Struct StateDelta

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

Represents a modification to some state - similar to a diff in source code.

The exact format of a delta is determined by the contract. A contract implementation will determine whether a delta is valid - perhaps by verifying it is signed by someone authorized to modify the contract state. A delta may be created in response to a State Summary as part of the State Synchronization mechanism.

Implementations

impl StateDelta<'_>

pub fn size(&self) -> usize

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

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

Extracts the owned data as a Vec<u8>.

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

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 StateDelta<'_>

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

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

impl<'a> Clone for StateDelta<'a>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Debug for StateDelta<'a>

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

Formats the value using the given formatter.

impl<'a> Deref for StateDelta<'a>

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

The resulting type after dereferencing.

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

Dereferences the value.

impl DerefMut for StateDelta<'_>

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

Mutably dereferences the value.

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

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

Converts to this type from the input type.

impl<'a> From<StateDelta<'a>> for UpdateData<'a>

fn from(delta: StateDelta<'a>) -> Self

Converts to this type from the input type.

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

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

Converts to this type from the input type.

impl<'a> PartialEq for StateDelta<'a>

fn eq(&self, other: &StateDelta<'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<'a> Serialize for StateDelta<'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 StateDelta<'a>

impl<'a> StructuralPartialEq for StateDelta<'a>