// Protocol Buffers - Google's data interchange format

// Copyright 2008 Google Inc.  All rights reserved.

//

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file or at

// https://developers.google.com/open-source/licenses/bsd

#ifndef GOOGLE_PROTOBUF_STUBS_CALLBACK_H_

#define GOOGLE_PROTOBUF_STUBS_CALLBACK_H_

#include <type_traits>

#include "google/protobuf/port_def.inc"

// ===================================================================

// emulates google3/base/callback.h

namespace google {

namespace protobuf {

// Abstract interface for a callback.  When calling an RPC, you must provide

// a Closure to call when the procedure completes.  See the Service interface

// in service.h.

//

// To automatically construct a Closure which calls a particular function or

// method with a particular set of parameters, use the NewCallback() function.

// Example:

//   void FooDone(const FooResponse* response) {

//     ...

//   }

//

//   void CallFoo() {

//     ...

//     // When done, call FooDone() and pass it a pointer to the response.

//     Closure* callback = NewCallback(&FooDone, response);

//     // Make the call.

//     service->Foo(controller, request, response, callback);

//   }

//

// Example that calls a method:

//   class Handler {

//    public:

//     ...

//

//     void FooDone(const FooResponse* response) {

//       ...

//     }

//

//     void CallFoo() {

//       ...

//       // When done, call FooDone() and pass it a pointer to the response.

//       Closure* callback = NewCallback(this, &Handler::FooDone, response);

//       // Make the call.

//       service->Foo(controller, request, response, callback);

//     }

//   };

//

// Currently NewCallback() supports binding zero, one, or two arguments.

//

// Callbacks created with NewCallback() automatically delete themselves when

// executed.  They should be used when a callback is to be called exactly

// once (usually the case with RPC callbacks).  If a callback may be called

// a different number of times (including zero), create it with

// NewPermanentCallback() instead.  You are then responsible for deleting the

// callback (using the "delete" keyword as normal).

//

// Note that NewCallback() is a bit touchy regarding argument types.  Generally,

// the values you provide for the parameter bindings must exactly match the

// types accepted by the callback function.  For example:

//   void Foo(std::string s);

//   NewCallback(&Foo, "foo");          // WON'T WORK:  const char* != string

//   NewCallback(&Foo, std::string("foo"));  // WORKS

// Also note that the arguments cannot be references:

//   void Foo(const std::string& s);

//   std::string my_str;

//   NewCallback(&Foo, my_str);  // WON'T WORK:  Can't use references.

// However, correctly-typed pointers will work just fine.

class PROTOBUF_EXPORT Closure {

 public:

  Closure() {}

  Closure(const Closure&) = delete;

  Closure& operator=(const Closure&) = delete;

  virtual ~Closure();

  virtual void Run() = 0;

};

template<typename R>

class ResultCallback {

 public:

  ResultCallback() {}

  ResultCallback(const ResultCallback&) = delete;

  ResultCallback& operator=(const ResultCallback&) = delete;

  virtual ~ResultCallback() {}

  virtual R Run() = 0;

};

template <typename R, typename A1>

class PROTOBUF_EXPORT ResultCallback1 {

 public:

  ResultCallback1() {}

  ResultCallback1(const ResultCallback1&) = delete;

  ResultCallback1& operator=(const ResultCallback1&) = delete;

  virtual ~ResultCallback1() {}

  virtual R Run(A1) = 0;

};

template <typename R, typename A1, typename A2>

class PROTOBUF_EXPORT ResultCallback2 {

 public:

  ResultCallback2() {}

  ResultCallback2(const ResultCallback2&) = delete;

  ResultCallback2& operator=(const ResultCallback2&) = delete;

  virtual ~ResultCallback2() {}

  virtual R Run(A1,A2) = 0;

};

namespace internal {

class PROTOBUF_EXPORT FunctionClosure0 : public Closure {

 public:

  typedef void (*FunctionType)();

  FunctionClosure0(FunctionType function, bool self_deleting)

    : function_(function), self_deleting_(self_deleting) {}

  ~FunctionClosure0();

  void Run() override {

    bool needs_delete = self_deleting_;  // read in case callback deletes

    function_();

    if (needs_delete) delete this;

  }

 private:

  FunctionType function_;

  bool self_deleting_;

};

template <typename Class>

class MethodClosure0 : public Closure {

 public:

  typedef void (Class::*MethodType)();

  MethodClosure0(Class* object, MethodType method, bool self_deleting)

    : object_(object), method_(method), self_deleting_(self_deleting) {}

  ~MethodClosure0() {}

  void Run() override {

    bool needs_delete = self_deleting_;  // read in case callback deletes

    (object_->*method_)();

    if (needs_delete) delete this;

