migrate get_completion_signatures customizations to member function (NVIDIA#1330)

* migrate `get_completion_signatures` customizations to member function

* fix the system scheduler

Author: ericniebler

.clang-format

@@ -27,8 +27,7 @@ AlwaysBreakAfterReturnType: None
 AlwaysBreakBeforeMultilineStrings: true
 AlwaysBreakTemplateDeclarations: Yes
 AttributeMacros: [
-  '__EXEC__SYSTEM_CONTEXT__INLINE',
-  '__EXEC_WEAK_ATTRIBUTE'
+  'STDEXEC_SYSTEM_CONTEXT_INLINE'
 ]
 BinPackArguments: false
 BinPackParameters: false

examples/algorithms/retry.hpp

@@ -121,7 +121,7 @@ struct _retry_sender {
   using _value = stdexec::completion_signatures<stdexec::set_value_t(Ts...)>;
 
   template <class Env>
-  friend auto tag_invoke(stdexec::get_completion_signatures_t, const _retry_sender&, Env)
+  auto get_completion_signatures(Env&&) const
     -> stdexec::make_completion_signatures<
       S&,
       Env,

examples/algorithms/then.hpp

@@ -74,8 +74,8 @@ struct _then_sender {
       _set_value_t>;
 
   template <class Env>
-  STDEXEC_MEMFN_DECL(auto get_completion_signatures)(this _then_sender&&, Env&&) {
-    return _completions_t<Env>();
+  auto get_completion_signatures(Env&&) && -> _completions_t<Env> {
+    return {};
   }
 
   // Connect:

examples/benchmark/static_thread_pool_old.hpp

@@ -489,7 +489,7 @@ namespace exec_old {
     }
 
     template <stdexec::__decays_to<bulk_sender> Self, class Env>
-    friend auto tag_invoke(stdexec::get_completion_signatures_t, Self&&, Env&&)
+    static auto get_completion_signatures(Self&&, Env&&)
       -> completion_signatures<Self, Env> {
       return {};
     }

include/exec/__detail/__basic_sequence.hpp

@@ -62,16 +62,11 @@ namespace exec {
       return _Self::__tag().get_env(*this);
     }
 
-    template <
-      stdexec::same_as<stdexec::get_completion_signatures_t> _Tag,
-      stdexec::__decays_to<__seqexpr> _Self,
-      class _Env>
-    friend auto tag_invoke(_Tag, _Self&& __self, _Env&& __env) //
-      -> stdexec::__msecond<
-        stdexec::__if_c<stdexec::same_as<_Tag, stdexec::get_completion_signatures_t>>,
-        decltype(__self.__tag().get_completion_signatures(
-          static_cast<_Self&&>(__self),
-          static_cast<_Env&&>(__env)))> {
+    template <stdexec::__decays_to<__seqexpr> _Self, class _Env>
+    static auto get_completion_signatures(_Self&& __self, _Env&& __env) //
+      -> decltype(__self.__tag().get_completion_signatures(
+        static_cast<_Self&&>(__self),
+        static_cast<_Env&&>(__env))) {
       return {};
     }
 

include/exec/__detail/__system_context_default_impl.hpp

@@ -18,18 +18,17 @@
 #include "__system_context_if.h"
 #include "stdexec/execution.hpp"
 #include "exec/static_thread_pool.hpp"
-#include "__weak_attribute.hpp"
 
 namespace exec::__system_context_default_impl {
   using namespace stdexec::tags;
 
   using __pool_scheduler_t = decltype(std::declval<exec::static_thread_pool>().get_scheduler());
 
   /// Receiver that calls the callback when the operation completes.
-  template <class __Sender>
+  template <class _Sender>
   struct __operation;
 
-  template <class __Sender>
+  template <class _Sender>
   struct __recv {
     using receiver_concept = stdexec::receiver_t;
 
@@ -40,7 +39,7 @@ namespace exec::__system_context_default_impl {
     void* __data_;
 
     /// The owning operation state, to be destructed when the operation completes.
-    __operation<__Sender>* __op_;
+    __operation<_Sender>* __op_;
 
     void set_value() noexcept {
       __cb_(__data_, 0, nullptr);
@@ -55,18 +54,18 @@ namespace exec::__system_context_default_impl {
     }
   };
 
-  template <typename __Sender>
+  template <typename _Sender>
   struct __operation {
     /// The inner operation state, that results out of connecting the underlying sender with the receiver.
-    stdexec::connect_result_t<__Sender, __recv<__Sender>> __inner_op_;
+    stdexec::connect_result_t<_Sender, __recv<_Sender>> __inner_op_;
     /// True if the operation is on the heap, false if it is in the preallocated space.
     bool __on_heap_;
 
