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1[/
2    Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
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/boostorg/beast
8]
9
10[section:FieldsWriter FieldsWriter]
11
12A [*FieldsWriter] provides a algorithm to obtain a sequence of buffers
13representing the complete serialized HTTP/1 header for a set of fields.
14The implementation constructs an instance of this type when needed, and
15calls into it once to retrieve the buffers.
16
17[heading Associated Types]
18
19* __FieldsWriter__
20
21[heading Requirements]
22
23[warning
24    These requirements may undergo non-backward compatible
25    changes in subsequent versions.
26]
27
28In this table:
29
30* `W` denotes a type that meets the requirements of [*FieldsWriter].
31* `F` denotes a __Fields__ where
32      `std::is_same<W, F::writer>::value == true`.
33* `a` is a value of type `W`.
34* `f` is a value of type `F`.
35* `v` is an `unsigned` value representing the HTTP version.
36* `c` is an `unsigned` representing the HTTP status-code.
37* `m` is a value of type [link beast.ref.boost__beast__http__verb `verb`].
38
39[table Valid expressions
40[[expression][type][semantics, pre/post-conditions]]
41[
42    [`W::const_buffers_type`]
43    []
44    [
45        A type which meets the requirements of __ConstBufferSequence__.
46        This is the type of buffer returned by `W::get`.
47    ]
48][
49    [`W{f,v,m}`]
50    []
51    [
52        The implementation calls this constructor to indicate
53        that the fields being serialized form part of an HTTP
54        request. The lifetime of `f` is guaranteed
55        to end no earlier than after the `W` is destroyed.
56    ]
57][
58    [`W{f,v,c}`]
59    []
60    [
61        The implementation calls this constructor to indicate
62        that the fields being serialized form part of an HTTP
63        response. The lifetime of `f` is guaranteed
64        to end no earlier than after the `W` is destroyed.
65    ]
66][
67    [`W{f}`]
68    []
69    [
70        The implementation calls this constructor to indicate
71        that the fields being serialized form part of a chunked
72        encoding final-chunk trailer. The lifetime of `f` is
73        guaranteed to end no earlier than after the `W` is
74        destroyed.
75    ]
76][
77    [`a.get()`]
78    [`W::const_buffers_type`]
79    [
80        Called once after construction, this function returns
81        a constant buffer sequence containing the serialized
82        representation of the HTTP request or response including
83        the final carriage return linefeed sequence (`"\r\n"`).
84
85        Copies may be made of the returned sequence, but the
86        underlying memory is still owned by the writer. The
87        implementation will destroy all copies of the buffer
88        sequence before destroying `a`.
89    ]
90]]
91
92[heading Exemplar]
93
94[concept_FieldsWriter]
95
96[heading Models]
97
98* [link beast.ref.boost__beast__http__basic_fields.writer `basic_fields::writer`]
99
100[endsect]
101