Module format 

Serialization formats for cached values.

Cache backends need to serialize values to bytes for storage. The Format trait provides a dyn-compatible interface that allows backends to select serialization format at runtime.

See the crate-level documentation for a comparison of available formats.

Why dyn-compatible?

The Backend trait returns its format via value_format() -> &dyn Format. This design enables:

• Runtime format selection: Choose format based on configuration, not compile-time generics
• Heterogeneous backends: Combine backends with different formats in composition layers
• Format switching: Change serialization strategy without recompiling

Making Format dyn-compatible required a callback-based API (Format::with_serializer, Format::with_deserializer) instead of returning serializers directly. This avoids self-referential lifetime issues that would prevent trait object usage.

Extending with Custom Formats

Implement Format to add custom serialization. Use FormatTypeId::Custom with a unique identifier string to ensure your format can be distinguished from built-in ones.

Structs

BincodeDecoder

Opaque bincode decoder wrapper.

BincodeEncoder

Opaque bincode encoder wrapper.

BincodeFormat

Fast, compact binary serialization.

JsonFormat

JSON serialization format.

RkyvFormatrkyv_format

Rkyv format - high-performance zero-copy serialization (rkyv 0.8)

RonFormat

RON (Rusty Object Notation) serialization format.

Enums

FormatDeserializer

Deserializer passed to Format::with_deserializer callbacks.

FormatError

Errors from serialization and deserialization operations.

FormatSerializer

Serializer passed to Format::with_serializer callbacks.

FormatTypeId

Identifies a format type for equality comparison.

Traits

Format

Dyn-compatible serialization format.

FormatExt

Ergonomic serialization methods for Format.