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DoubleMapStorage

gear_common::storage

Trait DoubleMapStorage 

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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> { ... }
}
Expand description

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§

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type Key1

Map’s first key type.

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type Key2

Map’s second key type.

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type Value

Map’s stored value type.

Required Methods§

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

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

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

Gets value stored under given keys, if present.

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

Inserts value with given keys.

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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.

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

Mutates all stored values with given convert function.

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

Removes value stored under the given keys.

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fn clear()

Removes all values.

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

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

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fn clear_prefix(first_key: Self::Key1)

Remove items from the map matching a first_key prefix.

Provided Methods§

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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.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§