DisplayBuffer: add range and compute_range methods

src/display_buffer.cc

@@ -17,4 +17,26 @@ DisplayLine::iterator DisplayLine::split(iterator it, BufferIterator pos)
     return m_atoms.insert(it, std::move(atom));
 }
 
+void DisplayBuffer::compute_range()
+{
+    m_range.first  = BufferIterator();
+    m_range.second = BufferIterator();
+    for (auto& line : m_lines)
+    {
+        for (auto& atom : line)
+        {
+            if (not atom.content.has_buffer_range())
+                continue;
+
+            if (not m_range.first.is_valid() or m_range.first > atom.content.begin())
+                m_range.first = atom.content.begin();
+
+            if (not m_range.second.is_valid() or m_range.second < atom.content.end())
+                m_range.second = atom.content.end();
+        }
+    }
+    assert(m_range.first.is_valid() and m_range.second.is_valid());
+    assert(m_range.first <= m_range.second);
+}
+
 }

src/display_buffer.hh

@@ -144,6 +144,8 @@ private:
     AtomList m_atoms;
 };
 
+using BufferRange = std::pair<BufferIterator, BufferIterator>;
+
 class DisplayBuffer
 {
 public:
@@ -152,8 +154,15 @@ public:
 
     LineList& lines() { return m_lines; }
     const LineList& lines() const { return m_lines; }
+
+    // returns the smallest BufferIterator range which contains every DisplayAtoms
+    const BufferRange& range() const { return m_range; }
+    void compute_range();
+
 private:
     LineList m_lines;
+
+    BufferRange m_range;
 };
 
 }

src/highlighters.cc

@@ -18,6 +18,9 @@ void highlight_range(DisplayBuffer& display_buffer,
                      BufferIterator begin, BufferIterator end,
                      bool skip_replaced, T func)
 {
+    if (end <= display_buffer.range().first or begin >= display_buffer.range().second)
+        return;
+
     for (auto& line : display_buffer.lines())
     {
         if (line.buffer_line() >= begin.line() and line.buffer_line() <= end.line())
@@ -50,11 +53,11 @@ void highlight_range(DisplayBuffer& display_buffer,
 }
 
 void colorize_regex(DisplayBuffer& display_buffer,
-                    const Buffer& buffer,
                     const Regex& ex,
                     Color fg_color, Color bg_color = Color::Default)
 {
-    RegexIterator re_it(buffer.begin(), buffer.end(), ex, boost::match_nosubs);
+    const BufferRange& range = display_buffer.range();
+    RegexIterator re_it(range.first, range.second, ex, boost::match_nosubs);
     RegexIterator re_end;
     for (; re_it != re_end; ++re_it)
     {
@@ -94,8 +97,7 @@ HighlighterAndId colorize_regex_factory(Window& window,
     String id = "colre'" + params[0] + "'";
 
     return HighlighterAndId(id, std::bind(colorize_regex,
-                                          _1, std::ref(window.buffer()),
-                                          ex, fg_color, bg_color));
+                                          _1,  ex, fg_color, bg_color));
 }
 
 void expand_tabulations(Window& window, DisplayBuffer& display_buffer)

src/window.cc

@@ -61,6 +61,7 @@ void Window::update_display_buffer()
         lines.back().push_back(DisplayAtom(AtomContent(pos,end)));
     }
 
+    m_display_buffer.compute_range();
     m_highlighters(m_display_buffer);
 }