ButtonRebindsFilter: Support disabled buttons

It's sometimes wanted that you disable certain buttons on the device,
such as an annoyingly place side button on a drawing tablet. This now
makes it possible to do so by putting "Disabled" in the config. The
rebind filter will then ensure the events are stopped and none are
emitted.

src/plugins/buttonrebinds/buttonrebindsfilter.cpp

@@ -224,16 +224,26 @@ bool ButtonRebindsFilter::tabletToolButtonEvent(uint button, bool pressed, const
 
 void ButtonRebindsFilter::insert(TriggerType type, const Trigger &trigger, const QStringList &entry)
 {
-    if (entry.size() != 2) {
+    if (entry.empty()) {
         qCWarning(KWIN_BUTTONREBINDS) << "Failed to rebind to" << entry;
         return;
     }
     if (entry.first() == QLatin1String("Key")) {
+        if (entry.size() != 2) {
+            qCWarning(KWIN_BUTTONREBINDS) << "Invalid key" << entry;
+            return;
+        }
+
         const auto keys = QKeySequence::fromString(entry.at(1), QKeySequence::PortableText);
         if (!keys.isEmpty()) {
             m_actions.at(type).insert(trigger, keys);
         }
     } else if (entry.first() == QLatin1String("MouseButton")) {
+        if (entry.size() != 2) {
+            qCWarning(KWIN_BUTTONREBINDS) << "Invalid mouse button" << entry;
+            return;
+        }
+
         bool ok = false;
         const MouseButton mb{entry.last().toUInt(&ok)};
         if (ok) {
@@ -242,6 +252,12 @@ void ButtonRebindsFilter::insert(TriggerType type, const Trigger &trigger, const
             qCWarning(KWIN_BUTTONREBINDS) << "Could not convert" << entry << "into a mouse button";
         }
     } else if (entry.first() == QLatin1String("TabletToolButton")) {
+        if (entry.size() != 2) {
+            qCWarning(KWIN_BUTTONREBINDS)
+                << "Invalid tablet tool button" << entry;
+            return;
+        }
+
         bool ok = false;
         const TabletToolButton tb{entry.last().toUInt(&ok)};
         if (ok) {
@@ -249,6 +265,8 @@ void ButtonRebindsFilter::insert(TriggerType type, const Trigger &trigger, const
         } else {
             qCWarning(KWIN_BUTTONREBINDS) << "Could not convert" << entry << "into a mouse button";
         }
+    } else if (entry.first() == QLatin1String("Disabled")) {
+        m_actions.at(type).insert(trigger, DisabledButton{});
     }
 }
 
@@ -269,6 +287,10 @@ bool ButtonRebindsFilter::send(TriggerType type, const Trigger &trigger, bool pr
     if (const auto tb = std::get_if<TabletToolButton>(&action)) {
         return sendTabletToolButton(tb->button, pressed, timestamp);
     }
+    if (std::get_if<DisabledButton>(&action)) {
+        // Intentional, we don't want to anything to anybody
+        return true;
+    }
     return false;
 }
 

src/plugins/buttonrebinds/buttonrebindsfilter.h

@@ -68,6 +68,9 @@ public:
     {
         quint32 button;
     };
+    struct DisabledButton
+    {
+    };
 
     explicit ButtonRebindsFilter();
     bool pointerEvent(KWin::MouseEvent *event, quint32 nativeButton) override;
@@ -83,7 +86,7 @@ private:
     bool sendTabletToolButton(quint32 button, bool pressed, std::chrono::microseconds time);
 
     InputDevice m_inputDevice;
-    std::array<QHash<Trigger, std::variant<QKeySequence, MouseButton, TabletToolButton>>, LastType> m_actions;
+    std::array<QHash<Trigger, std::variant<QKeySequence, MouseButton, TabletToolButton, DisabledButton>>, LastType> m_actions;
     KConfigWatcher::Ptr m_configWatcher;
     std::optional<KWin::TabletToolId> m_tabletTool;
 };