consensus-slots: cleanup SlotDuration config (#10878)

* consensus-slots: cleanup the SlotDuration config

* fix tests

* address review comments

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

@@ -58,12 +58,11 @@ impl InherentDataProvider {
 
 	/// Creates the inherent data provider by calculating the slot from the given
 	/// `timestamp` and `duration`.
-	pub fn from_timestamp_and_duration(
+	pub fn from_timestamp_and_slot_duration(
 		timestamp: sp_timestamp::Timestamp,
-		duration: std::time::Duration,
+		slot_duration: sp_consensus_slots::SlotDuration,
 	) -> Self {
-		let slot =
-			InherentType::from((timestamp.as_duration().as_millis() / duration.as_millis()) as u64);
+		let slot = InherentType::from_timestamp(timestamp, slot_duration);
 
 		Self { slot }
 	}

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

@@ -62,7 +62,7 @@ pub mod ed25519 {
 	pub type AuthorityId = app_ed25519::Public;
 }
 
-pub use sp_consensus_slots::Slot;
+pub use sp_consensus_slots::{Slot, SlotDuration};
 
 /// The `ConsensusEngineId` of AuRa.
 pub const AURA_ENGINE_ID: ConsensusEngineId = [b'a', b'u', b'r', b'a'];
@@ -93,28 +93,3 @@ sp_api::decl_runtime_apis! {
 		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)
-	}
-}

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

@@ -18,7 +18,6 @@
 //! Inherents for BABE
 
 use sp_inherents::{Error, InherentData, InherentIdentifier};
-
 use sp_std::result::Result;
 
 /// The BABE inherent identifier.
@@ -60,12 +59,11 @@ impl InherentDataProvider {
 
 	/// Creates the inherent data provider by calculating the slot from the given
 	/// `timestamp` and `duration`.
-	pub fn from_timestamp_and_duration(
+	pub fn from_timestamp_and_slot_duration(
 		timestamp: sp_timestamp::Timestamp,
-		duration: std::time::Duration,
+		slot_duration: sp_consensus_slots::SlotDuration,
 	) -> Self {
-		let slot =
-			InherentType::from((timestamp.as_duration().as_millis() / duration.as_millis()) as u64);
+		let slot = InherentType::from_timestamp(timestamp, slot_duration);
 
 		Self { slot }
 	}

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

@@ -79,7 +79,7 @@ pub const MEDIAN_ALGORITHM_CARDINALITY: usize = 1200; // arbitrary suggestion by
 /// The index of an authority.
 pub type AuthorityIndex = u32;
 
-pub use sp_consensus_slots::Slot;
+pub use sp_consensus_slots::{Slot, SlotDuration};
 
 /// An equivocation proof for multiple block authorships on the same slot (i.e. double vote).
 pub type EquivocationProof<H> = sp_consensus_slots::EquivocationProof<H, AuthorityId>;
@@ -237,13 +237,6 @@ impl AllowedSlots {
 	}
 }
 
-#[cfg(feature = "std")]
-impl sp_consensus::SlotData for BabeGenesisConfiguration {
-	fn slot_duration(&self) -> std::time::Duration {
-		std::time::Duration::from_millis(self.slot_duration)
-	}
-}
-
 /// Configuration data used by the BABE consensus engine.
 #[derive(Clone, PartialEq, Eq, Encode, Decode, RuntimeDebug, MaxEncodedLen, TypeInfo)]
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize))]

