Struct NoteMetadata

pub struct NoteMetadata { /* private fields */ }

Metadata associated with a note.

Note type and tag must be internally consistent according to the following rules:

• For private and encrypted notes, the two most significant bits of the tag must be 0b11.
• For public notes, the two most significant bits of the tag can be set to any value.

Word layout & validity

NoteMetadata can be encoded into a Word with the following layout:

1st felt: [sender_id_prefix (64 bits)]
2nd felt: [sender_id_suffix (56 bits) | note_type (2 bits) | note_execution_hint_tag (6 bits)]
3rd felt: [note_execution_hint_payload (32 bits) | note_tag (32 bits)]
4th felt: [aux (64 bits)]

The rationale for the above layout is to ensure the validity of each felt:

• 1st felt: Is equivalent to the prefix of the account ID so it inherits its validity.
• 2nd felt: The lower 8 bits of the account ID suffix are 0 by construction, so that they can be overwritten with other data. The suffix is designed such that it retains its felt validity even if all of its lower 8 bits are be set to 1. This is because the most significant bit is always zero.
• 3rd felt: The note execution hint payload must contain at least one 0 bit in its encoding, so the upper 32 bits of the felt will contain at least one 0 bit making the entire felt valid.
• 4th felt: The aux value must be a felt itself.

Implementations

impl NoteMetadata

pub fn new( sender: AccountId, note_type: NoteType, tag: NoteTag, execution_hint: NoteExecutionHint, aux: Felt, ) -> Result<Self, NoteError>

Returns a new NoteMetadata instantiated with the specified parameters.

Errors

Returns an error if the note type and note tag are inconsistent.

pub fn sender(&self) -> AccountId

Returns the account which created the note.

pub fn note_type(&self) -> NoteType

Returns the note’s type.

pub fn tag(&self) -> NoteTag

Returns the tag associated with the note.

pub fn execution_hint(&self) -> NoteExecutionHint

Returns the execution hint associated with the note.

pub fn aux(&self) -> Felt

Returns the note’s aux field.

pub fn is_private(&self) -> bool

Returns true if the note is private.

Trait Implementations

impl Clone for NoteMetadata

fn clone(&self) -> NoteMetadata

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for NoteMetadata

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

Formats the value using the given formatter.

impl Deserializable for NoteMetadata

fn read_from<R: ByteReader>( source: &mut R, ) -> Result<Self, DeserializationError>

Reads a sequence of bytes from the provided source, attempts to deserialize these bytes into Self, and returns the result.

fn read_from_bytes(bytes: &[u8]) -> Result<Self, DeserializationError>

Attempts to deserialize the provided bytes into Self and returns the result.

impl From<&NoteMetadata> for Word

fn from(metadata: &NoteMetadata) -> Self

Convert a NoteMetadata into a Word.

The produced layout of the word is documented on the NoteMetadata type.

impl From<NoteMetadata> for Word

fn from(metadata: NoteMetadata) -> Self

Convert a NoteMetadata into a Word.

The produced layout of the word is documented on the NoteMetadata type.

impl PartialEq for NoteMetadata

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl Serializable for NoteMetadata

fn write_into<W: ByteWriter>(&self, target: &mut W)

Serializes self into bytes and writes these bytes into the target.

fn to_bytes(&self) -> Vec<u8>

Serializes self into a vector of bytes.

fn get_size_hint(&self) -> usize

Returns an estimate of how many bytes are needed to represent self.

impl TryFrom<[BaseElement; 4]> for NoteMetadata

fn try_from(elements: Word) -> Result<Self, Self::Error>

Tries to decode a Word into a NoteMetadata.

The expected layout of the word is documented on the NoteMetadata type.

type Error = NoteError

The type returned in the event of a conversion error.

impl Copy for NoteMetadata

impl Eq for NoteMetadata

impl StructuralPartialEq for NoteMetadata