  }

 private:

  Class* object_;

  MethodType method_;

  bool self_deleting_;

};

template <typename Arg1>

class FunctionClosure1 : public Closure {

 public:

  typedef void (*FunctionType)(Arg1 arg1);

  FunctionClosure1(FunctionType function, bool self_deleting,

                   Arg1 arg1)

    : function_(function), self_deleting_(self_deleting),

      arg1_(arg1) {}

  ~FunctionClosure1() {}

  void Run() override {

    bool needs_delete = self_deleting_;  // read in case callback deletes

    function_(arg1_);

    if (needs_delete) delete this;

  }

 private:

  FunctionType function_;

  bool self_deleting_;

  Arg1 arg1_;

};

template <typename Class, typename Arg1>

class MethodClosure1 : public Closure {

 public:

  typedef void (Class::*MethodType)(Arg1 arg1);

  MethodClosure1(Class* object, MethodType method, bool self_deleting,

                 Arg1 arg1)

    : object_(object), method_(method), self_deleting_(self_deleting),

      arg1_(arg1) {}

  ~MethodClosure1() {}

  void Run() override {

    bool needs_delete = self_deleting_;  // read in case callback deletes

    (object_->*method_)(arg1_);

    if (needs_delete) delete this;

  }

 private:

  Class* object_;

  MethodType method_;

  bool self_deleting_;

  Arg1 arg1_;

};

template <typename Arg1, typename Arg2>

class FunctionClosure2 : public Closure {

 public:

  typedef void (*FunctionType)(Arg1 arg1, Arg2 arg2);

  FunctionClosure2(FunctionType function, bool self_deleting,

                   Arg1 arg1, Arg2 arg2)

    : function_(function), self_deleting_(self_deleting),

      arg1_(arg1), arg2_(arg2) {}

  ~FunctionClosure2() {}

  void Run() override {

    bool needs_delete = self_deleting_;  // read in case callback deletes

    function_(arg1_, arg2_);

    if (needs_delete) delete this;

  }

 private:

  FunctionType function_;

  bool self_deleting_;

  Arg1 arg1_;

  Arg2 arg2_;

};

template <typename Class, typename Arg1, typename Arg2>

class MethodClosure2 : public Closure {

 public:

  typedef void (Class::*MethodType)(Arg1 arg1, Arg2 arg2);

  MethodClosure2(Class* object, MethodType method, bool self_deleting,

                 Arg1 arg1, Arg2 arg2)

    : object_(object), method_(method), self_deleting_(self_deleting),

      arg1_(arg1), arg2_(arg2) {}

  ~MethodClosure2() {}

  void Run() override {

    bool needs_delete = self_deleting_;  // read in case callback deletes

    (object_->*method_)(arg1_, arg2_);

    if (needs_delete) delete this;

  }

 private:

  Class* object_;

  MethodType method_;

  bool self_deleting_;

  Arg1 arg1_;

  Arg2 arg2_;

};

template<typename R>

class FunctionResultCallback_0_0 : public ResultCallback<R> {

 public:

  typedef R (*FunctionType)();

  FunctionResultCallback_0_0(FunctionType function, bool self_deleting)

      : function_(function), self_deleting_(self_deleting) {}

  ~FunctionResultCallback_0_0() {}

  R Run() override {

    bool needs_delete = self_deleting_;  // read in case callback deletes

    R result = function_();

    if (needs_delete) delete this;

    return result;

  }

 private:

  FunctionType function_;

  bool self_deleting_;

};

template<typename R, typename P1>

class FunctionResultCallback_1_0 : public ResultCallback<R> {

 public:

  typedef R (*FunctionType)(P1);

  FunctionResultCallback_1_0(FunctionType function, bool self_deleting,

                             P1 p1)

      : function_(function), self_deleting_(self_deleting), p1_(p1) {}

  ~FunctionResultCallback_1_0() {}

  R Run() override {

    bool needs_delete = self_deleting_;  // read in case callback deletes

    R result = function_(p1_);

    if (needs_delete) delete this;

    return result;

  }

 private:

  FunctionType function_;

  bool self_deleting_;

  P1 p1_;

};

template<typename R, typename Arg1>

class FunctionResultCallback_0_1 : public ResultCallback1<R, Arg1> {

 public:

  typedef R (*FunctionType)(Arg1 arg1);

  FunctionResultCallback_0_1(FunctionType function, bool self_deleting)

      : function_(function), self_deleting_(self_deleting) {}

  ~FunctionResultCallback_0_1() {}

  R Run(Arg1 a1) override {

    bool needs_delete = self_deleting_;  // read in case callback deletes

    R result = function_(a1);

    if (needs_delete) delete this;

    return result;