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

@@ -327,9 +327,3 @@ impl<Block: BlockT> CanAuthorWith<Block> for NeverCanAuthor {
 		Err("Authoring is always disabled.".to_string())
 	}
 }
-
-/// A type from which a slot duration can be obtained.
-pub trait SlotData {
-	/// Gets the slot duration.
-	fn slot_duration(&self) -> sp_std::time::Duration;
-}

substrate/primitives/consensus/slots/Cargo.toml

@@ -16,8 +16,10 @@ targets = ["x86_64-unknown-linux-gnu"]
 codec = { package = "parity-scale-codec", version = "2.2.0", default-features = false, features = ["derive", "max-encoded-len"] }
 scale-info = { version = "1.0", default-features = false, features = ["derive"] }
 serde = { version = "1.0", features = ["derive"], optional = true }
-sp-runtime = { version = "5.0.0", default-features = false, path = "../../runtime" }
 sp-arithmetic = { version = "4.0.0", default-features = false, path = "../../arithmetic" }
+sp-runtime = { version = "5.0.0", default-features = false, path = "../../runtime" }
+sp-std = { version = "4.0.0", default-features = false, path = "../../std" }
+sp-timestamp = { version = "4.0.0-dev", default-features = false, path = "../../timestamp" }
 
 [features]
 default = ["std"]
@@ -25,6 +27,8 @@ std = [
 	"codec/std",
 	"scale-info/std",
 	"serde",
-	"sp-runtime/std",
 	"sp-arithmetic/std",
+	"sp-runtime/std",
+	"sp-std/std",
+	"sp-timestamp/std",
 ]

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

@@ -21,6 +21,7 @@
 
 use codec::{Decode, Encode, MaxEncodedLen};
 use scale_info::TypeInfo;
+use sp_timestamp::Timestamp;
 
 /// Unit type wrapper that represents a slot.
 #[derive(Debug, Encode, MaxEncodedLen, Decode, Eq, Clone, Copy, Default, Ord, TypeInfo)]
@@ -64,6 +65,11 @@ impl<T: Into<u64> + Copy> core::cmp::PartialOrd<T> for Slot {
 }
 
 impl Slot {
+	/// Create a new slot by calculating it from the given timestamp and slot duration.
+	pub const fn from_timestamp(timestamp: Timestamp, slot_duration: SlotDuration) -> Self {
+		Slot(timestamp.as_millis() / slot_duration.as_millis())
+	}
+
 	/// Saturating addition.
 	pub fn saturating_add<T: Into<u64>>(self, rhs: T) -> Self {
 		Self(self.0.saturating_add(rhs.into()))
@@ -94,6 +100,32 @@ impl From<Slot> for u64 {
 	}
 }
 
+/// A slot duration defined in milliseconds.
+#[derive(Clone, Copy, Debug, Encode, Decode, Hash, PartialOrd, Ord, PartialEq, Eq, TypeInfo)]
+pub struct SlotDuration(u64);
+
+impl SlotDuration {
+	/// Initialize from the given milliseconds.
+	pub const fn from_millis(millis: u64) -> Self {
+		Self(millis)
+	}
+}
+
+impl SlotDuration {
+	/// Returns `self` as a `u64` representing the duration in milliseconds.
+	pub const fn as_millis(&self) -> u64 {
+		self.0
+	}
+}
+
+#[cfg(feature = "std")]
+impl SlotDuration {
+	/// Returns `self` as [`sp_std::time::Duration`].
+	pub const fn as_duration(&self) -> sp_std::time::Duration {
+		sp_std::time::Duration::from_millis(self.0)
+	}
+}
+
 /// Represents an equivocation proof. An equivocation happens when a validator
 /// produces more than one block on the same slot. The proof of equivocation
 /// are the given distinct headers that were signed by the validator and which

substrate/primitives/timestamp/src/lib.rs

@@ -42,10 +42,16 @@ impl Timestamp {
 	}
 
 	/// Returns `self` as [`Duration`].
-	pub fn as_duration(self) -> Duration {
+	pub const fn as_duration(self) -> Duration {
 		Duration::from_millis(self.0)
 	}
 
+	/// Returns `self` as a `u64` representing the elapsed time since the UNIX_EPOCH in
+	/// milliseconds.
+	pub const fn as_millis(&self) -> u64 {
+		self.0
+	}
+
 	/// Checked subtraction that returns `None` on an underflow.
 	pub fn checked_sub(self, other: Self) -> Option<Self> {
 		self.0.checked_sub(other.0).map(Self)