From 618d09115185efa05f6948247d86087f4aa96118 Mon Sep 17 00:00:00 2001
From: aycabta <aycabta@gmail.com>
Date: Tue, 17 Dec 2019 13:10:39 +0900
Subject: Support change search direction

---
 lib/reline/line_editor.rb           | 37 +++++++++++++++++----
 test/reline/test_key_actor_emacs.rb | 64 +++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+), 7 deletions(-)

diff --git a/lib/reline/line_editor.rb b/lib/reline/line_editor.rb
index c74db5286d..9d8185ff00 100644
--- a/lib/reline/line_editor.rb
+++ b/lib/reline/line_editor.rb
@@ -1196,6 +1196,7 @@ class Reline::LineEditor
       loop do
         key = Fiber.yield(search_word)
         search_again = false
+        change_direction = false
         case key
         when -1 # determined
           Reline.last_incremental_search = search_word
@@ -1207,7 +1208,11 @@ class Reline::LineEditor
             search_word = grapheme_clusters.join
           end
         when "\C-r".ord, "\C-s".ord
-          search_again = true if prev_search_key == key
+          if prev_search_key == key
+            search_again = true
+          else
+            change_direction = true
+          end
           prev_search_key = key
         else
           multibyte_buf << key
@@ -1229,10 +1234,19 @@ class Reline::LineEditor
               case prev_search_key
               when "\C-r".ord
                 history_pointer_base = 0
-                history = Reline::HISTORY[0..(@history_pointer - 1)]
+                if change_direction
+                  history = Reline::HISTORY[0..@history_pointer]
+                else
+                  history = Reline::HISTORY[0..(@history_pointer - 1)]
+                end
               when "\C-s".ord
-                history_pointer_base = @history_pointer + 1
-                history = Reline::HISTORY[(@history_pointer + 1)..-1]
+                if change_direction
+                  history_pointer_base = @history_pointer
+                  history = Reline::HISTORY[(@history_pointer)..-1]
+                else
+                  history_pointer_base = @history_pointer + 1
+                  history = Reline::HISTORY[(@history_pointer + 1)..-1]
+                end
               end
             else
               history_pointer_base = 0
@@ -1242,10 +1256,19 @@ class Reline::LineEditor
             case prev_search_key
             when "\C-r".ord
               history_pointer_base = 0
-              history = Reline::HISTORY[0..@history_pointer]
+              if change_direction
+                history = Reline::HISTORY[0..@history_pointer]
+              else
+                history = Reline::HISTORY[0..@history_pointer]
+              end
             when "\C-s".ord
-              history_pointer_base = @history_pointer
-              history = Reline::HISTORY[@history_pointer..-1]
+              if change_direction
+                history_pointer_base = @history_pointer
+                history = Reline::HISTORY[(@history_pointer - 1)..-1]
+              else
+                history_pointer_base = @history_pointer
+                history = Reline::HISTORY[@history_pointer..-1]
+              end
             end
           else
             history_pointer_base = 0
diff --git a/test/reline/test_key_actor_emacs.rb b/test/reline/test_key_actor_emacs.rb
index 5e5be0c15c..8854df56a2 100644
--- a/test/reline/test_key_actor_emacs.rb
+++ b/test/reline/test_key_actor_emacs.rb
@@ -1620,6 +1620,70 @@ class Reline::KeyActor::Emacs::Test < Reline::TestCase
     assert_cursor_max(0)
   end
 
+  def test_search_history_front_and_back
+    Reline::HISTORY.concat([
+      '1235', # old
+      '12aa',
+      '1234' # new
+    ])
+    assert_line('')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-s12")
+    assert_line('1235')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0) # doesn't determine yet
+    input_keys("\C-s")
+    assert_line('12aa')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-r")
+    assert_line('12aa')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-r")
+    assert_line('1235')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+  end
+
+  def test_search_history_back_and_front
+    Reline::HISTORY.concat([
+      '1235', # old
+      '12aa',
+      '1234' # new
+    ])
+    assert_line('')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-r12")
+    assert_line('1234')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0) # doesn't determine yet
+    input_keys("\C-r")
+    assert_line('12aa')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-s")
+    assert_line('12aa')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+    input_keys("\C-s")
+    assert_line('1234')
+    assert_byte_pointer_size('')
+    assert_cursor(0)
+    assert_cursor_max(0)
+  end
+
   def test_search_history_to_back_in_the_middle_of_histories
     Reline::HISTORY.concat([
       '1235', # old
-- 
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