Add QFutureInterfaceBase::get() to retrieve internals of QFuture

For generic interop with other parts of Qt, we need to be able to
extract the type-erased internal storage of QFuture<T>. In particular,
QtWebChannel needs this to transparently support QFuture<T> as a method
return type.

Task-number: QTBUG-92903
Change-Id: I763f054656b8810d58720262d364baf42c47eb37
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>

1 files changed, 11 insertions, 0 deletions

diff --git a/tests/auto/corelib/thread/qfuture/tst_qfuture.cpp b/tests/auto/corelib/thread/qfuture/tst_qfuture.cpp
index eff07ce309..8eadaee62a 100644
--- a/tests/auto/corelib/thread/qfuture/tst_qfuture.cpp
+++ b/tests/auto/corelib/thread/qfuture/tst_qfuture.cpp
@@ -163,6 +163,8 @@ private slots:
 
     void createReadyFutures();
 
+    void getFutureInterface();
+
 private:
     using size_type = std::vector<int>::size_type;
 
@@ -3521,5 +3523,14 @@ void tst_QFuture::createReadyFutures()
 #endif
 }
 
+void tst_QFuture::getFutureInterface()
+{
+    const int val = 42;
+    QFuture<int> f = QtFuture::makeReadyFuture(val);
+
+    auto interface = QFutureInterfaceBase::get(f);
+    QCOMPARE(interface.resultCount(), 1);
+}
+
 QTEST_MAIN(tst_QFuture)
 #include "tst_qfuture.moc"