destream

Rust library for asynchronous stream (de)serialization.

Use FromStream, ToStream, and IntoStream for ordinary typed values; fixed-schema types can implement visitors and delegate their fields to these traits.

For data whose nesting is determined by input, use iterative traversal with an explicit frame stack. This avoids call-stack exhaustion through uncontrolled recursion (CWE-674). Depth and allocation limits remain necessary to bound heap usage and work. Recursive value owners must also make destruction and other structural operations stack-safe.

• Decoding uses a container cursor: peek_kind, open_container, and finish_child let the owner drive its frame stack and delegate typed leaves through FromStream. Complete each child before advancing its cursor; discard the decoder after failed or interrupted traversal.
• Encoding uses a pull-based structural event stream: encode_events consumes sequence/map starts, leaves, and container ends. For example, [[1], 2] emits SeqStart, SeqStart, Value(1), End, Value(2), End (size hints omitted). Event::Value delegates a leaf's ordinary encoding; recursive containers must be emitted as events. The codec retains one active leaf stream, accepting borrowed input without requiring Unpin or 'static.

Events describe traversal; stack safety comes from the iterative implementation. Arbitrary recursive visitors or leaf encoders do not become stack-safe automatically.

Each codec owns root/container validation, byte framing, and leaf encoding. inspect_any supplies structural observations without constructing decoded payloads; value owners supply allocation policy.