DolphinMainWindow: show a banner when the user presses the shortcut of a disabled action

Currently, there's no feedback when the user presses a shortcut of a disabled
action, e.g. cut / paste in a read-only directory. This patch shows a banner
in that case.

It's implemented by enabling a QShortcut for each disabled action. the
QShortcut is deleted when the action is enabled again.

The following actions are included:
cut
paste
rename
moveToTrash
deleteWithTrashShortcut
deleted
createDir
copyToOtherView
moveToOtherView

1 files changed, 51 insertions, 0 deletions

diff --git a/src/disabledactionnotifier.cpp b/src/disabledactionnotifier.cpp
new file mode 100644
index 000000000..844e66228
--- /dev/null
+++ b/src/disabledactionnotifier.cpp
@@ -0,0 +1,51 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Jin Liu <[email protected]>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "disabledactionnotifier.h"
+
+DisabledActionNotifier::DisabledActionNotifier(QObject *parent)
+    : QObject(parent)
+{
+}
+
+void DisabledActionNotifier::setDisabledReason(QAction *action, QStringView reason)
+{
+    if (action->isEnabled()) {
+        return;
+    }
+
+    if (m_shortcuts.contains(action)) {
+        m_shortcuts.take(action)->deleteLater();
+    }
+
+    QShortcut *shortcut = new QShortcut(action->shortcut(), parent());
+    m_shortcuts.insert(action, shortcut);
+
+    connect(action, &QAction::enabledChanged, this, [this, action](bool enabled) {
+        if (enabled) {
+            m_shortcuts.take(action)->deleteLater();
+        }
+    });
+
+    // Don't capture QStringView, as it may reference a temporary QString
+    QString reasonString = reason.toString();
+    connect(shortcut, &QShortcut::activated, this, [this, action, reasonString]() {
+        Q_EMIT disabledActionTriggered(action, reasonString);
+    });
+}
+
+void DisabledActionNotifier::clearDisabledReason(QAction *action)
+{
+    if (action->isEnabled()) {
+        return;
+    }
+
+    if (m_shortcuts.contains(action)) {
+        m_shortcuts.take(action)->deleteLater();
+    }
+}
+
+#include "moc_disabledactionnotifier.cpp"