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//
 
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// Copyright (c) 2026 Michael Vandeberg
 
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//
 
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
 
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
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//
 
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// Official repository: https://github.com/cppalliance/corosio
 
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//
 
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#ifndef BOOST_COROSIO_LOCAL_ENDPOINT_HPP
 
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#define BOOST_COROSIO_LOCAL_ENDPOINT_HPP
 
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#include <boost/corosio/detail/config.hpp>
 
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#include <algorithm>
 
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#include <compare>
 
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#include <cstddef>
 
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#include <cstdint>
 
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#include <cstring>
 
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#include <iosfwd>
 
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#include <string_view>
 
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#include <system_error>
 
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namespace boost::corosio {
 
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/* A Unix domain socket endpoint (filesystem path).
 
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   Stores the path in a fixed-size buffer, avoiding heap
 
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   allocation. The object is trivially copyable.
 
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   Abstract sockets (Linux-only) are represented by paths whose
 
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   first character is '\0'. The full path including the leading
 
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   null byte is stored.
 
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   The library does NOT automatically unlink the socket path on
 
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   close — callers are responsible for cleanup.
 
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   Thread Safety:
 
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     Distinct objects: Safe.
 
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     Shared objects: Safe.
 
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*/
 
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class BOOST_COROSIO_DECL local_endpoint
 
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{
 
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    // sun_path is 108 on Linux, 104 on macOS/FreeBSD. Use the
 
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    // minimum so local_endpoint is portable across all three.
 
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    char path_[104]{};
 
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    std::uint8_t len_ = 0;
 
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public:
 
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    /// Maximum path length for a Unix domain socket (excluding null terminator).
 
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    static constexpr std::size_t max_path_length = 103;
 
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    /// Default constructor. Creates an empty (unbound) endpoint.
 
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    local_endpoint() noexcept = default;
 
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    /** Construct from a path.
 
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        @param path The filesystem path for the socket.
 
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            Must not exceed @ref max_path_length bytes.
 
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        @throws std::system_error if the path is too long.
 
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    */
 
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    explicit local_endpoint(std::string_view path);
 
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    /** Construct from a path (no-throw).
 
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        @param path The filesystem path for the socket.
 
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        @param ec Set to an error if the path is too long.
 
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    */
 
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    local_endpoint(std::string_view path, std::error_code& ec) noexcept;
 
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    /// Return the socket path.
 
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    std::string_view path() const noexcept
 
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    {
 
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        return std::string_view(path_, len_);
 
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    }
 
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    /** Check if this is an abstract socket (Linux-only).
 
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        Abstract sockets live in a kernel namespace rather than
 
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        the filesystem. They are identified by a leading null byte
 
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        in the path.
 
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        @return `true` if the path starts with '\\0'.
 
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    */
 
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    bool is_abstract() const noexcept
 
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    {
 
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        return len_ > 0 && path_[0] == '\0';
 
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    }
 
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    /// Return true if the endpoint has no path.
 
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    bool empty() const noexcept
 
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    {
 
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        return len_ == 0;
 
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    }
 
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    /// Compare endpoints for equality.
 
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    friend bool
 
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    operator==(local_endpoint const& a, local_endpoint const& b) noexcept
 
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    {
 
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        return a.len_ == b.len_ &&
 
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            std::memcmp(a.path_, b.path_, a.len_) == 0;
 
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    }
 
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    /** Format the endpoint for stream output.
 
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        Non-abstract paths are printed as-is. Abstract paths
 
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        (leading null byte) are printed as `[abstract:name]`.
 
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        Empty endpoints produce no output.
 
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    */
 
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    friend BOOST_COROSIO_DECL std::ostream&
 
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    operator<<(std::ostream& os, local_endpoint const& ep);
 
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    /// Lexicographic ordering on stored path bytes.
 
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    friend std::strong_ordering
 
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    operator<=>(local_endpoint const& a, local_endpoint const& b) noexcept
 
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    {
 
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        auto common = (std::min)(a.len_, b.len_);
 
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        if (int cmp = std::memcmp(a.path_, b.path_, common); cmp != 0)
 
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            return cmp <=> 0;
 
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        return a.len_ <=> b.len_;
 
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    }
 
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};
 
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} // namespace boost::corosio
 
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#endif // BOOST_COROSIO_LOCAL_ENDPOINT_HPP