Specialize the continuation chainer in case ready continuables are chained

include/continuable/continuable-base.hpp

@@ -90,13 +90,13 @@ using is_continuable = detail::base::is_continuable<T>;
 ///
 /// \since 1.0.0
 template <typename Data, typename Annotation>
-class continuable_base
-    : public detail::annotation_trait<Annotation>::template //
-      annotation_base<continuable_base<Data, Annotation>> {
+class continuable_base {
 
   /// \cond false
   using ownership = detail::util::ownership;
 
+  using annotation_trait = detail::annotation_trait<Annotation>;
+
   template <typename, typename>
   friend class continuable_base;
   friend struct detail::base::attorney;
@@ -562,7 +562,6 @@ public:
     detail::base::finalize_continuation(std::move(*this));
   }
 
-#ifdef CONTINUABLE_HAS_DOXYGEN
   /// Materializes the continuation expression template and finishes
   /// the current applied strategy such that the resulting continuable
   /// will always be a concrete type and Continuable::is_concrete holds.
@@ -587,8 +586,9 @@ public:
   ///       on conversion.
   ///
   /// \since 4.0.0
-  unspecified finish() &&;
-#endif // CONTINUABLE_HAS_DOXYGEN
+  auto finish() && {
+    return annotation_trait::finish(std::move(*this));
+  }
 
   /// Predicate to check whether the cti::continuable_base is frozen or not.
   ///

include/continuable/detail/connection/connection-all.hpp

@@ -189,7 +189,8 @@ struct connection_finalizer<connection_strategy_all_tag> {
 /// Specialization for a connection annotation
 template <>
 struct annotation_trait<connection::connection_strategy_all_tag>
-    : connection::connection_annotation_trait {};
+    : connection::connection_annotation_trait<
+          connection::connection_strategy_all_tag> {};
 
 } // namespace detail
 } // namespace cti

include/continuable/detail/connection/connection-any.hpp

@@ -193,10 +193,11 @@ struct connection_finalizer<connection_strategy_any_tag> {
 };
 } // namespace connection
 
-  /// Specialization for a connection annotation
+/// Specialization for a connection annotation
 template <>
 struct annotation_trait<connection::connection_strategy_any_tag>
-  : connection::connection_annotation_trait {};
+    : connection::connection_annotation_trait<
+          connection::connection_strategy_any_tag> {};
 
 } // namespace detail
 } // namespace cti

include/continuable/detail/connection/connection-seq.hpp

@@ -164,7 +164,8 @@ struct connection_finalizer<connection_strategy_seq_tag> {
 /// Specialization for a connection annotation
 template <>
 struct annotation_trait<connection::connection_strategy_seq_tag>
-    : connection::connection_annotation_trait {};
+    : connection::connection_annotation_trait<
+          connection::connection_strategy_seq_tag> {};
 
 } // namespace detail
 } // namespace cti

include/continuable/detail/connection/connection.hpp

@@ -124,25 +124,22 @@ auto connect(Strategy strategy, continuable_base<LData, LAnnotation>&& left,
 template <typename Strategy>
 struct connection_finalizer;
 
+template <typename Strategy>
 struct connection_annotation_trait {
+  /// Finalizes the connection logic of a given connection
   template <typename Continuable>
-  struct annotation_base;
-  template <typename Data, typename Strategy>
-  struct annotation_base<continuable_base<Data, Strategy>> {
-    /// Finalizes the connection logic of a given connection
-    auto finish() && {
-      using continuable_t = continuable_base<Data, Strategy>;
-      auto&& continuation = std::move(*static_cast<continuable_t*>(this));
+  static auto finish(Continuable&& continuable) {
+    using continuable_t = traits::unrefcv_t<Continuable>;
 
-      using finalizer = connection_finalizer<Strategy>;
+    using finalizer = connection_finalizer<Strategy>;
 
-      util::ownership ownership = base::attorney::ownership_of(continuation);
-      auto connection = base::attorney::consume(std::move(continuation));
+    util::ownership ownership = base::attorney::ownership_of(continuable);
+    auto connection =
+        base::attorney::consume(std::forward<Continuable>(continuable));
 
