dbusmenu: Refactor the code to allow dynamic updating of menus

* Transfer propertiesUpdated and updated signals from submenus to parent
  menus. Without this, the adaptor only receives this signal from top-level
  menu items, and doesn't receive it from items of submenus. Connect to
  these signals when a menu item is added or synced, and disconnect when it
  is removed.
* Make QDBusPlatformMenus use IDs of items containing them, not their own
  IDs (own IDs do not make any sense since they are not exported over D-Bus).
* Store toplevel menus per-adaptor, to make it possible to export multiple
  menus (for example a menubar and a tray icon menu).
* Adjust the QDBusMenuLayoutItem::populate methods to always get the menu
  via its containing item and to populate the menus recursively.
* Map D-Bus menu AboutToShow method to platform menu aboutToShow method,
  and map hovered and closed events to hovered and aboutToHide signals.
  (QTBUG-46293)
* Always set the visible property on item. Otherwise, when an item becomes
  visible, the D-Bus menu still thinks it's invisible because that property
  was not changed back to true. (QTBUG-48647)
* Call emitUpdated from insertMenuItem and removeMenuItem methods, as they
  really update layout. Do not call it from syncMenuItem, it changes only
  properties but not the layout.
* Start revision numbering with 1, because libdbusmenu-based hosts ignore
  updated signal with revision=1.

Task-number: QTBUG-46293
Task-number: QTBUG-48647
Change-Id: Icf713405db0443e25462c1a19046df7689fe5e78
Reviewed-by: Shawn Rutledge <shawn.rutledge@theqtcompany.com>
Reviewed-by: Błażej Szczygieł <spaz16@wp.pl>

1 files changed, 49 insertions, 22 deletions

diff --git a/src/platformsupport/dbusmenu/qdbusplatformmenu.cpp b/src/platformsupport/dbusmenu/qdbusplatformmenu.cpp
index 62f041bc86..9f99ef97e5 100644
--- a/src/platformsupport/dbusmenu/qdbusplatformmenu.cpp
+++ b/src/platformsupport/dbusmenu/qdbusplatformmenu.cpp
@@ -41,9 +41,7 @@ QT_BEGIN_NAMESPACE
 Q_LOGGING_CATEGORY(qLcMenu, "qt.qpa.menu")
 
 static int nextDBusID = 1;
-QHash<int, QDBusPlatformMenu *> menusByID;
 QHash<int, QDBusPlatformMenuItem *> menuItemsByID;
-QList<QDBusPlatformMenu *> QDBusPlatformMenu::m_topLevelMenus;
 
 QDBusPlatformMenuItem::QDBusPlatformMenuItem(quintptr tag)
     : m_tag(tag ? tag : reinterpret_cast<quintptr>(this)) // QMenu will overwrite this later
@@ -85,7 +83,11 @@ void QDBusPlatformMenuItem::setIcon(const QIcon &icon)
 */
 void QDBusPlatformMenuItem::setMenu(QPlatformMenu *menu)
 {
-    m_subMenu = static_cast<QDBusPlatformMenu *>(menu);
+    if (m_subMenu)
+        static_cast<QDBusPlatformMenu *>(m_subMenu)->setContainingMenuItem(Q_NULLPTR);
+    m_subMenu = menu;
+    if (menu)
+        static_cast<QDBusPlatformMenu *>(menu)->setContainingMenuItem(this);
 }
 
 void QDBusPlatformMenuItem::setEnabled(bool enabled)
@@ -130,7 +132,11 @@ void QDBusPlatformMenuItem::trigger()
 
 QDBusPlatformMenuItem *QDBusPlatformMenuItem::byId(int id)
 {
-    return menuItemsByID[id];
+    // We need to check contains because otherwise QHash would insert
+    // a default-constructed nullptr value into menuItemsByID
+    if (menuItemsByID.contains(id))
+        return menuItemsByID[id];
+    return Q_NULLPTR;
 }
 
 QList<const QDBusPlatformMenuItem *> QDBusPlatformMenuItem::byIds(const QList<int> &ids)
@@ -149,18 +155,13 @@ QDBusPlatformMenu::QDBusPlatformMenu(quintptr tag)
     , m_isEnabled(true)
     , m_isVisible(true)
     , m_isSeparator(false)
-    , m_dbusID(nextDBusID++)
-    , m_revision(0)
+    , m_revision(1)
+    , m_containingMenuItem(Q_NULLPTR)
 {
-    menusByID.insert(m_dbusID, this);
-    // Assume it's top-level until we find out otherwise
-    m_topLevelMenus << this;
 }
 
