Utility module for doing stuff like batch calls (#3759)

* Implement and test batch

* Add files.

* Remove comments.

* Update srml/utility/src/lib.rs

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Fixes

substrate/Cargo.lock

@@ -2486,6 +2486,7 @@ dependencies = [
  "srml-system 2.0.0",
  "srml-timestamp 2.0.0",
  "srml-treasury 2.0.0",
+ "srml-utility 2.0.0",
  "substrate-authority-discovery-primitives 2.0.0",
  "substrate-client 2.0.0",
  "substrate-consensus-babe-primitives 2.0.0",
@@ -4421,6 +4422,21 @@ dependencies = [
  "substrate-primitives 2.0.0",
 ]
 
+[[package]]
+name = "srml-utility"
+version = "2.0.0"
+dependencies = [
+ "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.101 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-io 2.0.0",
+ "sr-primitives 2.0.0",
+ "sr-std 2.0.0",
+ "srml-balances 2.0.0",
+ "srml-support 2.0.0",
+ "srml-system 2.0.0",
+ "substrate-primitives 2.0.0",
+]
+
 [[package]]
 name = "stable_deref_trait"
 version = "1.1.1"

substrate/Cargo.toml

@@ -103,6 +103,7 @@ members = [
 	"srml/system",
 	"srml/timestamp",
 	"srml/treasury",
+	"srml/utility",
 	"node/cli",
 	"node/executor",
 	"node/primitives",

substrate/node/runtime/Cargo.toml

@@ -48,6 +48,7 @@ support = { package = "srml-support", path = "../../srml/support", default-featu
 system = { package = "srml-system", path = "../../srml/system", default-features = false }
 timestamp = { package = "srml-timestamp", path = "../../srml/timestamp", default-features = false }
 treasury = { package = "srml-treasury", path = "../../srml/treasury", default-features = false }
+utility = { package = "srml-utility", path = "../../srml/utility", default-features = false }
 
 [build-dependencies]
 wasm-builder-runner = { package = "substrate-wasm-builder-runner", version = "1.0.2", path = "../../core/utils/wasm-builder-runner" }
@@ -92,5 +93,6 @@ std = [
 	"system/std",
 	"timestamp/std",
 	"treasury/std",
+	"utility/std",
 	"version/std",
 ]

substrate/node/runtime/src/lib.rs

@@ -134,6 +134,11 @@ impl system::Trait for Runtime {
 	type Version = Version;
 }
 
+impl utility::Trait for Runtime {
+	type Event = Event;
+	type Call = Call;
+}
+
 parameter_types! {
 	pub const EpochDuration: u64 = EPOCH_DURATION_IN_SLOTS;
 	pub const ExpectedBlockTime: Moment = MILLISECS_PER_BLOCK;
@@ -492,6 +497,7 @@ construct_runtime!(
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
 		System: system::{Module, Call, Storage, Config, Event},
+		Utility: utility::{Module, Call, Event<T>},
 		Babe: babe::{Module, Call, Storage, Config, Inherent(Timestamp)},
 		Timestamp: timestamp::{Module, Call, Storage, Inherent},
 		Authorship: authorship::{Module, Call, Storage, Inherent},

substrate/srml/assets/src/lib.rs

@@ -196,10 +196,11 @@ decl_module! {
 }
 
 decl_event!(
-	pub enum Event<T>
-		where <T as system::Trait>::AccountId,
-		      <T as Trait>::Balance,
-		      <T as Trait>::AssetId {
+	pub enum Event<T> where
+		<T as system::Trait>::AccountId,
+		<T as Trait>::Balance,
+		<T as Trait>::AssetId,
+	{
 		/// Some assets were issued.
 		Issued(AssetId, AccountId, Balance),
 		/// Some assets were transferred.

substrate/srml/utility/Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+name = "srml-utility"
+version = "2.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[dependencies]
+serde = { version = "1.0", optional = true }
+codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false }
+support = { package = "srml-support", path = "../support", default-features = false }
+system = { package = "srml-system", path = "../system", default-features = false }
+sr-primitives = { path = "../../core/sr-primitives", default-features = false }
+rstd = { package = "sr-std", path = "../../core/sr-std", default-features = false }
+runtime-io = { package = "sr-io", path = "../../core/sr-io", default-features = false }
+
+[dev-dependencies]
+primitives = { package = "substrate-primitives",  path = "../../core/primitives" }
+balances = { package = "srml-balances", path = "../balances" }
+
+[features]
+default = ["std"]
+std = [
+	"serde",
+	"codec/std",
+	"sr-primitives/std",
+	"support/std",
+	"system/std",
+	"runtime-io/std",
+	"rstd/std"
+]

