Struct near_sdk::collections::LazyOption

pub struct LazyOption<T> { /* fields omitted */ }

An persistent lazy option, that stores a value in the storage.

Implementations

impl<T> LazyOption<T>

pub fn is_some(&self) -> bool

Returns true if the value is present in the storage.

pub fn is_none(&self) -> bool

Returns true if the value is not present in the storage.

impl<T> LazyOption<T> where
    T: BorshSerialize + BorshDeserialize, 

pub fn new<S>(storage_key: S, value: Option<&T>) -> Self where
    S: IntoStorageKey, 

Create a new lazy option with the given storage_key and the initial value.

pub fn remove(&mut self) -> bool

Removes the value from storage without reading it. Returns whether the value was present.

pub fn take(&mut self) -> Option<T>

Removes the value from storage and returns it as an option.

pub fn get(&self) -> Option<T>

Gets the value from storage and returns it as an option.

pub fn set(&mut self, value: &T) -> bool

Sets the value into the storage without reading the previous value and returns whether the previous value was present.

pub fn replace(&mut self, value: &T) -> Option<T>

Replaces the value in the storage and returns the previous value as an option.

Trait Implementations

impl<T> BorshDeserialize for LazyOption<T> where
    Vec<u8>: BorshDeserialize, 

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

Deserializes this instance from a given slice of bytes. Updates the buffer to point at the remaining bytes.

fn try_from_slice(v: &[u8]) -> Result<Self, Error>

Deserialize this instance from a slice of bytes.

fn is_u8() -> bool

Whether Self is u8. NOTE: Vec<u8> is the most common use-case for serialization and deserialization, it’s worth handling it as a special case to improve performance. It’s a workaround for specific Vec<u8> implementation versus generic Vec<T> implementation. See https://github.com/rust-lang/rfcs/pull/1210 for details.

impl<T> BorshSerialize for LazyOption<T> where
    Vec<u8>: BorshSerialize, 

fn serialize<W: Write>(&self, writer: &mut W) -> Result<(), Error>

fn try_to_vec(&self) -> Result<Vec<u8, Global>, Error>

Serialize this instance into a vector of bytes.

fn is_u8() -> bool

Whether Self is u8. NOTE: Vec<u8> is the most common use-case for serialization and deserialization, it’s worth handling it as a special case to improve performance. It’s a workaround for specific Vec<u8> implementation versus generic Vec<T> implementation. See https://github.com/rust-lang/rfcs/pull/1210 for details.