Module sp_io::storage

Interface for accessing the storage from within the runtime.

Structs

HostFunctions

Provides implementations for the extern host functions.

Functions

append

Append the encoded value to the storage item at key.

changes_root

Always returns None. This function exists for compatibility reasons.

clear

Clear the storage of the given key and its value.

clear_prefix

Clear the storage of each key-value pair where the key starts with the given prefix.

commit_transaction

Commit the last transaction started by start_transaction.

exists

Check whether the given key exists in storage.

get

Returns the data for key in the storage or None if the key can not be found.

next_key

Get the next key in storage after the given one in lexicographic order.

read

Get key from storage, placing the value into value_out and return the number of bytes that the entry in storage has beyond the offset or None if the storage entry doesn’t exist at all. If value_out length is smaller than the returned length, only value_out length bytes are copied into value_out.

rollback_transaction

Rollback the last transaction started by start_transaction.

root

“Commit” all existing operations and compute the resulting storage root.

set

Set key to value in the storage.

start_transaction

Start a new nested transaction.