From 33740d06eed248787beed8b0f07c83bb8cc93bf4 Mon Sep 17 00:00:00 2001
From: Maxime Coste <frrrwww@gmail.com>
Date: Fri, 3 May 2013 13:53:23 +0200
Subject: [PATCH] Editor: tweak behaviour on undo/redo when selecting modified
 ranges

---
 src/editor.cc    | 52 ++++++++++++++++++++++++------------------------
 src/selection.hh |  6 ++++++
 2 files changed, 32 insertions(+), 26 deletions(-)

diff --git a/src/editor.cc b/src/editor.cc
index aa7fd1d5..ac7f4ec8 100644
--- a/src/editor.cc
+++ b/src/editor.cc
@@ -128,31 +128,11 @@ static bool compare_selections(const Selection& lhs, const Selection& rhs)
     return lhs.begin() < rhs.begin();
 }
 
-template<bool already_sorted = false>
-void sort_and_merge_overlapping(SelectionList& selections, size_t& main_selection)
+template<typename OverlapsFunc>
+void merge_overlapping(SelectionList& selections, size_t& main_selection,
+                       OverlapsFunc overlaps)
 {
-    if (selections.size() == 1)
-        return;
-
-    if (already_sorted)
-    {
-        kak_assert(std::is_sorted(selections.begin(), selections.end(), compare_selections));
-    }
-    else
-    {
-        const auto& main = selections[main_selection];
-        const auto main_begin = main.begin();
-        main_selection = std::count_if(selections.begin(), selections.end(),
-                                       [&](const Selection& sel) {
-                                           auto begin = sel.begin();
-                                           if (begin == main_begin)
-                                               return &sel < &main;
-                                           else
-                                               return sel.begin() < main_begin;
-                                       });
-        std::stable_sort(selections.begin(), selections.end(), compare_selections);
-    }
-
+    kak_assert(std::is_sorted(selections.begin(), selections.end(), compare_selections));
     for (size_t i = 0; i+1 < selections.size() and selections.size() > 1;)
     {
         if (overlaps(selections[i], selections[i+1]))
@@ -167,6 +147,26 @@ void sort_and_merge_overlapping(SelectionList& selections, size_t& main_selectio
     }
 }
 
+void sort_and_merge_overlapping(SelectionList& selections, size_t& main_selection)
+{
+    if (selections.size() == 1)
+        return;
+
+    const auto& main = selections[main_selection];
+    const auto main_begin = main.begin();
+    main_selection = std::count_if(selections.begin(), selections.end(),
+                                   [&](const Selection& sel) {
+                                       auto begin = sel.begin();
+                                       if (begin == main_begin)
+                                           return &sel < &main;
+                                       else
+                                           return sel.begin() < main_begin;
+                                   });
+    std::stable_sort(selections.begin(), selections.end(), compare_selections);
+
+    merge_overlapping(selections, main_selection, overlaps);
+}
+
 void Editor::move_selections(CharCount offset, SelectMode mode)
 {
     kak_assert(mode == SelectMode::Replace or mode == SelectMode::Extend);
@@ -391,7 +391,7 @@ bool Editor::undo()
     {
         m_selections = std::move(listener.ranges());
         m_main_sel = m_selections.size() - 1;
-        sort_and_merge_overlapping<true>(m_selections, m_main_sel);
+        merge_overlapping(m_selections, m_main_sel, touches);
     }
     check_invariant();
     return res;
@@ -405,7 +405,7 @@ bool Editor::redo()
     {
         m_selections = std::move(listener.ranges());
         m_main_sel = m_selections.size() - 1;
-        sort_and_merge_overlapping<true>(m_selections, m_main_sel);
+        merge_overlapping(m_selections, m_main_sel, touches);
     }
     check_invariant();
     return res;
diff --git a/src/selection.hh b/src/selection.hh
index d24bc87e..e5361a4d 100644
--- a/src/selection.hh
+++ b/src/selection.hh
@@ -45,6 +45,12 @@ inline bool overlaps(const Range& lhs, const Range& rhs)
            (lhs.first() <= rhs.last()  and lhs.last() >= rhs.last());
 }
 
+inline bool touches(const Range& lhs, const Range& rhs)
+{
+    return lhs.begin() <= rhs.begin() ? lhs.end() >= rhs.begin()
+                                      : lhs.begin() <= rhs.end();
+}
+
 using CaptureList = std::vector<String>;
 
 // A selection is a Range, associated with a CaptureList