2 files changed, 50 insertions, 0 deletions

diff --git a/async/src/async.h b/async/src/async.h
index 386722a..d21caf8 100644
--- a/async/src/async.h
+++ b/async/src/async.h
@@ -291,6 +291,12 @@ public:
             new Private::SyncThenExecutor<OutOther, InOther ...>(func, errorFunc, mExecutor)));
     }
 
+    template<typename OutOther, typename ... InOther>
+    Job<OutOther, InOther ...> then(Job<OutOther, InOther ...> otherJob, ErrorHandler errorFunc = ErrorHandler())
+    {
+        return then<OutOther, InOther ...>(nestedJobWrapper<OutOther, InOther ...>(otherJob), errorFunc);
+    }
+
     template<typename OutOther, typename InOther>
     Job<OutOther, InOther> each(EachTask<OutOther, InOther> func, ErrorHandler errorFunc = ErrorHandler())
     {
@@ -308,6 +314,13 @@ public:
     }
 
     template<typename OutOther, typename InOther>
+    Job<OutOther, InOther> each(Job<OutOther, InOther> otherJob, ErrorHandler errorFunc = ErrorHandler())
+    {
+        eachInvariants<OutOther>();
+        return each<OutOther, InOther>(nestedJobWrapper<OutOther, InOther>(otherJob), errorFunc);
+    }
+
+    template<typename OutOther, typename InOther>
     Job<OutOther, InOther> reduce(ReduceTask<OutOther, InOther> func, ErrorHandler errorFunc = ErrorHandler())
     {
         reduceInvariants<InOther>();
@@ -323,6 +336,12 @@ public:
             new Private::SyncReduceExecutor<OutOther, InOther>(func, errorFunc, mExecutor)));
     }
 
+    template<typename OutOther, typename InOther>
+    Job<OutOther, InOther> reduce(Job<OutOther, InOther> otherJob, ErrorHandler errorFunc = ErrorHandler())
+    {
+        return reduce<OutOther, InOther>(nestedJobWrapper<OutOther, InOther>(otherJob), errorFunc);
+    }
+
     template<typename FirstIn>
     Async::Future<Out> exec(FirstIn in)
     {
@@ -377,6 +396,22 @@ private:
         static_assert(std::is_same<typename Out::value_type, typename InOther::value_type>::value,
                       "The return type of previous task must be compatible with input type of this task");
     }
+
+    template<typename OutOther, typename ... InOther>
+    inline std::function<void(InOther ..., Async::Future<OutOther>&)> nestedJobWrapper(Job<OutOther, InOther ...> otherJob) {
+        return [otherJob](InOther ... in, Async::Future<OutOther> &future) {
+            // copy by value is const
+            auto job = otherJob;
+            FutureWatcher<OutOther> *watcher = new FutureWatcher<OutOther>();
+            QObject::connect(watcher, &FutureWatcherBase::futureReady,
+                             [watcher, &future]() {
+                                 Async::detail::copyFutureValue(watcher->future(), future);
+                                 future.setFinished();
+                                 watcher->deleteLater();
+                             });
+            watcher->setFuture(job.exec(in ...));
+        };
+    }
 };
 
 } // namespace Async
diff --git a/async/src/async_impl.h b/async/src/async_impl.h
index 58f6ced..eccbc9b 100644
--- a/async/src/async_impl.h
+++ b/async/src/async_impl.h
@@ -19,6 +19,7 @@
 #define ASYNC_IMPL_H
 
 #include "async.h"
+#include <type_traits>
 
 namespace Async {
 
@@ -45,6 +46,20 @@ struct prevOut {
     using type = typename std::tuple_element<0, std::tuple<T ..., void>>::type;
 };
 
+template<typename T>
+inline typename std::enable_if<!std::is_void<T>::value, void>::type
+copyFutureValue(const Async::Future<T> &in, Async::Future<T> &out)
+{
+    out.setValue(in.value());
+}
+
+template<typename T>
+inline typename std::enable_if<std::is_void<T>::value, void>::type
+copyFutureValue(const Async::Future<T> &in, Async::Future<T> &out)
+{
+    // noop
+}
+
 } // namespace Detail
 
 } // namespace Async