to integrate new lib uv (new error checking mechannizm) #21

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1. divanvisagie commented on Aug 22, 2013

   

   divanvisagie

   on Aug 22, 2013

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   TODO: look into updating libuv dependency version
2. sebjameswml commented on Nov 7, 2013

   

   sebjameswml

   on Nov 7, 2013

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   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?
3. sebjameswml commented on Nov 7, 2013

   

   sebjameswml

   on Nov 7, 2013

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   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.