Crate willow_data_model

Willow Data Model

This crate provides implementation of the Willow Data Model, including:

• Traits to assist in your implementation of Willow parameters, such as NamespaceId and SubspaceId.
• A zero-copy implementation of Willow paths and their constituent components.
• An implementation of Willow’s entries.
• Utilities for Willow’s entry groupings, such as ranges and areas
• Implementations of various relative encodings.

This crate does not yet have anything for Willow’s concept of stores. Stay tuned!

Type parameters

Willow is a parametrised family of protocols, and so this crate makes heavy use of generic parameters.

The following generic parameter names are used consistently across this crate:

• MCL - A usize representing max_component_length.
• MCC - A usize representing max_component_count.
• MPL - A usize representing max_path_length.
• N - The type used for NamespaceId (willowprotocol.org), must implement the NamespaceId trait.
• S - The type used for SubspaceId (willowprotocol.org), must implement the SubspaceId trait.
• PD - The type used for PayloadDigest (willowprotocol.org), must implement the PayloadDigest trait.
• AT - The type used for AuthorisationToken (willowprotocol.org), must implement the AuthorisationToken trait.

Modules

grouping

Utilities for Willow’s entry groupings.

Structs

AuthorisedEntry

An AuthorisedEntry is a pair of an Entry and AuthorisationToken for which [Entry::is_authorised_write] returns true. Definition.

Component

A component of a Willow Path.

Entry

The metadata associated with each Payload. Definition.

OwnedComponent

An owned component of a Willow Path that uses reference counting for cheap cloning.

Path

An immutable Willow path. Thread-safe, cheap to clone, cheap to take prefixes of, expensive to append to.

UnauthorisedWriteError

An error indicating an AuthorisationToken does not authorise the writing of this entry.

Enums

InvalidPathError

An error arising from trying to construct a invalid Path from valid components.

Traits

AuthorisationToken

Determines whether this type (nominally a AuthorisationToken) is able to prove write permission for a given Entry.

NamespaceId

A type for identifying namespaces. Definition.

PayloadDigest

A totally ordered type for content-addressing the data that Willow stores. Definition.

SubspaceId

A type for identifying subspaces. Definition.

Type Aliases

Timestamp

A Timestamp is a 64-bit unsigned integer, that is, a natural number between zero (inclusive) and 2^64 (exclusive). Timestamps are to be interpreted as a time in microseconds since the Unix epoch. Definition.