Add typedefs for storage types (#4654)

* Add typedefs for storage types

* Fix after merge

substrate/client/db/src/lib.rs

@@ -45,7 +45,7 @@ use std::collections::HashMap;
 
 use sc_client_api::{execution_extensions::ExecutionExtensions, ForkBlocks, UsageInfo, MemoryInfo, BadBlocks, IoInfo};
 use sc_client_api::backend::NewBlockState;
-use sc_client_api::backend::{PrunableStateChangesTrieStorage, StorageCollection, ChildStorageCollection};
+use sc_client_api::backend::PrunableStateChangesTrieStorage;
 use sp_blockchain::{
 	Result as ClientResult, Error as ClientError,
 	well_known_cache_keys, HeaderBackend,
@@ -66,8 +66,9 @@ use sp_runtime::traits::{
 };
 use sc_executor::RuntimeInfo;
 use sp_state_machine::{
-	DBValue, ChangesTrieTransaction, ChangesTrieCacheAction,
-	backend::Backend as StateBackend, UsageInfo as StateUsageInfo,
+	DBValue, ChangesTrieTransaction, ChangesTrieCacheAction, UsageInfo as StateUsageInfo,
+	StorageCollection, ChildStorageCollection,
+	backend::Backend as StateBackend,
 };
 use crate::utils::{DatabaseType, Meta, db_err, meta_keys, read_db, read_meta};
 use crate::changes_tries_storage::{DbChangesTrieStorage, DbChangesTrieStorageTransaction};

substrate/client/db/src/storage_cache.rs

@@ -24,17 +24,17 @@ use hash_db::Hasher;
 use sp_runtime::traits::{Block as BlockT, Header, HasherFor, NumberFor};
 use sp_core::hexdisplay::HexDisplay;
 use sp_core::storage::ChildInfo;
-use sp_state_machine::{backend::Backend as StateBackend, TrieBackend};
+use sp_state_machine::{
+	backend::Backend as StateBackend, TrieBackend, StorageKey, StorageValue,
+	StorageCollection, ChildStorageCollection,
+};
 use log::trace;
-use sc_client_api::backend::{StorageCollection, ChildStorageCollection};
 use std::hash::Hash as StdHash;
 use crate::stats::StateUsageStats;
 
 const STATE_CACHE_BLOCKS: usize = 12;
 
-type StorageKey = Vec<u8>;
 type ChildStorageKey = (Vec<u8>, Vec<u8>);
-type StorageValue = Vec<u8>;
 
 /// Shared canonical state cache.
 pub struct Cache<B: BlockT> {