Fix a very important bug when streaming pointer through QVariant for

containers. The QVariant that receives the stream must be reinitialize
at each step, otherwise it keeps the same poiinter to stream the data.
In other words, it was the same pointer that was push_back in the container.

src/dtkMeta/dtkMeta.tpp

@@ -72,8 +72,9 @@ template <typename T> inline QDataStream& operator << (QDataStream& s, T *t)
 
 template <typename T> inline QDataStream& operator >> (QDataStream& s, T *& t)
 {
-    if (!t)
+    if (!t) {
         t = new T();
+    }
 
     s >> *t;
     return s;
@@ -91,8 +92,8 @@ template<typename T> inline QDataStream& operator >> (QDataStream& s, const QLis
 {
     l.clear();
     quint32 c; s >> c;
-    QVariant var;
     for(quint32 i = 0; i < c; ++i) {
+        QVariant var;
         s >> var;
         l << var.value<T *>();
         if (s.atEnd())
@@ -114,8 +115,8 @@ template<typename T> inline QDataStream& operator >> (QDataStream& s, QVector<T
     v.clear();
     quint32 c; s >> c;
     v.resize(c);
-    QVariant var;
     for(quint32 i = 0; i < c; ++i) {
+        QVariant var;
         s >> var;
         v[i] = var.value<T *>();
     }
@@ -134,8 +135,8 @@ template<typename T> inline QDataStream& operator >> (QDataStream& s, const std:
 {
     l.clear();
     quint32 c; s >> c;
-    QVariant var;
     for(quint32 i = 0; i < c; ++i) {
+        QVariant var;
         s >> var;
         l.push_back(var.value<T *>());
         if (s.atEnd())
@@ -157,8 +158,8 @@ template<typename T> inline QDataStream& operator >> (QDataStream& s, const std:
     v.clear();
     quint32 c; s >> c;
     v.resize(c);
-    QVariant var;
     for(quint32 i = 0; i < c; ++i) {
+        QVariant var; // Very important to instantiate a void QVariant at each step, otherwise, it keeps the same pointer T* to store the stream.
         s >> var;
         v[i] = var.value<T *>();
     }