Initial commit

psc_global_include/Singleton.hpp

@@ -0,0 +1,37 @@
+#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);
+      if (temp == nullptr) {
+        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_;
+}