[AVRO-1541] Specific.hh is over-specialized for standard C++ containers

• Type: Improvement
• Status: Open
• Priority: Trivial
• Resolution: Unresolved
• Affects Version/s: 1.7.6
• Component/s: c++
• Assignee: Thiruvalluvan M. G.
• Reporter: Sean Middleditch
• Created: 12/Jul/14 00:56
• Updated: 17/Jan/19 02:21

Description

The encoders in Specific.hh for the C++ stdlib types like string, vector, etc. are over-specialized and take only specific variations of these templated templates. The specializations of codec_traits should be partial specializations to support std::string, std::vector, std::map, and so on using user-specific allocators and (for std:set and std::map) a user-specific comparator, as Avro has absolutely no reason to care about these details.

These partial specializations will not require any API incompatible breaks. They'd look something like:

template <typename T, typename Allocator>
template <>
struct codec_traits<std::vector<T, Allocator> > {
void encode(Encoder& e, const std::vector<T, Allocator>& s)

{ // ... }
void encode(Encoder& d, std::vector<T, Allocator>& s) { // ... }

};

std::string could be the trickier one since it should probably be a partial specialization over the supported variants of basic_string, though partial specialization of std::string, std::u16string, std::u32string, and std::wstring (which can all have custom allocators).

Don't forget that std::set and std::map can have both a custom allocator and a custom comparator.