Martin Slachta
53 lines
1.5 KiB
C++
53 lines
1.5 KiB
C++
#pragma once
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#include <cerrno>
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#include <cstring>
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#include <netdb.h>
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#include <string>
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namespace tw::net {
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/**
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* A failed host lookup.
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*
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* Kept apart from NetworkError because getaddrinfo reports EAI_ codes, which
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* are their own mostly-negative space: sharing one enum would map a lookup
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* failure onto whichever errno happened to carry the same number.
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*/
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struct ResolutionError {
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int m_code;
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int m_errno;
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public:
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/**
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* Only EAI_SYSTEM defers to errno, and errno will not have survived by the
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* time message() runs, so it is captured here.
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*/
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static ResolutionError from_gai(int code) {
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return { code, errno };
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}
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std::string message() const {
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switch (m_code) {
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case EAI_NONAME:
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return "The host name is not known.";
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case EAI_AGAIN:
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return "The name server is unreachable or busy; the lookup may succeed later.";
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case EAI_FAIL:
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return "The name server returned a permanent failure.";
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case EAI_FAMILY:
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return "The requested address family is not supported.";
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case EAI_SERVICE:
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return "The requested port is not available for this socket type.";
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case EAI_MEMORY:
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return "Insufficient memory was available to complete the lookup.";
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case EAI_SYSTEM:
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return std::string(strerror(m_errno));
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default:
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return std::string(gai_strerror(m_code));
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}
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}
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};
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}
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