add substrate finality grandpa primitives for WASM

substrate/core/finality-grandpa/Cargo.toml

@@ -14,6 +14,7 @@ substrate-client = { path = "../client" }
 log = "0.4"
 parking_lot = "0.4"
 tokio = "0.1.7"
+substrate-fg-primitives = { path = "primitives" }
 
 [dependencies.finality-grandpa]
 #version = "0.3.0"

substrate/core/finality-grandpa/primitives/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "substrate-fg-primitives"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+
+[dependencies]
+substrate-primitives = { path = "../../primitives", default-features = false }
+parity-codec = { version = "2.1", default-features = false }
+parity-codec-derive = { version = "2.1", default-features = false }
+sr-api = { path = "../../sr-api", default-features = false }
+sr-primitives = { path = "../../sr-primitives", default-features = false }
+
+[features]
+default = ["std"]
+std = [
+	"substrate-primitives/std",
+	"parity-codec/std",
+	"parity-codec-derive/std",
+	"sr-api/std",
+	"sr-primitives/std",
+]

substrate/core/finality-grandpa/primitives/src/lib.rs

@@ -0,0 +1,73 @@
+// Copyright 2018 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 GRANDPA integration, suitable for WASM compilation.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+extern crate substrate_primitives;
+extern crate sr_primitives;
+extern crate parity_codec;
+
+#[macro_use]
+extern crate parity_codec_derive;
+
+#[macro_use]
+extern crate sr_api;
+
+use substrate_primitives::AuthorityId;
+use sr_primitives::traits::{Block as BlockT, DigestFor, NumberFor};
+
+/// A scheduled change of authority set.
+#[cfg_attr(feature = "std", derive(Debug, PartialEq))]
+#[derive(Encode, Decode)]
+pub struct ScheduledChange<N> {
+	/// The new authorities after the change, along with their respective weights.
+	pub next_authorities: Vec<(AuthorityId, u64)>,
+	/// The number of blocks to delay.
+	pub delay: N,
+}
+
+/// WASM function call to check for pending changes.
+pub const PENDING_CHANGE_CALL: &str = "grandpa_pending_change";
+/// WASM function call to get current GRANDPA authorities.
+pub const AUTHORITIES_CALL: &str = "grandpa_pending_change";
+
+decl_apis! {
+	/// APIs for integrating the GRANDPA finality gadget into runtimes.
+	///
+	/// This is primarily used for negotiating authority-set changes for the
+	/// gadget. GRANDPA uses a signalling model of changing authority sets:
+	/// changes should be signalled with a delay of N blocks, and then automatically
+	/// applied in the runtime after those N blocks have passed.
+	///
+	/// The consensus protocol will coordinate the handoff externally.
+	pub trait Api<B: BlockT> {
+		/// Check a digest for pending changes.
+		/// Return `None` if there are no pending changes.
+		///
+		/// Precedence towards earlier or later digest items can be given
+		/// based on the rules of the chain.
+		///
+		/// No change should be scheduled if one is already and the delay has not
+		/// passed completely.
+		fn grandpa_pending_change(digest: DigestFor<B>) -> Option<ScheduledChange<NumberFor<B>>>;
+
+		/// Get the current GRANDPA authorities. This should not change except
+		/// for when changes are scheduled and the corresponding delay has passed.
+		fn grandpa_authorities() -> Vec<AuthorityId>;
+	}
+}

substrate/core/finality-grandpa/src/lib.rs

@@ -14,11 +14,9 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-// tag::description[]
 //! Integration of the GRANDPA finality gadget into substrate.
 //!
 //! This is a long-running future that produces finality notifications.
-// end::description[]
 
 extern crate finality_grandpa as grandpa;
 extern crate futures;
@@ -29,6 +27,7 @@ extern crate substrate_primitives;
 extern crate tokio;
 extern crate parking_lot;
 extern crate parity_codec as codec;
+extern crate substrate_fg_primitives as fg_primitives;
 
 #[macro_use]
 extern crate log;
@@ -64,6 +63,8 @@ use std::time::{Instant, Duration};
 
 use authorities::SharedAuthoritySet;
 
+pub use fg_primitives::ScheduledChange;
+
 mod authorities;
 
 const LAST_COMPLETED_KEY: &[u8] = b"grandpa_completed_round";
@@ -485,26 +486,6 @@ impl<Block: BlockT, B, E, N> grandpa::Chain<Block::Hash, NumberFor<Block>> for E
 	}
 }
 
-/// A scheduled change of authority set.
-#[derive(Debug, PartialEq)]
-pub struct ScheduledChange<N> {
-	/// The new authorities after the change, along with their respective weights.
-	pub next_authorities: Vec<(AuthorityId, u64)>,
-	/// The number of blocks to delay.
-	pub delay: N,
-}
-
-/// A GRANDPA-compatible DigestItem. This can describe when GRANDPA set changes
-/// are scheduled.
-//
-// With specialization, could do a blanket implementation so this trait
-// doesn't have to be implemented by users.
-pub trait CompatibleDigestItem<N> {
-	/// If this digest item notes a GRANDPA set change, return information about
-	/// the scheduled change.
-	fn scheduled_change(&self) -> Option<ScheduledChange<N>> { None }
-}
-
 /// A new authority set along with the canonical block it changed at.
 #[derive(Debug)]
 struct NewAuthoritySet<H, N> {