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use std::fmt;
#[derive(Clone, Copy, PartialEq, Eq)]
pub(crate) struct DecodedLength(u64);
#[cfg(any(feature = "http1", feature = "http2"))]
impl From<Option<u64>> for DecodedLength {
fn from(len: Option<u64>) -> Self {
len.and_then(|len| {
// If the length is u64::MAX, oh well, just reported chunked.
Self::checked_new(len).ok()
})
.unwrap_or(DecodedLength::CHUNKED)
}
}
#[cfg(any(feature = "http1", feature = "http2", test))]
const MAX_LEN: u64 = std::u64::MAX - 2;
impl DecodedLength {
pub(crate) const CLOSE_DELIMITED: DecodedLength = DecodedLength(::std::u64::MAX);
pub(crate) const CHUNKED: DecodedLength = DecodedLength(::std::u64::MAX - 1);
pub(crate) const ZERO: DecodedLength = DecodedLength(0);
#[cfg(test)]
pub(crate) fn new(len: u64) -> Self {
debug_assert!(len <= MAX_LEN);
DecodedLength(len)
}
/// Takes the length as a content-length without other checks.
///
/// Should only be called if previously confirmed this isn't
/// CLOSE_DELIMITED or CHUNKED.
#[inline]
#[cfg(feature = "http1")]
pub(crate) fn danger_len(self) -> u64 {
debug_assert!(self.0 < Self::CHUNKED.0);
self.0
}
/// Converts to an Option<u64> representing a Known or Unknown length.
pub(crate) fn into_opt(self) -> Option<u64> {
match self {
DecodedLength::CHUNKED | DecodedLength::CLOSE_DELIMITED => None,
DecodedLength(known) => Some(known),
}
}
/// Checks the `u64` is within the maximum allowed for content-length.
#[cfg(any(feature = "http1", feature = "http2"))]
pub(crate) fn checked_new(len: u64) -> Result<Self, crate::error::Parse> {
use tracing::warn;
if len <= MAX_LEN {
Ok(DecodedLength(len))
} else {
warn!("content-length bigger than maximum: {} > {}", len, MAX_LEN);
Err(crate::error::Parse::TooLarge)
}
}
pub(crate) fn sub_if(&mut self, amt: u64) {
match *self {
DecodedLength::CHUNKED | DecodedLength::CLOSE_DELIMITED => (),
DecodedLength(ref mut known) => {
*known -= amt;
}
}
}
/// Returns whether this represents an exact length.
///
/// This includes 0, which of course is an exact known length.
///
/// It would return false if "chunked" or otherwise size-unknown.
#[cfg(feature = "http2")]
pub(crate) fn is_exact(&self) -> bool {
self.0 <= MAX_LEN
}
}
impl fmt::Debug for DecodedLength {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
DecodedLength::CLOSE_DELIMITED => f.write_str("CLOSE_DELIMITED"),
DecodedLength::CHUNKED => f.write_str("CHUNKED"),
DecodedLength(n) => f.debug_tuple("DecodedLength").field(&n).finish(),
}
}
}
impl fmt::Display for DecodedLength {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
DecodedLength::CLOSE_DELIMITED => f.write_str("close-delimited"),
DecodedLength::CHUNKED => f.write_str("chunked encoding"),
DecodedLength::ZERO => f.write_str("empty"),
DecodedLength(n) => write!(f, "content-length ({} bytes)", n),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn sub_if_known() {
let mut len = DecodedLength::new(30);
len.sub_if(20);
assert_eq!(len.0, 10);
}
#[test]
fn sub_if_chunked() {
let mut len = DecodedLength::CHUNKED;
len.sub_if(20);
assert_eq!(len, DecodedLength::CHUNKED);
}
}