Trait gear_common::storage::DoubleMapStorage

pub trait DoubleMapStorage {
    type Key1;
    type Key2;
    type Value;

    // Required methods
    fn contains_keys(key1: &Self::Key1, key2: &Self::Key2) -> bool;
    fn get(key1: &Self::Key1, key2: &Self::Key2) -> Option<Self::Value>;
    fn insert(key1: Self::Key1, key2: Self::Key2, value: Self::Value);
    fn mutate<R, F: FnOnce(&mut Option<Self::Value>) -> R>(
        key1: Self::Key1,
        key2: Self::Key2,
        f: F
    ) -> R;
    fn mutate_values<F: FnMut(Self::Value) -> Self::Value>(f: F);
    fn remove(key1: Self::Key1, key2: Self::Key2);
    fn clear();
    fn take(key1: Self::Key1, key2: Self::Key2) -> Option<Self::Value>;
    fn clear_prefix(first_key: Self::Key1);

    // Provided method
    fn mutate_exists<R, F: FnOnce(&mut Self::Value) -> R>(
        key1: Self::Key1,
        key2: Self::Key2,
        f: F
    ) -> Option<R> { ... }
}

Represents logic of managing globally stored double-key map for more complicated logic.

In fact, represents custom implementation/wrapper around of Substrate’s StorageDoubleMap with OptionQuery.

Required Associated Types

type Key1

Map’s first key type.

type Key2

Map’s second key type.

type Value

Map’s stored value type.

Required Methods

fn contains_keys(key1: &Self::Key1, key2: &Self::Key2) -> bool

Returns bool, defining does map contain value under given keys.

fn get(key1: &Self::Key1, key2: &Self::Key2) -> Option<Self::Value>

Gets value stored under given keys, if present.

fn insert(key1: Self::Key1, key2: Self::Key2, value: Self::Value)

Inserts value with given keys.

fn mutate<R, F: FnOnce(&mut Option<Self::Value>) -> R>( key1: Self::Key1, key2: Self::Key2, f: F ) -> R

Mutates value by Option reference, which stored (or not in None case) under given keys with given function.

May return generic type value.

fn mutate_values<F: FnMut(Self::Value) -> Self::Value>(f: F)

Mutates all stored values with given convert function.

fn remove(key1: Self::Key1, key2: Self::Key2)

Removes value stored under the given keys.

fn clear()

Removes all values.

fn take(key1: Self::Key1, key2: Self::Key2) -> Option<Self::Value>

Gets value stored under given keys, if present, and removes it from storage.

fn clear_prefix(first_key: Self::Key1)

Remove items from the map matching a first_key prefix.

Provided Methods

fn mutate_exists<R, F: FnOnce(&mut Self::Value) -> R>( key1: Self::Key1, key2: Self::Key2, f: F ) -> Option<R>

Works the same as Self::mutate, but triggers if value present.

Object Safety

This trait is not object safe.

Implementors