File 0010-Reuse-QAction-and-QMenu-items-on-updates.patch of Package plasma5-workspace

From 7fc50d60dbef6a18fffc2e2e7e1e3de5a01eb84a Mon Sep 17 00:00:00 2001
From: David Edmundson <kde@davidedmundson.co.uk>
Date: Wed, 11 Jan 2017 13:52:57 +0000
Subject: [PATCH 10/44] Reuse QAction and QMenu items on updates

Summary:
When updating a menu we would always delete all the actions and recreate
them.

This caused a problem that we would also be deleting submenus and
recreating them, meaning when we update the applet's submenu before
showing it, our submenu will always be destroyed.

This patch uses the DBusMenuItem IDs to re-use existing QAction / QMenu
objects and only create new instances when needed. It should also be (in
theory) faster as there's a lot less object creation every update.

Also replace QSignalMapper with a lambda and replace replace QMap<int,
QPointer<QAction*> with QMap<int, QAction*> and a lambda to do cleanup
on deletion.

Test Plan:
Tweked the applet to update before showing
Original QMenu object used before showing still has all the items

Reviewers: #plasma

Subscribers: broulik, markg, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D4057
---
 libdbusmenuqt/dbusmenuimporter.cpp | 49 ++++++++++++++++++++++++--------------
 1 file changed, 31 insertions(+), 18 deletions(-)

diff --git a/libdbusmenuqt/dbusmenuimporter.cpp b/libdbusmenuqt/dbusmenuimporter.cpp
index 9494c95f..2af1162f 100644
--- a/libdbusmenuqt/dbusmenuimporter.cpp
+++ b/libdbusmenuqt/dbusmenuimporter.cpp
@@ -29,7 +29,6 @@
 #include <QFont>
 #include <QMenu>
 #include <QPointer>
-#include <QSignalMapper>
 #include <QTime>
 #include <QTimer>
 #include <QToolButton>
@@ -82,9 +81,8 @@ public:
 
     QDBusAbstractInterface *m_interface;
     QMenu *m_menu;
-    typedef QMap<int, QPointer<QAction> > ActionForId;
+    using ActionForId = QMap<int, QAction* >;
     ActionForId m_actionForId;
-    QSignalMapper m_mapper;
     QTimer *m_pendingLayoutUpdateTimer;
 
     QSet<int> m_idsRefreshedByAboutToShow;
@@ -291,8 +289,6 @@ DBusMenuImporter::DBusMenuImporter(const QString &service, const QString &path,
     d->m_menu = 0;
     d->m_nPendingRequests = 0;
 
-    connect(&d->m_mapper, SIGNAL(mapped(int)), SLOT(sendClickedEvent(int)));
-
     d->m_pendingLayoutUpdateTimer = new QTimer(this);
     d->m_pendingLayoutUpdateTimer->setSingleShot(true);
     connect(d->m_pendingLayoutUpdateTimer, &QTimer::timeout, this, &DBusMenuImporter::processPendingLayoutUpdates);
@@ -411,22 +407,41 @@ void DBusMenuImporter::slotGetLayoutFinished(QDBusPendingCallWatcher *watcher)
         return;
     }
 
-    menu->clear();
+    //remove outdated actions
+    QSet<int> newDBusMenuItemIds;
+    newDBusMenuItemIds.reserve(rootItem.children.count());
+    for (const DBusMenuLayoutItem &item: rootItem.children) {
+        newDBusMenuItemIds << item.id;
+    }
+    for (QAction *action: menu->actions()) {
+        int id = action->property(DBUSMENU_PROPERTY_ID).toInt();
+        if (! newDBusMenuItemIds.contains(id)) {
+            action->deleteLater();
+            d->m_actionForId.remove(id);
+        }
+    }
 
-    Q_FOREACH(const DBusMenuLayoutItem &dbusMenuItem, rootItem.children) {
-        QAction *action = d->createAction(dbusMenuItem.id, dbusMenuItem.properties, menu);
+    //insert or update new actions into our menu
+    for (const DBusMenuLayoutItem &dbusMenuItem: rootItem.children) {
         DBusMenuImporterPrivate::ActionForId::Iterator it = d->m_actionForId.find(dbusMenuItem.id);
+        QAction *action = nullptr;
         if (it == d->m_actionForId.end()) {
-            d->m_actionForId.insert(dbusMenuItem.id, action);
+            int id = dbusMenuItem.id;
+            action = d->createAction(id, dbusMenuItem.properties, menu);
+            d->m_actionForId.insert(id, action);
+            connect(action, &QObject::destroyed, this, [this, id]() {
+                d->m_actionForId.remove(id);
+            });
+
+            connect(action, &QAction::triggered, this, [action, id, this]() {
+                sendClickedEvent(id);
+            });
+
+            menu->addAction(action);
         } else {
-            delete *it;
-            *it = action;
+            action = *it;
+            d->updateAction(*it, dbusMenuItem.properties, dbusMenuItem.properties.keys());
         }
-        menu->addAction(action);
-
-        connect(action, SIGNAL(triggered()),
-            &d->m_mapper, SLOT(map()));
-        d->m_mapper.setMapping(action, dbusMenuItem.id);
 
         if( action->menu() )
         {
@@ -515,8 +530,6 @@ void DBusMenuImporter::slotMenuAboutToShow()
     d->sendEvent(id, QStringLiteral("opened"));
 }
 
-
-
 QMenu *DBusMenuImporter::createMenu(QWidget *parent)
 {
     return new QMenu(parent);
-- 
2.12.0