Rework window redraw handling, should redraw window less often

src/client.cc

@@ -70,10 +70,7 @@ void Client::handle_available_input(EventMode mode)
                 if (*key == ctrl('c'))
                     killpg(getpgrp(), SIGINT);
                 else
-                {
                     m_input_handler.handle_key(*key);
-                    context().window().forget_timestamp();
-                }
             }
         }
         catch (Kakoune::runtime_error& error)
@@ -148,12 +145,8 @@ void Client::redraw_ifn()
 {
     Face default_face = get_face("Default");
 
-    if (context().window().timestamp() != context().buffer().timestamp())
+    if (context().window().needs_redraw(context()))
     {
-        CharCoord dimensions = context().ui().dimensions();
-        if (dimensions == CharCoord{0,0})
-            return;
-        context().window().set_dimensions(dimensions);
         context().window().update_display_buffer(context());
 
         context().ui().draw(context().window().display_buffer(), default_face);

src/client_manager.cc

@@ -86,7 +86,7 @@ WindowAndSelections ClientManager::get_free_window(Buffer& buffer)
     if (it == m_free_windows.rend())
         return { make_unique<Window>(buffer), { buffer, Selection{} } };
 
-    it->window->forget_timestamp();
+    it->window->force_redraw();
     WindowAndSelections res = std::move(*it);
     m_free_windows.erase(it.base()-1);
     res.selections.update();

src/commands.cc

@@ -1244,10 +1244,6 @@ void context_wrap(const ParametersParser& parser, Context& context, Func func)
 
         func(parser, *real_context);
     }
-
-    // force redraw of this client window
-    if (real_context != &context and real_context->has_window())
-        real_context->window().forget_timestamp();
 }
 
 const CommandDesc exec_string_cmd = {

src/normal.cc

@@ -686,6 +686,10 @@ void use_selection_as_search_pattern(Context& context, NormalParams)
             get_face("Information") });
     }
     RegisterManager::instance()['/'] = patterns;
+
+    // Hack, as Window do not take register state into account
+    if (context.has_window())
+        context.window().force_redraw();
 }
 
 void select_regex(Context& context, NormalParams)

src/window.cc

@@ -4,7 +4,8 @@
 #include "context.hh"
 #include "highlighter.hh"
 #include "hook_manager.hh"
-#include "client.hh"
+#include "input_handler.hh"
+#include "user_interface.hh"
 
 #include <algorithm>
 #include <sstream>
@@ -60,14 +61,36 @@ void Window::scroll(CharCount offset)
     m_position.column = std::max(0_char, m_position.column + offset);
 }
 
+size_t Window::compute_hash(const Context& context) const
+{
+    size_t res = hash_values(m_position, context.ui().dimensions(), context.buffer().timestamp());
+
+    auto& selections = context.selections();
+    res = combine_hash(res, hash_value(selections.main_index()));
+    for (auto& sel : selections)
+        res = combine_hash(res, hash_values((const ByteCoord&)sel.cursor(), sel.anchor()));
+
+    return res;
+}
+
+bool Window::needs_redraw(const Context& context) const
+{
+    size_t hash = compute_hash(context);
+    return hash != m_hash;
+}
+
 void Window::update_display_buffer(const Context& context)
 {
-    kak_assert(&buffer() == &context.buffer());
-    scroll_to_keep_selection_visible_ifn(context);
-
     DisplayBuffer::LineList& lines = m_display_buffer.lines();
     lines.clear();
 
+    m_dimensions = context.ui().dimensions();
+    if (m_dimensions == CharCoord{0,0})
+        return;
+
+    kak_assert(&buffer() == &context.buffer());
+    scroll_to_keep_selection_visible_ifn(context);
+
     for (LineCount line = 0; line < m_dimensions.line; ++line)
     {
         LineCount buffer_line = m_position.line + line;
@@ -86,7 +109,7 @@ void Window::update_display_buffer(const Context& context)
         line.trim(m_position.column, m_dimensions.column, true);
     m_display_buffer.optimize();
 
-    m_timestamp = buffer().timestamp();
+    m_hash = compute_hash(context);
 }
 
 void Window::set_position(CharCoord position)
@@ -294,7 +317,7 @@ void Window::on_option_changed(const Option& option)
                             format("{}={}", option.name(), option.get_as_string()));
 
     // an highlighter might depend on the option, so we need to redraw
-    forget_timestamp();
+    force_redraw();
 }
 
 

src/window.hh

@@ -38,8 +38,8 @@ public:
 
     Buffer& buffer() const { return *m_buffer; }
 
-    size_t timestamp() const { return m_timestamp; }
-    void   forget_timestamp() { m_timestamp = -1; }
+    bool needs_redraw(const Context& context) const;
+    void force_redraw() { m_hash = -1; }
 
     ByteCoord offset_coord(ByteCoord coord, CharCount offset);
     ByteCoordAndTarget offset_coord(ByteCoordAndTarget coord, LineCount offset);
@@ -53,6 +53,8 @@ private:
 
     void run_hook_in_own_context(StringView hook_name, StringView param);
 
+    size_t compute_hash(const Context& context) const;
+
     SafePtr<Buffer> m_buffer;
 
     CharCoord m_position;
@@ -62,7 +64,8 @@ private:
     HighlighterGroup m_highlighters;
     HighlighterGroup m_builtin_highlighters;
 
-    size_t m_timestamp = -1;
+    // hash used to determine if a redraw is necessary
+    size_t m_hash = -1;
 };
 
 }