Method read_message_begin

lib/rs/src/protocol/binary.rs:103–150

(&mut self)

{
    #[allow(clippy::collapsible_if)]
    fn read_message_begin(&mut self) -> crate::Result<TMessageIdentifier> {
        // TODO: Once specialization is stable, call the message size tracking here
        let mut first_bytes = vec![0; 4];
        self.transport.read_exact(&mut first_bytes[..])?;

        // the thrift version header is intentionally negative
        // so the first check we'll do is see if the sign bit is set
        // and if so - assume it's the protocol-version header
        if (first_bytes[0] & 0x80) != 0 {
            // apparently we got a protocol-version header - check
            // it, and if it matches, read the rest of the fields
            if first_bytes[0..2] != [0x80, 0x01] {
                Err(crate::Error::Protocol(ProtocolError {
                    kind: ProtocolErrorKind::BadVersion,
                    message: format!("received bad version: {:?}", &first_bytes[0..2]),
                }))
            } else {
                let message_type: TMessageType = TryFrom::try_from(first_bytes[3])?;
                let name = self.read_string()?;
                let sequence_number = self.read_i32()?;
                Ok(TMessageIdentifier::new(name, message_type, sequence_number))
            }
        } else {
            // apparently we didn't get a protocol-version header,
            // which happens if the sender is not using the strict protocol
            if self.strict {
                // we're in strict mode however, and that always
                // requires the protocol-version header to be written first
                Err(crate::Error::Protocol(ProtocolError {
                    kind: ProtocolErrorKind::BadVersion,
                    message: format!("received bad version: {:?}", &first_bytes[0..2]),
                }))
            } else {
                // in the non-strict version the first message field
                // is the message name. strings (byte arrays) are length-prefixed,
                // so we've just read the length in the first 4 bytes
                let name_size = BigEndian::read_i32(&first_bytes) as usize;
                let mut name_buf: Vec<u8> = vec![0; name_size];
                self.transport.read_exact(&mut name_buf)?;
                let name = String::from_utf8(name_buf)?;

                // read the rest of the fields
                let message_type: TMessageType = self.read_byte().and_then(TryFrom::try_from)?;
                let sequence_number = self.read_i32()?;
                Ok(TMessageIdentifier::new(name, message_type, sequence_number))
            }
        }
    }

    fn read_message_end(&mut self) -> crate::Result<()> {
        Ok(())