2 files changed, 56 insertions, 3 deletions

diff --git a/src/corelib/tools/qlist.cpp b/src/corelib/tools/qlist.cpp
index d954160..868bed1 100644
--- a/src/corelib/tools/qlist.cpp
+++ b/src/corelib/tools/qlist.cpp
@@ -98,12 +98,45 @@ QListData::Data *QListData::detach()
  *
  *  \internal
  */
+#if QT_VERSION >= 0x050000
+#  error "Remove QListData::detach2(), it is only required for binary compatibility for 4.3.x to 4.5.x"
+#endif
 QListData::Data *QListData::detach2()
 {
     Data *x = d;
     Data* t = static_cast<Data *>(qMalloc(DataHeaderSize + x->alloc * sizeof(void *)));
     Q_CHECK_PTR(t);
 
+    ::memcpy(x, d, DataHeaderSize + d->alloc * sizeof(void *));
+
+    t->ref = 1;
+    t->sharable = true;
+    t->alloc = x->alloc;
+    if (!t->alloc) {
+        t->begin = 0;
+        t->end = 0;
+    } else {
+        t->begin = x->begin;
+        t->end   = x->end;
+    }
+    d = t;
+
+    return x;
+}
+
+/*!
+ *  Detaches the QListData by reallocating new memory.
+ *  Returns the old (shared) data, it is up to the caller to deref() and free()
+ *  For the new data node_copy needs to be called.
+ *
+ *  \internal
+ */
+QListData::Data *QListData::detach3()
+{
+    Data *x = d;
+    Data* t = static_cast<Data *>(qMalloc(DataHeaderSize + x->alloc * sizeof(void *)));
+    Q_CHECK_PTR(t);
+
     t->ref = 1;
     t->sharable = true;
     t->alloc = x->alloc;
@@ -150,6 +183,9 @@ void **QListData::append()
 }
 
 // ensures that enough space is available to append the list
+#if QT_VERSION >= 0x050000
+#  error "Remove QListData::append(), it is only required for binary compatibility up to 4.5.x"
+#endif
 void **QListData::append(const QListData& l)
 {
     Q_ASSERT(d->ref == 1);
@@ -158,6 +194,21 @@ void **QListData::append(const QListData& l)
     if (n) {
         if (e + n > d->alloc)
             realloc(grow(e + l.d->end - l.d->begin));
+        ::memcpy(d->array + d->end, l.d->array + l.d->begin, n*sizeof(void*));
+        d->end += n;
+    }
+    return d->array + e;
+}
+
+// ensures that enough space is available to append the list
+void **QListData::append2(const QListData& l)
+{
+    Q_ASSERT(d->ref == 1);
+    int e = d->end;
+    int n = l.d->end - l.d->begin;
+    if (n) {
+        if (e + n > d->alloc)
+            realloc(grow(e + l.d->end - l.d->begin));
         d->end += n;
     }
     return d->array + e;
diff --git a/src/corelib/tools/qlist.h b/src/corelib/tools/qlist.h
index ab6f7bd..331f448 100644
--- a/src/corelib/tools/qlist.h
+++ b/src/corelib/tools/qlist.h
@@ -72,13 +72,15 @@ struct Q_CORE_EXPORT QListData {
     enum { DataHeaderSize = sizeof(Data) - sizeof(void *) };
 
     Data *detach(); // remove in 5.0
-    Data *detach2();
+    Data *detach2(); // remove in 5.0
+    Data *detach3();
     void realloc(int alloc);
     static Data shared_null;
     Data *d;
     void **erase(void **xi);
     void **append();
     void **append(const QListData &l);
+    void **append2(const QListData &l); // remove in 5.0
     void **prepend();
     void **insert(int i);
     void remove(int i);
@@ -593,7 +595,7 @@ template <typename T>
 Q_OUTOFLINE_TEMPLATE void QList<T>::detach_helper()
 {
     Node *n = reinterpret_cast<Node *>(p.begin());
-    QListData::Data *x = p.detach2();
+    QListData::Data *x = p.detach3();
     QT_TRY {
         node_copy(reinterpret_cast<Node *>(p.begin()), reinterpret_cast<Node *>(p.end()), n);
     } QT_CATCH(...) {
@@ -693,7 +695,7 @@ template <typename T>
 Q_OUTOFLINE_TEMPLATE QList<T> &QList<T>::operator+=(const QList<T> &l)
 {
     detach();
-    Node *n = reinterpret_cast<Node *>(p.append(l.p));
+    Node *n = reinterpret_cast<Node *>(p.append2(l.p));
     QT_TRY{
         node_copy(n, reinterpret_cast<Node *>(p.end()), reinterpret_cast<Node *>(l.p.begin()));
     } QT_CATCH(...) {