Struct DecodeContext 

pub struct DecodeContext<'a> { /* private fields */ }

Per-decode limits threaded through every merge call.

Carries the remaining recursion depth and a shared unknown-field allowance. The context is Copy — passing it to a callee hands over the current depth by value, while the unknown-field allowance lives in a Cell owned by the top-level decode entry point, so every field decoded under one entry point draws from the same allowance.

Constructed automatically by the Message convenience methods (decode, decode_from_slice, merge_from_slice) and by DecodeOptions. Construct one manually only when calling Message::merge or the other depth-threading methods directly — and construct a fresh limit cell per top-level decode. Reusing one cell across decode calls makes the limit cumulative: each call drains it further until every decode fails with DecodeError::UnknownFieldLimitExceeded.

use core::cell::Cell;
use buffa::{DecodeContext, Message, DEFAULT_UNKNOWN_FIELD_LIMIT, RECURSION_LIMIT};

let limit = Cell::new(DEFAULT_UNKNOWN_FIELD_LIMIT);
let mut msg = Person::default();
msg.merge(&mut bytes, DecodeContext::new(RECURSION_LIMIT, &limit))?;

Implementations

impl<'a> DecodeContext<'a>

pub fn new(depth: u32, unknown_field_limit: &'a Cell<usize>) -> Self

Create a context with depth remaining recursion levels and the remaining unknown-field allowance stored in unknown_field_limit.

pub fn depth(&self) -> u32

The remaining recursion depth.

pub fn remaining_unknown_fields(&self) -> usize

The number of additional unknown fields this decode may materialize.

pub fn descend(self) -> Result<Self, DecodeError>

Consume one level of recursion depth.

Errors

Returns DecodeError::RecursionLimitExceeded when the depth budget is exhausted.

pub fn register_unknown_field(&self) -> Result<(), DecodeError>

Consume one slot of the shared unknown-field allowance.

Call before materializing an UnknownField.

Errors

Returns DecodeError::UnknownFieldLimitExceeded (leaving the allowance unchanged) when no slots remain.

Trait Implementations

impl<'a> Clone for DecodeContext<'a>

fn clone(&self) -> DecodeContext<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Copy for DecodeContext<'a>

impl<'a> Debug for DecodeContext<'a>

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

Formats the value using the given formatter.