Add basic BABE consensus type (#2165)

* Add basic BABE consensus type

* Update core/consensus/babe/slots/Cargo.toml

Co-Authored-By: DemiMarie-parity <48690212+DemiMarie-parity@users.noreply.github.com>

* Fix parameterization and run `rustfmt`

* Respond to review comments

* Update various Cargo.lock files

* Revert "Update various Cargo.lock files"

This reverts commit af53d7624752a744320e9cbb25749fdd8e6f46d2.

* `BabeSealSignature` → `BabeSeal`

* Move slot code to its own crate

This was highly non-trivial, due to cyclic dependencies.

* Remove redundancy between AuRa and BABE

Some of the code duplication was removed using a macro.

* Fix build error

* Avoid non-`#[doc(hidden)]` re-exports

Also, bump some library versions in `Cargo.toml`.

* Remove dead code in AuRa

* Remove impl_slot macro

It was more trouble than it was worth.

Also, delete useless dependencies on Serde.

* AuRa and BABE need different DB keys

* Bring back `aura::Network`, but deprecate it.

* Improve docs and add `slot_duration` inherent method

* Add docs to `substrate_consensus_aura::SlotDuration`

* Add missing documentation and #![forbid(missing_docs, unsafe_code)]

* Add a #![forbid(missing_docs)]

* Remove dependency of `test-runtime` on `slots`

* Update core/consensus/babe/src/lib.rs

Co-Authored-By: DemiMarie-parity <48690212+DemiMarie-parity@users.noreply.github.com>

* Remove wrongly added file

* Fix copyright notice

Co-Authored-By: DemiMarie-parity <48690212+DemiMarie-parity@users.noreply.github.com>

* Bump `impl_version` and `spec_version`

* Fix deprecation version; remove spurious carets

* Update Cargo.lock

* Update dependencies

substrate/Cargo.toml

@@ -25,7 +25,9 @@ members = [
 	"core/client/db",
 	"core/consensus/common",
 	"core/consensus/aura",
+	"core/consensus/babe",
 	"core/consensus/rhd",
+	"core/consensus/slots",
 	"core/executor",
 	"core/finality-grandpa",
 	"core/finality-grandpa/primitives",

substrate/core/consensus/aura/Cargo.toml

@@ -1,23 +1,22 @@
 [package]
 name = "substrate-consensus-aura"
-version = "1.0.0"
+version = "1.0.1"
 authors = ["Parity Technologies <admin@parity.io>"]
 description = "Aura consensus algorithm for substrate"
 edition = "2018"
 
 [dependencies]
-parity-codec = "3.3"
-client = { package = "substrate-client", path = "../../client" }
+parity-codec = "3.4"
 primitives = { package = "substrate-primitives", path = "../../primitives" }
 runtime_support = { package = "srml-support", path = "../../../srml/support" }
-runtime_primitives = { package = "sr-primitives", path = "../../sr-primitives" }
 runtime_version = { package = "sr-version", path = "../../sr-version" }
 runtime_io = { package = "sr-io", path = "../../sr-io" }
-aura_slots = { package = "substrate-consensus-aura-slots", path = "slots" }
+slots = { package = "substrate-consensus-slots", path = "../slots" }
 aura_primitives = { package = "substrate-consensus-aura-primitives", path = "primitives" }
 inherents = { package = "substrate-inherents", path = "../../inherents" }
 srml-consensus = { path = "../../../srml/consensus" }
 srml-aura = { path = "../../../srml/aura" }
+client = { package = "substrate-client", path = "../../client" }
 substrate-telemetry = { path = "../../telemetry" }
 futures = "0.1.17"
 tokio = "0.1.7"
@@ -26,6 +25,7 @@ error-chain = "0.12"
 log = "0.4"
 consensus_common = { package = "substrate-consensus-common", path = "../common" }
 authorities = { package = "substrate-consensus-authorities", path = "../authorities" }
+runtime_primitives = { package = "sr-primitives", path = "../../sr-primitives" }
 
 [dev-dependencies]
 keyring = { package = "substrate-keyring", path = "../../keyring" }

substrate/core/consensus/aura/src/lib.rs

@@ -25,7 +25,8 @@
 //!
 //! Blocks from future steps will be either deferred or rejected depending on how
 //! far in the future they are.
-#![deny(deprecated)]
+#![deny(warnings)]
+#![forbid(missing_docs, unsafe_code)]
 use std::{sync::Arc, time::Duration, thread, marker::PhantomData, hash::Hash, fmt::Debug};
 
