Enum wnfs_common::Link

pub enum Link<T> {
    Encoded {
        cid: Cid,
        value_cache: OnceCell<T>,
    },
    Decoded {
        value: T,
    },
}

A data structure that represents a link in the IPLD graph. Basically it is a “link” to some content addressable value of T.

It supports representing the “link” with a Cid or the deserialized value itself.

Link needs a BlockStore to be able to resolve Cids to corresponding values of T and vice versa.

Variants

Encoded

Fields

cid: Cid

value_cache: OnceCell<T>

A variant of Link that started out as a Cid. If the decoded value is resolved using resolve_value, then the value_cache gets populated and further calls to resolve_value will just return from that cache.

Decoded

Fields

value: T

A variant of Link that started out as a deserialized value T. If the cid is resolved using resolve_cid, then T’s .persisted_as from the Storable trait is called and that OnceCell<Cid> is populated, preventing further calls to resolve_cid from duplicating work.

Implementations

impl<T: Storable + CondSync> Link<T>

pub fn from_cid(cid: Cid) -> Self

Creates a new Link that starts out as a Cid.

pub async fn resolve_cid(&self, store: &impl BlockStore) -> Result<Cid>

Gets the Cid stored in type. It attempts to get it from the store if it is not present in type.

pub async fn resolve_value(&self, store: &impl BlockStore) -> Result<&T>

Gets the value stored in link. It attempts to get it from the store if it is not present in link.

pub async fn resolve_value_mut( &mut self, store: &impl BlockStore ) -> Result<&mut T>

Gets mut value stored in link. It attempts to get it from the store if it is not present in link.

pub fn get_cid(&self) -> Option<&Cid>

Gets the cid data stored in type.

NOTE: This does not attempt to get it from the store if it does not exist..

pub fn get_value(&self) -> Option<&T>

Gets the value stored in type.

NOTE: This does not attempt to get it from the store if it does not exist.

pub async fn resolve_owned_value(self, store: &impl BlockStore) -> Result<T>

where T: Storable,

Gets an owned value from type. It attempts to it get from the store if it is not present in type.

pub fn has_cid(&self) -> bool

Checks if there is a Cid cached in link.

pub fn has_value(&self) -> bool

Checks if there is a value stored in link.

pub async fn deep_eq( &self, other: &Link<T>, store: &impl BlockStore ) -> Result<bool>

where T: PartialEq + Storable,

Compares two links for equality. Attempts to get them from store if they are not already cached.

Trait Implementations

impl<T> Clone for Link<T>

where T: Clone,

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> Debug for Link<T>

where T: Debug,

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

Formats the value using the given formatter.

impl<T: Storable> From<T> for Link<T>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<T> PartialEq for Link<T>

where T: PartialEq + Storable + CondSync,

fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.