src/corosio/src/host_name.cpp

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host_name.cpp

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boost::corosio::host_name[abi:cxx11]() :47 6x 60.0% 50.0% 37.0%

Line	Branch	Hits	Source Code
1			//
2			// Copyright (c) 2026 Steve Gerbino
3			//
4			// Distributed under the Boost Software License, Version 1.0. (See accompanying
5			// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6			//
7			// Official repository: https://github.com/cppalliance/corosio
8			//
9
10			#include <boost/corosio/host_name.hpp>
11			#include <boost/corosio/detail/platform.hpp>
12
13			#include <string>
14			#include <system_error>
15
16			#if BOOST_COROSIO_POSIX
17			#include <cerrno>
18			#include <cstring>
19			#include <unistd.h>
20			#elif BOOST_COROSIO_HAS_IOCP
21			#include <windows.h>
22			#endif
23
24			namespace boost::corosio {
25
26			#if BOOST_COROSIO_POSIX
27
28			capy::io_result<std::string>
29			host_name()
30			{
31			// 256 exceeds POSIX's _POSIX_HOST_NAME_MAX floor of 255 and
32			// every mainstream OS's actual cap (Linux 64, macOS/BSD 255).
33			char buf[256];
34			if (::gethostname(buf, sizeof(buf)) != 0)
35			return {std::error_code(errno, std::system_category()), {}};
36
37			// POSIX does not guarantee NUL termination on truncation.
38			if (std::memchr(buf, '\0', sizeof(buf)) == nullptr)
39			return {make_error_code(std::errc::value_too_large), {}};
40
41			return {std::error_code{}, std::string(buf)};
42			}
43
44			#elif BOOST_COROSIO_HAS_IOCP
45
46			capy::io_result<std::string>
47		6x	host_name()
48			{
49			// Size query: returns ERROR_MORE_DATA and writes the required
50			// wide-char count (including the trailing NUL) into `size`.
51		6x	DWORD size = 0;
52	1/1 ✓ Branch 2 → 3 taken 6 times.	6x	BOOL ok = ::GetComputerNameExW(
53			ComputerNameDnsHostname, nullptr, &size);
54	1/1 ✓ Branch 3 → 4 taken 6 times.	6x	DWORD err = ::GetLastError();
55	1/2 ✗ Branch 4 → 5 not taken. ✓ Branch 4 → 10 taken 6 times.	6x	if (ok)
56			{
57			// Can't-happen guard: a zero-length size query succeeding
58			// would leave `size` meaningless.
59		✗	return {make_error_code(std::errc::protocol_error), {}};
60			}
61	1/2 ✗ Branch 10 → 11 not taken. ✓ Branch 10 → 16 taken 6 times.	6x	if (err != ERROR_MORE_DATA)
62			return {
63		✗	std::error_code(static_cast<int>(err), std::system_category()),
64		✗	{}};
65
66			// On success, GetComputerNameExW rewrites `size` to the count
67			// without the NUL, so resize(size) below trims to the hostname.
68	1/1 ✓ Branch 18 → 19 taken 6 times.	6x	std::wstring wide(size, L'\0');
69	2/3 ✓ Branch 21 → 22 taken 6 times. ✗ Branch 22 → 23 not taken. ✓ Branch 22 → 29 taken 6 times.	6x	if (!::GetComputerNameExW(
70			ComputerNameDnsHostname, wide.data(), &size))
71			return {
72		✗	std::error_code(
73		✗	static_cast<int>(::GetLastError()), std::system_category()),
74		✗	{}};
75	1/1 ✓ Branch 29 → 30 taken 6 times.	6x	wide.resize(size);
76
77	1/1 ✓ Branch 32 → 33 taken 6 times.	6x	int needed = ::WideCharToMultiByte(
78		6x	CP_UTF8, 0, wide.data(), static_cast<int>(wide.size()),
79			nullptr, 0, nullptr, nullptr);
80	1/2 ✗ Branch 33 → 34 not taken. ✓ Branch 33 → 40 taken 6 times.	6x	if (needed <= 0)
81			return {
82		✗	std::error_code(
83		✗	static_cast<int>(::GetLastError()), std::system_category()),
84		✗	{}};
85
86	1/1 ✓ Branch 42 → 43 taken 6 times.	6x	std::string out(static_cast<std::size_t>(needed), '\0');
87	1/1 ✓ Branch 47 → 48 taken 6 times.	12x	int written = ::WideCharToMultiByte(
88		6x	CP_UTF8, 0, wide.data(), static_cast<int>(wide.size()),
89			out.data(), needed, nullptr, nullptr);
90	1/2 ✗ Branch 48 → 49 not taken. ✓ Branch 48 → 55 taken 6 times.	6x	if (written != needed)
91			return {
92		✗	std::error_code(
93		✗	static_cast<int>(::GetLastError()), std::system_category()),
94		✗	{}};
95		6x	return {std::error_code{}, std::move(out)};
96		6x	}
97
98			#endif
99
100			} // namespace boost::corosio
101