Aura and Slots refactoring (#8386)

* Make slot duration being exposed as `Duration` to the outside

* Some slot info love

* Add `build_aura_worker` utility function

* Copy copy copy

substrate/primitives/consensus/aura/Cargo.toml

@@ -21,6 +21,7 @@ sp-runtime = { version = "3.0.0", default-features = false, path = "../../runtim
 sp-inherents = { version = "3.0.0", default-features = false, path = "../../inherents" }
 sp-timestamp = { version = "3.0.0", default-features = false, path = "../../timestamp" }
 sp-consensus-slots = { version = "0.9.0", default-features = false, path = "../slots" }
+sp-consensus = { version = "0.9.0", path = "../common", optional = true }
 
 [features]
 default = ["std"]
@@ -32,4 +33,6 @@ std = [
 	"sp-runtime/std",
 	"sp-inherents/std",
 	"sp-timestamp/std",
+	"sp-consensus-slots/std",
+	"sp-consensus",
 ]

substrate/primitives/consensus/aura/src/inherents.rs

@@ -51,12 +51,12 @@ impl AuraInherentData for InherentData {
 // TODO: Remove in the future. https://github.com/paritytech/substrate/issues/8029
 #[cfg(feature = "std")]
 pub struct InherentDataProvider {
-	slot_duration: u64,
+	slot_duration: std::time::Duration,
 }
 
 #[cfg(feature = "std")]
 impl InherentDataProvider {
-	pub fn new(slot_duration: u64) -> Self {
+	pub fn new(slot_duration: std::time::Duration) -> Self {
 		Self {
 			slot_duration
 		}
@@ -88,7 +88,7 @@ impl ProvideInherentData for InherentDataProvider {
 		use sp_timestamp::TimestampInherentData;
 
 		let timestamp = inherent_data.timestamp_inherent_data()?;
-		let slot = *timestamp / self.slot_duration;
+		let slot = *timestamp / self.slot_duration.as_millis() as u64;
 		inherent_data.put_data(INHERENT_IDENTIFIER, &slot)
 	}
 

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

@@ -84,14 +84,39 @@ pub enum ConsensusLog<AuthorityId: Codec> {
 sp_api::decl_runtime_apis! {
 	/// API necessary for block authorship with aura.
 	pub trait AuraApi<AuthorityId: Codec> {
-		/// Return the slot duration in seconds for Aura.
-		/// Currently, only the value provided by this type at genesis
-		/// will be used.
+		/// Returns the slot duration for Aura.
 		///
-		/// Dynamic slot duration may be supported in the future.
-		fn slot_duration() -> u64;
+		/// Currently, only the value provided by this type at genesis will be used.
+		fn slot_duration() -> SlotDuration;
 
 		// Return the current set of authorities.
 		fn authorities() -> Vec<AuthorityId>;
 	}
 }
+
+/// Aura slot duration.
+///
+/// Internally stored as milliseconds.
+#[derive(sp_runtime::RuntimeDebug, Encode, Decode, PartialEq, Clone, Copy)]
+pub struct SlotDuration(u64);
+
+impl SlotDuration {
+	/// Initialize from the given milliseconds.
+	pub fn from_millis(val: u64) -> Self {
+		Self(val)
+	}
+
+	/// Returns the slot duration in milli seconds.
+	pub fn get(&self) -> u64 {
+		self.0
+	}
+}
+
+#[cfg(feature = "std")]
+impl sp_consensus::SlotData for SlotDuration {
+	fn slot_duration(&self) -> std::time::Duration {
+		std::time::Duration::from_millis(self.0)
+	}
+
+	const SLOT_KEY: &'static [u8] = b"aura_slot_duration";
+}

substrate/primitives/consensus/babe/src/inherents.rs

@@ -55,13 +55,13 @@ impl BabeInherentData for InherentData {
 // TODO: Remove in the future. https://github.com/paritytech/substrate/issues/8029
 #[cfg(feature = "std")]
 pub struct InherentDataProvider {
-	slot_duration: u64,
+	slot_duration: std::time::Duration,
 }
 
 #[cfg(feature = "std")]
 impl InherentDataProvider {
 	/// Constructs `Self`
-	pub fn new(slot_duration: u64) -> Self {
+	pub fn new(slot_duration: std::time::Duration) -> Self {
 		Self { slot_duration }
 	}
 }
@@ -83,7 +83,7 @@ impl ProvideInherentData for InherentDataProvider {
 
 	fn provide_inherent_data(&self, inherent_data: &mut InherentData) -> Result<(), Error> {
 		let timestamp = inherent_data.timestamp_inherent_data()?;
-		let slot = *timestamp / self.slot_duration;
+		let slot = *timestamp / self.slot_duration.as_millis() as u64;
 		inherent_data.put_data(INHERENT_IDENTIFIER, &slot)
 	}
 

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

@@ -242,8 +242,8 @@ impl AllowedSlots {
 
 #[cfg(feature = "std")]
 impl sp_consensus::SlotData for BabeGenesisConfiguration {
-	fn slot_duration(&self) -> u64 {
-		self.slot_duration
+	fn slot_duration(&self) -> std::time::Duration {
+		std::time::Duration::from_millis(self.slot_duration)
 	}
 
 	const SLOT_KEY: &'static [u8] = b"babe_configuration";

substrate/primitives/consensus/common/src/lib.rs

@@ -303,16 +303,8 @@ impl<Block: BlockT> CanAuthorWith<Block> for NeverCanAuthor {
 /// A type from which a slot duration can be obtained.
 pub trait SlotData {
 	/// Gets the slot duration.
-	fn slot_duration(&self) -> u64;
+	fn slot_duration(&self) -> sp_std::time::Duration;
 
 	/// The static slot key
 	const SLOT_KEY: &'static [u8];
 }
-
-impl SlotData for u64 {
-	fn slot_duration(&self) -> u64 {
-		*self
-	}
-
-	const SLOT_KEY: &'static [u8] = b"aura_slot_duration";
-}

substrate/primitives/timestamp/src/lib.rs

@@ -23,6 +23,7 @@ use codec::{Encode, Decode};
 #[cfg(feature = "std")]
 use sp_inherents::ProvideInherentData;
 use sp_inherents::{InherentIdentifier, IsFatalError, InherentData};
+use sp_std::time::Duration;
 
 use sp_runtime::RuntimeString;
 
@@ -43,6 +44,11 @@ impl Timestamp {
 	pub const fn new(inner: u64) -> Self {
 		Self(inner)
 	}
+
+	/// Returns `self` as [`Duration`].
+	pub fn as_duration(&self) -> Duration {
+		Duration::from_millis(self.0)
+	}
 }
 
 impl sp_std::ops::Deref for Timestamp {
@@ -100,8 +106,8 @@ impl From<Timestamp> for u64 {
 	}
 }
 
-impl From<sp_std::time::Duration> for Timestamp {
-	fn from(duration: sp_std::time::Duration) -> Self {
+impl From<Duration> for Timestamp {
+	fn from(duration: Duration) -> Self {
 		Timestamp(duration.as_millis() as u64)
 	}
 }