From 834e2d2fe3d9a67497dd34e6551e80df90c00458 Mon Sep 17 00:00:00 2001
From: Maxime Coste <frrrwww@gmail.com>
Date: Thu, 29 Sep 2011 09:10:27 +0000
Subject: [PATCH] DisplayBuffer: check_invariant method to assert atoms
 consistency

---
 src/display_buffer.cc | 12 +++++++++++-
 src/display_buffer.hh |  2 ++
 src/window.cc         |  3 +++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/display_buffer.cc b/src/display_buffer.cc
index 03cc5b18..0865211a 100644
--- a/src/display_buffer.cc
+++ b/src/display_buffer.cc
@@ -1,6 +1,6 @@
 #include "display_buffer.hh"
 
-#include "assert.h"
+#include "assert.hh"
 
 namespace Kakoune
 {
@@ -22,4 +22,14 @@ DisplayBuffer::iterator DisplayBuffer::split(iterator atom, size_t pos_in_atom)
     return insert(atom, std::move(new_atom));
 }
 
+void DisplayBuffer::check_invariant() const
+{
+    for (size_t i = 0; i < m_atoms.size(); ++i)
+    {
+        assert(m_atoms[i].end > m_atoms[i].begin);
+        if (i > 0)
+            assert(m_atoms[i-1].end == m_atoms[i].begin);
+    }
+}
+
 }
diff --git a/src/display_buffer.hh b/src/display_buffer.hh
index e422e38a..62b4731c 100644
--- a/src/display_buffer.hh
+++ b/src/display_buffer.hh
@@ -75,6 +75,8 @@ public:
 
     const_iterator begin() const { return m_atoms.begin(); }
     const_iterator end()   const { return m_atoms.end(); }
+
+    void check_invariant() const;
 private:
     AtomList m_atoms;
 };
diff --git a/src/window.cc b/src/window.cc
index e94394c9..122767ee 100644
--- a/src/window.cc
+++ b/src/window.cc
@@ -309,7 +309,10 @@ void Window::update_display_buffer()
     m_display_buffer.append(DisplayAtom(begin, end, m_buffer.string(begin, end)));
 
     for (auto& filter : m_filters)
+    {
         filter(m_display_buffer);
+        m_display_buffer.check_invariant();
+    }
 }
 
 void Window::set_dimensions(const WindowCoord& dimensions)