Introduce StandardShortcutWatcher to watch for runtime changes

Currently an application needs to be restarted before it can see
any changes made to the standard shortcut configuration. To notify
about changes a new class is introduced that looks for those
changes using KConfigWatcher and also updates the global map.
CCBUG:426656

5 files changed, 130 insertions, 3 deletions

diff --git a/src/gui/CMakeLists.txt b/src/gui/CMakeLists.txt
index 2136ec9f..403b0367 100644
--- a/src/gui/CMakeLists.txt
+++ b/src/gui/CMakeLists.txt
@@ -9,6 +9,7 @@ target_sources(KF5ConfigGui PRIVATE
     kconfigloader.cpp
     kconfigskeleton.cpp
     kstandardshortcut.cpp
+    kstandardshortcutwatcher.cpp
     kwindowconfig.cpp
 )
 
@@ -37,6 +38,7 @@ ecm_generate_headers(KConfigGui_HEADERS
   KConfigLoader
   KConfigSkeleton
   KStandardShortcut
+  KStandardShortcutWatcher
   KWindowConfig
 
    REQUIRED_HEADERS KConfigGui_HEADERS
@@ -60,6 +62,7 @@ if (PythonModuleGeneration_FOUND)
       kconfigloader.h
       kconfigskeleton.h
       kstandardshortcut.h
+      kstandardshortcutwatcher.h
       kwindowconfig.h
   )
 endif()
diff --git a/src/gui/kstandardshortcut.cpp b/src/gui/kstandardshortcut.cpp
index 1f67901f..e7639219 100644
--- a/src/gui/kstandardshortcut.cpp
+++ b/src/gui/kstandardshortcut.cpp
@@ -8,8 +8,10 @@
 */
 
 #include "kstandardshortcut.h"
+#include "kstandardshortcutwatcher.h"
 
 #include "kconfig.h"
+#include "kconfigwatcher.h"
 #include "ksharedconfig.h"
 #include <kconfiggroup.h>
 
@@ -437,7 +439,7 @@ static void sanitizeShortcutList(QList<QKeySequence> *list)
     On X11, if QApplication was initialized with GUI disabled,
     the default will always be used.
 */
-static void initialize(StandardShortcut id)
+void initialize(StandardShortcut id)
 {
     KStandardShortcutInfo *info = guardedStandardShortcutInfo(id);
 
@@ -483,7 +485,8 @@ void saveShortcut(StandardShortcut id, const QList<QKeySequence> &newShortcut)
         // If the shortcut is the equal to the hardcoded one we remove it from
         // kdeglobal if necessary and return.
         if (cg.hasKey(info->name)) {
-            cg.deleteEntry(info->name, KConfig::Global | KConfig::Persistent);
+            cg.deleteEntry(info->name, KConfig::Global | KConfig::Persistent | KConfig::Notify);
+            cg.sync();
         }
 
         return;
@@ -491,7 +494,8 @@ void saveShortcut(StandardShortcut id, const QList<QKeySequence> &newShortcut)
 
     // Write the changed shortcut to kdeglobals
     sanitizeShortcutList(&info->cut);
-    cg.writeEntry(info->name, QKeySequence::listToString(info->cut), KConfig::Global | KConfig::Persistent);
+    cg.writeEntry(info->name, QKeySequence::listToString(info->cut), KConfig::Global | KConfig::Persistent | KConfig::Notify);
+    cg.sync();
 }
 
