Block builder (substrate) (#73)

* Block builder (substrate)

* Fix wasm build

* Bulid on any block

* Test for block builder.

* Block import tests for client.

* Tidy ups

* clean up block builder instantiation

* Propert block generation for tests

* Fixed rpc tests

substrate/client/Cargo.toml

@@ -13,8 +13,10 @@ ed25519 = { path = "../ed25519" }
 substrate-codec = { path = "../codec" }
 substrate-executor = { path = "../executor" }
 substrate-primitives = { path = "../primitives" }
+substrate-runtime-io = { path = "../runtime-io" }
 substrate-runtime-support = { path = "../runtime-support" }
-substrate-serializer = { path = "../serializer" }
 substrate-state-machine = { path = "../state-machine" }
-substrate-test-runtime = { path = "../test-runtime" }
 substrate-keyring = { path = "../../substrate/keyring" }
+
+[dev-dependencies]
+substrate-test-runtime = { path = "../test-runtime" }

substrate/client/src/backend.rs

@@ -21,32 +21,34 @@ use error;
 use primitives::block;
 use blockchain::{self, BlockId};
 
-/// Block insertion transction. Keeps hold if the inserted block state and data.
+/// Block insertion operation. Keeps hold if the inserted block state and data.
 pub trait BlockImportOperation {
 	/// Associated state backend type.
 	type State: state_machine::backend::Backend;
 
 	/// Returns pending state.
-	fn state(&self) -> error::Result<Self::State>;
+	fn state(&self) -> error::Result<&Self::State>;
 	/// Append block data to the transaction.
-	fn import_block(&mut self, header: block::Header, body: Option<block::Body>, is_new_best: bool) -> error::Result<()>;
+	fn set_block_data(&mut self, header: block::Header, body: Option<block::Body>, is_new_best: bool) -> error::Result<()>;
+	/// Inject storage data into the database.
+	fn set_storage<I: Iterator<Item=(Vec<u8>, Vec<u8>)>>(&mut self, iter: I) -> error::Result<()>;
 	/// Inject storage data into the database.
 	fn reset_storage<I: Iterator<Item=(Vec<u8>, Vec<u8>)>>(&mut self, iter: I) -> error::Result<()>;
 }
 
 /// Client backend. Manages the data layer.
 pub trait Backend {
-	/// Associated block insertion transaction type.
+	/// Associated block insertion operation type.
 	type BlockImportOperation: BlockImportOperation;
 	/// Associated blockchain backend type.
 	type Blockchain: blockchain::Backend;
 	/// Associated state backend type.
 	type State: state_machine::backend::Backend;
 
 	/// Begin a new block insertion transaction with given parent block id.
-	fn begin_transaction(&self, block: BlockId) -> error::Result<Self::BlockImportOperation>;
+	fn begin_operation(&self, block: BlockId) -> error::Result<Self::BlockImportOperation>;
 	/// Commit block insertion.
-	fn commit_transaction(&self, transaction: Self::BlockImportOperation) -> error::Result<()>;
+	fn commit_operation(&self, transaction: Self::BlockImportOperation) -> error::Result<()>;
 	/// Returns reference to blockchain backend.
 	fn blockchain(&self) -> &Self::Blockchain;
 	/// Returns state backend for specified block.

