Delay NormalMode clearing of status line and info box to next idle

A common pattern is for info/echo messages to be generated by idle
hooks but the clearing of previous info/echo was done immediately on
normal mode events. This led to flickering of the info box especially
when a hook was repeatidly generating the same info (like moving
a cursor in the same word where the hook reacts to the word under
the cursor).

1 files changed, 38 insertions, 11 deletions

diff --git a/src/input_handler.cc b/src/input_handler.cc
index 2703b51a..89613aee 100644
--- a/src/input_handler.cc
+++ b/src/input_handler.cc
@@ -23,13 +23,6 @@
 namespace Kakoune
 {
 
-static void clear_info_and_echo(Context& context)
-{
-    context.print_status({});
-    if (context.has_client())
-        context.client().info_hide();
-}
-
 class InputMode : public RefCountable
 {
 public:
@@ -101,8 +94,6 @@ void InputMode::paste(StringView content)
         context().print_status({error.what().str(), context().faces()["Error"] });
         context().hooks().run_hook(Hook::RuntimeError, error.what(), context());
     }
-
-    clear_info_and_echo(context());
 }
 
 namespace InputModes
@@ -221,6 +212,14 @@ constexpr StringView register_doc =
 
 class Normal : public InputMode
 {
+    enum class PendingClear
+    {
+        None = 0,
+        Info = 0b01,
+        StatusLine = 0b10
+    };
+    friend constexpr bool with_bit_ops(Meta::Type<PendingClear>) { return true; }
+
 public:
     Normal(InputHandler& input_handler, bool single_command = false)
         : InputMode(input_handler),
@@ -228,6 +227,15 @@ public:
                        context().flags() & Context::Flags::Draft ?
                            Timer::Callback{} : [this](Timer&) {
               RefPtr<InputMode> keep_alive{this}; // hook could trigger pop_mode()
+              if (context().has_client())
+              {
+                  if (m_pending_clear & PendingClear::StatusLine)
+                        context().client().print_status({});
+                  if (m_pending_clear & PendingClear::Info)
+                        context().client().info_hide();
+              }
+              m_pending_clear = PendingClear::None;
+
               context().hooks().run_hook(Hook::NormalIdle, "", context());
           }},
           m_fs_check_timer{TimePoint::max(),
@@ -275,6 +283,8 @@ public:
 
     void on_key(Key key, bool) override
     {
+        bool should_clear = false;
+
         kak_assert(m_state != State::PopOnEnabled);
         ScopedSetBool set_in_on_key{m_in_on_key};
 
@@ -291,7 +301,7 @@ public:
 
         if (m_mouse_handler.handle_key(key, context()))
         {
-            clear_info_and_echo(context());
+            should_clear = true;
 
             if (not transient)
                 m_idle_timer.set_next_date(Clock::now() + get_idle_timeout(context()));
@@ -338,7 +348,7 @@ public:
                      m_state = State::PopOnEnabled;
             });
 
-            clear_info_and_echo(context());
+            should_clear = true;
 
             // Hack to parse keys sent by terminals using the 8th bit to mark the
             // meta key. In normal mode, give priority to a potential alt-key than
@@ -369,7 +379,12 @@ public:
 
         context().hooks().run_hook(Hook::NormalKey, to_string(key), context());
         if (enabled() and not transient) // The hook might have changed mode
+        {
+            if (should_clear and context().has_client())
+                m_pending_clear = (context().client().info_pending() ? PendingClear::None : PendingClear::Info)
+                                | (context().client().status_line_pending() ? PendingClear::None : PendingClear::StatusLine);
             m_idle_timer.set_next_date(Clock::now() + get_idle_timeout(context()));
+        }
     }
 
     ModeInfo mode_info() const override
@@ -395,6 +410,17 @@ public:
         return {atoms, m_params};
     }
 
+    void paste(StringView content) override
+    {
+        InputMode::paste(content);
+        if (not (context().flags() & Context::Flags::Draft))
+        {
+            if (context().has_client())
+                m_pending_clear = PendingClear::Info | PendingClear::StatusLine;
+            m_idle_timer.set_next_date(Clock::now() + get_idle_timeout(context()));
+        }
+    }
+
     KeymapMode keymap_mode() const override { return KeymapMode::Normal; }
 
     StringView name() const override { return "normal"; }
@@ -408,6 +434,7 @@ private:
     Timer m_idle_timer;
     Timer m_fs_check_timer;
     MouseHandler m_mouse_handler;
+    PendingClear m_pending_clear = PendingClear::None;
 
     enum class State { Normal, SingleCommand, PopOnEnabled };
     State m_state;