  }

 private:

  FunctionType function_;

  bool self_deleting_;

};

template<typename R, typename P1, typename A1>

class FunctionResultCallback_1_1 : public ResultCallback1<R, A1> {

 public:

  typedef R (*FunctionType)(P1, A1);

  FunctionResultCallback_1_1(FunctionType function, bool self_deleting,

                             P1 p1)

      : function_(function), self_deleting_(self_deleting), p1_(p1) {}

  ~FunctionResultCallback_1_1() {}

  R Run(A1 a1) override {

    bool needs_delete = self_deleting_;  // read in case callback deletes

    R result = function_(p1_, a1);

    if (needs_delete) delete this;

    return result;

  }

 private:

  FunctionType function_;

  bool self_deleting_;

  P1 p1_;

};

template <typename T>

struct InternalConstRef {

  typedef typename std::remove_reference<T>::type base_type;

  typedef const base_type& type;

};

template<typename R, typename T>

class MethodResultCallback_0_0 : public ResultCallback<R> {

 public:

  typedef R (T::*MethodType)();

  MethodResultCallback_0_0(T* object, MethodType method, bool self_deleting)

      : object_(object),

        method_(method),

        self_deleting_(self_deleting) {}

  ~MethodResultCallback_0_0() {}

  R Run() {

    bool needs_delete = self_deleting_;

    R result = (object_->*method_)();

    if (needs_delete) delete this;

    return result;

  }

 private:

  T* object_;

  MethodType method_;

  bool self_deleting_;

};

template <typename R, typename T, typename P1, typename P2, typename P3,

          typename P4, typename P5, typename P6, typename A1, typename A2>

class MethodResultCallback_6_2 : public ResultCallback2<R, A1, A2> {

 public:

  typedef R (T::*MethodType)(P1, P2, P3, P4, P5, P6, A1, A2);

  MethodResultCallback_6_2(T* object, MethodType method, bool self_deleting,

                           P1 p1, P2 p2, P3 p3, P4 p4, P5 p5, P6 p6)

      : object_(object),

        method_(method),

        self_deleting_(self_deleting),

        p1_(p1),

        p2_(p2),

        p3_(p3),

        p4_(p4),

        p5_(p5),

        p6_(p6) {}

  ~MethodResultCallback_6_2() {}

  R Run(A1 a1, A2 a2) override {

    bool needs_delete = self_deleting_;

    R result = (object_->*method_)(p1_, p2_, p3_, p4_, p5_, p6_, a1, a2);

    if (needs_delete) delete this;

    return result;

  }

 private:

  T* object_;

  MethodType method_;

  bool self_deleting_;

  typename std::remove_reference<P1>::type p1_;

  typename std::remove_reference<P2>::type p2_;

  typename std::remove_reference<P3>::type p3_;

  typename std::remove_reference<P4>::type p4_;

  typename std::remove_reference<P5>::type p5_;

  typename std::remove_reference<P6>::type p6_;

};

}  // namespace internal

// See Closure.

inline Closure* NewCallback(void (*function)()) {

  return new internal::FunctionClosure0(function, true);

}

// See Closure.

inline Closure* NewPermanentCallback(void (*function)()) {

  return new internal::FunctionClosure0(function, false);

}

// See Closure.

template <typename Class>

inline Closure* NewCallback(Class* object, void (Class::*method)()) {

  return new internal::MethodClosure0<Class>(object, method, true);

}

// See Closure.

template <typename Class>

inline Closure* NewPermanentCallback(Class* object, void (Class::*method)()) {

  return new internal::MethodClosure0<Class>(object, method, false);

}

// See Closure.

template <typename Arg1>

inline Closure* NewCallback(void (*function)(Arg1),

                            Arg1 arg1) {

  return new internal::FunctionClosure1<Arg1>(function, true, arg1);

}

// See Closure.

template <typename Arg1>

inline Closure* NewPermanentCallback(void (*function)(Arg1),

                                     Arg1 arg1) {

  return new internal::FunctionClosure1<Arg1>(function, false, arg1);

}

// See Closure.

template <typename Class, typename Arg1>

inline Closure* NewCallback(Class* object, void (Class::*method)(Arg1),

                            Arg1 arg1) {

  return new internal::MethodClosure1<Class, Arg1>(object, method, true, arg1);

}

// See Closure.

template <typename Class, typename Arg1>

inline Closure* NewPermanentCallback(Class* object, void (Class::*method)(Arg1),

                                     Arg1 arg1) {

  return new internal::MethodClosure1<Class, Arg1>(object, method, false, arg1);

}

// See Closure.

