Trait frame_support::storage::StorageDecodeLength
source · pub trait StorageDecodeLength: Sealed + DecodeLength {
// Provided method
fn decode_len(key: &[u8]) -> Option<usize> { ... }
}Expand description
Marker trait that will be implemented for types that support to decode their length in an
efficient way. It is expected that the length is at the beginning of the encoded object
and that the length is a Compact<u32>.
This trait is sealed.
Provided Methods§
sourcefn decode_len(key: &[u8]) -> Option<usize>
fn decode_len(key: &[u8]) -> Option<usize>
Decode the length of the storage value at key.
This function assumes that the length is at the beginning of the encoded object
and is a Compact<u32>.
Returns None if the storage value does not exist or the decoding failed.