1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
#[cfg(feature = "http1")]
use bytes::BytesMut;
use http::header::CONTENT_LENGTH;
use http::header::{HeaderValue, ValueIter};
use http::HeaderMap;
#[cfg(all(feature = "http2", feature = "client"))]
use http::Method;

#[cfg(feature = "http1")]
pub(super) fn connection_keep_alive(value: &HeaderValue) -> bool {
    connection_has(value, "keep-alive")
}

#[cfg(feature = "http1")]
pub(super) fn connection_close(value: &HeaderValue) -> bool {
    connection_has(value, "close")
}

#[cfg(feature = "http1")]
fn connection_has(value: &HeaderValue, needle: &str) -> bool {
    if let Ok(s) = value.to_str() {
        for val in s.split(',') {
            if val.trim().eq_ignore_ascii_case(needle) {
                return true;
            }
        }
    }
    false
}

#[cfg(all(feature = "http1", feature = "server"))]
pub(super) fn content_length_parse(value: &HeaderValue) -> Option<u64> {
    from_digits(value.as_bytes())
}

pub(super) fn content_length_parse_all(headers: &HeaderMap) -> Option<u64> {
    content_length_parse_all_values(headers.get_all(CONTENT_LENGTH).into_iter())
}

pub(super) fn content_length_parse_all_values(values: ValueIter<'_, HeaderValue>) -> Option<u64> {
    // If multiple Content-Length headers were sent, everything can still
    // be alright if they all contain the same value, and all parse
    // correctly. If not, then it's an error.

    let mut content_length: Option<u64> = None;
    for h in values {
        if let Ok(line) = h.to_str() {
            for v in line.split(',') {
                if let Some(n) = from_digits(v.trim().as_bytes()) {
                    if content_length.is_none() {
                        content_length = Some(n)
                    } else if content_length != Some(n) {
                        return None;
                    }
                } else {
                    return None
                }
            }
        } else {
            return None
        }
    }

    return content_length
}

fn from_digits(bytes: &[u8]) -> Option<u64> {
    // cannot use FromStr for u64, since it allows a signed prefix
    let mut result = 0u64;
    const RADIX: u64 = 10;

    if bytes.is_empty() {
        return None;
    }

    for &b in bytes {
        // can't use char::to_digit, since we haven't verified these bytes
        // are utf-8.
        match b {
            b'0'..=b'9' => {
                result = result.checked_mul(RADIX)?;
                result = result.checked_add((b - b'0') as u64)?;
            },
            _ => {
                // not a DIGIT, get outta here!
                return None;
            }
        }
    }

    Some(result)
}

#[cfg(all(feature = "http2", feature = "client"))]
pub(super) fn method_has_defined_payload_semantics(method: &Method) -> bool {
    match *method {
        Method::GET | Method::HEAD | Method::DELETE | Method::CONNECT => false,
        _ => true,
    }
}

#[cfg(feature = "http2")]
pub(super) fn set_content_length_if_missing(headers: &mut HeaderMap, len: u64) {
    headers
        .entry(CONTENT_LENGTH)
        .or_insert_with(|| HeaderValue::from(len));
}

#[cfg(feature = "http1")]
pub(super) fn transfer_encoding_is_chunked(headers: &HeaderMap) -> bool {
    is_chunked(headers.get_all(http::header::TRANSFER_ENCODING).into_iter())
}

#[cfg(feature = "http1")]
pub(super) fn is_chunked(mut encodings: ValueIter<'_, HeaderValue>) -> bool {
    // chunked must always be the last encoding, according to spec
    if let Some(line) = encodings.next_back() {
        return is_chunked_(line);
    }

    false
}

#[cfg(feature = "http1")]
pub(super) fn is_chunked_(value: &HeaderValue) -> bool {
    // chunked must always be the last encoding, according to spec
    if let Ok(s) = value.to_str() {
        if let Some(encoding) = s.rsplit(',').next() {
            return encoding.trim().eq_ignore_ascii_case("chunked");
        }
    }

    false
}

#[cfg(feature = "http1")]
pub(super) fn add_chunked(mut entry: http::header::OccupiedEntry<'_, HeaderValue>) {
    const CHUNKED: &str = "chunked";

    if let Some(line) = entry.iter_mut().next_back() {
        // + 2 for ", "
        let new_cap = line.as_bytes().len() + CHUNKED.len() + 2;
        let mut buf = BytesMut::with_capacity(new_cap);
        buf.extend_from_slice(line.as_bytes());
        buf.extend_from_slice(b", ");
        buf.extend_from_slice(CHUNKED.as_bytes());

        *line = HeaderValue::from_maybe_shared(buf.freeze())
            .expect("original header value plus ascii is valid");
        return;
    }

    entry.insert(HeaderValue::from_static(CHUNKED));
}