锁优化

psc_global_include/Singleton.hpp

@@ -1,37 +1,16 @@
 #pragma once
-#include <mutex>
-#include <atomic>
 namespace Psc {
   template<typename Derived>
   class Singleton {
   public:
     static Derived *instance() {
-      Derived *temp = instance_.load(std::memory_order_acquire);
+      static Derived instance;
-      if (temp == nullptr) {
+      return &instance;
-        std::lock_guard<std::mutex> lock(mutex_);
-        temp = instance_.load(std::memory_order_relaxed);
-        if (temp == nullptr) {
-          temp = new Derived;
-          instance_.store(temp, std::memory_order_release);
-        }
-      }
-      return temp;
-    }
-    static void destroy() {
-      Derived* temp = instance_.exchange(nullptr, std::memory_order_acq_rel);
-      delete temp;   // 若为 nullptr，delete 安全
     }
     Singleton(const Singleton &) = delete;
     Singleton &operator=(const Singleton &) = delete;
   protected:
     Singleton() = default;
     ~Singleton() = default;
-  private:
-    static std::atomic<Derived *> instance_;
-    static std::mutex mutex_;
   };
-  template<typename Derived>
+}
-  std::atomic<Derived *> Singleton<Derived>::instance_(nullptr);
-  template<typename Derived>
-  std::mutex Singleton<Derived>::mutex_;
-}