substrate/srml/utility/src/lib.rs

@@ -0,0 +1,173 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! # Utility Module
+//! A module full of useful helpers for practical chain management.
+
+// Ensure we're `no_std` when compiling for Wasm.
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use rstd::prelude::*;
+use support::{decl_module, decl_event, Parameter};
+use system::ensure_root;
+use sr_primitives::{
+	traits::{Dispatchable, DispatchResult}, weights::SimpleDispatchInfo
+};
+
+/// Configuration trait.
+pub trait Trait: system::Trait {
+	/// The overarching event type.
+	type Event: From<Event<Self>> + Into<<Self as system::Trait>::Event>;
+
+	/// The overarching call type.
+	type Call: Parameter + Dispatchable<Origin=Self::Origin>;
+}
+
+pub type DispatchResultOf<T> = DispatchResult<<<T as Trait>::Call as Dispatchable>::Error>;
+
+decl_event!(
+	/// Events type.
+	pub enum Event<T> where
+		DispatchResult = DispatchResultOf<T>,
+	{
+		BatchExecuted(Vec<DispatchResult>),
+	}
+);
+
+decl_module! {
+	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
+		/// Deposit one of this module's events by using the default implementation.
+		fn deposit_event() = default;
+
+		/// Send a batch of dispatch calls (only root).
+		#[weight = SimpleDispatchInfo::FreeOperational]
+		fn batch(origin, calls: Vec<<T as Trait>::Call>) {
+			ensure_root(origin)?;
+			let results = calls.into_iter()
+				.map(|call| call.dispatch(system::RawOrigin::Root.into()))
+				.collect::<Vec<_>>();
+			Self::deposit_event(RawEvent::BatchExecuted(results));
+		}
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	use support::{assert_ok, assert_noop, impl_outer_origin, parameter_types, impl_outer_dispatch};
+	use runtime_io::with_externalities;
+	use primitives::{H256, Blake2Hasher};
+	use sr_primitives::{
+		Perbill, traits::{BlakeTwo256, IdentityLookup}, testing::Header
+	};
+
+	impl_outer_origin! {
+		pub enum Origin for Test {}
+	}
+
+	impl_outer_dispatch! {
+		pub enum Call for Test where origin: Origin {
+			balances::Balances,
+			utility::Utility,
+		}
+	}
+
+	// For testing the module, we construct most of a mock runtime. This means
+	// first constructing a configuration type (`Test`) which `impl`s each of the
+	// configuration traits of modules we want to use.
+	#[derive(Clone, Eq, PartialEq)]
+	pub struct Test;
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+		pub const MaximumBlockWeight: u32 = 1024;
+		pub const MaximumBlockLength: u32 = 2 * 1024;
+		pub const AvailableBlockRatio: Perbill = Perbill::one();
+	}
+	impl system::Trait for Test {
+		type Origin = Origin;
+		type Index = u64;
+		type BlockNumber = u64;
+		type Hash = H256;
+		type Call = Call;
+		type Hashing = BlakeTwo256;
+		type AccountId = u64;
+		type Lookup = IdentityLookup<Self::AccountId>;
+		type Header = Header;
+		type WeightMultiplierUpdate = ();
+		type Event = ();
+		type BlockHashCount = BlockHashCount;
+		type MaximumBlockWeight = MaximumBlockWeight;
+		type MaximumBlockLength = MaximumBlockLength;
+		type AvailableBlockRatio = AvailableBlockRatio;
+		type Version = ();
+	}
+	parameter_types! {
+		pub const ExistentialDeposit: u64 = 0;
+		pub const TransferFee: u64 = 0;
+		pub const CreationFee: u64 = 0;
+		pub const TransactionBaseFee: u64 = 0;
+		pub const TransactionByteFee: u64 = 0;
+	}
+	impl balances::Trait for Test {
+		type Balance = u64;
+		type OnFreeBalanceZero = ();
+		type OnNewAccount = ();
+		type Event = ();
+		type TransactionPayment = ();
+		type TransferPayment = ();
+		type DustRemoval = ();
+		type ExistentialDeposit = ExistentialDeposit;
+		type TransferFee = TransferFee;
+		type CreationFee = CreationFee;
+		type TransactionBaseFee = TransactionBaseFee;
+		type TransactionByteFee = TransactionByteFee;
+		type WeightToFee = ();
+	}
+	impl Trait for Test {
+		type Event = ();
+		type Call = Call;
+	}
+	type Balances = balances::Module<Test>;
+	type Utility = Module<Test>;
+
+	fn new_test_ext() -> runtime_io::TestExternalities<Blake2Hasher> {
+		let mut t = system::GenesisConfig::default().build_storage::<Test>().unwrap();
+		balances::GenesisConfig::<Test> {
+			balances: vec![(1, 10), (2, 0)],
+			vesting: vec![],
+		}.assimilate_storage(&mut t).unwrap();
+		t.into()
+	}
+
+	#[test]
+	fn batch_works() {
+		with_externalities(&mut new_test_ext(), || {
+			assert_eq!(Balances::free_balance(1), 10);
+			assert_eq!(Balances::free_balance(2), 0);
+			assert_noop!(Utility::batch(Origin::signed(1), vec![
+				Call::Balances(balances::Call::force_transfer(1, 2, 5)),
+				Call::Balances(balances::Call::force_transfer(1, 2, 5))
+			]), "RequireRootOrigin");
+			assert_ok!(Utility::batch(Origin::ROOT, vec![
+				Call::Balances(balances::Call::force_transfer(1, 2, 5)),
+				Call::Balances(balances::Call::force_transfer(1, 2, 5))
+			]));
+			assert_eq!(Balances::free_balance(1), 0);
+			assert_eq!(Balances::free_balance(2), 10);
+		});
+	}
+}