     /// Try to construct the operation in the preallocated memory if it fits, otherwise allocate a new operation.
     static __operation* __construct_maybe_alloc(
       void* __preallocated,
       size_t __psize,
-      __Sender __sndr,
+      _Sender __sndr,
       __exec_system_context_completion_callback_t __cb,
       void* __data) {
       if (__preallocated == nullptr || __psize < sizeof(__operation)) {
@@ -87,11 +86,11 @@ namespace exec::__system_context_default_impl {
 
    private:
     __operation(
-      __Sender __sndr,
+      _Sender __sndr,
       __exec_system_context_completion_callback_t __cb,
       void* __data,
       bool __on_heap)
-      : __inner_op_(stdexec::connect(std::move(__sndr), __recv<__Sender>{__cb, __data, this}))
+      : __inner_op_(stdexec::connect(std::move(__sndr), __recv<_Sender>{__cb, __data, this}))
       , __on_heap_(__on_heap) {
     }
   };

include/exec/__detail/__system_context_default_impl_entry.hpp

@@ -15,23 +15,28 @@
  */
 #pragma once
 
-// Assumes __EXEC__SYSTEM_CONTEXT__INLINE is defined
+// Assumes STDEXEC_SYSTEM_CONTEXT_INLINE is defined
+
+#if !defined(STDEXEC_SYSTEM_CONTEXT_INLINE)
+#  error "STDEXEC_SYSTEM_CONTEXT_INLINE must be defined before including this header"
+#endif
 
 #include "__system_context_default_impl.hpp"
-#include "__weak_attribute.hpp"
 
 STDEXEC_PRAGMA_PUSH()
 STDEXEC_PRAGMA_IGNORE_GNU("-Wattributes") // warning: inline function '[...]' declared weak
 
 /// Gets the default system context implementation.
-extern "C" __EXEC__SYSTEM_CONTEXT__INLINE __EXEC_WEAK_ATTRIBUTE __exec_system_context_interface*
+extern "C" STDEXEC_SYSTEM_CONTEXT_INLINE STDEXEC_ATTRIBUTE((weak))
+__exec_system_context_interface*
   __get_exec_system_context_impl() {
   return exec::__system_context_default_impl::__instance_holder::__singleton()
     .__get_current_instance();
 }
 
 /// Sets the default system context implementation.
-extern "C" __EXEC__SYSTEM_CONTEXT__INLINE __EXEC_WEAK_ATTRIBUTE void
+extern "C" STDEXEC_SYSTEM_CONTEXT_INLINE STDEXEC_ATTRIBUTE((weak))
+  void
   __set_exec_system_context_impl(__exec_system_context_interface* __instance) {
   return exec::__system_context_default_impl::__instance_holder::__singleton()
     .__set_current_instance(__instance);

include/exec/__detail/__system_context_if.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef __EXEC__SYSTEM_CONTEXT_IF_H__
-#define __EXEC__SYSTEM_CONTEXT_IF_H__
+#ifndef STDEXEC_SYSTEM_CONTEXT_IF_H
+#define STDEXEC_SYSTEM_CONTEXT_IF_H
 
 #include <stddef.h>
 #include <stdint.h>

include/exec/__detail/__weak_attribute.hpp

@@ -111,7 +111,7 @@ namespace exec {
         }
 
         template <__decays_to<__t> _Self, class _Env>
-        STDEXEC_MEMFN_DECL(auto get_completion_signatures)(this _Self&&, _Env&&)
+        static auto get_completion_signatures(_Self&&, _Env&&)
           -> completion_signatures_of_t<__copy_cvref_t<_Self, _Constrained>, __env_t<_Env>> {
           return {};
         }
@@ -252,7 +252,7 @@ namespace exec {
         }
 
         template <__decays_to<__t> _Self, class _Env>
-        STDEXEC_MEMFN_DECL(auto get_completion_signatures)(this _Self&&, _Env&&)
+        static auto get_completion_signatures(_Self&&, _Env&&)
           -> completion_signatures_of_t<__copy_cvref_t<_Self, _Constrained>, __env_t<_Env>> {
           return {};
         }
@@ -598,7 +598,15 @@ namespace exec {
       using _Sender = stdexec::__t<_SenderId>;
       using _Env = stdexec::__t<_EnvId>;
 
-      struct __t {
+      class __t {
+        template <class _Self>
+        using __completions_t = __future_completions_t<__mfront<_Sender, _Self>, _Env>;
+
+        template <class _Receiver>
+        using __future_op_t =
+          stdexec::__t<__future_op<_SenderId, _EnvId, stdexec::__id<_Receiver>>>;
+
+       public:
         using __id = __future;
         using sender_concept = stdexec::sender_t;
 