template <typename Arg1, typename Arg2>

inline Closure* NewCallback(void (*function)(Arg1, Arg2),

                            Arg1 arg1, Arg2 arg2) {

  return new internal::FunctionClosure2<Arg1, Arg2>(

    function, true, arg1, arg2);

}

// See Closure.

template <typename Arg1, typename Arg2>

inline Closure* NewPermanentCallback(void (*function)(Arg1, Arg2),

                                     Arg1 arg1, Arg2 arg2) {

  return new internal::FunctionClosure2<Arg1, Arg2>(

    function, false, arg1, arg2);

}

// See Closure.

template <typename Class, typename Arg1, typename Arg2>

inline Closure* NewCallback(Class* object, void (Class::*method)(Arg1, Arg2),

                            Arg1 arg1, Arg2 arg2) {

  return new internal::MethodClosure2<Class, Arg1, Arg2>(

    object, method, true, arg1, arg2);

}

// See Closure.

template <typename Class, typename Arg1, typename Arg2>

inline Closure* NewPermanentCallback(

    Class* object, void (Class::*method)(Arg1, Arg2),

    Arg1 arg1, Arg2 arg2) {

  return new internal::MethodClosure2<Class, Arg1, Arg2>(

    object, method, false, arg1, arg2);

}

// See ResultCallback

template<typename R>

inline ResultCallback<R>* NewCallback(R (*function)()) {

  return new internal::FunctionResultCallback_0_0<R>(function, true);

}

// See ResultCallback

template<typename R>

inline ResultCallback<R>* NewPermanentCallback(R (*function)()) {

  return new internal::FunctionResultCallback_0_0<R>(function, false);

}

// See ResultCallback

template<typename R, typename P1>

inline ResultCallback<R>* NewCallback(R (*function)(P1), P1 p1) {

  return new internal::FunctionResultCallback_1_0<R, P1>(

      function, true, p1);

}

// See ResultCallback

template<typename R, typename P1>

inline ResultCallback<R>* NewPermanentCallback(

    R (*function)(P1), P1 p1) {

  return new internal::FunctionResultCallback_1_0<R, P1>(

      function, false, p1);

}

// See ResultCallback1

template<typename R, typename A1>

inline ResultCallback1<R, A1>* NewCallback(R (*function)(A1)) {

  return new internal::FunctionResultCallback_0_1<R, A1>(function, true);

}

// See ResultCallback1

template<typename R, typename A1>

inline ResultCallback1<R, A1>* NewPermanentCallback(R (*function)(A1)) {

  return new internal::FunctionResultCallback_0_1<R, A1>(function, false);

}

// See ResultCallback1

template<typename R, typename P1, typename A1>

inline ResultCallback1<R, A1>* NewCallback(R (*function)(P1, A1), P1 p1) {

  return new internal::FunctionResultCallback_1_1<R, P1, A1>(

      function, true, p1);

}

// See ResultCallback1

template<typename R, typename P1, typename A1>

inline ResultCallback1<R, A1>* NewPermanentCallback(

    R (*function)(P1, A1), P1 p1) {

  return new internal::FunctionResultCallback_1_1<R, P1, A1>(

      function, false, p1);

}

// See MethodResultCallback_0_0

template <typename R, typename T1, typename T2>

inline ResultCallback<R>* NewPermanentCallback(

    T1* object, R (T2::*function)()) {

  return new internal::MethodResultCallback_0_0<R, T1>(object, function, false);

}

// See MethodResultCallback_6_2

template <typename R, typename T, typename P1, typename P2, typename P3,

          typename P4, typename P5, typename P6, typename A1, typename A2>

inline ResultCallback2<R, A1, A2>* NewPermanentCallback(

    T* object, R (T::*function)(P1, P2, P3, P4, P5, P6, A1, A2),

    typename internal::InternalConstRef<P1>::type p1,

    typename internal::InternalConstRef<P2>::type p2,

    typename internal::InternalConstRef<P3>::type p3,

    typename internal::InternalConstRef<P4>::type p4,

    typename internal::InternalConstRef<P5>::type p5,

    typename internal::InternalConstRef<P6>::type p6) {

  return new internal::MethodResultCallback_6_2<R, T, P1, P2, P3, P4, P5, P6,

                                                A1, A2>(object, function, false,

                                                        p1, p2, p3, p4, p5, p6);

}

// A function which does nothing.  Useful for creating no-op callbacks, e.g.:

//   Closure* nothing = NewCallback(&DoNothing);

void PROTOBUF_EXPORT DoNothing();

}  // namespace protobuf

}  // namespace google

#include "google/protobuf/port_undef.inc"

#endif  // GOOGLE_PROTOBUF_STUBS_CALLBACK_H_