From 62868e596d073c5774d1e4712bd5136456747e2f Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Mon, 19 Mar 2018 23:20:32 -0400
Subject: [PATCH] Jump to line number for :<n> commands

---
 src/core/BufferView.cc | 36 ++++++++++++++++++++++++++++++++++++
 src/core/BufferView.h  |  1 +
 src/gui/BufferPane.cc  | 10 ++++++++++
 src/gui/BufferPane.h   |  1 +
 src/gui/Window.cc      | 22 ++++++++++++++++++++++
 5 files changed, 70 insertions(+)

diff --git a/src/core/BufferView.cc b/src/core/BufferView.cc
index f461301..82d2ad7 100644
--- a/src/core/BufferView.cc
+++ b/src/core/BufferView.cc
@@ -229,6 +229,42 @@ bool BufferView::cursor_move(CursorMovement which, uint32_t c, bool allow_eol)
     return moved;
 }
 
+bool BufferView::cursor_move_to_line(size_t target_line)
+{
+    size_t current_line = m_iterator->line();
+    std::shared_ptr<Buffer::Iterator> it;
+    if (target_line <= current_line / 2u)
+    {
+        it = m_buffer->beginp();
+    }
+    else if (target_line <= ((current_line + m_buffer->end().line()) / 2u))
+    {
+        it = m_iterator->clonep();
+    }
+    else
+    {
+        it = m_buffer->endp();
+        it->go_back();
+        it->go_start_of_line();
+    }
+    while (it->line() < target_line)
+    {
+        if (!it->go_next_line())
+            break;
+    }
+    while (it->line() > target_line)
+    {
+        if (!it->go_previous_line())
+            break;
+    }
+    if (current_line != it->line())
+    {
+        *m_iterator = *it;
+        return true;
+    }
+    return false;
+}
+
 void BufferView::scroll_view_up(int n_lines, bool allow_eol)
 {
     int orig_cursor_screen_row = m_cursor_screen_row;
diff --git a/src/core/BufferView.h b/src/core/BufferView.h
index e9b09c1..1a71fcd 100644
--- a/src/core/BufferView.h
+++ b/src/core/BufferView.h
@@ -83,6 +83,7 @@ public:
         return BufferLineWalker(m_buffer, start_of_line, m_width, m_character_width_determiner);
     }
     bool cursor_move(CursorMovement which, uint32_t c, bool allow_eol);
+    bool cursor_move_to_line(size_t line);
     int cursor_screen_row() const { return m_cursor_screen_row; }
     int cursor_screen_column() const { return m_cursor_screen_column; }
     int cursor_virtual_column() const { return m_cursor_virtual_column; }
diff --git a/src/gui/BufferPane.cc b/src/gui/BufferPane.cc
index 0662a28..95ac3f8 100644
--- a/src/gui/BufferPane.cc
+++ b/src/gui/BufferPane.cc
@@ -377,6 +377,16 @@ void BufferPane::cursor_move(BufferPane::CursorMovement which, uint32_t c)
     }
 }
 
+void BufferPane::cursor_move_to_line(size_t target_line)
+{
+    bool moved = m_buffer_view->cursor_move_to_line(target_line);
+    if (moved)
+    {
+        m_buffer_view->update();
+        m_window->request_redraw();
+    }
+}
+
 void BufferPane::enter_insert_mode(Window::EnterInsertModeMode which)
 {
     if (insert_mode())
diff --git a/src/gui/BufferPane.h b/src/gui/BufferPane.h
index 5c79edc..50a5174 100644
--- a/src/gui/BufferPane.h
+++ b/src/gui/BufferPane.h
@@ -32,6 +32,7 @@ public:
     void resize(int width, int height) override;
     void draw();
     void cursor_move(CursorMovement which, uint32_t c);
+    void cursor_move_to_line(size_t target_line);
     void enter_insert_mode(Window::EnterInsertModeMode which);
     void insert_code_point(uint32_t code_point);
     void exit_insert_mode();
diff --git a/src/gui/Window.cc b/src/gui/Window.cc
index 1366e71..1710129 100644
--- a/src/gui/Window.cc
+++ b/src/gui/Window.cc
@@ -504,6 +504,19 @@ void Window::change_focus(std::shared_ptr<BufferPane> buffer_pane)
     request_redraw();
 }
 
+static bool is_number(const EncodedString & s)
+{
+    size_t size = s.size();
+    if (size < 1u)
+        return false;
+    for (size_t i = 0u; i < size; i++)
+    {
+        if ((s[i] < '0') || (s[i] > '9'))
+            return false;
+    }
+    return true;
+}
+
 void Window::handle_command(const EncodedString & command)
 {
     CommandParser cp;
@@ -519,6 +532,15 @@ void Window::handle_command(const EncodedString & command)
             {
                 command_quit(cp);
             }
+            else if (is_number(cp[0]))
+            {
+                size_t target_line = (size_t)atoi((const char *)&cp[0][0]);
+                if (target_line != 0u)
+                {
+                    target_line--;
+                }
+                m_focused_buffer_pane->cursor_move_to_line(target_line);
+            }
         }
     }
     else