Use prefixed keys for trie node. (#2130)

* Account for pending insertions when pruning

* Prefixed trie storage

* Comments

* Prefixed trie storage

* Fixed tests

* Fixed tests

* Bumped runtime version

* Bumped runtime version again

substrate/core/state-machine/src/changes_trie/changes_iterator.rs

@@ -115,7 +115,7 @@ pub fn key_changes_proof_check<S: RootsStorage<H>, H: Hasher>(
 
 	let mut proof_db = MemoryDB::<H>::default();
 	for item in proof {
-		proof_db.insert(&item);
+		proof_db.insert(&[], &item);
 	}
 
 	let proof_db = InMemoryStorage::with_db(proof_db);

substrate/core/state-machine/src/changes_trie/mod.rs

@@ -77,7 +77,7 @@ pub trait RootsStorage<H: Hasher>: Send + Sync {
 /// Changes trie storage. Provides access to trie roots and trie nodes.
 pub trait Storage<H: Hasher>: RootsStorage<H> {
 	/// Get a trie node.
-	fn get(&self, key: &H::Out) -> Result<Option<DBValue>, String>;
+	fn get(&self, key: &H::Out, prefix: &[u8]) -> Result<Option<DBValue>, String>;
 }
 
 /// Changes trie configuration.

substrate/core/state-machine/src/changes_trie/storage.rs

@@ -92,7 +92,7 @@ impl<H: Hasher> InMemoryStorage<H> where H::Out: HeapSizeOf {
 	pub fn remove_from_storage(&self, keys: &HashSet<H::Out>) {
 		let mut data = self.data.write();
 		for key in keys {
-			data.mdb.remove_and_purge(key);
+			data.mdb.remove_and_purge(key, &[]);
 		}
 	}
 
@@ -116,8 +116,8 @@ impl<H: Hasher> RootsStorage<H> for InMemoryStorage<H> where H::Out: HeapSizeOf
 }
 
 impl<H: Hasher> Storage<H> for InMemoryStorage<H> where H::Out: HeapSizeOf {
-	fn get(&self, key: &H::Out) -> Result<Option<DBValue>, String> {
-		MemoryDB::<H>::get(&self.data.read().mdb, key)
+	fn get(&self, key: &H::Out, prefix: &[u8]) -> Result<Option<DBValue>, String> {
+		MemoryDB::<H>::get(&self.data.read().mdb, key, prefix)
 	}
 }
 
@@ -128,7 +128,9 @@ impl<'a, H: Hasher, S: 'a + Storage<H>> TrieBackendAdapter<'a, H, S> {
 }
 
 impl<'a, H: Hasher, S: 'a + Storage<H>> TrieBackendStorage<H> for TrieBackendAdapter<'a, H, S> {
-	fn get(&self, key: &H::Out) -> Result<Option<DBValue>, String> {
-		self.storage.get(key)
+	type Overlay = MemoryDB<H>;
+
+	fn get(&self, key: &H::Out, prefix: &[u8]) -> Result<Option<DBValue>, String> {
+		self.storage.get(key, prefix)
 	}
 }