Trait frame_support::storage::IterableStorageDoubleMap

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pub trait IterableStorageDoubleMap<K1: FullCodec, K2: FullCodec, V: FullCodec>: StorageDoubleMap<K1, K2, V> {
    type PartialKeyIterator: Iterator<Item = K2>;
    type PrefixIterator: Iterator<Item = (K2, V)>;
    type FullKeyIterator: Iterator<Item = (K1, K2)>;
    type Iterator: Iterator<Item = (K1, K2, V)>;

    // Required methods
    fn iter_prefix(k1: impl EncodeLike<K1>) -> Self::PrefixIterator;
    fn iter_prefix_from(
        k1: impl EncodeLike<K1>,
        starting_raw_key: Vec<u8>
    ) -> Self::PrefixIterator;
    fn iter_key_prefix(k1: impl EncodeLike<K1>) -> Self::PartialKeyIterator;
    fn iter_key_prefix_from(
        k1: impl EncodeLike<K1>,
        starting_raw_key: Vec<u8>
    ) -> Self::PartialKeyIterator;
    fn drain_prefix(k1: impl EncodeLike<K1>) -> Self::PrefixIterator;
    fn iter() -> Self::Iterator;
    fn iter_from(starting_raw_key: Vec<u8>) -> Self::Iterator;
    fn iter_keys() -> Self::FullKeyIterator;
    fn iter_keys_from(starting_raw_key: Vec<u8>) -> Self::FullKeyIterator;
    fn drain() -> Self::Iterator;
    fn translate<O: Decode, F: FnMut(K1, K2, O) -> Option<V>>(f: F);
}
Expand description

A strongly-typed double map in storage whose secondary keys and values can be iterated over.

Required Associated Types§

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type PartialKeyIterator: Iterator<Item = K2>

The type that iterates over all key2.

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type PrefixIterator: Iterator<Item = (K2, V)>

The type that iterates over all (key2, value).

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type FullKeyIterator: Iterator<Item = (K1, K2)>

The type that iterates over all (key1, key2).

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type Iterator: Iterator<Item = (K1, K2, V)>

The type that iterates over all (key1, key2, value).

Required Methods§

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fn iter_prefix(k1: impl EncodeLike<K1>) -> Self::PrefixIterator

Enumerate all elements in the map with first key k1 in lexicographical order of the encoded key. If you add or remove values whose first key is k1 to the map while doing this, you’ll get undefined results.

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fn iter_prefix_from( k1: impl EncodeLike<K1>, starting_raw_key: Vec<u8> ) -> Self::PrefixIterator

Enumerate all elements in the map with first key k1 after a specified starting_raw_key in lexicographical order of the encoded key. If you add or remove values whose first key is k1 to the map while doing this, you’ll get undefined results.

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fn iter_key_prefix(k1: impl EncodeLike<K1>) -> Self::PartialKeyIterator

Enumerate all second keys k2 in the map with the same first key k1 in lexicographical order of the encoded key. If you add or remove values whose first key is k1 to the map while doing this, you’ll get undefined results.

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fn iter_key_prefix_from( k1: impl EncodeLike<K1>, starting_raw_key: Vec<u8> ) -> Self::PartialKeyIterator

Enumerate all second keys k2 in the map with the same first key k1 after a specified starting_raw_key in lexicographical order of the encoded key. If you add or remove values whose first key is k1 to the map while doing this, you’ll get undefined results.

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fn drain_prefix(k1: impl EncodeLike<K1>) -> Self::PrefixIterator

Remove all elements from the map with first key k1 and iterate through them in lexicographical order of the encoded key. If you add elements with first key k1 to the map while doing this, you’ll get undefined results.

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fn iter() -> Self::Iterator

Enumerate all elements in the map in lexicographical order of the encoded key. If you add or remove values to the map while doing this, you’ll get undefined results.

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fn iter_from(starting_raw_key: Vec<u8>) -> Self::Iterator

Enumerate all elements in the map after a specified starting_raw_key in lexicographical order of the encoded key. If you add or remove values to the map while doing this, you’ll get undefined results.

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fn iter_keys() -> Self::FullKeyIterator

Enumerate all keys k1 and k2 in the map in lexicographical order of the encoded key. If you add or remove values to the map while doing this, you’ll get undefined results.

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fn iter_keys_from(starting_raw_key: Vec<u8>) -> Self::FullKeyIterator

Enumerate all keys k1 and k2 in the map after a specified starting_raw_key in lexicographical order of the encoded key. If you add or remove values to the map while doing this, you’ll get undefined results.

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fn drain() -> Self::Iterator

Remove all elements from the map and iterate through them in lexicographical order of the encoded key. If you add elements to the map while doing this, you’ll get undefined results.

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fn translate<O: Decode, F: FnMut(K1, K2, O) -> Option<V>>(f: F)

Translate the values of all elements by a function f, in the map in lexicographical order of the encoded key. By returning None from f for an element, you’ll remove it from the map.

NOTE: If a value fail to decode because storage is corrupted then it is skipped.

Implementors§