fix mouseover error when only one cursor is defined

If only cursor-click or cursor-scroll is defined, but not the other, the
bar could try to set the cursor to the empty string which resulted in an
error.

include/components/bar.hpp

@@ -31,12 +31,7 @@ namespace tags {
 
 class bar : public xpp::event::sink<evt::button_press, evt::expose, evt::property_notify, evt::enter_notify,
                 evt::leave_notify, evt::motion_notify, evt::destroy_notify, evt::client_message, evt::configure_notify>,
-            public signal_receiver<SIGN_PRIORITY_BAR, signals::ui::dim_window
-#if WITH_XCURSOR
-                ,
-                signals::ui::cursor_change
-#endif
-                > {
+            public signal_receiver<SIGN_PRIORITY_BAR, signals::ui::dim_window> {
  public:
   using make_type = unique_ptr<bar>;
   static make_type make(eventloop::loop&, bool only_initialize_values = false);
@@ -80,8 +75,14 @@ class bar : public xpp::event::sink<evt::button_press, evt::expose, evt::propert
   void handle(const evt::configure_notify& evt) override;
 
   bool on(const signals::ui::dim_window&) override;
+
 #if WITH_XCURSOR
-  bool on(const signals::ui::cursor_change&) override;
+  /**
+   * Change cursor to the given cursor name.
+   *
+   * The cursor name must be valid (cursor_util::valid)
+   */
+  void change_cursor(const string& name);
 #endif
 
  private:

include/events/signal.hpp

@@ -45,7 +45,7 @@ namespace signals {
      private:
       const void* m_ptr;
     };
-  }  // namespace detail
+  } // namespace detail
 
   namespace eventqueue {
     struct exit_reload : public detail::base_signal<exit_reload> {
@@ -60,7 +60,7 @@ namespace signals {
     struct check_state : public detail::base_signal<check_state> {
       using base_type::base_type;
     };
-  }  // namespace eventqueue
+  } // namespace eventqueue
 
   namespace ipc {
     struct command : public detail::value_signal<command, string> {
@@ -72,7 +72,7 @@ namespace signals {
     struct action : public detail::value_signal<action, string> {
       using base_type::base_type;
     };
-  }  // namespace ipc
+  } // namespace ipc
 
   namespace ui {
     struct changed : public detail::base_signal<changed> {
@@ -81,9 +81,6 @@ namespace signals {
     struct button_press : public detail::value_signal<button_press, string> {
       using base_type::base_type;
     };
-    struct cursor_change : public detail::value_signal<cursor_change, string> {
-      using base_type::base_type;
-    };
     struct visibility_change : public detail::value_signal<visibility_change, bool> {
       using base_type::base_type;
     };
@@ -101,13 +98,13 @@ namespace signals {
     struct update_geometry : public detail::base_signal<update_geometry> {
       using base_type::base_type;
     };
-  }  // namespace ui
+  } // namespace ui
 
   namespace ui_tray {
     struct mapped_clients : public detail::value_signal<mapped_clients, unsigned int> {
       using base_type::base_type;
     };
-  }  // namespace ui_tray
-}  // namespace signals
+  } // namespace ui_tray
+} // namespace signals
 
 POLYBAR_NS_END

include/events/signal_fwd.hpp

@@ -19,25 +19,24 @@ namespace signals {
     struct notify_change;
     struct notify_forcechange;
     struct check_state;
-  }  // namespace eventqueue
+  } // namespace eventqueue
   namespace ipc {
     struct command;
     struct hook;
     struct action;
-  }  // namespace ipc
+  } // namespace ipc
   namespace ui {
     struct changed;
     struct button_press;
-    struct cursor_change;
     struct visibility_change;
     struct dim_window;
     struct request_snapshot;
     struct update_background;
     struct update_geometry;
-  }  // namespace ui
+  } // namespace ui
   namespace ui_tray {
     struct mapped_clients;
   }
-}  // namespace signals
+} // namespace signals
 
 POLYBAR_NS_END

src/components/bar.cpp

@@ -43,16 +43,16 @@ bar::make_type bar::make(loop& loop, bool only_initialize_values) {
 
