Enum Codec 

pub enum Codec {
    Json,
    MsgPack,
}

Wire codec for the stdin/stdout protocol.

Json uses newline-delimited JSON. MsgPack uses a 4-byte big-endian length prefix followed by a MessagePack payload.

Variants

Json

Newline-delimited JSON (JSONL).

MsgPack

Length-prefixed MessagePack.

Implementations

impl Codec

pub fn encode<T: Serialize>(&self, value: &T) -> Result<Vec<u8>, String>

Encode a value to wire bytes ready to write to stdout.

• JSON: serde_json serialization + trailing \n.
• MsgPack: 4-byte BE u32 length prefix + rmp_serde named serialization.

Allocates a new Vec per call. In practice, encode is called once per outgoing message (not per render frame), and the messages are small enough that the allocation is negligible relative to the I/O cost. Buffer reuse would add complexity for no measurable gain.

Errors

Returns an error when serialization fails or when the encoded payload exceeds the 4 GiB msgpack frame limit.

pub fn encode_binary_message( &self, map: Map<String, Value>, binary_field: Option<(&str, &[u8])>, ) -> Result<Vec<u8>, String>

Encode a JSON map with an optional binary field to wire bytes.

For MsgPack: binary fields are encoded as native msgpack binary (rmpv::Value::Binary), avoiding the ~33% size overhead of base64. The map is built via rmpv::Value::Map to preserve the binary type.

For JSON: binary fields are base64-encoded as strings.

Use this instead of encode when the message contains raw byte data (e.g. pixel buffers) that should use native binary encoding over msgpack.

Errors

Returns an error when JSON or msgpack serialization fails, or when the encoded msgpack payload exceeds the 4 GiB frame limit.

pub fn decode<T: DeserializeOwned>(&self, bytes: &[u8]) -> Result<T, String>

Decode a raw payload (framing already stripped) into a typed value.

For JSON, bytes is the UTF-8 JSON text (without the trailing newline). For MsgPack, bytes is the raw msgpack payload (without the length prefix).

MsgPack decoding routes through rmpv::Value as an intermediate. This preserves binary data (msgpack’s bin type) as base64 strings, which the deserialize_binary_field custom deserializer in protocol.rs can reconstruct into Vec<u8>. The serde_json::Value intermediate is still needed for tag dispatch (#[serde(tag = "type")]) which rmp-serde doesn’t handle reliably for externally-produced msgpack.

Errors

Returns an error when the payload fails the msgpack depth check, cannot be decoded from the selected wire format, or cannot be deserialized into the requested target type.

pub fn read_message<R: BufRead>( &self, reader: &mut R, ) -> Result<Option<Vec<u8>>>

Read one framed message from a buffered reader, returning the raw payload.

• JSON: reads until \n, returns the line bytes (without the newline).
• MsgPack: reads a 4-byte BE u32 length, then reads that many bytes.

Returns Ok(None) on EOF (clean shutdown).

Errors

Returns an I/O error when the reader fails, when a JSON line or msgpack frame exceeds MAX_MESSAGE_SIZE, or when msgpack framing is truncated or otherwise malformed.

pub fn detect_from_first_byte(byte: u8) -> Codec

Detect codec from the first byte of input.

{ (0x7B) indicates JSON. Anything else indicates MsgPack (the first byte of a 4-byte length prefix).

Trait Implementations

impl Clone for Codec

fn clone(&self) -> Codec

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Codec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Codec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Codec

fn eq(&self, other: &Codec) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Codec

impl Eq for Codec

impl StructuralPartialEq for Codec