Manual Seal (#4143)

* instant/manual seal

unbounded queues are evil

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Co-Authored-By: Robert Habermeier <rphmeier@gmail.com>

add fork tests, docs, remove todos

moar docs

Update client/consensus/manual-seal/src/rpc.rs

Co-Authored-By: Robert Habermeier <rphmeier@gmail.com>

remove unbound generic, parameter, docs, deps, code style changes

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Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

code style chnges

remove unused deps, remove dep renames, check if block is empty before importing, use ? for error propagation

fix tests

log errors for instant seal

use debug

code style changes, updated copyright dates

use txpool::Pool instead of BasicPool, code style changes

fixed tests

* fix tests

* requested changes from review

* check inherents len

* rebase

substrate/client/consensus/manual-seal/src/error.rs

@@ -0,0 +1,98 @@
+// Copyright 2020 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/>.
+
+//! A manual sealing engine: the engine listens for rpc calls to seal blocks and create forks.
+//! This is suitable for a testing environment.
+use sp_consensus::{Error as ConsensusError, ImportResult};
+use sp_blockchain::Error as BlockchainError;
+use sp_inherents::Error as InherentsError;
+use futures::channel::{oneshot, mpsc::SendError};
+
+/// Error code for rpc
+mod codes {
+	pub const SERVER_SHUTTING_DOWN: i64 = 10_000;
+	pub const BLOCK_IMPORT_FAILED: i64 = 11_000;
+	pub const EMPTY_TRANSACTION_POOL: i64 = 12_000;
+	pub const BLOCK_NOT_FOUND: i64 = 13_000;
+	pub const CONSENSUS_ERROR: i64 = 14_000;
+	pub const INHERENTS_ERROR: i64 = 15_000;
+	pub const BLOCKCHAIN_ERROR: i64 = 16_000;
+	pub const UNKNOWN_ERROR: i64 = 20_000;
+}
+
+/// errors encountered by background block authorship task
+#[derive(Debug, derive_more::Display, derive_more::From)]
+pub enum Error {
+	/// An error occurred while importing the block
+	#[display(fmt = "Block import failed: {:?}", _0)]
+	BlockImportError(ImportResult),
+	/// Transaction pool is empty, cannot create a block
+	#[display(fmt = "Transaction pool is empty, set create_empty to true,\
+	if you want to create empty blocks")]
+	EmptyTransactionPool,
+	/// encountered during creation of Proposer.
+	#[display(fmt = "Consensus Error: {}", _0)]
+	ConsensusError(ConsensusError),
+	/// Failed to create Inherents data
+	#[display(fmt = "Inherents Error: {}", _0)]
+	InherentError(InherentsError),
+	/// error encountered during finalization
+	#[display(fmt = "Finalization Error: {}", _0)]
+	BlockchainError(BlockchainError),
+	/// Supplied parent_hash doesn't exist in chain
+	#[display(fmt = "Supplied parent_hash: {} doesn't exist in chain", _0)]
+	#[from(ignore)]
+	BlockNotFound(String),
+	/// Some string error
+	#[display(fmt = "{}", _0)]
+	#[from(ignore)]
+	StringError(String),
+	///send error
+	#[display(fmt = "Consensus process is terminating")]
+	Canceled(oneshot::Canceled),
+	///send error
+	#[display(fmt = "Consensus process is terminating")]
+	SendError(SendError),
+	/// Some other error.
+	#[display(fmt="Other error: {}", _0)]
+	Other(Box<dyn std::error::Error + Send>),
+}
+
+impl Error {
+	fn to_code(&self) -> i64 {
+		use Error::*;
+		match self {
+			BlockImportError(_) => codes::BLOCK_IMPORT_FAILED,
+			BlockNotFound(_) => codes::BLOCK_NOT_FOUND,
+			EmptyTransactionPool => codes::EMPTY_TRANSACTION_POOL,
+			ConsensusError(_) => codes::CONSENSUS_ERROR,
+			InherentError(_) => codes::INHERENTS_ERROR,
+			BlockchainError(_) => codes::BLOCKCHAIN_ERROR,
+			SendError(_) | Canceled(_) => codes::SERVER_SHUTTING_DOWN,
+			_ => codes::UNKNOWN_ERROR
+		}
+	}
+}
+
+impl std::convert::From<Error> for jsonrpc_core::Error {
+	fn from(error: Error) -> Self {
+		jsonrpc_core::Error {
+			code: jsonrpc_core::ErrorCode::ServerError(error.to_code()),
+			message: format!("{}", error),
+			data: None
+		}
+	}
+}