Struct canonical::Id

pub struct Id { /* private fields */ }

This is the Id type, that uniquely identifies slices of bytes, in rust equivalent to &[u8]. As in the case with &[u8] the length is also encoded in the type, making it a kind of a fat-pointer for content addressed byte-slices.

The length of the corresponding byte-string is encoded in the first two bytes in big endian.

If the length of the byteslice is less than or equal to 32 bytes, the bytes are stored directly inline in the bytes field.

Proposal: The trailing bytes in an inlined value MUST be set to zero

Implementations

impl Id

pub fn new<T>(t: &T) -> Self where
    T: Canon, 

Creates a new Id from a type

pub fn hash(&self) -> IdHash

Returns the computed hash of the value.

Note that this is different from the payload itself in case of an inlined value, that normally does not get hashed.

Useful for giving a well-distributed unique id for all Canon types, for use in hash maps for example.

pub fn payload(&self) -> &[u8; 32]

Returns the bytes of the identifier

pub fn into_payload(self) -> [u8; 32]

Consumes the Id and returns the payload bytes

pub const fn size(&self) -> usize

Returns the length of the represented data

pub fn reify<T>(&self) -> Result<T, CanonError> where
    T: Canon, 

Attempts to reify the Id as an instance of type T

pub fn take_bytes(&self) -> Result<Option<Vec<u8>>, CanonError>

Takes the bytes corresponding to this id out of the underlying store.

If the Id is inlined, this is a no-op and returns Ok(None)

Trait Implementations

impl<'a> Arbitrary<'a> for Id

fn arbitrary(u: &mut Unstructured<'a>) -> Result<Self>

Generate an arbitrary value of Self from the given unstructured data.

fn arbitrary_take_rest(u: Unstructured<'a>) -> Result<Self, Error>

Generate an arbitrary value of Self from the entirety of the given unstructured data.

fn size_hint(depth: usize) -> (usize, Option<usize>)

Get a size hint for how many bytes out of an Unstructured this type needs to construct itself.

impl Canon for Id

fn encode(&self, sink: &mut Sink<'_>)

Write the encoded value as bytes to a Sink

fn decode(source: &mut Source<'_>) -> Result<Self, CanonError>

Return the decoded value from bytes in a Source

fn encoded_len(&self) -> usize

Returns the number of bytes needed to encode this value

impl Clone for Id

fn clone(&self) -> Id

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Id

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

Formats the value using the given formatter.

impl Default for Id

fn default() -> Id

Returns the “default value” for a type.

impl Hash for Id

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl Ord for Id

fn cmp(&self, other: &Id) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl PartialEq<Id> for Id

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

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

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

This method tests for !=.

impl PartialOrd<Id> for Id

fn partial_cmp(&self, other: &Id) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for Id

impl Eq for Id

impl StructuralEq for Id

impl StructuralPartialEq for Id