From 56429d3adc0e513eb5a69568ff66d4b2852a5c55 Mon Sep 17 00:00:00 2001
From: Michael Olbrich <michael.olbrich@gmx.net>
Date: Sat, 1 Sep 2007 22:23:03 +0000
Subject: [PATCH] check for unused DataContainers in a way that actually works.

svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=707450
---
 datacontainer.cpp | 19 +++++--------------
 datacontainer.h   |  9 ++++++++-
 dataengine.cpp    |  6 +++++-
 3 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/datacontainer.cpp b/datacontainer.cpp
index f77cedc4f..765a0315d 100644
--- a/datacontainer.cpp
+++ b/datacontainer.cpp
@@ -33,7 +33,6 @@ class DataContainer::Private
         {}
 
         DataEngine::Data data;
-        int connectCount;
         bool dirty : 1;
 };
 
@@ -87,25 +86,17 @@ void DataContainer::checkForUpdate()
     }
 }
 
-void DataContainer::connectNotify(const char *signal)
+void DataContainer::checkUsage()
 {
-    if (QLatin1String(signal) == QMetaObject::normalizedSignature(SIGNAL(updated(QString, Plasma::DataEngine::Data))).constData()) {
-        ++d->connectCount;
+    if (receivers(SIGNAL(updated(QString, Plasma::DataEngine::Data))) < 1) {
+        // DO NOT CALL ANYTHING AFTER THIS LINE AS IT MAY GET DELETED!
+        emit unused(objectName());
     }
 }
 
 void DataContainer::disconnectNotify(const char *signal)
 {
-    if (QLatin1String(signal) == QMetaObject::normalizedSignature(SIGNAL(updated(QString, Plasma::DataEngine::Data))).constData()) {
-        if (d->connectCount > 0) {
-            --d->connectCount;
-        }
-
-        if (d->connectCount < 1) {
-            // DO NOT CALL ANYTHING AFTER THIS LINE AS IT MAY GET DELETED!
-            emit unused(objectName());
-        }
-    }
+    checkUsage();
 }
 
 } // Plasma namespace
diff --git a/datacontainer.h b/datacontainer.h
index 8864012a7..1e39f1987 100644
--- a/datacontainer.h
+++ b/datacontainer.h
@@ -80,6 +80,14 @@ class PLASMA_EXPORT DataContainer : public QObject
          **/
         void checkForUpdate();
 
+    public Q_SLOTS:
+        /**
+         * Check if the DataContainer is still in use.
+         * If not the signal "unused" will be emitted.
+         * Warning: The DataContainer may be invalid after calling this function.
+         */
+        void checkUsage();
+
     Q_SIGNALS:
         /**
          * Emitted when the data has been updated, allowing visualization to
@@ -93,7 +101,6 @@ class PLASMA_EXPORT DataContainer : public QObject
         void unused(const QString& source);
 
     protected:
-        void connectNotify(const char *signal);
         void disconnectNotify(const char *signal);
 
     private:
diff --git a/dataengine.cpp b/dataengine.cpp
index 719c42133..c0d3d6454 100644
--- a/dataengine.cpp
+++ b/dataengine.cpp
@@ -154,6 +154,7 @@ void DataEngine::connectSource(const QString& source, QObject* visualization) co
         return;
     }
 
+    connect(visualization, SIGNAL(destroyed(QObject*)), s, SLOT(checkUsage()), Qt::QueuedConnection);
     connect(s, SIGNAL(updated(QString,Plasma::DataEngine::Data)),
             visualization, SLOT(updated(QString,Plasma::DataEngine::Data)));
     QMetaObject::invokeMethod(visualization, "updated",
@@ -200,7 +201,9 @@ DataEngine::Data DataEngine::query(const QString& source) const
         return DataEngine::Data();
     }
 
-    return s->data();
+    DataEngine::Data data = s->data();
+    s->checkUsage();
+    return data;
 }
 
 void DataEngine::startInit()
@@ -296,6 +299,7 @@ void DataEngine::removeSource(const QString& source)
     SourceDict::iterator it = d->sources.find(source);
     if (it != d->sources.end()) {
         emit sourceRemoved(it.key());
+        it.value()->deleteLater();
         d->sources.erase(it);
     }
 }