Support smart pointers in base::DispatchToMethod

base/tuple.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A Tuple is a generic templatized container, similar in concept to std::pair
 // and std::tuple.  The convenient MakeTuple() function takes any number of
 // arguments and will construct and return the appropriate Tuple object.  The
 // functions DispatchToMethod and DispatchToFunction take a function pointer or
 // instance and method pointer, and unpack a tuple into arguments to the call.
 //
@@ skipping 178 matching lines @@
 // Helper functions that call the given method on an object, with the unpacked
 // tuple arguments.  Notice that they all have the same number of arguments,
 // so you need only write:
 //   DispatchToMethod(object, &Object::method, args);
 // This is very useful for templated dispatchers, since they don't need to know
 // what type |args| is.
 
 // Non-Static Dispatchers with no out params.
 
 template <typename ObjT, typename Method, typename... Ts, size_t... Ns>
-inline void DispatchToMethodImpl(ObjT* obj,
+inline void DispatchToMethodImpl(const ObjT& obj,
                                  Method method,
                                  const Tuple<Ts...>& arg,
                                  IndexSequence<Ns...>) {
   (obj->*method)(base::internal::UnwrapTraits<Ts>::Unwrap(get<Ns>(arg))...);

[Nico, 2016/02/15 15:22:34]

Why doesn't this have to be (obj.*method) now?

[tzik, 2016/02/15 20:46:26]

In new code, obj will be a const ref to a T* or a const ref to a
scoped_refptr<T> or scoped_ptr<T>.
It's possible to assume the type is a ref to the object, but that requires a
caller side change from ptr to *ptr.

Hm, there are only small number of caller of DispatchToMethod. I can update them
if we should.

 }
 
 template <typename ObjT, typename Method, typename... Ts>
-inline void DispatchToMethod(ObjT* obj,
+inline void DispatchToMethod(const ObjT& obj,
                              Method method,
                              const Tuple<Ts...>& arg) {
   DispatchToMethodImpl(obj, method, arg, MakeIndexSequence<sizeof...(Ts)>());
 }
 
 // Static Dispatchers with no out params.
 
 template <typename Function, typename... Ts, size_t... Ns>
 inline void DispatchToFunctionImpl(Function function,
                                    const Tuple<Ts...>& arg,
                                    IndexSequence<Ns...>) {
   (*function)(base::internal::UnwrapTraits<Ts>::Unwrap(get<Ns>(arg))...);
 }
 
 template <typename Function, typename... Ts>
 inline void DispatchToFunction(Function function, const Tuple<Ts...>& arg) {
   DispatchToFunctionImpl(function, arg, MakeIndexSequence<sizeof...(Ts)>());
 }
 
 // Dispatchers with out parameters.
 
 template <typename ObjT,
           typename Method,
           typename... InTs,
           typename... OutTs,
           size_t... InNs,
           size_t... OutNs>
-inline void DispatchToMethodImpl(ObjT* obj,
+inline void DispatchToMethodImpl(const ObjT& obj,
                                  Method method,
                                  const Tuple<InTs...>& in,
                                  Tuple<OutTs...>* out,
                                  IndexSequence<InNs...>,
                                  IndexSequence<OutNs...>) {
   (obj->*method)(base::internal::UnwrapTraits<InTs>::Unwrap(get<InNs>(in))...,

[Nico, 2016/02/15 15:22:34]

same question

                  &get<OutNs>(*out)...);
 }
 
 template <typename ObjT, typename Method, typename... InTs, typename... OutTs>
-inline void DispatchToMethod(ObjT* obj,
+inline void DispatchToMethod(const ObjT& obj,
                              Method method,
                              const Tuple<InTs...>& in,
                              Tuple<OutTs...>* out) {
   DispatchToMethodImpl(obj, method, in, out,
                        MakeIndexSequence<sizeof...(InTs)>(),
                        MakeIndexSequence<sizeof...(OutTs)>());
 }
 
 }  // namespace base
 
 #endif  // BASE_TUPLE_H_