 QDBusPlatformMenu::~QDBusPlatformMenu()
 {
-    menusByID.remove(m_dbusID);
-    m_topLevelMenus.removeOne(this);
 }
 
 void QDBusPlatformMenu::insertMenuItem(QPlatformMenuItem *menuItem, QPlatformMenuItem *before)
@@ -174,38 +175,59 @@ void QDBusPlatformMenu::insertMenuItem(QPlatformMenuItem *menuItem, QPlatformMen
     else
         m_items.insert(idx, item);
     m_itemsByTag.insert(item->tag(), item);
-    // If a menu is found as a submenu under an item, we know that it's not a top-level menu.
     if (item->menu())
-        m_topLevelMenus.removeOne(const_cast<QDBusPlatformMenu *>(static_cast<const QDBusPlatformMenu *>(item->menu())));
+        syncSubMenu(static_cast<const QDBusPlatformMenu *>(item->menu()));
+    emitUpdated();
 }
 
 void QDBusPlatformMenu::removeMenuItem(QPlatformMenuItem *menuItem)
 {
-    m_items.removeAll(static_cast<QDBusPlatformMenuItem *>(menuItem));
+    QDBusPlatformMenuItem *item = static_cast<QDBusPlatformMenuItem *>(menuItem);
+    m_items.removeAll(item);
     m_itemsByTag.remove(menuItem->tag());
+    if (item->menu()) {
+        // disconnect from the signals we connected to in syncSubMenu()
+        const QDBusPlatformMenu *menu = static_cast<const QDBusPlatformMenu *>(item->menu());
+        disconnect(menu, &QDBusPlatformMenu::propertiesUpdated,
+                   this, &QDBusPlatformMenu::propertiesUpdated);
+        disconnect(menu, &QDBusPlatformMenu::updated,
+                   this, &QDBusPlatformMenu::updated);
+    }
+    emitUpdated();
+}
+
+void QDBusPlatformMenu::syncSubMenu(const QDBusPlatformMenu *menu)
+{
+    // The adaptor is only connected to the propertiesUpdated signal of the top-level
+    // menu, so the submenus should transfer their signals to their parents.
+    connect(menu, &QDBusPlatformMenu::propertiesUpdated,
+            this, &QDBusPlatformMenu::propertiesUpdated, Qt::UniqueConnection);
+    connect(menu, &QDBusPlatformMenu::updated,
+            this, &QDBusPlatformMenu::updated, Qt::UniqueConnection);
 }
 
 void QDBusPlatformMenu::syncMenuItem(QPlatformMenuItem *menuItem)
 {
+    QDBusPlatformMenuItem *item = static_cast<QDBusPlatformMenuItem *>(menuItem);
+    // if a submenu was added to this item, we need to connect to its signals
+    if (item->menu())
+        syncSubMenu(static_cast<const QDBusPlatformMenu *>(item->menu()));
     // TODO keep around copies of the QDBusMenuLayoutItems so they can be updated?
     // or eliminate them by putting dbus streaming operators in this class instead?
     // or somehow tell the dbusmenu client that something has changed, so it will ask for properties again
-    emitUpdated();
     QDBusMenuItemList updated;
     QDBusMenuItemKeysList removed;
-    updated << QDBusMenuItem(static_cast<QDBusPlatformMenuItem *>(menuItem));
+    updated << QDBusMenuItem(item);
     qCDebug(qLcMenu) << updated;
     emit propertiesUpdated(updated, removed);
 }
 
-QDBusPlatformMenu *QDBusPlatformMenu::byId(int id)
-{
-    return menusByID[id];
-}
-
 void QDBusPlatformMenu::emitUpdated()
 {
-    emit updated(++m_revision, m_dbusID);
+    if (m_containingMenuItem)
+        emit updated(++m_revision, m_containingMenuItem->dbusID());
+    else
+        emit updated(++m_revision, 0);
 }
 
 void QDBusPlatformMenu::setTag(quintptr tag)
@@ -233,6 +255,11 @@ void QDBusPlatformMenu::setVisible(bool isVisible)
     m_isVisible = isVisible;
 }
 
+void QDBusPlatformMenu::setContainingMenuItem(QDBusPlatformMenuItem *item)
+{
+    m_containingMenuItem = item;
+}
+
 QPlatformMenuItem *QDBusPlatformMenu::menuItemAt(int position) const
 {
     return m_items.at(position);