Enhance decl storage (#777)

* enhance macro decl_storage()

* update the state root hash

* fix one comment

substrate/srml/system/src/lib.rs

@@ -179,19 +179,35 @@ impl From<RawLog<substrate_primitives::H256>> for primitives::testing::DigestIte
 decl_storage! {
 	trait Store for Module<T: Trait> as System {
 
-		pub AccountNonce get(account_nonce): default map [ T::AccountId => T::Index ];
+		pub AccountNonce get(account_nonce): map T::AccountId => T::Index;
 
-		ExtrinsicCount: u32;
-		pub BlockHash get(block_hash): required map [ T::BlockNumber => T::Hash ];
-		ExtrinsicData get(extrinsic_data): required map [ u32 => Vec<u8> ];
-		RandomSeed get(random_seed): required T::Hash;
+		ExtrinsicCount: Option<u32>;
+		pub BlockHash get(block_hash) build(|_| vec![(T::BlockNumber::zero(), [69u8; 32])]): map T::BlockNumber => T::Hash;
+		ExtrinsicData get(extrinsic_data): map u32 => Vec<u8>;
+		RandomSeed get(random_seed) build(|_| [0u8; 32]): T::Hash;
 		/// The current block number being processed. Set by `execute_block`.
-		Number get(block_number): required T::BlockNumber;
-		ParentHash get(parent_hash): required T::Hash;
-		ExtrinsicsRoot get(extrinsics_root): required T::Hash;
-		Digest get(digest): default T::Digest;
+		Number get(block_number) build(|_| 1u64): T::BlockNumber;
+		ParentHash get(parent_hash) build(|_| [69u8; 32]): T::Hash;
+		ExtrinsicsRoot get(extrinsics_root): T::Hash;
+		Digest get(digest): T::Digest;
 
-		Events get(events): default Vec<EventRecord<T::Event>>;
+		Events get(events): Vec<EventRecord<T::Event>>;
+	}
+	add_extra_genesis {
+		config(changes_trie_config): Option<ChangesTrieConfiguration>;
+		config(_phantom): ::std::marker::PhantomData<T>;
+
+		build(|storage: &mut primitives::StorageMap, config: &GenesisConfig<T>| {
+			use codec::Encode;
+
+			storage.insert(well_known_keys::EXTRINSIC_INDEX.to_vec(), 0u32.encode());
+
+			if let Some(ref changes_trie_config) = config.changes_trie_config {
+				storage.insert(
+					well_known_keys::CHANGES_TRIE_CONFIG.to_vec(),
+					changes_trie_config.encode());
+			}
+		});
 	}
 }
 
@@ -396,52 +412,6 @@ impl<T: Trait> BlockNumberToHash for Module<T> {
 	}
 }
 
-#[cfg(any(feature = "std", test))]
-#[derive(Serialize, Deserialize)]
-#[serde(rename_all = "camelCase")]
-#[serde(deny_unknown_fields)]
-pub struct GenesisConfig<T: Trait> {
-	/// Changes trie configuration.
-	pub changes_trie_config: Option<ChangesTrieConfiguration>,
-	/// Marker for 'storing' T.
-	pub _phantom: ::std::marker::PhantomData<T>,
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> Default for GenesisConfig<T> {
-	fn default() -> Self {
-		GenesisConfig {
-			changes_trie_config: Default::default(),
-			_phantom: Default::default(),
-		}
-	}
-}
-
-#[cfg(any(feature = "std", test))]
-impl<T: Trait> primitives::BuildStorage for GenesisConfig<T>
-{
-	fn build_storage(self) -> Result<primitives::StorageMap, String> {
-		use codec::Encode;
-
-		let mut storage: primitives::StorageMap = map![
-			Self::hash(&<BlockHash<T>>::key_for(T::BlockNumber::zero())).to_vec() => [69u8; 32].encode(),
-			Self::hash(<Number<T>>::key()).to_vec() => 1u64.encode(),
-			Self::hash(<ParentHash<T>>::key()).to_vec() => [69u8; 32].encode(),
-			Self::hash(<RandomSeed<T>>::key()).to_vec() => [0u8; 32].encode()
-		];
-
-		storage.insert(well_known_keys::EXTRINSIC_INDEX.to_vec(), 0u32.encode());
-
-		if let Some(changes_trie_config) = self.changes_trie_config {
-			storage.insert(
-				well_known_keys::CHANGES_TRIE_CONFIG.to_vec(),
-				changes_trie_config.encode());
-		}
-
-		Ok(storage)
-	}
-}
-
 #[cfg(test)]
 mod tests {
 	use super::*;