Struct NoteTag

pub struct NoteTag(/* private fields */);

NoteTag`s are best effort filters for notes registered with the network.

Tags are light-weight values used to speed up queries. The 2 most signification bits of the tags have the following interpretation:

Prefix	Execution hint	Target	Allowed NoteType
0b00	Network	Specific	NoteType::Public
0b01	Network	Use case	NoteType::Public
0b10	Local	Any	NoteType::Public
0b11	Local	Any	Any

Where:

• NoteExecutionMode is set to NoteExecutionMode::Network to hint a super::Note should be consumed by the network. These notes will be further validated and if possible consumed by it.
• Target describes how to further interpret the bits in the tag. For tags with a specific target, the rest of the tag is interpreted as an account_id. For use case values, the meaning of the rest of the tag is not specified by the protocol and can be used by applications built on top of the rollup.

The note type is the only value enforced by the protocol. The rationale is that any note intended to be consumed by the network must be public to have all the details available. The public note for local execution is intended to allow users to search for notes that can be consumed right away, without requiring an off-band communication channel.

Implementations

impl NoteTag

pub fn from_account_id( account_id: AccountId, execution: NoteExecutionMode, ) -> Result<Self, NoteError>

Returns a new NoteTag instantiated from the specified account ID and execution mode.

The tag is constructed as follows:

• For local execution, the two most significant bits are set to 0b11, which allows for any note type to be used, the following 14 bits are set to the 14 most significant bits of the account ID, and the remaining 16 bits are set to 0.
• For network execution, the most significant bit is set to 0b0 and the remaining bits are set to the 31 most significant bits of the account ID. Note that this results in the two most significant bits of the tag being set to 0b00, because the network execution requires a public account which always have the high bit set to 0.

Errors

This will return an error if the account_id is not for a public account and the execution hint is set to NoteExecutionMode::Network.

pub fn for_public_use_case( use_case_id: u16, payload: u16, execution: NoteExecutionMode, ) -> Result<Self, NoteError>

Returns a new NoteTag instantiated for a custom use case which requires a public note.

The public use_case tag requires a NoteType::Public note.

The two high bits are set to the b10 or b01 depending on the execution hint, the next 14 bits are set to the use_case_id, and the low 16 bits are set to payload.

Errors

• If use_case_id is larger than or equal to $2^{14}$.

pub fn for_local_use_case( use_case_id: u16, payload: u16, ) -> Result<Self, NoteError>

Returns a new NoteTag instantiated for a custom local use case.

The local use_case tag is the only tag type that allows for NoteType::Private notes.

The two high bits are set to the b11, the next 14 bits are set to the use_case_id, and the low 16 bits are set to payload.

Errors

• If use_case_id is larger than or equal to $2^{14}$.

pub fn is_single_target(&self) -> bool

Returns true if the note is intended for execution by a specific account.

A note is intended for execution by a single account if the first two bits are zeros

pub fn execution_hint(&self) -> NoteExecutionMode

Returns note execution mode defined by this tag.

If the most significant bit of the tag is 0 or the 3 most significant bits are equal to 0b101, the note is intended for local execution; otherwise, the note is intended for network execution.

pub fn inner(&self) -> u32

Returns the inner u32 value of this tag.

pub fn validate(&self, note_type: NoteType) -> Result<Self, NoteError>

Returns an error if this tag is not consistent with the specified note type, and self otherwise.

Trait Implementations

impl Clone for NoteTag

fn clone(&self) -> NoteTag

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for NoteTag

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

Formats the value using the given formatter.

impl Deserializable for NoteTag

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 Display for NoteTag

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

Formats the value using the given formatter.

impl From<NoteTag> for Felt

fn from(value: NoteTag) -> Self

Converts to this type from the input type.

impl From<NoteTag> for u32

fn from(value: NoteTag) -> Self

Converts to this type from the input type.

impl From<NoteTag> for u64

fn from(value: NoteTag) -> Self

Converts to this type from the input type.

impl From<u32> for NoteTag

fn from(value: u32) -> Self

Converts to this type from the input type.

impl Ord for NoteTag

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

This method returns an Ordering between self and other.

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

where Self: Sized,

Compares and returns the maximum of two values.

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

where Self: Sized,

Compares and returns the minimum of two values.

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

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for NoteTag

fn eq(&self, other: &NoteTag) -> 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 PartialOrd for NoteTag

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

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

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

Tests less than (for self and other) and is used by the < operator.

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

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

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

Tests greater than (for self and other) and is used by the > operator.

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

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

impl Serializable for NoteTag

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> for NoteTag

type Error = TryFromIntError

The type returned in the event of a conversion error.

fn try_from(value: Felt) -> Result<Self, Self::Error>

Performs the conversion.

impl TryFrom<u64> for NoteTag

type Error = TryFromIntError

The type returned in the event of a conversion error.

fn try_from(value: u64) -> Result<Self, Self::Error>

Performs the conversion.

impl Copy for NoteTag

impl Eq for NoteTag

impl StructuralPartialEq for NoteTag