collect()

[folly.git] / folly / futures / Future.h

diff --git a/folly/futures/Future.h b/folly/futures/Future.h
index 6919fd4e32a89e049ba802eb263829895576b489..90207dd8a1000a807b9a18a9ba99b1d17d2a2934 100644 (file)
--- a/folly/futures/Future.h
+++ b/folly/futures/Future.h
@@ -56,6 +56,7 @@ namespace detail {
 
 template <class> struct Core;
 template <class...> struct VariadicContext;
+template <class> struct CollectContext;
 
 template<typename F, typename... Args>
 using resultOf = decltype(std::declval<F>()(std::declval<Args>()...));
@@ -622,6 +623,15 @@ typename detail::VariadicContext<
   typename std::decay<Fs>::type::value_type...>::type
 whenAll(Fs&&... fs);
 
+/// Like whenAll, but will short circuit on the first exception. Thus, the
+/// type of the returned Future is std::vector<T> instead of
+/// std::vector<Try<T>>
+template <class InputIterator>
+Future<typename detail::CollectContext<
+  typename std::iterator_traits<InputIterator>::value_type::value_type
+>::result_type>
+collect(InputIterator first, InputIterator last);
+
 /** The result is a pair of the index of the first Future to complete and
   the Try. If multiple Futures complete at the same time (or are already
   complete when passed in), the "winner" is chosen non-deterministically.