substrate/client/src/block_builder.rs

@@ -0,0 +1,90 @@
+// Copyright 2017 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/>.
+
+//! Utility struct to build a block.
+
+use std::vec::Vec;
+use codec::{Joiner, Slicable};
+use state_machine::{self, CodeExecutor};
+use primitives::{Header, Block};
+use primitives::block::Transaction;
+use {backend, error, BlockId, Client};
+use triehash::ordered_trie_root;
+
+/// Utility for building new (valid) blocks from a stream of transactions.
+pub struct BlockBuilder<B, E> where
+	B: backend::Backend,
+	E: CodeExecutor + Clone,
+	error::Error: From<<<B as backend::Backend>::State as state_machine::backend::Backend>::Error>,
+{
+	header: Header,
+	transactions: Vec<Transaction>,
+	executor: E,
+	state: B::State,
+	changes: state_machine::OverlayedChanges,
+}
+
+impl<B, E> BlockBuilder<B, E> where
+	B: backend::Backend,
+	E: CodeExecutor + Clone,
+	error::Error: From<<<B as backend::Backend>::State as state_machine::backend::Backend>::Error>,
+{
+	/// Create a new instance of builder from the given client, building on the latest block.
+	pub fn new(client: &Client<B, E>) -> error::Result<Self> {
+		client.info().and_then(|i| Self::at_block(&BlockId::Hash(i.chain.best_hash), client))
+	}
+
+	/// Create a new instance of builder from the given client using a particular block's ID to
+	/// build upon.
+	pub fn at_block(block_id: &BlockId, client: &Client<B, E>) -> error::Result<Self> {
+		Ok(BlockBuilder {
+			header: Header {
+				number: client.block_number_from_id(block_id)?.ok_or(error::ErrorKind::UnknownBlock(*block_id))? + 1,
+				parent_hash: client.block_hash_from_id(block_id)?.ok_or(error::ErrorKind::UnknownBlock(*block_id))?,
+				state_root: Default::default(),
+				transaction_root: Default::default(),
+				digest: Default::default(),
+			},
+			transactions: Default::default(),
+			executor: client.clone_executor(),
+			state: client.state_at(block_id)?,
+			changes: Default::default(),
+		})
+	}
+
+	/// Push a transaction onto the block's list of transactions. This will ensure the transaction
+	/// can be validly executed (by executing it); if it is invalid, it'll be returned along with
+	/// the error. Otherwise, it will return a mutable reference to self (in order to chain).
+	pub fn push(&mut self, tx: Transaction) -> error::Result<()> {
+		let output = state_machine::execute(&self.state, &mut self.changes, &self.executor, "execute_transaction",
+			&vec![].and(&self.header).and(&tx))?;
+		self.header = Header::decode(&mut &output[..]).expect("Header came straight out of runtime so must be valid");
+		self.transactions.push(tx);
+		Ok(())
+	}
+
+	/// Consume the builder to return a valid `Block` containing all pushed transactions.
+	pub fn bake(mut self) -> error::Result<Block> {
+		self.header.transaction_root = ordered_trie_root(self.transactions.iter().map(Slicable::encode)).0.into();
+		let output = state_machine::execute(&self.state, &mut self.changes, &self.executor, "finalise_block",
+			&self.header.encode())?;
+		self.header = Header::decode(&mut &output[..]).expect("Header came straight out of runtime so must be valid");
+		Ok(Block {
+			header: self.header,
+			transactions: self.transactions,
+		})
+	}
+}

substrate/client/src/in_mem.rs

@@ -21,13 +21,13 @@ use parking_lot::RwLock;
 use state_machine;
 use error;
 use backend;
-use primitives;
-use ser;
+use runtime_support::Hashable;
 use primitives::block::{self, HeaderHash};
 use blockchain::{self, BlockId, BlockStatus};
+use state_machine::backend::Backend as StateBackend;
 
 fn header_hash(header: &block::Header) -> block::HeaderHash {
-	primitives::hashing::blake2_256(&ser::encode(header)).into()
+	header.blake2_256().into()
 }
 
 struct PendingBlock {
@@ -41,7 +41,7 @@ struct Block {
 	body: Option<block::Body>,
 }
 
-/// In-memory transaction.
+/// In-memory operation.
 pub struct BlockImportOperation {
 	pending_block: Option<PendingBlock>,
 	pending_state: state_machine::backend::InMemory,
@@ -156,12 +156,12 @@ impl blockchain::Backend for Blockchain {
 impl backend::BlockImportOperation for BlockImportOperation {
 	type State = state_machine::backend::InMemory;
 
-	fn state(&self) -> error::Result<Self::State> {
-		Ok(self.pending_state.clone())
+	fn state(&self) -> error::Result<&Self::State> {
+		Ok(&self.pending_state)
 	}
 