 use parity_codec::{Encode, Decode};
@@ -34,10 +35,14 @@ use consensus_common::{self, Authorities, BlockImport, Environment, Proposer,
 };
 use consensus_common::well_known_cache_keys;
 use consensus_common::import_queue::{Verifier, BasicQueue, SharedBlockImport, SharedJustificationImport};
-use client::ChainHead;
-use client::block_builder::api::BlockBuilder as BlockBuilderApi;
-use client::blockchain::ProvideCache;
-use client::runtime_api::{ApiExt, Core as CoreApi};
+use client::{
+	ChainHead,
+	block_builder::api::BlockBuilder as BlockBuilderApi,
+	blockchain::ProvideCache,
+	runtime_api::{ApiExt, Core as CoreApi},
+	error::Result as CResult,
+	backend::AuxStore,
+};
 use aura_primitives::AURA_ENGINE_ID;
 use runtime_primitives::{generic, generic::BlockId, Justification};
 use runtime_primitives::traits::{
@@ -47,7 +52,7 @@ use primitives::Pair;
 use inherents::{InherentDataProviders, InherentData, RuntimeString};
 use authorities::AuthoritiesApi;
 
-use futures::{Stream, Future, IntoFuture, future};
+use futures::{Future, IntoFuture, future, stream::Stream};
 use tokio::timer::Timeout;
 use log::{warn, debug, info, trace};
 
@@ -57,9 +62,8 @@ use srml_aura::{
 };
 use substrate_telemetry::{telemetry, CONSENSUS_TRACE, CONSENSUS_DEBUG, CONSENSUS_WARN, CONSENSUS_INFO};
 
-use aura_slots::{CheckedHeader, SlotWorker, SlotInfo, SlotCompatible};
+use slots::{CheckedHeader, SlotWorker, SlotInfo, SlotCompatible};
 
-pub use aura_slots::SlotDuration;
 pub use aura_primitives::*;
 pub use consensus_common::SyncOracle;
 
@@ -70,6 +74,10 @@ type Signature<P> = <P as Pair>::Signature;
 /// handle to a gossip service or similar.
 ///
 /// Intended to be a lightweight handle such as an `Arc`.
+#[deprecated(
+	since = "1.0.1",
+	note = "This is dead code and will be removed in a future release",
+)]
 pub trait Network: Clone {
 	/// A stream of input messages for a topic.
 	type In: Stream<Item=Vec<u8>,Error=()>;
@@ -78,6 +86,25 @@ pub trait Network: Clone {
 	fn send_message(&self, slot: u64, message: Vec<u8>);
 }
 
+/// A slot duration. Create with `get_or_compute`.
+pub struct SlotDuration(slots::SlotDuration<u64>);
+
+impl SlotDuration {
+	/// Either fetch the slot duration from disk or compute it from the genesis
+	/// state.
+	pub fn get_or_compute<B: Block, C>(client: &C) -> CResult<Self>
+	where
+		C: AuxStore, C: ProvideRuntimeApi, C::Api: AuraApi<B>,
+	{
+		slots::SlotDuration::get_or_compute(client, |a, b| a.slot_duration(b)).map(Self)
+	}
+
+	/// Get the slot duration in milliseconds.
+	pub fn get(&self) -> u64 {
+		self.0.get()
+	}
+}
+
 /// Get slot author for given block along with authorities.
 fn slot_author<P: Pair>(slot_num: u64, authorities: &[AuthorityId<P>]) -> Option<&AuthorityId<P>> {
 	if authorities.is_empty() { return None }
@@ -153,6 +180,7 @@ impl<P, Hash> CompatibleDigestItem<P> for generic::DigestItem<Hash, P::Public, P
 	}
 }
 
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 struct AuraSlotCompatible;
 
 impl SlotCompatible for AuraSlotCompatible {
@@ -203,8 +231,8 @@ pub fn start_aura_thread<B, C, E, I, P, SO, Error, OnExit>(
 		force_authoring,
 	};
 
-	aura_slots::start_slot_worker_thread::<_, _, _, _, AuraSlotCompatible, _>(
-		slot_duration,
+	slots::start_slot_worker_thread::<_, _, _, _, AuraSlotCompatible, u64, _>(
+		slot_duration.0,
 		client,
 		Arc::new(worker),
 		sync_oracle,
@@ -249,8 +277,8 @@ pub fn start_aura<B, C, E, I, P, SO, Error, OnExit>(
 		sync_oracle: sync_oracle.clone(),
 		force_authoring,
 	};
-	aura_slots::start_slot_worker::<_, _, _, _, AuraSlotCompatible, _>(
-		slot_duration,
+	slots::start_slot_worker::<_, _, _, _, _, AuraSlotCompatible, _>(
+		slot_duration.0,
 		client,
 		Arc::new(worker),
 		sync_oracle,
@@ -803,9 +831,9 @@ mod tests {
 	use client::BlockchainEvents;
 	use test_client;
 
-	type Error = ::client::error::Error;
+	type Error = client::error::Error;
 
