1 files changed, 200 insertions, 0 deletions
diff --git a/third_party/rust/prost/src/message.rs b/third_party/rust/prost/src/message.rs
new file mode 100644
index 0000000000..a190f6b47b
--- /dev/null
+++ b/third_party/rust/prost/src/message.rs
@@ -0,0 +1,200 @@
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+
+use core::fmt::Debug;
+use core::usize;
+
+use bytes::{Buf, BufMut};
+
+use crate::encoding::{
+    decode_key, encode_varint, encoded_len_varint, message, DecodeContext, WireType,
+};
+use crate::DecodeError;
+use crate::EncodeError;
+
+/// A Protocol Buffers message.
+pub trait Message: Debug + Send + Sync {
+    /// Encodes the message to a buffer.
+    ///
+    /// This method will panic if the buffer has insufficient capacity.
+    ///
+    /// Meant to be used only by `Message` implementations.
+    #[doc(hidden)]
+    fn encode_raw<B>(&self, buf: &mut B)
+    where
+        B: BufMut,
+        Self: Sized;
+
+    /// Decodes a field from a buffer, and merges it into `self`.
+    ///
+    /// Meant to be used only by `Message` implementations.
+    #[doc(hidden)]
+    fn merge_field<B>(
+        &mut self,
+        tag: u32,
+        wire_type: WireType,
+        buf: &mut B,
+        ctx: DecodeContext,
+    ) -> Result<(), DecodeError>
+    where
+        B: Buf,
+        Self: Sized;
+
+    /// Returns the encoded length of the message without a length delimiter.
+    fn encoded_len(&self) -> usize;
+
+    /// Encodes the message to a buffer.
+    ///
+    /// An error will be returned if the buffer does not have sufficient capacity.
+    fn encode<B>(&self, buf: &mut B) -> Result<(), EncodeError>
+    where
+        B: BufMut,
+        Self: Sized,
+    {
+        let required = self.encoded_len();
+        let remaining = buf.remaining_mut();
+        if required > buf.remaining_mut() {
+            return Err(EncodeError::new(required, remaining));
+        }
+
+        self.encode_raw(buf);
+        Ok(())
+    }
+
+    /// Encodes the message to a newly allocated buffer.
+    fn encode_to_vec(&self) -> Vec<u8>
+    where
+        Self: Sized,
+    {
+        let mut buf = Vec::with_capacity(self.encoded_len());
+
+        self.encode_raw(&mut buf);
+        buf
+    }
+
+    /// Encodes the message with a length-delimiter to a buffer.
+    ///
+    /// An error will be returned if the buffer does not have sufficient capacity.
+    fn encode_length_delimited<B>(&self, buf: &mut B) -> Result<(), EncodeError>
+    where
+        B: BufMut,
+        Self: Sized,
+    {
+        let len = self.encoded_len();
+        let required = len + encoded_len_varint(len as u64);
+        let remaining = buf.remaining_mut();
+        if required > remaining {
+            return Err(EncodeError::new(required, remaining));
+        }
+        encode_varint(len as u64, buf);
+        self.encode_raw(buf);
+        Ok(())
+    }
+
+    /// Encodes the message with a length-delimiter to a newly allocated buffer.
+    fn encode_length_delimited_to_vec(&self) -> Vec<u8>
+    where
+        Self: Sized,
+    {
+        let len = self.encoded_len();
+        let mut buf = Vec::with_capacity(len + encoded_len_varint(len as u64));
+
+        encode_varint(len as u64, &mut buf);
+        self.encode_raw(&mut buf);
+        buf
+    }
+
+    /// Decodes an instance of the message from a buffer.
+    ///
+    /// The entire buffer will be consumed.
+    fn decode<B>(mut buf: B) -> Result<Self, DecodeError>
+    where
+        B: Buf,
+        Self: Default,
+    {
+        let mut message = Self::default();
+        Self::merge(&mut message, &mut buf).map(|_| message)
+    }
+
+    /// Decodes a length-delimited instance of the message from the buffer.
+    fn decode_length_delimited<B>(buf: B) -> Result<Self, DecodeError>
+    where
+        B: Buf,
+        Self: Default,
+    {
+        let mut message = Self::default();
+        message.merge_length_delimited(buf)?;
+        Ok(message)
+    }
+
+    /// Decodes an instance of the message from a buffer, and merges it into `self`.
+    ///
+    /// The entire buffer will be consumed.
+    fn merge<B>(&mut self, mut buf: B) -> Result<(), DecodeError>
+    where
+        B: Buf,
+        Self: Sized,
+    {
+        let ctx = DecodeContext::default();
+        while buf.has_remaining() {
+            let (tag, wire_type) = decode_key(&mut buf)?;
+            self.merge_field(tag, wire_type, &mut buf, ctx.clone())?;
+        }
+        Ok(())
+    }
+
+    /// Decodes a length-delimited instance of the message from buffer, and
+    /// merges it into `self`.
+    fn merge_length_delimited<B>(&mut self, mut buf: B) -> Result<(), DecodeError>
+    where
+        B: Buf,
+        Self: Sized,
+    {
+        message::merge(
+            WireType::LengthDelimited,
+            self,
+            &mut buf,
+            DecodeContext::default(),
+        )
+    }
+
+    /// Clears the message, resetting all fields to their default.
+    fn clear(&mut self);
+}
+
+impl<M> Message for Box<M>
+where
+    M: Message,
+{
+    fn encode_raw<B>(&self, buf: &mut B)
+    where
+        B: BufMut,
+    {
+        (**self).encode_raw(buf)
+    }
+    fn merge_field<B>(
+        &mut self,
+        tag: u32,
+        wire_type: WireType,
+        buf: &mut B,
+        ctx: DecodeContext,
+    ) -> Result<(), DecodeError>
+    where
+        B: Buf,
+    {
+        (**self).merge_field(tag, wire_type, buf, ctx)
+    }
+    fn encoded_len(&self) -> usize {
+        (**self).encoded_len()
+    }
+    fn clear(&mut self) {
+        (**self).clear()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const _MESSAGE_IS_OBJECT_SAFE: Option<&dyn Message> = None;
+}