From 6bbdf4cb718bac1754f2701c41054bbd8912bccb Mon Sep 17 00:00:00 2001
From: Erki <erki@skullnet.me>
Date: Wed, 23 Jun 2021 12:27:32 +0300
Subject: [PATCH] Threads: Implement multivariate actors

---
 Threads/Inc/threads_actor.hpp | 49 +++++++++++++++++++++++++----------
 1 file changed, 35 insertions(+), 14 deletions(-)

diff --git a/Threads/Inc/threads_actor.hpp b/Threads/Inc/threads_actor.hpp
index a3cd524..0d7bc08 100644
--- a/Threads/Inc/threads_actor.hpp
+++ b/Threads/Inc/threads_actor.hpp
@@ -13,6 +13,7 @@
 #include <queue.h>
 
 #include <type_traits>
+#include <variant>
 
 #include "threads_primitivethread.hpp"
 #include "threads_signal.hpp"
@@ -20,18 +21,18 @@
 namespace Threads
 {
 
-template<typename T>
+template<typename CRTP, typename... Ts>
 class Actor
 {
 public:
-  using value_type = T;
+  using value_type = std::variant<Ts...>;
 
-  static_assert(std::is_default_constructible_v<value_type>, "T must be default constructible.");
-  static_assert(std::is_trivially_copyable_v<value_type>, "T must be trivially copyable.");
+  static_assert(std::is_default_constructible_v<value_type>, "Ts must be default constructible.");
+  static_assert(std::is_trivially_copyable_v<value_type>, "Ts must be trivially copyable.");
 
   Actor(const std::uint32_t queue_size, const char* name, const osPriority_t priority, const std::uint32_t stack_size)
       : thread_([](void* d) {
-          auto* dd = static_cast<Actor<value_type>*>(d);
+          auto* dd = static_cast<Actor<CRTP, Ts...>*>(d);
           (*dd)();
         },
                 this, name, priority, stack_size),
@@ -40,6 +41,8 @@ public:
     assert(msg_queue_);
   }
 
+  virtual ~Actor() {}
+
   Signallable<value_type>* getSignal()
   {
     return &signal_;
@@ -47,12 +50,28 @@ public:
 
 protected:
   virtual void init() = 0;
-  virtual void onSignal(const value_type& data) = 0;
 
 private:
   PrimitiveThread thread_;
   QueueHandle_t msg_queue_;
 
+  struct Visitor_
+  {
+    using parent = Actor<CRTP, Ts...>;
+    parent* q;
+
+    Visitor_(parent* q)
+        : q(q)
+    {}
+
+    template<typename U>
+    void operator()(const U& u)
+    {
+      CRTP* s = static_cast<CRTP*>(q);
+      s->onSignal(u);
+    }
+  };
+
   void operator()()
   {
     init();
@@ -65,7 +84,7 @@ private:
 
       if (got == pdTRUE)
       {
-        onSignal(data);
+        std::visit(Visitor_{this}, data);
       }
     }
   }
@@ -74,7 +93,7 @@ private:
 
   struct Signal_ : Signallable<value_type>
   {
-    using parent = Actor<value_type>;
+    using parent = Actor<CRTP, Ts...>;
     parent& q;
 
     explicit Signal_(parent& q)
@@ -99,15 +118,15 @@ private:
   Signal_ signal_;
 };
 
-template<>
-class Actor<void>
+template<typename CRTP>
+class Actor<CRTP, void>
 {
 public:
   using value_type = void;
 
   Actor(const std::uint32_t queue_size, const char* name, const osPriority_t priority, const std::uint32_t stack_size)
       : thread_([](void* d) {
-          auto* dd = static_cast<Actor<value_type>*>(d);
+          auto* dd = static_cast<Actor<CRTP, value_type>*>(d);
           (*dd)();
         },
                 this, name, priority, stack_size),
@@ -116,6 +135,8 @@ public:
     assert(msg_queue_);
   }
 
+  virtual ~Actor() {}
+
   Signallable<value_type>* getSignal()
   {
     return &signal_;
@@ -123,7 +144,6 @@ public:
 
 protected:
   virtual void init() = 0;
-  virtual void onSignal() = 0;
 
 private:
   PrimitiveThread thread_;
@@ -141,7 +161,8 @@ private:
 
       if (got == pdTRUE)
       {
-        onSignal();
+        auto* crtp = static_cast<CRTP*>(this);
+        crtp->onSignal();
       }
     }
   }
@@ -150,7 +171,7 @@ private:
 
   struct Signal_ : Signallable<value_type>
   {
-    using parent = Actor<value_type>;
+    using parent = Actor<CRTP, void>;
     parent& q;
 
     explicit Signal_(parent& q)