1 files changed, 123 insertions, 0 deletions
diff --git a/third_party/rust/hyper/src/body/length.rs b/third_party/rust/hyper/src/body/length.rs
new file mode 100644
index 0000000000..e2bbee8039
--- /dev/null
+++ b/third_party/rust/hyper/src/body/length.rs
@@ -0,0 +1,123 @@
+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);
+    }
+}