Use [u8; 4] for well known cache keys (#2152)

* Use [u8; 4] for well known cache keys

* Use type alias

substrate/core/client/src/backend.rs

@@ -23,6 +23,7 @@ use runtime_primitives::{generic::BlockId, Justification, StorageOverlay, Childr
 use runtime_primitives::traits::{Block as BlockT, NumberFor};
 use state_machine::backend::Backend as StateBackend;
 use state_machine::ChangesTrieStorage as StateChangesTrieStorage;
+use consensus::well_known_cache_keys;
 use hash_db::Hasher;
 use trie::MemoryDB;
 
@@ -75,7 +76,7 @@ pub trait BlockImportOperation<Block, H> where
 	) -> error::Result<()>;
 
 	/// Update cached data.
-	fn update_cache(&mut self, cache: HashMap<Vec<u8>, Vec<u8>>);
+	fn update_cache(&mut self, cache: HashMap<well_known_cache_keys::Id, Vec<u8>>);
 	/// Inject storage data into the database.
 	fn update_db_storage(&mut self, update: <Self::State as StateBackend<H>>::Transaction) -> error::Result<()>;
 	/// Inject storage data into the database replacing any existing data.

substrate/core/client/src/blockchain.rs

@@ -21,6 +21,7 @@ use std::sync::Arc;
 use runtime_primitives::traits::{Block as BlockT, Header as HeaderT, NumberFor};
 use runtime_primitives::generic::BlockId;
 use runtime_primitives::Justification;
+use consensus::well_known_cache_keys;
 
 use crate::error::{ErrorKind, Result};
 
@@ -100,7 +101,7 @@ pub trait ProvideCache<Block: BlockT> {
 /// Blockchain optional data cache.
 pub trait Cache<Block: BlockT>: Send + Sync {
 	/// Returns cached value by the given key.
-	fn get_at(&self, key: &[u8], block: &BlockId<Block>) -> Option<Vec<u8>>;
+	fn get_at(&self, key: &well_known_cache_keys::Id, block: &BlockId<Block>) -> Option<Vec<u8>>;
 }
 
 /// Blockchain info

substrate/core/client/src/client.rs

@@ -27,7 +27,7 @@ use runtime_primitives::{
 };
 use consensus::{
 	Error as ConsensusError, ErrorKind as ConsensusErrorKind, ImportBlock, ImportResult,
-	BlockOrigin, ForkChoiceStrategy,
+	BlockOrigin, ForkChoiceStrategy, well_known_cache_keys::Id as CacheKeyId,
 };
 use runtime_primitives::traits::{
 	Block as BlockT, Header as HeaderT, Zero, As, NumberFor, CurrentHeight, BlockNumberToHash,
@@ -672,7 +672,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		&self,
 		operation: &mut ClientImportOperation<Block, Blake2Hasher, B>,
 		import_block: ImportBlock<Block>,
-		new_cache: HashMap<Vec<u8>, Vec<u8>>,
+		new_cache: HashMap<CacheKeyId, Vec<u8>>,
 	) -> error::Result<ImportResult> where
 		E: CallExecutor<Block, Blake2Hasher> + Send + Sync + Clone,
 	{
@@ -743,7 +743,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		import_headers: PrePostHeader<Block::Header>,
 		justification: Option<Justification>,
 		body: Option<Vec<Block::Extrinsic>>,
-		new_cache: HashMap<Vec<u8>, Vec<u8>>,
+		new_cache: HashMap<CacheKeyId, Vec<u8>>,
 		finalized: bool,
 		aux: Vec<(Vec<u8>, Option<Vec<u8>>)>,
 		fork_choice: ForkChoiceStrategy,
@@ -1396,7 +1396,7 @@ impl<B, E, Block, RA> consensus::BlockImport<Block> for Client<B, E, Block, RA>
 	fn import_block(
 		&self,
 		import_block: ImportBlock<Block>,
-		new_cache: HashMap<Vec<u8>, Vec<u8>>,
+		new_cache: HashMap<CacheKeyId, Vec<u8>>,
 	) -> Result<ImportResult, Self::Error> {
 		self.lock_import_and_run(|operation| {
 			self.apply_block(operation, import_block, new_cache)

substrate/core/client/src/in_mem.rs

@@ -29,6 +29,7 @@ use state_machine::{self, InMemoryChangesTrieStorage, ChangesTrieAnchorBlockId};
 use hash_db::Hasher;
 use heapsize::HeapSizeOf;
 use trie::MemoryDB;
+use consensus::well_known_cache_keys::Id as CacheKeyId;
 