 QString name(StandardShortcut id)
diff --git a/src/gui/kstandardshortcut_p.h b/src/gui/kstandardshortcut_p.h
new file mode 100644
index 00000000..f4b0a0fb
--- /dev/null
+++ b/src/gui/kstandardshortcut_p.h
@@ -0,0 +1,20 @@
+/*
+    This file is part of the KDE libraries
+    SPDX-FileCopyrightText: 1997 Stefan Taferner <taferner@alpin.or.at>
+    SPDX-FileCopyrightText: 2000 Nicolas Hadacek <haadcek@kde.org>
+    SPDX-FileCopyrightText: 2001, 2002 Ellis Whitehead <ellis@kde.org>
+
+    SPDX-License-Identifier: LGPL-2.0-or-later
+*/
+
+#ifndef KSTANDARDSHORTCUT_P_H
+#define KSTANDARDSHORTCUT_P_H
+
+#include "kstandardshortcut.h"
+
+namespace KStandardShortcut
+{
+void initialize(StandardShortcut id);
+}
+
+#endif
diff --git a/src/gui/kstandardshortcutwatcher.cpp b/src/gui/kstandardshortcutwatcher.cpp
new file mode 100644
index 00000000..1be5e503
--- /dev/null
+++ b/src/gui/kstandardshortcutwatcher.cpp
@@ -0,0 +1,46 @@
+/*
+    SPDX-FileCopyrightText: 2022 David Redondo <kde@david-redondo.de>
+
+    SPDX-License-Identifier: LGPL-2.0-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#include "kstandardshortcutwatcher.h"
+
+#include "kconfigwatcher.h"
+#include "kstandardshortcut_p.h"
+
+namespace KStandardShortcut
+{
+class StandardShortcutWatcherPrivate
+{
+public:
+    KConfigWatcher::Ptr watcher = KConfigWatcher::create(KSharedConfig::openConfig());
+};
+
+StandardShortcutWatcher::StandardShortcutWatcher(QObject *parent)
+    : QObject(parent)
+    , d(std::make_unique<StandardShortcutWatcherPrivate>())
+{
+    connect(d->watcher.get(), &KConfigWatcher::configChanged, this, [this](const KConfigGroup &group, const QByteArrayList &keys) {
+        if (group.name() != QStringLiteral("Shortcuts")) {
+            return;
+        }
+        for (const auto &key : keys) {
+            const StandardShortcut shortcut = KStandardShortcut::findByName(QString::fromUtf8(key));
+            if (shortcut != KStandardShortcut::AccelNone) {
+                initialize(shortcut);
+                Q_EMIT shortcutChanged(shortcut, KStandardShortcut::shortcut(shortcut));
+            }
+        }
+    });
+}
+
+StandardShortcutWatcher::~StandardShortcutWatcher() = default;
+
+StandardShortcutWatcher *shortcutWatcher()
+{
+    static StandardShortcutWatcher watcher;
+    return &watcher;
+}
+
+}
diff --git a/src/gui/kstandardshortcutwatcher.h b/src/gui/kstandardshortcutwatcher.h
new file mode 100644
index 00000000..64c6d3d4
--- /dev/null
+++ b/src/gui/kstandardshortcutwatcher.h
@@ -0,0 +1,54 @@
+/*
+    SPDX-FileCopyrightText: 2022 David Redondo <kde@david-redondo.de>
+
+    SPDX-License-Identifier: LGPL-2.0-only OR LGPL-3.0-only OR LicenseRef-KDE-Accepted-LGPL
+*/
+
+#ifndef KSTANDARDSHORTCUTWATCHER_H
+#define KSTANDARDSHORTCUTWATCHER_H
+
+#include "kstandardshortcut.h"
+
+#include <QObject>
+
+#include <memory>
+
+#include <kconfiggui_export.h>
+
+namespace KStandardShortcut
+{
+class StandardShortcutWatcherPrivate;
+
+/**
+ * Watches for changes made to standard shortcuts and notifies about those changes.
+ * @see KStandardShortcut::shortcutWatcher
+ * @since 5.91
+ */
+class KCONFIGGUI_EXPORT StandardShortcutWatcher : public QObject
+{
+    Q_OBJECT
+public:
+    ~StandardShortcutWatcher();
+Q_SIGNALS:
+    /**
+     * The standardshortcut @p id was changed to @p shortcut
+     */
+    void shortcutChanged(KStandardShortcut::StandardShortcut id, const QList<QKeySequence> &shortcut);
+
+private:
+    explicit StandardShortcutWatcher(QObject *parent = nullptr);
+    friend StandardShortcutWatcher *shortcutWatcher();
+    std::unique_ptr<StandardShortcutWatcherPrivate> d;
+};
+
+/**
+ * Returns the global KStandardShortcutWatcher instance of this program.
+ * In addition to the notifying about changes it also keeps the information returned by the
+ * functions in @p KStandardShortcut up to date.
+ * The object is created by the first call to this function.
+ * @since 5.91
+ */
+KCONFIGGUI_EXPORT StandardShortcutWatcher *shortcutWatcher();
+}
+
+#endif