1 files changed, 17 insertions, 54 deletions

diff --git a/src/google/protobuf/stubs/once.h b/src/google/protobuf/stubs/once.h
index 1f082c37..f3835ccd 100644
--- a/src/google/protobuf/stubs/once.h
+++ b/src/google/protobuf/stubs/once.h
@@ -78,88 +78,51 @@
 #ifndef GOOGLE_PROTOBUF_STUBS_ONCE_H__
 #define GOOGLE_PROTOBUF_STUBS_ONCE_H__
 
-#include <google/protobuf/stubs/atomicops.h>
-#include <google/protobuf/stubs/callback.h>
-#include <google/protobuf/stubs/common.h>
+#include <mutex>
+#include <utility>
 
 namespace google {
 namespace protobuf {
+namespace internal {
 
-#ifdef GOOGLE_PROTOBUF_NO_THREAD_SAFETY
-
-typedef bool ProtobufOnceType;
-
-#define GOOGLE_PROTOBUF_ONCE_INIT false
-
-inline void GoogleOnceInit(ProtobufOnceType* once, void (*init_func)()) {
-  if (!*once) {
-    *once = true;
-    init_func();
-  }
+using once_flag = std::once_flag;
+template <typename... Args>
+void call_once(Args&&... args ) {
+  std::call_once(std::forward<Args>(args)...);
 }
 
-template <typename Arg>
-inline void GoogleOnceInit(ProtobufOnceType* once, void (*init_func)(Arg),
-    Arg arg) {
-  if (!*once) {
-    *once = true;
-    init_func(arg);
-  }
-}
+}  // namespace internal
 
-#else
-
-enum {
-  ONCE_STATE_UNINITIALIZED = 0,
-  ONCE_STATE_EXECUTING_CLOSURE = 1,
-  ONCE_STATE_DONE = 2
-};
-
-typedef internal::AtomicWord ProtobufOnceType;
-
-#define GOOGLE_PROTOBUF_ONCE_INIT ::google::protobuf::ONCE_STATE_UNINITIALIZED
-
-LIBPROTOBUF_EXPORT
-void GoogleOnceInitImpl(ProtobufOnceType* once, Closure* closure);
+// TODO(gerbens) remove this once third_party is fully extracted
+using ProtobufOnceType = internal::once_flag;
 
 inline void GoogleOnceInit(ProtobufOnceType* once, void (*init_func)()) {
-  if (internal::Acquire_Load(once) != ONCE_STATE_DONE) {
-    internal::FunctionClosure0 func(init_func, false);
-    GoogleOnceInitImpl(once, &func);
-  }
+  std::call_once(*once, init_func);
 }
 
 template <typename Arg>
-inline void GoogleOnceInit(ProtobufOnceType* once, void (*init_func)(Arg*),
-    Arg* arg) {
-  if (internal::Acquire_Load(once) != ONCE_STATE_DONE) {
-    internal::FunctionClosure1<Arg*> func(init_func, false, arg);
-    GoogleOnceInitImpl(once, &func);
-  }
+inline void GoogleOnceInitArg(ProtobufOnceType* once, void (*init_func)(Arg*),
+                              Arg* arg) {
+  std::call_once(*once, init_func, arg);
 }
 
-#endif  // GOOGLE_PROTOBUF_NO_THREAD_SAFETY
-
 class GoogleOnceDynamic {
  public:
-  GoogleOnceDynamic() : state_(GOOGLE_PROTOBUF_ONCE_INIT) { }
-
   // If this->Init() has not been called before by any thread,
   // execute (*func_with_arg)(arg) then return.
   // Otherwise, wait until that prior invocation has finished
   // executing its function, then return.
   template<typename T>
   void Init(void (*func_with_arg)(T*), T* arg) {
-    GoogleOnceInit<T>(&this->state_,
-                      func_with_arg,
-                      arg);
+    GoogleOnceInitArg<T>(&this->state_, func_with_arg, arg);
   }
  private:
   ProtobufOnceType state_;
 };
 
+#define GOOGLE_PROTOBUF_ONCE_TYPE ::google::protobuf::ProtobufOnceType
 #define GOOGLE_PROTOBUF_DECLARE_ONCE(NAME) \
-  ::google::protobuf::ProtobufOnceType NAME = GOOGLE_PROTOBUF_ONCE_INIT
+  ::google::protobuf::ProtobufOnceType NAME
 
 }  // namespace protobuf
 }  // namespace google