 use crate::error;
 use crate::backend::{self, NewBlockState};
@@ -390,7 +391,7 @@ impl<Block: BlockT> light::blockchain::Storage<Block> for Blockchain<Block>
 	fn import_header(
 		&self,
 		header: Block::Header,
-		_cache: HashMap<Vec<u8>, Vec<u8>>,
+		_cache: HashMap<CacheKeyId, Vec<u8>>,
 		state: NewBlockState,
 		aux_ops: Vec<(Vec<u8>, Option<Vec<u8>>)>,
 	) -> error::Result<()> {
@@ -431,7 +432,7 @@ impl<Block: BlockT> light::blockchain::Storage<Block> for Blockchain<Block>
 /// In-memory operation.
 pub struct BlockImportOperation<Block: BlockT, H: Hasher> {
 	pending_block: Option<PendingBlock<Block>>,
-	pending_cache: HashMap<Vec<u8>, Vec<u8>>,
+	pending_cache: HashMap<CacheKeyId, Vec<u8>>,
 	old_state: InMemory<H>,
 	new_state: Option<InMemory<H>>,
 	changes_trie_update: Option<MemoryDB<H>>,
@@ -468,7 +469,7 @@ where
 		Ok(())
 	}
 
-	fn update_cache(&mut self, cache: HashMap<Vec<u8>, Vec<u8>>) {
+	fn update_cache(&mut self, cache: HashMap<CacheKeyId, Vec<u8>>) {
 		self.pending_cache = cache;
 	}
 

substrate/core/client/src/light/backend.rs

@@ -34,6 +34,7 @@ use crate::light::fetcher::{Fetcher, RemoteReadRequest};
 use hash_db::Hasher;
 use trie::MemoryDB;
 use heapsize::HeapSizeOf;
+use consensus::well_known_cache_keys;
 
 const IN_MEMORY_EXPECT_PROOF: &str = "InMemory state backend has Void error type and always suceeds; qed";
 
@@ -46,7 +47,7 @@ pub struct Backend<S, F, H> {
 /// Light block (header and justification) import operation.
 pub struct ImportOperation<Block: BlockT, S, F, H> {
 	header: Option<Block::Header>,
-	cache: HashMap<Vec<u8>, Vec<u8>>,
+	cache: HashMap<well_known_cache_keys::Id, Vec<u8>>,
 	leaf_state: NewBlockState,
 	aux_ops: Vec<(Vec<u8>, Option<Vec<u8>>)>,
 	finalized_blocks: Vec<BlockId<Block>>,
@@ -254,7 +255,7 @@ where
 		Ok(())
 	}
 
-	fn update_cache(&mut self, cache: HashMap<Vec<u8>, Vec<u8>>) {
+	fn update_cache(&mut self, cache: HashMap<well_known_cache_keys::Id, Vec<u8>>) {
 		self.cache = cache;
 	}
 

substrate/core/client/src/light/blockchain.rs

@@ -23,6 +23,7 @@ use parking_lot::Mutex;
 
 use runtime_primitives::{Justification, generic::BlockId};
 use runtime_primitives::traits::{Block as BlockT, Header as HeaderT, NumberFor, Zero};
+use consensus::well_known_cache_keys;
 
 use crate::backend::{AuxStore, NewBlockState};
 use crate::blockchain::{Backend as BlockchainBackend, BlockStatus, Cache as BlockchainCache,
@@ -40,7 +41,7 @@ pub trait Storage<Block: BlockT>: AuxStore + BlockchainHeaderBackend<Block> {
 	fn import_header(
 		&self,
 		header: Block::Header,
-		cache: HashMap<Vec<u8>, Vec<u8>>,
+		cache: HashMap<well_known_cache_keys::Id, Vec<u8>>,
 		state: NewBlockState,
 		aux_ops: Vec<(Vec<u8>, Option<Vec<u8>>)>,
 	) -> ClientResult<()>;
@@ -252,7 +253,7 @@ pub mod tests {
 		fn import_header(
 			&self,
 			_header: Header,
-			_cache: HashMap<Vec<u8>, Vec<u8>>,
+			_cache: HashMap<well_known_cache_keys::Id, Vec<u8>>,
 			_state: NewBlockState,
 			_aux_ops: Vec<(Vec<u8>, Option<Vec<u8>>)>,
 		) -> ClientResult<()> {