hyper/body/
length.rs

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1use std::fmt;
2
3#[derive(Clone, Copy, PartialEq, Eq)]
4pub(crate) struct DecodedLength(u64);
5
6#[cfg(any(feature = "http1", feature = "http2"))]
7impl From<Option<u64>> for DecodedLength {
8    fn from(len: Option<u64>) -> Self {
9        len.and_then(|len| {
10            // If the length is u64::MAX, oh well, just reported chunked.
11            Self::checked_new(len).ok()
12        })
13        .unwrap_or(DecodedLength::CHUNKED)
14    }
15}
16
17#[cfg(any(feature = "http1", feature = "http2", test))]
18const MAX_LEN: u64 = std::u64::MAX - 2;
19
20impl DecodedLength {
21    pub(crate) const CLOSE_DELIMITED: DecodedLength = DecodedLength(::std::u64::MAX);
22    pub(crate) const CHUNKED: DecodedLength = DecodedLength(::std::u64::MAX - 1);
23    pub(crate) const ZERO: DecodedLength = DecodedLength(0);
24
25    #[cfg(test)]
26    pub(crate) fn new(len: u64) -> Self {
27        debug_assert!(len <= MAX_LEN);
28        DecodedLength(len)
29    }
30
31    /// Takes the length as a content-length without other checks.
32    ///
33    /// Should only be called if previously confirmed this isn't
34    /// CLOSE_DELIMITED or CHUNKED.
35    #[inline]
36    #[cfg(feature = "http1")]
37    pub(crate) fn danger_len(self) -> u64 {
38        debug_assert!(self.0 < Self::CHUNKED.0);
39        self.0
40    }
41
42    /// Converts to an Option<u64> representing a Known or Unknown length.
43    pub(crate) fn into_opt(self) -> Option<u64> {
44        match self {
45            DecodedLength::CHUNKED | DecodedLength::CLOSE_DELIMITED => None,
46            DecodedLength(known) => Some(known),
47        }
48    }
49
50    /// Checks the `u64` is within the maximum allowed for content-length.
51    #[cfg(any(feature = "http1", feature = "http2"))]
52    pub(crate) fn checked_new(len: u64) -> Result<Self, crate::error::Parse> {
53        use tracing::warn;
54
55        if len <= MAX_LEN {
56            Ok(DecodedLength(len))
57        } else {
58            warn!("content-length bigger than maximum: {} > {}", len, MAX_LEN);
59            Err(crate::error::Parse::TooLarge)
60        }
61    }
62
63    pub(crate) fn sub_if(&mut self, amt: u64) {
64        match *self {
65            DecodedLength::CHUNKED | DecodedLength::CLOSE_DELIMITED => (),
66            DecodedLength(ref mut known) => {
67                *known -= amt;
68            }
69        }
70    }
71
72    /// Returns whether this represents an exact length.
73    ///
74    /// This includes 0, which of course is an exact known length.
75    ///
76    /// It would return false if "chunked" or otherwise size-unknown.
77    #[cfg(feature = "http2")]
78    pub(crate) fn is_exact(&self) -> bool {
79        self.0 <= MAX_LEN
80    }
81}
82
83impl fmt::Debug for DecodedLength {
84    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
85        match *self {
86            DecodedLength::CLOSE_DELIMITED => f.write_str("CLOSE_DELIMITED"),
87            DecodedLength::CHUNKED => f.write_str("CHUNKED"),
88            DecodedLength(n) => f.debug_tuple("DecodedLength").field(&n).finish(),
89        }
90    }
91}
92
93impl fmt::Display for DecodedLength {
94    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
95        match *self {
96            DecodedLength::CLOSE_DELIMITED => f.write_str("close-delimited"),
97            DecodedLength::CHUNKED => f.write_str("chunked encoding"),
98            DecodedLength::ZERO => f.write_str("empty"),
99            DecodedLength(n) => write!(f, "content-length ({} bytes)", n),
100        }
101    }
102}
103
104#[cfg(test)]
105mod tests {
106    use super::*;
107
108    #[test]
109    fn sub_if_known() {
110        let mut len = DecodedLength::new(30);
111        len.sub_if(20);
112
113        assert_eq!(len.0, 10);
114    }
115
116    #[test]
117    fn sub_if_chunked() {
118        let mut len = DecodedLength::CHUNKED;
119        len.sub_if(20);
120
121        assert_eq!(len, DecodedLength::CHUNKED);
122    }
123}
hyper/body/length.rs

hyper/body/
length.rs
