Trait trie_db::NodeCodec

pub trait NodeCodec: Sized {
    type Error: Error;
    type HashOut: AsRef<[u8]> + AsMut<[u8]> + Default + MaybeDebug + PartialEq + Eq + Hash + Send + Sync + Clone + Copy;

    const ESCAPE_HEADER: Option<u8> = None;

    fn hashed_null_node() -> Self::HashOut;
    fn decode_plan(data: &[u8]) -> Result<NodePlan, Self::Error>;
    fn is_empty_node(data: &[u8]) -> bool;
    fn empty_node() -> &'static [u8] ;
    fn leaf_node(
        partial: impl Iterator<Item = u8>,
        number_nibble: usize,
        value: Value<'_>
    ) -> Vec<u8> ;
    fn extension_node(
        partial: impl Iterator<Item = u8>,
        number_nibble: usize,
        child_ref: ChildReference<Self::HashOut>
    ) -> Vec<u8> ;
    fn branch_node(
        children: impl Iterator<Item = impl Borrow<Option<ChildReference<Self::HashOut>>>>,
        value: Option<Value<'_>>
    ) -> Vec<u8> ;
    fn branch_node_nibbled(
        partial: impl Iterator<Item = u8>,
        number_nibble: usize,
        children: impl Iterator<Item = impl Borrow<Option<ChildReference<Self::HashOut>>>>,
        value: Option<Value<'_>>
    ) -> Vec<u8> ;

    fn decode<'a>(data: &'a [u8]) -> Result<Node<'a>, Self::Error> { ... }
}

Trait for trie node encoding/decoding. Uses a type parameter to allow registering positions without colling decode plan.

Required Associated Types

type Error: Error

Codec error type.

type HashOut: AsRef<[u8]> + AsMut<[u8]> + Default + MaybeDebug + PartialEq + Eq + Hash + Send + Sync + Clone + Copy

Output type of encoded node hasher.

Provided Associated Constants

const ESCAPE_HEADER: Option<u8> = None

Escape header byte sequence to indicate next node is a branch or leaf with hash of value, followed by the value node.

Required Methods

fn hashed_null_node() -> Self::HashOut

Get the hashed null node.

fn decode_plan(data: &[u8]) -> Result<NodePlan, Self::Error>

Decode bytes to a NodePlan. Returns Self::E on failure.

fn is_empty_node(data: &[u8]) -> bool

Check if the provided bytes correspond to the codecs “empty” node.

fn empty_node() -> &'static [u8]

Returns an encoded empty node.

fn leaf_node(
    partial: impl Iterator<Item = u8>,
    number_nibble: usize,
    value: Value<'_>
) -> Vec<u8>

Returns an encoded leaf node

Note that number_nibble is the number of element of the iterator it can possibly be obtain by Iterator size_hint, but for simplicity it is used directly as a parameter.

fn extension_node(
    partial: impl Iterator<Item = u8>,
    number_nibble: usize,
    child_ref: ChildReference<Self::HashOut>
) -> Vec<u8>

Returns an encoded extension node

Note that number_nibble is the number of element of the iterator it can possibly be obtain by Iterator size_hint, but for simplicity it is used directly as a parameter.

fn branch_node(
    children: impl Iterator<Item = impl Borrow<Option<ChildReference<Self::HashOut>>>>,
    value: Option<Value<'_>>
) -> Vec<u8>

Returns an encoded branch node. Takes an iterator yielding ChildReference<Self::HashOut> and an optional value.

fn branch_node_nibbled(
    partial: impl Iterator<Item = u8>,
    number_nibble: usize,
    children: impl Iterator<Item = impl Borrow<Option<ChildReference<Self::HashOut>>>>,
    value: Option<Value<'_>>
) -> Vec<u8>

Returns an encoded branch node with a possible partial path. number_nibble is the partial path length as in extension_node.

Provided Methods

fn decode<'a>(data: &'a [u8]) -> Result<Node<'a>, Self::Error>

Decode bytes to a Node. Returns Self::E on failure.

Implementors