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/finality-tracker/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/>.
+
+//! SRML module that tracks the last finalized block, as perceived by block authors.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use inherents::{InherentIdentifier, InherentData, Error};
+use codec::Decode;
+
+#[cfg(feature = "std")]
+use codec::Encode;
+
+/// The identifier for the `finalnum` inherent.
+pub const INHERENT_IDENTIFIER: InherentIdentifier = *b"finalnum";
+
+/// Auxiliary trait to extract finalized inherent data.
+pub trait FinalizedInherentData<N: Decode> {
+	/// Get finalized inherent data.
+	fn finalized_number(&self) -> Result<N, Error>;
+}
+
+impl<N: Decode> FinalizedInherentData<N> for InherentData {
+	fn finalized_number(&self) -> Result<N, Error> {
+		self.get_data(&INHERENT_IDENTIFIER)
+			.and_then(|r| r.ok_or_else(|| "Finalized number inherent data not found".into()))
+	}
+}
+
+/// Provider for inherent data.
+#[cfg(feature = "std")]
+pub struct InherentDataProvider<F, N> {
+	inner: F,
+	_marker: std::marker::PhantomData<N>,
+}
+
+#[cfg(feature = "std")]
+impl<F, N> InherentDataProvider<F, N> {
+	pub fn new(final_oracle: F) -> Self {
+		InherentDataProvider { inner: final_oracle, _marker: Default::default() }
+	}
+}
+
+#[cfg(feature = "std")]
+impl<F, N: Encode> inherents::ProvideInherentData for InherentDataProvider<F, N>
+	where F: Fn() -> Result<N, Error>
+{
+	fn inherent_identifier(&self) -> &'static InherentIdentifier {
+		&INHERENT_IDENTIFIER
+	}
+
+	fn provide_inherent_data(
+		&self,
+		inherent_data: &mut InherentData,
+	) -> Result<(), Error> {
+		(self.inner)()
+			.and_then(|n| inherent_data.put_data(INHERENT_IDENTIFIER, &n))
+	}
+
+	fn error_to_string(&self, _error: &[u8]) -> Option<String> {
+		Some(format!("no further information"))
+	}
+}