Refactor/substrate state machine generic (#553)

* Genric over hasher

* WIP start adding NodeCodec

* Add codec to TrieBackend

* Typechecks

* Fix error type

* Cleanup

* Tests build (and fail)

* Fix tests: don't use MemoryDB::default()

* Lockfile

* Address grumbles

* Teach environmental! about generics

* Add Finder artifacts

* whitespace

* Add a toy impl of Hasher and plug it in to Externalities

* Use `uint` and `fixed-hash` from `parity-common`
Remove unused U512
Add test to ensure H256 impls heapsizeof

* lock file updates

* Make hashes Encodable/Decodable

* lock file updates

* Impl FromIterator for TestExternalities so we can collect() and use map!

* Use rustc-hex from crates
Use rlp from master so dependencies do not mess up the scope

* Fix tests in runtime-io

* lockfile shenanigans

* Add a BlakeHasher impl

* Use BlakeHasher in runtime-io

* lockfile updates

* ws

* Add a Blake2/RLP-flavoured NodeCodec

* Use Blake-flavoured Hasher and NodeCodec

* lockfile

* Implement PartialEq and Default for TestExternalities

* Add note about limitations of environmental!

* Make it compile, but this is probably broken

* Derive Debug so tests in executor can work

* Make executor use BlakeHasher

* ws

* WIP make client generic

* typechecks

* cleanup

* client tests pass

* Fix client/db

* cleanup

* Fix network

* Fix rpc

* Fix service

* Make TestExternalities work better au lieu d'un HashMap

* Fix tests in council

* Fix tests in contract

* Fix tests in council

* Fix democracy

* Add comment about odd-looking reexports in tests

* Don't need to load branch

* Fix staking

* Fix session

* Some polkadot fixes and lockfile

* Fix executive

* fixup lockfile

* Fix polkadot/api

* Fix polkadot/service

* Fix polkadot/runtime tests

* Fix tests in test-runtime

* Test fixes

* Fix missing component in the `std` feature

* Use PhantomData and Result from core

* Fix paths
Use core

* load heapsize on wasm

* implement `HeapSizeOf` for wasm

* Add toy impl of `blake2_256` for no_std

* lockfile

* Use kvdb* from parity-common and fix errors

* rebuilt lockfile

* Add dummy impl of `on_advance_round` for rhododendron::Context

* Fix build after merge

* Add HeapSizeOf bound where needed

* Sort out dependencies for no_std

* Add HeapSizeOf bound where needed

* use temp branch pending PR merges

* Remove unneeded tests

* Lock file and wasm artifacts

* lockfile

* Use magic commit for libp2p

* Cleanup

* Implement blake2_256 for no_std

* Back on parity-common master

* missing type params

* Update Cargo.lock

* whitespace

* Rename concrete Rlp node codec "RlpCodec" and use everywhere
Implement a Keccak-flavoured Rlp NodeCodec and use everywhere
Add a KeccakHasher

* Switch to use KeccakHasher

* Lock file and runtimes

* fixup lockfile

* Fix outstanding issue using concrete types (thanks @gnunicorn)

* Cleanup

* More cleanup

* Comment out Blake2 Hasher

* implement ext_keccak256

* Address todo: FetchChecker is generic

* all tests passing

polkadot/availability-store/src/lib.rs

@@ -66,20 +66,6 @@ pub struct Data {
 	pub extrinsic: Option<Extrinsic>,
 }
 
-fn extract_io_err(err: ::kvdb::Error) -> io::Error {
-	match err {
-		::kvdb::Error(::kvdb::ErrorKind::Io(io_err), _) => io_err,
-		::kvdb::Error(::kvdb::ErrorKind::Msg(msg), _) => io::Error::new(
-			io::ErrorKind::Other,
-			msg,
-		),
-		x => io::Error::new(
-			io::ErrorKind::Other,
-			format!("Unexpected error variant: {:?}", x), // only necessary because of nonexaustive match.
-		)
-	}
-}
-
 fn block_data_key(relay_parent: &Hash, candidate_hash: &Hash) -> Vec<u8> {
 	(relay_parent, candidate_hash, 0i8).encode()
 }
@@ -99,14 +85,13 @@ impl Store {
 	pub fn new(config: Config) -> io::Result<Self> {
 		let mut db_config = DatabaseConfig::with_columns(Some(columns::NUM_COLUMNS));
 		db_config.memory_budget = config.cache_size;
-		db_config.wal = true;
 
 		let path = config.path.to_str().ok_or_else(|| io::Error::new(
 			io::ErrorKind::Other,
 			format!("Bad database path: {:?}", config.path),
 		))?;
 
-		let db = Database::open(&db_config, &path).map_err(extract_io_err)?;
+		let db = Database::open(&db_config, &path)?;
 
 		Ok(Store {
 			inner: Arc::new(db),
@@ -151,7 +136,7 @@ impl Store {
 			);
 		}
 
-		self.inner.write(tx).map_err(extract_io_err)
+		self.inner.write(tx)
 	}
 
 	/// Note that a set of candidates have been included in a finalized block with given hash and parent hash.
@@ -175,7 +160,7 @@ impl Store {
 			}
 		}
 
-		self.inner.write(tx).map_err(extract_io_err)
+		self.inner.write(tx)
 	}
 
 	/// Query block data.