(BufferIterator begin, BufferIterator end)
 {
-    iterator res = m_atoms.insert(where, atom);
+    DisplayCoord coord;
-    // check_invariant();
+    if (not m_atoms.empty())
+        coord = m_atoms.back().end_coord();
+    m_atoms.push_back(DisplayAtom(std::move(coord), std::move(begin), std::move(end)));
+    return --(this->end());
+}
+
+DisplayBuffer::iterator DisplayBuffer::insert_empty_atom_before(iterator where)
+{
+    assert(where != end());
+    iterator res = m_atoms.insert(
+        where, DisplayAtom(where->coord(), where->begin(), where->begin()));
     return res;
 }
 
@@ -124,6 +134,7 @@ DisplayBuffer::iterator DisplayBuffer::atom_containing(const BufferIterator& whe
 
 DisplayBuffer::iterator DisplayBuffer::split(iterator atom, const BufferIterator& pos)
 {
+    assert(atom->splitable());
     assert(pos > atom->begin());
     assert(pos < atom->end());
 
@@ -136,7 +147,7 @@ DisplayBuffer::iterator DisplayBuffer::split(iterator atom, const BufferIterator
     iterator insert_pos = atom;
     ++insert_pos;
     m_atoms.insert(insert_pos, std::move(new_atom));
-    // check_invariant();
+    check_invariant();
     return atom;
 }
 
@@ -147,7 +158,10 @@ void DisplayBuffer::check_invariant() const
     {
         assert(it->end() >= it->begin());
         if (it != begin())
+        {
             assert(prev_it->end() == it->begin());
+            assert(prev_it->end_coord() == it->coord());
+        }
         prev_it = it;
     }
 }

src/display_buffer.hh

@@ -52,19 +52,6 @@ enum class Color
 // text stored in the replacement_string field.
 struct DisplayAtom
 {
-    DisplayAtom(const DisplayCoord& coord,
-                const BufferIterator& begin, const BufferIterator& end,
-                Color fg_color = Color::Default,
-                Color bg_color = Color::Default,
-                Attribute attribute = Attributes::Normal)
-        : m_content_mode(BufferText),
-          m_coord(coord),
-          m_begin(begin), m_end(end),
-          m_fg_color(fg_color),
-          m_bg_color(bg_color),
-          m_attribute(attribute)
-    {}
-
     const DisplayCoord&   coord()     const { return m_coord; }
     const BufferIterator& begin()     const { return m_begin; }
     const BufferIterator& end()       const { return m_end; }
@@ -72,6 +59,12 @@ struct DisplayAtom
     const Color&          bg_color()  const { return m_bg_color; }
     const Attribute&      attribute() const { return m_attribute; }
 
+    enum ContentMode
+    {
+        BufferText,
+        ReplacementText
+    };
+    ContentMode    content_mode() const { return m_content_mode; }
 
     Color&         fg_color()  { return m_fg_color; }
     Color&         bg_color()  { return m_bg_color; }
@@ -82,16 +75,23 @@ struct DisplayAtom
     BufferIterator iterator_at(const DisplayCoord& coord) const;
     DisplayCoord   line_and_column_at(const BufferIterator& iterator) const;
 
-    bool           splitable() const { return m_replacement_text.empty(); }
+    bool           splitable() const { return m_content_mode != ReplacementText; }
 
 private:
     friend class DisplayBuffer;
+    DisplayAtom(DisplayCoord coord,
+                BufferIterator begin, BufferIterator end,
+                Color fg_color = Color::Default,
+                Color bg_color = Color::Default,
+                Attribute attribute = Attributes::Normal)
+        : m_content_mode(BufferText),
+          m_coord(std::move(coord)),
+          m_begin(std::move(begin)), m_end(std::move(end)),
+          m_fg_color(fg_color),
+          m_bg_color(bg_color),
+          m_attribute(attribute)
+    {}
 
-    enum ContentMode
-    {
-        BufferText,
-        ReplacementText
-    };
     ContentMode    m_content_mode;
 
