Make runtime api calls native when possible (#1302)

* Add simple benchmark for the runtime api

* Make the executor support native calls

* Some documentation

* Hide behind `feature = "std"`

* Rework the native calls

* Make all tests compile again

* Make every parameter using the Block serialized/deserialized in the native call

* Forward `UnwindSafe` requirement

* Remove debug stuff

* Add some documentation

* Fixes warnings

* Fixes errors after master rebase

* Fixes compilation after master rebase

* Fixes compilation after rebase

substrate/core/test-runtime/src/lib.rs

@@ -186,13 +186,14 @@ pub fn changes_trie_config() -> primitives::ChangesTrieConfiguration {
 	}
 }
 
-pub mod test_api {
-	use super::AccountId;
-
-	decl_runtime_apis! {
-		pub trait TestAPI {
-			fn balance_of(id: AccountId) -> u64;
-		}
+decl_runtime_apis! {
+	pub trait TestAPI {
+		fn balance_of(id: AccountId) -> u64;
+		/// A benchmkark function that adds one to the given value and returns the result.
+		fn benchmark_add_one(val: &u64) -> u64;
+		/// A benchmark function that adds one to each value in the given vector and returns the
+		/// result.
+		fn benchmark_vector_add_one(vec: &Vec<u64>) -> Vec<u64>;
 	}
 }
 
@@ -220,7 +221,7 @@ impl_runtime_apis! {
 			system::execute_block(block)
 		}
 
-		fn initialise_block(header: <Block as BlockT>::Header) {
+		fn initialise_block(header: &<Block as BlockT>::Header) {
 			system::initialise_block(header)
 		}
 	}
@@ -259,10 +260,20 @@ impl_runtime_apis! {
 		}
 	}
 
-	impl self::test_api::TestAPI<Block> for Runtime {
+	impl self::TestAPI<Block> for Runtime {
 		fn balance_of(id: AccountId) -> u64 {
 			system::balance_of(id)
 		}
+
+		fn benchmark_add_one(val: &u64) -> u64 {
+			val + 1
+		}
+
+		fn benchmark_vector_add_one(vec: &Vec<u64>) -> Vec<u64> {
+			let mut vec = vec.clone();
+			vec.iter_mut().for_each(|v| *v += 1);
+			vec
+		}
 	}
 
 	impl aura_api::AuraApi<Block> for Runtime {