-	type TestClient = ::client::Client<test_client::Backend, test_client::Executor, TestBlock, test_client::runtime::RuntimeApi>;
+	type TestClient = client::Client<test_client::Backend, test_client::Executor, TestBlock, test_client::runtime::RuntimeApi>;
 
 	struct DummyFactory(Arc<TestClient>);
 	struct DummyProposer(u64, Arc<TestClient>);

substrate/core/consensus/babe/Cargo.toml

@@ -0,0 +1,40 @@
+[package]
+name = "substrate-consensus-babe"
+version = "1.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+description = "BABE consensus algorithm for substrate"
+edition = "2018"
+
+[dependencies]
+parity-codec = "3.4.0"
+parity-codec-derive = "3.3.0"
+babe_primitives = { package = "substrate-consensus-babe-primitives", path = "primitives" }
+primitives = { package = "substrate-primitives", path = "../../primitives" }
+runtime_support = { package = "srml-support", path = "../../../srml/support" }
+runtime_version = { package = "sr-version", path = "../../sr-version" }
+runtime_io = { package = "sr-io", path = "../../sr-io" }
+inherents = { package = "substrate-inherents", path = "../../inherents" }
+srml-consensus = { path = "../../../srml/consensus" }
+substrate-telemetry = { path = "../../telemetry" }
+client = { package = "substrate-client", path = "../../client" }
+consensus_common = { package = "substrate-consensus-common", path = "../common" }
+authorities = { package = "substrate-consensus-authorities", path = "../authorities" }
+slots = { package = "substrate-consensus-slots", path = "../slots"  }
+runtime_primitives = { package = "sr-primitives", path = "../../sr-primitives" }
+futures = "0.1.26"
+tokio = "0.1.18"
+parking_lot = "0.7.1"
+error-chain = "0.12.0"
+log = "0.4.6"
+
+[dependencies.schnorrkel]
+git = "https://github.com/paritytech/schnorrkel"
+branch = "master"
+
+[dev-dependencies]
+keyring = { package = "substrate-keyring", path = "../../keyring" }
+substrate-executor = { path = "../../executor" }
+network = { package = "substrate-network", path = "../../network", features = ["test-helpers"]}
+service = { package = "substrate-service", path = "../../service" }
+test_client = { package = "substrate-test-client", path = "../../test-client" }
+env_logger = "0.6.1"

substrate/core/consensus/babe/primitives/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "substrate-consensus-babe-primitives"
+version = "1.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+description = "Primitives for BABE consensus"
+edition = "2018"
+
+[dependencies]
+substrate-client = { path = "../../../client", default-features = false }
+runtime_primitives = { package = "sr-primitives", path = "../../../sr-primitives", default-features = false }
+slots = { package = "substrate-consensus-slots", path = "../../slots", optional = true }
+parity-codec = "^3.4.0"
+
+[features]
+default = ["std"]
+std = [
+	"substrate-client/std",
+	"slots",
+]

substrate/core/consensus/babe/primitives/src/lib.rs

@@ -0,0 +1,76 @@
+// 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/>.
+
+//! Primitives for BABE.
+#![forbid(warnings, unsafe_code, missing_docs)]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use runtime_primitives::ConsensusEngineId;
+use substrate_client::decl_runtime_apis;
+
+use parity_codec::{Encode, Decode};
+
+/// The `ConsensusEngineId` of BABE.
+pub const BABE_ENGINE_ID: ConsensusEngineId = [b'b', b'a', b'b', b'e'];
+
+/// Configuration data used by the BABE consensus engine.
+#[derive(Copy, Clone, Hash, PartialEq, Eq, Debug, Encode, Decode)]
+pub struct BabeConfiguration {
+	slot_duration: u64,
+	expected_block_time: u64,
+}
+
+impl BabeConfiguration {
+	/// Return the expected block time in milliseconds for BABE.  Currently,
+	/// only the value provided by this type at genesis will be used.
+	///
+	/// Dynamic expected block time may be supported in the future.
+	pub fn expected_block_time(&self) -> u64 {
+		self.expected_block_time
+	}
+
+	/// Return the slot duration in milliseconds for BABE.  Currently, only
+	/// the value provided by this type at genesis will be used.
+	///
+	/// Dynamic slot duration may be supported in the future.
+	pub fn slot_duration(&self) -> u64 {
+		self.slot_duration
+	}
+}
+
+#[cfg(feature = "std")]
+impl slots::SlotData for BabeConfiguration {
+	/// Return the slot duration in milliseconds for BABE.  Currently, only
+	/// the value provided by this type at genesis will be used.
+	///
+	/// Dynamic slot duration may be supported in the future.
+	fn slot_duration(&self) -> u64 {
+		self.slot_duration
+	}
+
+	const SLOT_KEY: &'static [u8] = b"babe_bootstrap_data";
+}
+
+decl_runtime_apis! {
+	/// API necessary for block authorship with BABE.
+	pub trait BabeApi {
+		/// Return the configuration for BABE.  Currently,
+		/// only the value provided by this type at genesis will be used.
+		///
+		/// Dynamic configuration may be supported in the future.
+		fn startup_data() -> BabeConfiguration;
+	}
+}