[/
    Copyright (c) 2013-2017 Vinnie Falco (vinnie dot falco at gmail dot com)

    Distributed under the Boost Software License, Version 1.0. (See accompanying
    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
]

[section:Fields Fields]

An instance of [*Fields] is a container for holding HTTP header fields
and their values. The implementation also calls upon the container to
store the request target and non-standard strings for method and obsolete
reason phrase as needed. Types which meet these requirements can always
be serialized.

In this table:

* `X` denotes a type that meets the requirements of [*Fields].

* `R` denotes a type meeting the requiremnets of __FieldsReader__.

* `a` denotes a value of type `X`.

* `c` denotes a (possibly const) value of type `X`.

* `s` is a value of type [link beast.ref.string_view `string_view`].

[table Fields requirements
[[expression][type][semantics, pre/post-conditions]]
[
    [`X::reader`]
    [`R`]
    [
        A type which meets the requirements of __FieldsReader__.
    ]
][
    [`c.has_close_impl()`]
    [`bool`]
    [
        Returns `true` if the value for Connection has "close" in the list.
    ]
][
    [`c.has_chunked_impl()`]
    [`bool`]
    [
        Returns `true` if "chunked" is the last Transfer-Encoding.
    ]
][
    [`c.has_content_length_impl()`]
    [`bool`]
    [
        Returns `true` if the Content-Length field is present.
    ]
][
    [`c.get_method_impl()`]
    [`string_view`]
    [
        Returns the method text.
        The implementation only calls this function for request
        headers when retrieving the method text previously set
        with a call to `set_method_impl` using a non-empty string.
    ]
][
    [`c.get_target_impl()`]
    [`string_view`]
    [
        Returns the target string.
        The implementation only calls this function for request headers.
    ]
][
    [`c.get_reason_impl()`]
    [`string_view`]
    [
        Returns the obsolete request text.
        The implementation only calls this for response headers when
        retrieving the reason text previously set with a call to
        `set_reason_impl` using a non-empty string.
    ]
][
    [`a.set_method_impl(s)`]
    []
    [
        Stores a copy of `s` as the method text, or erases the previously
        stored value if `s` is empty.
        The implementation only calls this function for request headers.
        This function may throw `std::invalid_argument` if the operation
        is not supported by the container.
    ]
][
    [`a.set_target_impl(s)`]
    []
    [
        Stores a copy of `s` as the target, or erases the previously
        stored value if `s` is empty.
        The implementation only calls this function for request headers.
        This function may throw `std::invalid_argument` if the operation
        is not supported by the container.
    ]
][
    [`a.set_reason_impl(s)`]
    []
    [
        Stores a copy of `s` as the reason text, or erases the previously
        stored value of the reason text if `s` is empty.
        The implementation only calls this function for request headers.
        This function may throw `std::invalid_argument` if the operation
        is not supported by the container.
    ]
]
]

[endsect]