-      // Return a new continuable which
-      return finalizer::finalize(std::move(connection), std::move(ownership));
-    }
-  };
+    // Return a new continuable which
+    return finalizer::finalize(std::move(connection), std::move(ownership));
+  }
 };
 
 class prepare_continuables {

include/continuable/detail/core/annotation.hpp

@@ -44,11 +44,9 @@ struct annotation_trait;
 template <typename... Args>
 struct annotation_trait<traits::identity<Args...>> {
   template <typename Continuable>
-  struct annotation_base {
-    Continuable&& finish() {
-      return std::move(*static_cast<Continuable*>(this));
-    }
-  };
+  static Continuable&& finish(Continuable&& continuable) {
+    return std::forward<Continuable>(continuable);
+  }
 };
 
 namespace hints {
@@ -57,11 +55,9 @@ namespace hints {
 ///
 /// This is the overload taking an arbitrary amount of args
 template <typename... HintArgs>
-struct from_args
-    : std::common_type<traits::identity<HintArgs...>> {};
+struct from_args : std::common_type<traits::identity<HintArgs...>> {};
 template <>
-struct from_args<void>
-    : std::common_type<traits::identity<>> {};
+struct from_args<void> : std::common_type<traits::identity<>> {};
 } // namespace hints
 } // namespace detail
 } // namespace cti

include/continuable/detail/core/base.hpp

@@ -761,8 +761,7 @@ struct chained_continuation<traits::identity<Args...>, HandleResults,
     if (is_ready) {
       // Invoke the proxy callback directly with the result to
       // avoid a potential type erasure.
-      // traits::unpack(std::move(proxy),
-      std::move(continuation_)(query_arg_t{});
+      traits::unpack(std::move(proxy), std::move(continuation_)(query_arg_t{}));
     } else {
       // Invoke the continuation with a proxy callback.
       // The proxy callback is responsible for passing
@@ -779,6 +778,48 @@ struct chained_continuation<traits::identity<Args...>, HandleResults,
     util::unreachable();
   }
 };
+// Specialization to unpack ready continuables directly
+template <typename... Args, handle_results HandleResults,
+          handle_errors HandleErrors, typename Callback, typename Executor>
+struct chained_continuation<traits::identity<Args...>, HandleResults,
+                            HandleErrors, ready_continuation<Args...>, Callback,
+                            Executor> {
+  ready_continuation<Args...> continuation_;
+  Callback callback_;
+  Executor executor_;
+
+  explicit chained_continuation(ready_continuation<Args...> continuation,
+                                Callback callback, Executor executor)
+      : continuation_(std::move(continuation)), callback_(std::move(callback)),
+        executor_(std::move(executor)) {
+  }
+
+  chained_continuation() = delete;
+  ~chained_continuation() = default;
+  chained_continuation(chained_continuation const&) = delete;
+  chained_continuation(chained_continuation&&) = default;
+  chained_continuation& operator=(chained_continuation const&) = delete;
+  chained_continuation& operator=(chained_continuation&&) = default;
+
+  template <typename NextCallback>
+  void operator()(NextCallback&& next_callback) {
+    auto proxy = callbacks::make_callback<traits::identity<Args...>,
+                                          HandleResults, HandleErrors>(
+        std::move(callback_), std::move(executor_),
+        std::forward<decltype(next_callback)>(next_callback));
+
+    // Extract the result out of the ready continuable
+    traits::unpack(std::move(proxy), std::move(continuation_)(query_arg_t{}));
+  }
+
+  bool operator()(is_ready_arg_t) const noexcept {
+    return false;
+  }
+
+  std::tuple<Args...> operator()(query_arg_t) {
+    util::unreachable();
+  }
+};
 
 /// Chains a callback together with a continuation and returns a
 /// continuation:

include/continuable/detail/utility/util.hpp

@@ -32,6 +32,7 @@
 #define CONTINUABLE_DETAIL_UTIL_HPP_INCLUDED
 
 #include <cassert>
+#include <cstdlib>
 #include <tuple>
 #include <type_traits>
 #include <utility>
@@ -258,11 +259,12 @@ private:
   __builtin_unreachable();
 #elif defined(__has_builtin) && __has_builtin(__builtin_unreachable)
   __builtin_unreachable();
+#else
+  std::abort();
 #endif
 }
 
-/// Causes the application to exit abnormally because we are
-/// in an invalid state.
+/// Causes the application to exit abnormally.
 [[noreturn]] inline void trap() {
 #if defined(_MSC_VER)
   __debugbreak();