Struct StorageMap

pub struct StorageMap<K: StorageKey, V: StorageType> { /* private fields */ }

Accessor for a storage-backed map.

Implementations

impl<K, V> StorageMap<K, V>

where K: StorageKey, V: StorageType,

pub fn getter(&self, key: K) -> StorageGuard<'_, V>

Gets an accessor to the element at the given key, or the zero-value if none is there. Note: the accessor is protected by a StorageGuard, which restricts its lifetime to that of &self.

pub fn setter(&mut self, key: K) -> StorageGuardMut<'_, V>

Gets a mutable accessor to the element at the given key, or the zero-value if none is there. Note: the accessor is protected by a StorageGuardMut, which restricts its lifetime to that of &mut self.

pub fn get(&self, key: K) -> V::Wraps<'_>

Gets the element at the given key, or the zero value if none is there.

impl<'a, K, V> StorageMap<K, V>

where K: StorageKey, V: SimpleStorageType<'a>,

pub fn insert(&mut self, key: K, value: V::Wraps<'a>)

Sets the element at a given key, overwriting what may have been there.

pub fn replace(&mut self, key: K, value: V::Wraps<'a>) -> V::Wraps<'a>

Replace the element at the given key. Returns the old element, or the zero-value if none was there.

pub fn take(&mut self, key: K) -> V::Wraps<'a>

Remove the element at the given key. Returns the element, or the zero-value if none was there.

impl<K, V> StorageMap<K, V>

where K: StorageKey, V: Erase,

pub fn delete(&mut self, key: K)

Delete the element at the given key, if it exists.

Trait Implementations

impl<K, V, T> From<&T> for StorageMap<K, V>

where K: StorageKey, V: StorageType, T: Host + Clone + 'static,

fn from(host: &T) -> Self

Converts to this type from the input type.

impl<K, V> HostAccess for StorageMap<K, V>

where K: StorageKey, V: StorageType,

fn vm(&self) -> &dyn Host

Provides access to the parametrized host of a contract, giving access to all the desired hostios from the user.

impl<K, V> StorageType for StorageMap<K, V>

where K: StorageKey, V: StorageType,

type Wraps<'a> = StorageGuard<'a, StorageMap<K, V>> where Self: 'a

For primitive types, this is the type being stored. For collections, this is the StorageType being collected.

type WrapsMut<'a> = StorageGuardMut<'a, StorageMap<K, V>> where Self: 'a

Mutable accessor to the type being stored.

unsafe fn new(slot: U256, offset: u8, host: VM) -> Self

Where in persistent storage the type should live. Although useful for framework designers creating new storage types, most user programs shouldn’t call this. Note: implementations will have to be const once generic_const_exprs stabilizes.

fn load<'s>(self) -> Self::Wraps<'s>

Load the wrapped type, consuming the accessor. Note: most types have a get and/or getter, which don’t consume Self.

fn load_mut<'s>(self) -> Self::WrapsMut<'s>

Load the wrapped mutable type, consuming the accessor. Note: most types have a set and/or setter, which don’t consume Self.

const SLOT_BYTES: usize = 32usize

The number of bytes in a slot needed to represent the type. Must not exceed 32. For types larger than 32 bytes that are stored inline with a struct’s fields, set this to 32 and return the full size in StorageType::new.

const REQUIRED_SLOTS: usize = 0usize

The number of words this type must fill. For primitives this is always 0. For complex types requiring more than one inline word, set this to the total size.