Struct FrameDecoder 

pub struct FrameDecoder { /* private fields */ }

Streaming Lumberjack v2 frame decoder.

Accepts arbitrary slices of bytes via FrameDecoder::feed and emits fully decoded Frame values via FrameDecoder::next_frame. The internal buffer grows on demand and is compacted when consumed bytes pass a threshold so long-lived decoders do not accumulate unbounded dead capacity.

The decoder is not zero-copy: each Frame variant owns its payload bytes. This is deliberate — yielded frames are typically JSON-decoded immediately and the original bytes are dropped.

Resource bounding

Both raw payload lengths (J, C frames) and decompressed inner sizes (C frame contents) are capped by FrameDecoder::with_max_frame_payload. The default is crate::DEFAULT_MAX_FRAME_PAYLOAD (64 MiB). This protects servers reading from untrusted peers from naive resource-exhaustion attacks (huge declared lengths, zlib bombs).

Implementations

impl FrameDecoder

pub const fn new() -> Self

Create a decoder with the default 64 MiB per-frame size cap.

pub const fn with_max_frame_payload(max_frame_payload: usize) -> Self

Create a decoder with a custom per-frame size cap.

Applies to both raw payload lengths and decompressed inner content of C frames. Set to usize::MAX for “no cap” (not recommended on inputs from untrusted peers).

pub fn feed(&mut self, bytes: &[u8])

Append bytes to the internal buffer. The bytes will be parsed on subsequent calls to Self::next_frame.

pub const fn pending(&self) -> usize

How many fed bytes remain unconsumed in the internal buffer.

pub fn next_frame(&mut self) -> Result<Option<Frame>, FrameError>

Try to decode one frame from the buffered bytes.

Returns:

• Ok(Some(frame)) — a complete frame is available.
• Ok(None) — not enough bytes yet; feed more.
• Err(_) — malformed input; the buffer is left untouched at the offending position so the caller may inspect it. To continue parsing, callers typically tear down the connection.

Trait Implementations

impl Debug for FrameDecoder

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

Formats the value using the given formatter.

impl Default for FrameDecoder

fn default() -> Self

Returns the “default value” for a type.