Set StateBackend::Transaction to PrefixedMemoryDB (#14612)

* Yep

* Try to get it working everywhere

* Make `from_raw_storage` start with an empty db

* More fixes!

* Make everything compile

* Fix `child_storage_root`

* Fix after merge

* Cleanups

* Update primitives/state-machine/src/overlayed_changes/mod.rs

Co-authored-by: Davide Galassi <davxy@datawok.net>

* Review comments

* Fix issues

* Silence warning

* FMT

* Clippy

---------

Co-authored-by: Davide Galassi <davxy@datawok.net>

substrate/client/api/src/backend.rs

@@ -36,17 +36,11 @@ use sp_storage::{ChildInfo, StorageData, StorageKey};
 
 use crate::{blockchain::Backend as BlockchainBackend, UsageInfo};
 
-pub use sp_state_machine::{Backend as StateBackend, KeyValueStates};
+pub use sp_state_machine::{Backend as StateBackend, BackendTransaction, KeyValueStates};
 
 /// Extracts the state backend type for the given backend.
 pub type StateBackendFor<B, Block> = <B as Backend<Block>>::State;
 
-/// Extracts the transaction for the given state backend.
-pub type TransactionForSB<B, Block> = <B as StateBackend<HashingFor<Block>>>::Transaction;
-
-/// Extracts the transaction for the given backend.
-pub type TransactionFor<B, Block> = TransactionForSB<StateBackendFor<B, Block>, Block>;
-
 /// Describes which block import notification stream should be notified.
 #[derive(Debug, Clone, Copy)]
 pub enum ImportNotificationAction {
@@ -181,7 +175,7 @@ pub trait BlockImportOperation<Block: BlockT> {
 	/// Inject storage data into the database.
 	fn update_db_storage(
 		&mut self,
-		update: TransactionForSB<Self::State, Block>,
+		update: BackendTransaction<HashingFor<Block>>,
 	) -> sp_blockchain::Result<()>;
 
 	/// Set genesis state. If `commit` is `false` the state is saved in memory, but is not written

substrate/client/api/src/call_executor.rs

@@ -26,7 +26,7 @@ use sp_state_machine::{OverlayedChanges, StorageProof};
 use std::cell::RefCell;
 
 use crate::execution_extensions::ExecutionExtensions;
-use sp_api::{ProofRecorder, StorageTransactionCache};
+use sp_api::{HashingFor, ProofRecorder};
 
 /// Executor Provider
 pub trait ExecutorProvider<Block: BlockT> {
@@ -72,12 +72,7 @@ pub trait CallExecutor<B: BlockT>: RuntimeVersionOf {
 		at_hash: B::Hash,
 		method: &str,
 		call_data: &[u8],
-		changes: &RefCell<OverlayedChanges>,
-		storage_transaction_cache: Option<
-			&RefCell<
-				StorageTransactionCache<B, <Self::Backend as crate::backend::Backend<B>>::State>,
-			>,
-		>,
+		changes: &RefCell<OverlayedChanges<HashingFor<B>>>,
 		proof_recorder: &Option<ProofRecorder<B>>,
 		call_context: CallContext,
 		extensions: &RefCell<Extensions>,

substrate/client/api/src/in_mem.rs

@@ -29,8 +29,8 @@ use sp_runtime::{
 	Justification, Justifications, StateVersion, Storage,
 };
 use sp_state_machine::{
-	Backend as StateBackend, ChildStorageCollection, InMemoryBackend, IndexOperation,
-	StorageCollection,
+	Backend as StateBackend, BackendTransaction, ChildStorageCollection, InMemoryBackend,
+	IndexOperation, StorageCollection,
 };
 use std::{
 	collections::{HashMap, HashSet},
@@ -480,9 +480,7 @@ impl<Block: BlockT> backend::AuxStore for Blockchain<Block> {
 pub struct BlockImportOperation<Block: BlockT> {
 	pending_block: Option<PendingBlock<Block>>,
 	old_state: InMemoryBackend<HashingFor<Block>>,
-	new_state: Option<
-		<InMemoryBackend<HashingFor<Block>> as StateBackend<HashingFor<Block>>>::Transaction,
-	>,
+	new_state: Option<BackendTransaction<HashingFor<Block>>>,
 	aux: Vec<(Vec<u8>, Option<Vec<u8>>)>,
 	finalized_blocks: Vec<(Block::Hash, Option<Justification>)>,
 	set_head: Option<Block::Hash>,
@@ -540,7 +538,7 @@ impl<Block: BlockT> backend::BlockImportOperation<Block> for BlockImportOperatio
 
 	fn update_db_storage(
 		&mut self,
-		update: <InMemoryBackend<HashingFor<Block>> as StateBackend<HashingFor<Block>>>::Transaction,
+		update: BackendTransaction<HashingFor<Block>>,
 	) -> sp_blockchain::Result<()> {
 		self.new_state = Some(update);
 		Ok(())