cocaine/cocaine-core — pull request #110 by noxiouz (2014-07-06 11:10:40+00:00)
Title: Message with verbosity 0 

Message with verbosity 0 leads cocaine-runtime to segfault as nullptr is sent to a stream.

```
* thread #2: tid = 0x10b25, 0x00007fff8ca05732 libsystem_c.dylib`strlen + 18, stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
* frame #0: 0x00007fff8ca05732 libsystem_c.dylib`strlen + 18
frame #1: 0x00000001002ba7f4 libcocaine-core.2.dylib`blackhole::aux::attachable_basic_ostringstream, std::__1::allocator >::operator<<(char const*) + 52
frame #2: 0x00000001001df2ce libcocaine-core.2.dylib`(anonymous namespace)::map_severity(blackhole::aux::attachable_basic_ostringstream, std::__1::allocator >&, cocaine::logging::priorities const&) + 62
frame #3: 0x000000010023a90c libcocaine-core.2.dylib`std::__1::__function::__func, std::__1::allocator >&, cocaine::logging::priorities const&), std::__1::allocator, std::__1::allocator >&, cocaine::logging::priorities const&)>, void (blackhole::aux::attachable_basic_ostringstream, std::__1::allocator >&, cocaine::logging::priorities const&)>::operator()(blackhole::aux::attachable_basic_ostringstream, std::__1::allocator >&, cocaine::logging::priorities const&) + 124
frame #4: 0x000000010023c904 libcocaine-core.2.dylib`std::__1::function, std::__1::allocator >&, cocaine::logging::priorities const&)>::operator()(blackhole::aux::attachable_basic_ostringstream, std::__1::allocator >&, cocaine::logging::priorities const&) const + 196
frame #5: 0x000000010023c836 libcocaine-core.2.dylib`blackhole::mapping::extracter::operator()(blackhole::aux::attachable_basic_ostringstream, std::__1::allocator >&, boost::variant, std::__1::allocator >, timeval, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_> const&) const + 70
frame #6: 0x000000010023c74c libcocaine-core.2.dylib`std::__1::__function::__func, std::__1::allocator >, void (blackhole::aux::attachable_basic_ostringstream, std::__1::allocator >&, boost::variant, std::__1::allocator >, timeval, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_> const&)>::operator()(blackhole::aux::attachable_basic_ostringstream, std::__1::allocator >&, boost::variant, std::__1::allocator >, timeval, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_, boost::detail::variant::void_> const&) + 124
```