Add an explicit refresh method to user interface

With this refresh method user interface can defer updating
the display until really needed.

5 files changed, 33 insertions, 6 deletions

diff --git a/src/client.cc b/src/client.cc
index cda0ef5c..8abef5ab 100644
--- a/src/client.cc
+++ b/src/client.cc
@@ -91,6 +91,7 @@ void Client::redraw_ifn()
         context().ui().draw(context().window().display_buffer(),
                             m_status_line, generate_mode_line());
     }
+    context().ui().refresh();
 }
 
 static void reload_buffer(Context& context, const String& filename)
diff --git a/src/ncurses.cc b/src/ncurses.cc
index 4380c419..0553a7ff 100644
--- a/src/ncurses.cc
+++ b/src/ncurses.cc
@@ -195,6 +195,14 @@ void NCursesUI::redraw()
     }
     doupdate();
 }
+
+void NCursesUI::refresh()
+{
+    if (m_dirty)
+        redraw();
+    m_dirty = false;
+}
+
 using Utf8Policy = utf8::InvalidBytePolicy::Pass;
 using Utf8Iterator = utf8::utf8_iterator<String::const_iterator, Utf8Policy>;
 void addutf8str(WINDOW* win, Utf8Iterator begin, Utf8Iterator end)
@@ -301,7 +309,7 @@ void NCursesUI::draw(const DisplayBuffer& display_buffer,
         printf("%s%s%s", tsl, title.c_str(), fsl);
     }
 
-    redraw();
+    m_dirty = true;
 }
 
 bool NCursesUI::is_key_available()
@@ -438,7 +446,7 @@ void NCursesUI::draw_menu()
         wattron(m_menu_win, COLOR_PAIR(menu_bg));
         waddstr(m_menu_win, is_mark ? "┃" : "│");
     }
-    redraw();
+    m_dirty = true;
 }
 
 void NCursesUI::menu_show(memoryview<String> items,
@@ -520,7 +528,7 @@ void NCursesUI::menu_hide()
                       (int)window_size(m_menu_win).line);
     delwin(m_menu_win);
     m_menu_win = nullptr;
-    redraw();
+    m_dirty = true;
 }
 
 static DisplayCoord compute_needed_size(const String& str)
@@ -711,7 +719,7 @@ void NCursesUI::info_show(const String& title, const String& content,
            break;
         it = eol + 1;
     }
-    redraw();
+    m_dirty = true;
 }
 
 void NCursesUI::info_hide()
@@ -722,7 +730,7 @@ void NCursesUI::info_hide()
                       (int)window_size(m_info_win).line);
     delwin(m_info_win);
     m_info_win = nullptr;
-    redraw();
+    m_dirty = true;
 }
 
 DisplayCoord NCursesUI::dimensions()
diff --git a/src/ncurses.hh b/src/ncurses.hh
index 40661fe4..4edd7502 100644
--- a/src/ncurses.hh
+++ b/src/ncurses.hh
@@ -37,6 +37,8 @@ public:
                    MenuStyle style) override;
     void info_hide() override;
 
+    void refresh() override;
+
     void set_input_callback(InputCallback callback) override;
 
     DisplayCoord dimensions() override;
@@ -63,6 +65,8 @@ private:
 
     FDWatcher     m_stdin_watcher;
     InputCallback m_input_callback;
+
+    bool m_dirty = false;
 };
 
 }
diff --git a/src/remote.cc b/src/remote.cc
index a72437ad..0c4ed900 100644
--- a/src/remote.cc
+++ b/src/remote.cc
@@ -25,7 +25,8 @@ enum class RemoteUIMsg
     MenuHide,
     InfoShow,
     InfoHide,
-    Draw
+    Draw,
+    Refresh
 };
 
 struct socket_error{};
@@ -256,6 +257,8 @@ public:
               const DisplayLine& status_line,
               const DisplayLine& mode_line) override;
 
+    void refresh() override;
+
     bool is_key_available() override;
     Key  get_key() override;
     DisplayCoord dimensions() override;
@@ -342,6 +345,12 @@ void RemoteUI::draw(const DisplayBuffer& display_buffer,
     msg.write(mode_line);
 }
 
+void RemoteUI::refresh()
+{
+    Message msg(m_socket_watcher.fd());
+    msg.write(RemoteUIMsg::Refresh);
+}
+
 static const Key::Modifiers resize_modifier = (Key::Modifiers)0x80;
 
 bool RemoteUI::is_key_available()
@@ -466,6 +475,9 @@ void RemoteClient::process_next_message()
         m_ui->draw(display_buffer, status_line, mode_line);
         break;
     }
+    case RemoteUIMsg::Refresh:
+        m_ui->refresh();
+        break;
     }
 }
 
diff --git a/src/user_interface.hh b/src/user_interface.hh
index affe822b..00366cb2 100644
--- a/src/user_interface.hh
+++ b/src/user_interface.hh
@@ -45,6 +45,8 @@ public:
     virtual bool is_key_available() = 0;
     virtual Key  get_key() = 0;
 
+    virtual void refresh() = 0;
+
     virtual void set_input_callback(InputCallback callback) = 0;
 };