1 files changed, 93 insertions, 0 deletions
diff --git a/third_party/rust/prost/src/lib.rs b/third_party/rust/prost/src/lib.rs
new file mode 100644
index 0000000000..9d4069e76e
--- /dev/null
+++ b/third_party/rust/prost/src/lib.rs
@@ -0,0 +1,93 @@
+#![doc(html_root_url = "https://docs.rs/prost/0.8.0")]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+// Re-export the alloc crate for use within derived code.
+#[doc(hidden)]
+pub extern crate alloc;
+
+// Re-export the bytes crate for use within derived code.
+#[doc(hidden)]
+pub use bytes;
+
+mod error;
+mod message;
+mod types;
+
+#[doc(hidden)]
+pub mod encoding;
+
+pub use crate::error::{DecodeError, EncodeError};
+pub use crate::message::Message;
+
+use bytes::{Buf, BufMut};
+
+use crate::encoding::{decode_varint, encode_varint, encoded_len_varint};
+
+// See `encoding::DecodeContext` for more info.
+// 100 is the default recursion limit in the C++ implementation.
+#[cfg(not(feature = "no-recursion-limit"))]
+const RECURSION_LIMIT: u32 = 100;
+
+/// Encodes a length delimiter to the buffer.
+///
+/// See [Message.encode_length_delimited] for more info.
+///
+/// An error will be returned if the buffer does not have sufficient capacity to encode the
+/// delimiter.
+pub fn encode_length_delimiter<B>(length: usize, buf: &mut B) -> Result<(), EncodeError>
+where
+    B: BufMut,
+{
+    let length = length as u64;
+    let required = encoded_len_varint(length);
+    let remaining = buf.remaining_mut();
+    if required > remaining {
+        return Err(EncodeError::new(required, remaining));
+    }
+    encode_varint(length, buf);
+    Ok(())
+}
+
+/// Returns the encoded length of a length delimiter.
+///
+/// Applications may use this method to ensure sufficient buffer capacity before calling
+/// `encode_length_delimiter`. The returned size will be between 1 and 10, inclusive.
+pub fn length_delimiter_len(length: usize) -> usize {
+    encoded_len_varint(length as u64)
+}
+
+/// Decodes a length delimiter from the buffer.
+///
+/// This method allows the length delimiter to be decoded independently of the message, when the
+/// message is encoded with [Message.encode_length_delimited].
+///
+/// An error may be returned in two cases:
+///
+///  * If the supplied buffer contains fewer than 10 bytes, then an error indicates that more
+///    input is required to decode the full delimiter.
+///  * If the supplied buffer contains more than 10 bytes, then the buffer contains an invalid
+///    delimiter, and typically the buffer should be considered corrupt.
+pub fn decode_length_delimiter<B>(mut buf: B) -> Result<usize, DecodeError>
+where
+    B: Buf,
+{
+    let length = decode_varint(&mut buf)?;
+    if length > usize::max_value() as u64 {
+        return Err(DecodeError::new(
+            "length delimiter exceeds maximum usize value",
+        ));
+    }
+    Ok(length as usize)
+}
+
+// Re-export #[derive(Message, Enumeration, Oneof)].
+// Based on serde's equivalent re-export [1], but enabled by default.
+//
+// [1]: https://github.com/serde-rs/serde/blob/v1.0.89/serde/src/lib.rs#L245-L256
+#[cfg(feature = "prost-derive")]
+#[allow(unused_imports)]
+#[macro_use]
+extern crate prost_derive;
+#[cfg(feature = "prost-derive")]
+#[doc(hidden)]
+pub use prost_derive::*;