put sourceLimit back in, add an accessor as well. used by akonadi

svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=800769

dataengine.cpp

@@ -418,6 +418,26 @@ void DataEngine::addSource(DataContainer* source)
     emit sourceAdded(source->objectName());
 }
 
+void DataEngine::setSourceLimit(uint limit)
+{
+    if (d->limit == limit) {
+        return;
+    }
+
+    d->limit = limit;
+
+    if (d->limit > 0) {
+        d->trimQueue();
+    } else {
+        d->sourceQueue.clear();
+    }
+}
+
+uint DataEngine::sourceLimit() const
+{
+    return d->limit;
+}
+
 void DataEngine::setMinimumPollingInterval(int minimumMs)
 {
     d->minPollingInterval = minimumMs;

dataengine.h

@@ -196,6 +196,14 @@ class PLASMA_EXPORT DataEngine : public QObject
          */
         bool isEmpty() const;
 
+        /**
+         * Returns the maximum number of sources this DataEngine will list
+         * at any given time.
+         *
+         * @return the maximum number of sources; zero means no limit.
+         */
+        uint sourceLimit() const;
+
         /**
          * @return the name of the icon for this data engine; and empty string
          *         is returned if there is no associated icon.
@@ -307,6 +315,15 @@ class PLASMA_EXPORT DataEngine : public QObject
          **/
         void addSource(DataContainer* source);
 
+        /**
+         * Sets an upper limit on the number of data sources to keep in this engine.
+         * If the limit is exceeded, then the oldest data source, as defined by last
+         * update, is dropped.
+         *
+         * @param limit the maximum number of sources to keep active
+         **/
+        void setSourceLimit(uint limit);
+
         /**
          * Sets the minimum amount of time, in milliseconds, that must pass between
          * successive updates of data. This can help prevent too many updates happening

scripting/dataenginescript.cpp

@@ -92,6 +92,13 @@ void DataEngineScript::removeData(const QString& source, const QString& key)
     }
 }
 
+void DataEngineScript::setSourceLimit(uint limit)
+{
+    if (d->dataEngine) {
+        d->dataEngine->setSourceLimit(limit);
+    }
+}
+
 void DataEngineScript::setMinimumPollingInterval(int minimumMs)
 {
     if (d->dataEngine) {

scripting/dataenginescript.h

@@ -80,6 +80,7 @@ protected:
     void setData(const QString &source, const QVariant &value);
     void clearData(const QString& source);
     void removeData(const QString& source, const QString& key);
+    void setSourceLimit(uint limit);
     void setMinimumPollingInterval(int minimumMs);
     int  minimumPollingInterval() const;
     void setPollingInterval(uint frequency);