@@ -619,20 +627,6 @@ namespace exec {
               __guard, __future_step::__future, __future_step::__no_future);
           }
         }
-       private:
-        friend struct async_scope;
-        template <class _Self>
-        using __completions_t = __future_completions_t<__mfront<_Sender, _Self>, _Env>;
-
-        template <class _Receiver>
-        using __future_op_t =
-          stdexec::__t<__future_op<_SenderId, _EnvId, stdexec::__id<_Receiver>>>;
-
-        explicit __t(std::unique_ptr<__future_state<_Sender, _Env>> __state) noexcept
-          : __state_(std::move(__state)) {
-          std::unique_lock __guard{__state_->__mutex_};
-          __state_->__step_from_to_(__guard, __future_step::__created, __future_step::__future);
-        }
 
         template <__decays_to<__t> _Self, receiver _Receiver>
           requires receiver_of<_Receiver, __completions_t<_Self>>
@@ -642,10 +636,19 @@ namespace exec {
         }
 
         template <__decays_to<__t> _Self, class _OtherEnv>
-        STDEXEC_MEMFN_DECL(auto get_completion_signatures)(this _Self&&, _OtherEnv&&) -> __completions_t<_Self> {
+        static auto get_completion_signatures(_Self&&, _OtherEnv&&) -> __completions_t<_Self> {
           return {};
         }
 
+       private:
+        friend struct async_scope;
+
+        explicit __t(std::unique_ptr<__future_state<_Sender, _Env>> __state) noexcept
+          : __state_(std::move(__state)) {
+          std::unique_lock __guard{__state_->__mutex_};
+          __state_->__step_from_to_(__guard, __future_step::__created, __future_step::__future);
+        }
+
         std::unique_ptr<__future_state<_Sender, _Env>> __state_;
       };
     };

include/exec/async_scope.hpp

@@ -94,7 +94,7 @@ namespace exec {
           }
 
           template <__decays_to<__t> _Self, class _Env>
-          STDEXEC_MEMFN_DECL(auto get_completion_signatures)(this _Self&&, _Env&&) -> __completion_signatures<_Env> {
+          static auto get_completion_signatures(_Self&&, _Env&&) -> __completion_signatures<_Env> {
             return {};
           }
 

include/exec/at_coroutine_exit.hpp

@@ -128,7 +128,7 @@ namespace exec {
       }
 
       template <class _Env>
-      STDEXEC_MEMFN_DECL(auto get_completion_signatures)(this __sender, _Env&&) -> __completions_t<_Env> {
+      auto get_completion_signatures(_Env&&) -> __completions_t<_Env> {
         return {};
       }
     };

include/exec/env.hpp

@@ -273,6 +273,17 @@ namespace exec {
         _InitialSender __initial_sndr_;
         _FinalSender __final_sndr_;
 
+       public:
+        using __id = __sender;
+        using sender_concept = stdexec::sender_t;
+
+        template <__decays_to<_InitialSender> _Initial, __decays_to<_FinalSender> _Final>
+        __t(_Initial&& __initial, _Final&& __final) //
+          noexcept(__nothrow_decay_copyable<_Initial> && __nothrow_decay_copyable<_Final>)
+          : __initial_sndr_{static_cast<_Initial&&>(__initial)}
+          , __final_sndr_{static_cast<_Final&&>(__final)} {
+        }
+
         template <__decays_to<__t> _Self, class _Rec>
         STDEXEC_MEMFN_DECL(auto connect)(this _Self&& __self, _Rec&& __receiver) noexcept -> __op_t<_Self, _Rec> {
           return {
@@ -282,23 +293,13 @@ namespace exec {
         }
 
         template <__decays_to<__t> _Self, class _Env>
-        STDEXEC_MEMFN_DECL(auto get_completion_signatures)(this _Self&&, _Env&&) noexcept -> __completion_signatures_t<
-          __copy_cvref_t<_Self, _InitialSender>,
-          __copy_cvref_t<_Self, _FinalSender>,
-          _Env> {
+        static auto
+          get_completion_signatures(_Self&&, _Env&&) noexcept -> __completion_signatures_t<
+            __copy_cvref_t<_Self, _InitialSender>,
+            __copy_cvref_t<_Self, _FinalSender>,
+            _Env> {
           return {};
         }
-
-       public:
-        using __id = __sender;
-        using sender_concept = stdexec::sender_t;
-
-        template <__decays_to<_InitialSender> _Initial, __decays_to<_FinalSender> _Final>
-        __t(_Initial&& __initial, _Final&& __final) //
-          noexcept(__nothrow_decay_copyable<_Initial> && __nothrow_decay_copyable<_Final>)
-          : __initial_sndr_{static_cast<_Initial&&>(__initial)}
-          , __final_sndr_{static_cast<_Final&&>(__final)} {
-        }
       };
     };
 

include/exec/finally.hpp

@@ -317,7 +317,7 @@ namespace exec {
     }
 
     template <stdexec::__decays_to<__t> Self, class Env>
-    STDEXEC_MEMFN_DECL(auto get_completion_signatures)(this Self &&, Env &&) -> __completions_t<Self, Env> {
+    static auto get_completion_signatures(Self &&, Env &&) -> __completions_t<Self, Env> {
       return {};
     }