From 6b9efad6025668a0172f6708e3c51997d9517e29 Mon Sep 17 00:00:00 2001
From: Denis Blank <denis.blank@outlook.com>
Date: Tue, 3 Oct 2017 01:21:32 +0200
Subject: [PATCH] Pass promises to type erased continuables instead of the raw
 callbacks

---
 include/continuable/continuable-trait.hpp | 19 +++++--------------
 include/continuable/continuable.hpp       |  2 +-
 test/playground/test-playground.cpp       | 22 +++++++++++-----------
 3 files changed, 17 insertions(+), 26 deletions(-)

diff --git a/include/continuable/continuable-trait.hpp b/include/continuable/continuable-trait.hpp
index 1f6ed18..c3e714d 100644
--- a/include/continuable/continuable-trait.hpp
+++ b/include/continuable/continuable-trait.hpp
@@ -52,24 +52,15 @@ namespace cti {
 template <template <typename...> class CallbackWrapper,
           template <typename...> class ContinuationWrapper, typename... Args>
 struct continuable_trait {
-  /// The callback type which is passed to continuations
-  // TODO This should be void(promise<...>) I think
-  using callback =
-      CallbackWrapper<void(Args...), void(detail::types::dispatch_error_tag,
-                                          detail::types::error_type)>;
-
-  /// The continuation type which is used to erase the internal data.
-  using continuation = ContinuationWrapper<void(
-      CallbackWrapper<void(Args...), void(detail::types::dispatch_error_tag,
-                                          detail::types::error_type)>)>;
-
   /// The promise type which is used to resolve continuations
-  using promise =
-      promise_base<callback, detail::hints::signature_hint_tag<Args...>>;
+  using promise = promise_base<
+      CallbackWrapper<void(Args...), void(detail::types::dispatch_error_tag,
+                                          detail::types::error_type)>,
+      detail::hints::signature_hint_tag<Args...>>;
 
   /// The continuable type for the given parameters.
   using continuable =
-      continuable_base<continuation,
+      continuable_base<ContinuationWrapper<void(promise)>,
                        detail::hints::signature_hint_tag<Args...>>;
 };
 } // namespace cti
diff --git a/include/continuable/continuable.hpp b/include/continuable/continuable.hpp
index 3138878..b40e33e 100644
--- a/include/continuable/continuable.hpp
+++ b/include/continuable/continuable.hpp
@@ -41,7 +41,7 @@ namespace cti {
 namespace detail {
 template<typename... Args>
 using trait_of = continuable_trait<
-  fu2::function,
+  fu2::unique_function,
   fu2::function,
   Args...
 >;
diff --git a/test/playground/test-playground.cpp b/test/playground/test-playground.cpp
index 4c78fb6..a6e361f 100644
--- a/test/playground/test-playground.cpp
+++ b/test/playground/test-playground.cpp
@@ -35,16 +35,6 @@ static cti::continuable<std::string> http_request(std::string url) {
   };
 }
 
-static cti::continuable<std::string> http_request3(std::string url) {
-  return [url = std::move(url)](auto promise) {
-    if (false) {
-      promise.set_value("");
-      promise("");
-    }
-    promise.set_exception(std::error_condition{});
-  };
-}
-
 static auto http_request2(std::string url) {
   return cti::make_continuable<std::string>(
       // ...
@@ -57,6 +47,16 @@ static auto http_request2(std::string url) {
       });
 }
 
+static cti::continuable<std::string> http_request3(std::string url) {
+  return [url = std::move(url)](auto&& promise) {
+    if (false) {
+      promise.set_value("");
+      promise("");
+    }
+    promise.set_exception(std::error_condition{});
+  };
+}
+
 int main(int, char**) {
   http_request("github.com")
       .then([](std::string) {
@@ -82,7 +82,7 @@ int main(int, char**) {
         // ...
       });
 
-  (http_request("github.com") && http_request("github.com"))
+  (http_request("github.com") && http_request3("github.com"))
       .then([](std::string, std::string) {
         // ...
       })