Wrap calls to Sequence::push_back

In C++11 push_back is overloaded to support rvalue-references,

   void std::vector<T>::push_back(const T &);
   void std::vector<T>::push_back(T &&);

so attempting to get the address for push_back is ambiguous.

Instead of hardcoding the function signature, the better and more
general solution is to allow the compiler to do the required overload
resolution itself, also allowing for implicit conversions to take place.

Task-number: QTBUG-18996
Done-with: Liang Qi
Reviewed-by: Olivier Goffart

1 files changed, 9 insertions, 11 deletions

diff --git a/src/corelib/concurrent/qtconcurrentfilter.h b/src/corelib/concurrent/qtconcurrentfilter.h
index 4b9c4ae..d8c5f43 100644
--- a/src/corelib/concurrent/qtconcurrentfilter.h
+++ b/src/corelib/concurrent/qtconcurrentfilter.h
@@ -102,10 +102,9 @@ namespace QtConcurrent {
 
 namespace QtConcurrent {
 
-template <typename Sequence, typename KeepFunctor, typename T, typename C, typename U>
-ThreadEngineStarter<void> filterInternal(Sequence &sequence, KeepFunctor keep, T (C::*reduce)(U))
+template <typename Sequence, typename KeepFunctor, typename ReduceFunctor>
+ThreadEngineStarter<void> filterInternal(Sequence &sequence, KeepFunctor keep, ReduceFunctor reduce)
 {
-    typedef MemberFunctionWrapper1<T, C, U> ReduceFunctor;
     typedef typename Sequence::const_iterator Iterator;
     typedef FilterKernel<Sequence, KeepFunctor, ReduceFunctor> KernelType;
     return startThreadEngine(new KernelType(sequence, keep, reduce));
@@ -115,7 +114,7 @@ ThreadEngineStarter<void> filterInternal(Sequence &sequence, KeepFunctor keep, T
 template <typename Sequence, typename KeepFunctor>
 QFuture<void> filter(Sequence &sequence, KeepFunctor keep)
 {
-    return filterInternal(sequence, QtPrivate::createFunctionWrapper(keep), &Sequence::push_back);
+    return filterInternal(sequence, QtPrivate::createFunctionWrapper(keep), QtPrivate::PushBackWrapper());
 }
 
 // filteredReduced() on sequences
@@ -184,7 +183,7 @@ QFuture<typename qValueType<Iterator>::value_type> filtered(Iterator begin, Iter
 template <typename Sequence, typename KeepFunctor>
 void blockingFilter(Sequence &sequence, KeepFunctor keep)
 {
-    filterInternal(sequence, QtPrivate::createFunctionWrapper(keep), &Sequence::push_back).startBlocking();
+    filterInternal(sequence, QtPrivate::createFunctionWrapper(keep), QtPrivate::PushBackWrapper()).startBlocking();
 }
 
 // blocking filteredReduced() on sequences
@@ -246,18 +245,17 @@ typename QtPrivate::ReduceResultType<ReduceFunctor>::ResultType blockingFiltered
 template <typename Sequence, typename KeepFunctor>
 Sequence blockingFiltered(const Sequence &sequence, KeepFunctor keep)
 {
-    return blockingFilteredReduced(sequence, QtPrivate::createFunctionWrapper(keep), &Sequence::push_back, OrderedReduce);
+    return startFilteredReduced<Sequence>(sequence, QtPrivate::createFunctionWrapper(keep), QtPrivate::PushBackWrapper(), OrderedReduce).startBlocking();
 }
 
 // blocking filtered() on iterators
 template <typename OutputSequence, typename Iterator, typename KeepFunctor>
 OutputSequence blockingFiltered(Iterator begin, Iterator end, KeepFunctor keep)
 {
-    return blockingFilteredReduced(begin,
-                                   end,
-                                   QtPrivate::createFunctionWrapper(keep),
-                                   &OutputSequence::push_back,
-                                   OrderedReduce);
+    return startFilteredReduced<OutputSequence>(begin, end,
+        QtPrivate::createFunctionWrapper(keep),
+        QtPrivate::PushBackWrapper(),
+        OrderedReduce).startBlocking();
 }
 
 } // namespace QtConcurrent