Struct State

pub struct State<'a>(/* private fields */);

Data associated with a contract that can be retrieved by Applications and Delegates.

For efficiency and flexibility, contract state is represented as a simple u8 byte array.

Implementations

impl State<'_>

pub fn size(&self) -> usize

Gets the number of bytes of data stored in the State.

pub fn into_owned(self) -> State<'static>

pub fn into_bytes(self) -> Vec<u8>

Extracts the owned data as a Vec<u8>.

pub fn to_mut(&mut self) -> &mut Vec<u8>

Acquires a mutable reference to the owned form of the State data.

Methods from Deref<Target = Cow<'a, [u8]>>

pub fn is_borrowed(&self) -> bool

🔬This is a nightly-only experimental API. (cow_is_borrowed)

Returns true if the data is borrowed, i.e. if to_mut would require additional work.

Examples

#![feature(cow_is_borrowed)]
use std::borrow::Cow;

let cow = Cow::Borrowed("moo");
assert!(cow.is_borrowed());

let bull: Cow<'_, str> = Cow::Owned("...moo?".to_string());
assert!(!bull.is_borrowed());

pub fn is_owned(&self) -> bool

🔬This is a nightly-only experimental API. (cow_is_borrowed)

Returns true if the data is owned, i.e. if to_mut would be a no-op.

Examples

#![feature(cow_is_borrowed)]
use std::borrow::Cow;

let cow: Cow<'_, str> = Cow::Owned("moo".to_string());
assert!(cow.is_owned());

let bull = Cow::Borrowed("...moo?");
assert!(!bull.is_owned());

pub fn to_mut(&mut self) -> &mut <B as ToOwned>::Owned

Acquires a mutable reference to the owned form of the data.

Clones the data if it is not already owned.

Examples

use std::borrow::Cow;

let mut cow = Cow::Borrowed("foo");
cow.to_mut().make_ascii_uppercase();

assert_eq!(
  cow,
  Cow::Owned(String::from("FOO")) as Cow<'_, str>
);

Trait Implementations

impl AsRef<[u8]> for State<'_>

fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.

impl<'a> Clone for State<'a>

fn clone(&self) -> State<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Debug for State<'a>

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

Formats the value using the given formatter.

impl<'a> Deref for State<'a>

type Target = Cow<'a, [u8]>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for State<'_>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<'de: 'a, 'a> Deserialize<'de> for State<'a>

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'a> From<&'a [u8]> for State<'a>

fn from(state: &'a [u8]) -> Self

Converts to this type from the input type.

impl From<Vec<u8>> for State<'_>

fn from(state: Vec<u8>) -> Self

Converts to this type from the input type.

impl From<WrappedState> for State<'static>

fn from(value: WrappedState) -> Self

Converts to this type from the input type.

impl<'a> PartialEq for State<'a>

fn eq(&self, other: &State<'a>) -> 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 Read for State<'_>

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

impl<'a> Serialize for State<'a>

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<'a> Eq for State<'a>

impl<'a> StructuralPartialEq for State<'a>