-	fn import_block(&mut self, header: block::Header, body: Option<block::Body>, is_new_best: bool) -> error::Result<()> {
-		assert!(self.pending_block.is_none(), "Only one block per transaction is allowed");
+	fn set_block_data(&mut self, header: block::Header, body: Option<block::Body>, is_new_best: bool) -> error::Result<()> {
+		assert!(self.pending_block.is_none(), "Only one block per operation is allowed");
 		self.pending_block = Some(PendingBlock {
 			block: Block {
 				header: header,
@@ -172,6 +172,11 @@ impl backend::BlockImportOperation for BlockImportOperation {
 		Ok(())
 	}
 
+	fn set_storage<I: Iterator<Item=(Vec<u8>, Vec<u8>)>>(&mut self, changes: I) -> error::Result<()> {
+		self.pending_state.commit(changes);
+		Ok(())
+	}
+
 	fn reset_storage<I: Iterator<Item=(Vec<u8>, Vec<u8>)>>(&mut self, iter: I) -> error::Result<()> {
 		self.pending_state = state_machine::backend::InMemory::from(iter.collect());
 		Ok(())
@@ -192,47 +197,14 @@ impl Backend {
 			blockchain: Blockchain::new(),
 		}
 	}
-
-	/// Generate and import a sequence of blocks. A user supplied function is allowed to modify each block header. Useful for testing.
-	pub fn generate_blocks<F>(&self, count: usize, edit_header: F) where F: Fn(&mut block::Header) {
-		use backend::{Backend, BlockImportOperation};
-		let info = blockchain::Backend::info(&self.blockchain).expect("In-memory backend never fails");
-		let mut best_num = info.best_number;
-		let mut best_hash = info.best_hash;
-		let state_root = blockchain::Backend::header(&self.blockchain, BlockId::Hash(best_hash))
-			.expect("In-memory backend never fails")
-			.expect("Best header always exists in the blockchain")
-			.state_root;
-		for _ in 0 .. count {
-			best_num = best_num + 1;
-			let mut header = block::Header {
-				parent_hash: best_hash,
-				number: best_num,
-				state_root: state_root,
-				transaction_root: Default::default(),
-				digest: Default::default(),
-			};
-			edit_header(&mut header);
-
-			let mut tx = self.begin_transaction(BlockId::Hash(best_hash)).expect("In-memory backend does not fail");
-			best_hash = header_hash(&header);
-			tx.import_block(header, None, true).expect("In-memory backend does not fail");
-			self.commit_transaction(tx).expect("In-memory backend does not fail");
-		}
-	}
-
-	/// Generate and import a sequence of blocks. Useful for testing.
-	pub fn push_blocks(&self, count: usize) {
-		self.generate_blocks(count, |_| {})
-	}
 }
 
 impl backend::Backend for Backend {
 	type BlockImportOperation = BlockImportOperation;
 	type Blockchain = Blockchain;
 	type State = state_machine::backend::InMemory;
 
-	fn begin_transaction(&self, block: BlockId) -> error::Result<Self::BlockImportOperation> {
+	fn begin_operation(&self, block: BlockId) -> error::Result<Self::BlockImportOperation> {
 		let state = match block {
 			BlockId::Hash(h) if h.is_zero() => Self::State::default(),
 			_ => self.state_at(block)?,
@@ -244,10 +216,10 @@ impl backend::Backend for Backend {
 		})
 	}
 
-	fn commit_transaction(&self, transaction: Self::BlockImportOperation) -> error::Result<()> {
-		if let Some(pending_block) = transaction.pending_block {
+	fn commit_operation(&self, operation: Self::BlockImportOperation) -> error::Result<()> {
+		if let Some(pending_block) = operation.pending_block {
 			let hash = header_hash(&pending_block.block.header);
-			self.states.write().insert(hash, transaction.pending_state);
+			self.states.write().insert(hash, operation.pending_state);
 			self.blockchain.insert(hash, pending_block.block.header, pending_block.block.body, pending_block.is_best);
 		}
 		Ok(())