to integrate new lib uv (new error checking mechannizm)

[shimondoodkin]

I have tried to update the libuv and found out that just now there was a major change in libuv.

https://github.com/joyent/libuv/commit/3ee4d3f183331a123ce35edd0d32268a2bb22aa5

https://github.com/joyent/libuv/issues/696

[divanvisagie]

TODO: look into updating libuv dependency version

[sebjameswml]

I've been looking at this. I think the error class gets simpler because there are fewer types to handle.

I've drafted out error.h as:

#ifndef __ERROR_H__
#define __ERROR_H__

#include "base.h"

namespace native
{
    class exception
    {
    public:
        exception(const std::string& message)
            : message_(message)
        {}

        virtual ~exception() {}

        const std::string& message() const { return message_; }

    private:
        std::string message_;
    };

    class error
    {
    public:
        error() : uv_err_(0) {}
        error(int e) : uv_err_(e) {}
        ~error() = default;

    public:
        operator bool() { return uv_err_ != 0; } // Is 0 the right number for no error in UV?

        int code() const { return uv_err_; }
        const char* name() const { return uv_err_name(uv_err_); }
        const char* str() const { return uv_strerror(uv_err_); }

    private:
        int uv_err_;
    };

    // uv no longer has uv_last_error. Instead use return from the uv call.
    //error get_last_error() { return uv_last_error(uv_default_loop()); }
}

#endif

But I don't know how to modify the calling code, such as tcp.h, fs.h and so on. Any hints from the original coder?

[sebjameswml]

For example, here's a call to uv_tcp_connect from tcp.h:

 bool connect(const std::string& ip, int port, std::function<void(error)> callback)
            {
                callbacks::store(get()->data, native::internal::uv_cid_connect, callback);
                return uv_tcp_connect(new uv_connect_t, get<uv_tcp_t>(), to_ip4_addr(ip, port), [](uv_connect_t* req, int status) {
                    callbacks::invoke<decltype(callback)>(req->handle->data, native::internal::uv_cid_connect, status?uv_last_error(req->handle->loop):error());
                    delete req;
                }) == 0;
            }

Previously you had to call uv_last_error to get the last error code, if any. Now, uv_tcp_connect returns the error directly, as an int. So what about the handling of "status" in the callback? I can't see how to do the right thing here.