KDE/kdelibs/solid/solid/backends/wmi

[Ralf Habacker]

SVN commit 986074 by habacker:

bug fix -> "When WmiQuery is created as static global object a dead lock problem occurs"

CCMAIL:kde-windows at kde.org


 M  +21 -5     wmidevice.cpp  


--- trunk/KDE/kdelibs/solid/solid/backends/wmi/wmidevice.cpp #986073:986074
@@ -69,10 +69,24 @@
         , m_wmiProperty()
         , m_wmiValue()
     {    
+        /*
+            To avoid multiple connects to wmi in a single application
+            one WmiQuery object is used. 
+            When WmiQuery is created as static global object 
+            a dead lock problem occurs (see wmiquery.cpp for details).
+            Because solid is only qt based and Q_GLOBAL_STATIC is 
+            marked as internal we make our own reference counting.
+       */
+        m_instanceCount++;
+        if (!m_query && m_instanceCount == 1)
+            m_query = new WmiQuery;
     }
 
     ~WmiDevicePrivate()
     {
+        m_instanceCount--;
+        if (m_instanceCount == 0)
+            delete m_query;
     }
     
     void discoverType()
@@ -90,7 +104,7 @@
     WmiQuery::ItemList sendQuery() 
     {
         QString query("SELECT * FROM " + m_wmiTable + " WHERE " + m_wmiProperty + "='" + m_wmiValue + "'");
-        WmiQuery::ItemList list = m_query.sendQuery(query);
+        WmiQuery::ItemList list = m_query->sendQuery(query);
         return list;
     }
     
@@ -119,7 +133,7 @@
             return false;
 
         QString query("SELECT * FROM " + wmiTable + " WHERE " + wmiProperty + "='" + wmiValue + "'");
-        WmiQuery::ItemList list = m_query.sendQuery(query);
+        WmiQuery::ItemList list = m_query->sendQuery(query);
         return list.size() > 0;
     }
 
@@ -256,7 +270,7 @@
     {
         QStringList result;
         
-        WmiQuery::ItemList list = m_query.sendQuery( "select * from " + getWMITable(type) );
+        WmiQuery::ItemList list = m_query->sendQuery( "select * from " + getWMITable(type) );
         foreach(WmiQuery::Item *item, list) {
             QString propertyName = getPropertyNameForUDI(type);
             QString property = item->getProperty(propertyName);
@@ -267,7 +281,8 @@
     }
     
     WmiDevice *parent;
-    static WmiQuery m_query;
+    static WmiQuery *m_query;
+    static int m_instanceCount;
     QString m_udi;
     QString m_wmiTable;
     QString m_wmiProperty;
@@ -275,7 +290,8 @@
     QStringList interfaceList;
 };
 
-WmiQuery WmiDevicePrivate::m_query;
+WmiQuery *WmiDevicePrivate::m_query = 0;
+int WmiDevicePrivate::m_instanceCount = 0;
 
 Q_DECLARE_METATYPE(ChangeDescription)
 Q_DECLARE_METATYPE(QList<ChangeDescription>)