> On Sept. 1, 2015, 4:46 p.m., Joseph Wu wrote:
> > 3rdparty/libprocess/3rdparty/stout/include/stout/protobuf.hpp, lines 553-555
> > <https://reviews.apache.org/r/37826/diff/3/?file=1061137#file1061137line553>
> >
> > Can you explain why this is a struct rather than a function?
>
> Alexander Rukletsov wrote:
> It's because we cannot partially specialize function templates and
> overload won't work since we take the same argument. Do you think a comment
> should be expanded?
>
> Alexander Rukletsov wrote:
> http://www.gotw.ca/publications/mill17.htm
>
> Joseph Wu wrote:
> Yes, I think a comment would be good regardless of how it ends up.
>
> What about using some C++11 type traits? (But I'm not sure if this will
> work.)
> Something like:
> ```
> // Specialization for non-repeated fields.
> template <typename T>
> Try<T> parse(const JSON::Value& value,
> typename std::enable_if<std::is_base_of<T,
> google::protobuf::Message>, int>::type = 0) {...}
> ```
>
> Note: This file uses some similar Boost type traits further up.
>
> Alexander Rukletsov wrote:
> I'm not sure how we can use type traits here. IIUC type traits facilitate
> compile-time checks, and not compile-time dispatch. If we want to keep the
> same function signature, we should rely on partial specialization. However,
> we can still add these checks into `Parse<>::operator()` methods.
Which boils down to replacing
```
{ google::protobuf::Message* message = (T*) NULL; (void) message; }
```
with
```
static_assert(std::is_base_of<google::protobuf::Message, T>::value,
"T must be a protobuf message");
```
Does it make sense?
- Alexander
-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/37826/#review97302
-----------------------------------------------------------
On Sept. 1, 2015, 2:20 p.m., Alexander Rukletsov wrote:
>
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/37826/
> -----------------------------------------------------------
>
> (Updated Sept. 1, 2015, 2:20 p.m.)
>
>
> Review request for mesos, Joseph Wu and Michael Park.
>
>
> Bugs: MESOS-3312
> https://issues.apache.org/jira/browse/MESOS-3312
>
>
> Repository: mesos
>
>
> Description
> -------
>
> See summary.
>
>
> Diffs
> -----
>
> 3rdparty/libprocess/3rdparty/stout/include/stout/protobuf.hpp
> 57d5fdf45273c620655b44b5f5572290cffa4bf6
>
> Diff: https://reviews.apache.org/r/37826/diff/
>
>
> Testing
> -------
>
> make check (Mac OS 10.10.4)
>
>
> Thanks,
>
> Alexander Rukletsov
>
>