     DisplayCoord   m_coord;
@@ -117,8 +117,8 @@ public:
     DisplayBuffer();
 
     void clear() { m_atoms.clear(); }
-    void append(const DisplayAtom& atom) { m_atoms.push_back(atom); }
+    iterator append(BufferIterator begin, BufferIterator end);
-    iterator insert(iterator where, const DisplayAtom& atom);
+    iterator insert_empty_atom_before(iterator where);
     iterator split(iterator atom, const BufferIterator& pos);
 
     void replace_atom_content(iterator atom, const String& replacement);

src/highlighters.cc

@@ -43,15 +43,18 @@ void colorize_regex_range(DisplayBuffer& display_buffer,
         auto begin_atom_it = display_buffer.atom_containing(begin, atom_it);
         assert(begin_atom_it != display_buffer.end());
         if (begin_atom_it->begin() != begin)
-            begin_atom_it = ++display_buffer.split(begin_atom_it, begin);
+        {
+            if (begin_atom_it->splitable())
+                begin_atom_it = ++display_buffer.split(begin_atom_it, begin);
+            else
+                ++begin_atom_it;
+        }
 
         auto end_atom_it = display_buffer.atom_containing(end, begin_atom_it);
         if (end_atom_it != display_buffer.end() and
-            end_atom_it->begin() != end)
+            end_atom_it->begin() != end and end_atom_it->splitable())
             end_atom_it = ++display_buffer.split(end_atom_it, end);
 
-        assert(begin_atom_it != end_atom_it);
-
         for (auto it = begin_atom_it; it != end_atom_it; ++it)
         {
             if (it->attribute() & Attributes::Final)
@@ -169,12 +172,10 @@ void show_line_numbers(DisplayBuffer& display_buffer)
 
                 atom_it = ++display_buffer.split(atom_it, line_start);
             }
-            atom_it = display_buffer.insert(
+            atom_it = display_buffer.insert_empty_atom_before(atom_it);
-                atom_it,
+            atom_it->fg_color() = Color::Black;
-                DisplayAtom(atom_it->coord(),
+            atom_it->bg_color() = Color::White;
-                            atom_it->begin(), atom_it->begin(),
+            atom_it->attribute() = Attributes::Final;
-                            Color::Black, Color::White,
-                            Attributes::Final));
 
             char buffer[10];
             snprintf(buffer, 10, format, coord.line + 1);
@@ -257,7 +258,7 @@ void highlight_selections(Window& window, DisplayBuffer& display_buffer)
         const BufferIterator& last = sel.last();
 
         DisplayBuffer::iterator atom_it = display_buffer.atom_containing(last);
-        if (atom_it == display_buffer.end())
+        if (atom_it == display_buffer.end() or not atom_it->splitable())
             continue;
 
         if (atom_it->begin() < last)

src/window.cc

@@ -83,13 +83,22 @@ void Window::update_display_buffer()
 
     m_display_buffer.clear();
 
-    BufferIterator begin = buffer().iterator_at(m_position);
+    for (auto line = 0; line < m_dimensions.line; ++line)
-    BufferIterator end = buffer().iterator_at(m_position +
+    {
-                                              BufferCoord(m_dimensions.line, m_dimensions.column))+2;
+        auto buffer_line = m_position.line + line;
-    if (begin == end)
+        if (buffer_line >= buffer().line_count())
-        return;
+            break;
+        BufferIterator pos        = buffer().iterator_at({ buffer_line, m_position.column });
+        BufferIterator line_begin = buffer().iterator_at_line_begin(pos);
+        BufferIterator line_end   = buffer().iterator_at_line_end(pos);
 
-    m_display_buffer.append(DisplayAtom(DisplayCoord(0,0), begin, end));
+        if (line_begin != pos)
+        {
+            auto atom_it = m_display_buffer.append(line_begin, pos);
+            m_display_buffer.replace_atom_content(atom_it, "");
+        }
+        m_display_buffer.append(pos, line_end);
+    }
 
     m_highlighters(m_display_buffer);
     m_display_buffer.check_invariant();
@@ -141,5 +150,4 @@ void Window::on_option_changed(const String& name, const Option& option)
     m_hook_manager.run_hook("WinSetOption", desc, Context(*this));
 }
 
-
 }