Move inherents to primitives (#4126)

* Split Aura and Timestamp inherents out of paint

* fixup node depedencies

* move babe inherents to primitives

* move authorship inherents into primitives

* Move finalty tracker inherents into primitives

* fix aura primitives import

substrate/primitives/timestamp/src/lib.rs

@@ -0,0 +1,115 @@
+// 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/>.
+
+//! Substrate core types and inherents for timestamps.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use codec::Encode;
+#[cfg(feature = "std")]
+use codec::Decode;
+#[cfg(feature = "std")]
+use inherents::ProvideInherentData;
+use inherents::{InherentIdentifier, ProvideInherent, IsFatalError, InherentData};
+
+use sr_primitives::RuntimeString;
+
+/// The identifier for the `timestamp` inherent.
+pub const INHERENT_IDENTIFIER: InherentIdentifier = *b"timstap0";
+/// The type of the inherent.
+pub type InherentType = u64;
+
+/// Errors that can occur while checking the timestamp inherent.
+#[derive(Encode, sr_primitives::RuntimeDebug)]
+#[cfg_attr(feature = "std", derive(Decode))]
+pub enum InherentError {
+	/// The timestamp is valid in the future.
+	/// This is a non-fatal-error and will not stop checking the inherents.
+	ValidAtTimestamp(InherentType),
+	/// Some other error.
+	Other(RuntimeString),
+}
+
+impl IsFatalError for InherentError {
+	fn is_fatal_error(&self) -> bool {
+		match self {
+			InherentError::ValidAtTimestamp(_) => false,
+			InherentError::Other(_) => true,
+		}
+	}
+}
+
+impl InherentError {
+	/// Try to create an instance ouf of the given identifier and data.
+	#[cfg(feature = "std")]
+	pub fn try_from(id: &InherentIdentifier, data: &[u8]) -> Option<Self> {
+		if id == &INHERENT_IDENTIFIER {
+			<InherentError as codec::Decode>::decode(&mut &data[..]).ok()
+		} else {
+			None
+		}
+	}
+}
+
+/// Auxiliary trait to extract timestamp inherent data.
+pub trait TimestampInherentData {
+	/// Get timestamp inherent data.
+	fn timestamp_inherent_data(&self) -> Result<InherentType, inherents::Error>;
+}
+
+impl TimestampInherentData for InherentData {
+	fn timestamp_inherent_data(&self) -> Result<InherentType, inherents::Error> {
+		self.get_data(&INHERENT_IDENTIFIER)
+			.and_then(|r| r.ok_or_else(|| "Timestamp inherent data not found".into()))
+	}
+}
+
+#[cfg(feature = "std")]
+pub struct InherentDataProvider;
+
+#[cfg(feature = "std")]
+impl ProvideInherentData for InherentDataProvider {
+	fn inherent_identifier(&self) -> &'static InherentIdentifier {
+		&INHERENT_IDENTIFIER
+	}
+
+	fn provide_inherent_data(
+		&self,
+		inherent_data: &mut InherentData,
+	) -> Result<(), inherents::Error> {
+		use std::time::SystemTime;
+
+		let now = SystemTime::now();
+		now.duration_since(SystemTime::UNIX_EPOCH)
+			.map_err(|_| {
+				"Current time is before unix epoch".into()
+			}).and_then(|d| {
+				let duration: InherentType = d.as_millis() as u64;
+				inherent_data.put_data(INHERENT_IDENTIFIER, &duration)
+			})
+	}
+
+	fn error_to_string(&self, error: &[u8]) -> Option<String> {
+		InherentError::try_from(&INHERENT_IDENTIFIER, error).map(|e| format!("{:?}", e))
+	}
+}
+
+
+/// A trait which is called when the timestamp is set.
+#[impl_trait_for_tuples::impl_for_tuples(30)]
+pub trait OnTimestampSet<Moment> {
+	fn on_timestamp_set(moment: Moment);
+}