Refactor column highlighter to make it more robust

Support arbitrary orders for column highlighters (it was previously
failing when column highlighters were not applied in column order).

Fix show_matching tab handling at the same time (horizontal scrolling,
tab characters and show_matching were behaving badly).

Window highlighting now runs user highlighters, then built-ins for each
phases, instead of running all phases for user highlighters, then all
phases for built-ins.

We now consider unprintable character to be 1-column width as we know
we will display them as "�".

Fixes #1615
Fixes #1023

1 files changed, 4 insertions, 1 deletions

diff --git a/src/window.cc b/src/window.cc
index c8d86e14..09652a9b 100644
--- a/src/window.cc
+++ b/src/window.cc
@@ -136,15 +136,18 @@ const DisplayBuffer& Window::update_display_buffer(const Context& context)
             buffer()[buffer_line].length()
           : get_byte_to_column(buffer(), tabstop, {buffer_line, m_position.column + m_range.column});
 
+        // The display buffer always has at least one buffer atom, which might be empty if
+        // beg_byte == end_byte
         lines.emplace_back(AtomList{ {buffer(), {buffer_line, beg_byte}, {buffer_line, end_byte}} });
     }
 
     m_display_buffer.compute_range();
     BufferRange range{{0,0}, buffer().end_coord()};
     for (auto pass : { HighlightPass::Wrap, HighlightPass::Move, HighlightPass::Colorize })
+    {
         m_highlighters.highlight(context, pass, m_display_buffer, range);
-    for (auto pass : { HighlightPass::Wrap, HighlightPass::Move, HighlightPass::Colorize })
         m_builtin_highlighters.highlight(context, pass, m_display_buffer, range);
+    }
 
     m_display_buffer.optimize();