   // clang-format off
   return std::make_unique<bar>(
-        connection::make(),
-        signal_emitter::make(),
-        config::make(),
-        logger::make(),
-        loop,
-        screen::make(),
-        tray_manager::make(),
-        tags::dispatch::make(*action_ctxt),
-        std::move(action_ctxt),
-        only_initialize_values);
+      connection::make(),
+      signal_emitter::make(),
+      config::make(),
+      logger::make(),
+      loop,
+      screen::make(),
+      tray_manager::make(),
+      tags::dispatch::make(*action_ctxt),
+      std::move(action_ctxt),
+      only_initialize_values);
   // clang-format on
 }
 
@@ -747,21 +747,14 @@ void bar::handle(const evt::motion_notify& evt) {
     return false;
   };
 
-  if (has_action({mousebtn::LEFT, mousebtn::MIDDLE, mousebtn::RIGHT, mousebtn::DOUBLE_LEFT, mousebtn::DOUBLE_MIDDLE,
-          mousebtn::DOUBLE_RIGHT})) {
-    if (m_opts.cursor != m_opts.cursor_click) {
-      m_opts.cursor = m_opts.cursor_click;
-      m_sig.emit(cursor_change{string{m_opts.cursor}});
-    }
-
+  if (!m_opts.cursor_click.empty() && has_action({mousebtn::LEFT, mousebtn::MIDDLE, mousebtn::RIGHT,
+                                          mousebtn::DOUBLE_LEFT, mousebtn::DOUBLE_MIDDLE, mousebtn::DOUBLE_RIGHT})) {
+    change_cursor(m_opts.cursor_click);
     return;
   }
 
-  if (has_action({mousebtn::SCROLL_DOWN, mousebtn::SCROLL_UP})) {
-    if (m_opts.cursor != m_opts.cursor_scroll) {
-      m_opts.cursor = m_opts.cursor_scroll;
-      m_sig.emit(cursor_change{string{m_opts.cursor}});
-    }
+  if (!m_opts.cursor_scroll.empty() && has_action({mousebtn::SCROLL_DOWN, mousebtn::SCROLL_UP})) {
+    change_cursor(m_opts.cursor_scroll);
     return;
   }
 
@@ -769,10 +762,7 @@ void bar::handle(const evt::motion_notify& evt) {
     if (!m_opts.cursor_click.empty() &&
         !(action.button == mousebtn::SCROLL_UP || action.button == mousebtn::SCROLL_DOWN ||
             action.button == mousebtn::NONE)) {
-      if (m_opts.cursor != m_opts.cursor_click) {
-        m_opts.cursor = m_opts.cursor_click;
-        m_sig.emit(cursor_change{string{m_opts.cursor}});
-      }
+      change_cursor(m_opts.cursor_click);
       return true;
     } else if (!m_opts.cursor_scroll.empty() &&
                (action.button == mousebtn::SCROLL_UP || action.button == mousebtn::SCROLL_DOWN)) {
@@ -786,25 +776,20 @@ void bar::handle(const evt::motion_notify& evt) {
   for (auto&& action : m_opts.actions) {
     if (!action.command.empty()) {
       m_log.trace("Found matching fallback handler");
-      if (find_click_area(action))
+      if (find_click_area(action)) {
         return;
+      }
     }
   }
 
   if (found_scroll) {
-    if (m_opts.cursor != m_opts.cursor_scroll) {
-      m_opts.cursor = m_opts.cursor_scroll;
-      m_sig.emit(cursor_change{string{m_opts.cursor}});
-    }
+    change_cursor(m_opts.cursor_scroll);
     return;
   }
 
-  if (m_opts.cursor != "default") {
-    m_log.trace("No matching cursor area found");
-    m_opts.cursor = "default";
-    m_sig.emit(cursor_change{string{m_opts.cursor}});
-    return;
-  }
+  m_log.trace("No matching cursor area found");
+  change_cursor("default");
+  return;
 #endif
 }
 
@@ -931,12 +916,17 @@ bool bar::on(const signals::ui::dim_window& sig) {
 }
 
 #if WITH_XCURSOR
-bool bar::on(const signals::ui::cursor_change& sig) {
-  if (!cursor_util::set_cursor(m_connection, m_connection.screen(), m_opts.window, sig.cast())) {
+void bar::change_cursor(const string& name) {
+  // This is already the same cursor, no need to update
+  if (m_opts.cursor == name) {
+    return;
+  }
+
+  m_opts.cursor = name;
+  if (!cursor_util::set_cursor(m_connection, m_connection.screen(), m_opts.window, name)) {
     m_log.warn("Failed to create cursor context");
   }
   m_connection.flush();
-  return false;
 }
 #endif