The runtime requires nightly to build, but there's an issue with the
nightly releases from 2020-05-25 and onwards which is causing builds
to fail. This rolls back the version of the nightly compiler so that
builds pass until a fix is found.

* Test defining an RPC API

* Add wrapper clients for the RPC API

* Implement most Ethereum RPCs

Does not include RPCs that require the bridge contract.

* Implement a few of the Substrate RPCs

Still missing proper error handling, as well as decoding responses from the
Substrate node.

* Make error handling more ergonomic

* Implement Substrate RPCs that use `state_call`

* Implement rest of Substrate RPCs

* Implement `eth_call` RPC

This can be used to implement higher level requests like fetching Substrate headers
from an Ethereum node.

* Build some of the higher level Ethereum RPCs

Uses the new Ethereum RPC interface to do so

* Build some of the higher level Substrate RPCs

* Remove old Ethereum RPC methods

* Remove old Substrate RPC methods

* Add some documentation to Substrate RPCs

* Fix typo in enum construction

* Revert commits `0f0435d2` to `ca755029`

This range of commits was mainly trying to integrate the new RPC interface into the existing
codebase, however this turned out to be a little out of scope for the current PR. Instead this work
will be incorporated into a PR which aims to close #72.

* Add documentation to RPCs

* Rename functions in RPC API to conform to snake_case

* Check that header contains a number and hash

* Put doc comments on trait instead of impl methods

* Remove expect() calls

* Replace runtime API enums with consts

* Accept Bytes when submitting extrinsic

Let's us avoid using a runtime specific Extrinsic.

* Add strictly typed arguments to RPC API

Missing two methods right now, which require a `serde::Deserialize`
implemenation before they can be changed.

* Add `chain_getBlock` Substrate RPC

* Use typed arguments for `eth_estimateGas` and `eth_call`

* Silence dead code warnings

* Add check for logs bloom

* Remove unused variables

* Add documentation to RPC error enums

* Use `CallRequest` type from rust-web3 crate

* Change CallRequest's `to` field to be optional

Required due to changes in upstream `rust-web3` crate.

* mute warnings from sub2sub module+relay

* cargo fmt --all

* Bump rust-web3 to latest master

* Use tagged release from crates.io

* Add check for `logs_bloom`

Since this is required by the runtime we want to enforce that an
incoming header has this.

* solidity contract

* continue

* upd

* cargo update

* fixes

* ehtereum_headers -> headers

* extracted some common stuff

* ethereum_sync.rs -> sync.rs

* make sync generic

* continue extracting

* continue

* add eth-contract argument

* continue

* some fixes

* contract v2

* continue

* more fixes

* more fixes

* deal with duplicated params

* removed multiple call_rpc variants

* bail_on_error!()

* fn submit_ethereum_transaction

* more fixes

* cargo fmt --all

* fix

* bail_on_arg_error!()

* fix

* fix

* remove async_extra stuff

* start work on finality builtin

remove async_extra stuff

continue

continue

local testnet (Alice + Bob) for node

* added TODO

* substrate-bridge.json -> substrate-bridge-abi.json

* get rid of substrate transactions hashes

* get rid of ethereum transactions hashes

* extracted contract bytecode to separate file

* cargo fmt --all

* avoid duplicate import in contracts

* removed Default::default()

* swapped configurations for sub2eth && eth2sub

* fix compilation

* do not double gas limit when submitting Substrate headers

* fix finality storage

* at least 1 validator required

* shift_session_manager_works

* cargo fmt --all

* solidity contract removed

* consts

* extracted solc compilation details to separate file

* removed (obsolete in future Vec<u8> justification)

* fixed cli option description

* fix typos

* fix grumble

* extracted constants

* log decoded header

* new substrate version + actually verify justification

* intermediate cargo fmt --all

* comments

* disable completion data resubmission

* increased timeouts + _MS -> Duration

* forget completion data after submission

* builtin tests

* headers tests

* cargo fmt --all

* update contract

* Update relays/ethereum/src/ethereum_sync_loop.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* Update relays/ethereum/src/ethereum_sync_loop.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* added docs

* OwnedFutureOutput

* more docs fixes

* cargo fmt --all

* encode headers

* consts + docs

* aliases again

* cargo fmt --all

* Update relays/ethereum/src/ethereum_sync_loop.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* Update relays/ethereum/src/ethereum_sync_loop.rs

Co-authored-by: Tomasz Drwięga <[email protected]>

* Use Duration::from_secs() instead of from_millis()

* grumbles

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* incomplete_headers_are_still_incomplete_after_advance

* add hex-encoded headers to substrate_header_without_signal_parsed

* cargo fmt --all

* Update relays/ethereum/src/sync_loop.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* Update relays/ethereum/src/headers.rs

Co-authored-by: Hernando Castano <[email protected]>

* added comments on Extra and Completion

Co-authored-by: Tomasz Drwięga <[email protected]>
Co-authored-by: Hernando Castano <[email protected]>

* solidity contract

* continue

* upd

* cargo update

* fixes

* ehtereum_headers -> headers

* extracted some common stuff

* ethereum_sync.rs -> sync.rs

* make sync generic

* continue extracting

* continue

* add eth-contract argument

* continue

* some fixes

* contract v2

* continue

* more fixes

* more fixes

* deal with duplicated params

* removed multiple call_rpc variants

* bail_on_error!()

* fn submit_ethereum_transaction

* more fixes

* cargo fmt --all

* fix

* bail_on_arg_error!()

* fix

* fix

* remove async_extra stuff

* substrate-bridge.json -> substrate-bridge-abi.json

* get rid of substrate transactions hashes

* get rid of ethereum transactions hashes

* extracted contract bytecode to separate file

* cargo fmt --all

* avoid duplicate import in contracts

* removed Default::default()

* swapped configurations for sub2eth && eth2sub

* fix compilation

* do not double gas limit when submitting Substrate headers

* cargo fmt --all

* solidity contract removed

* consts

* extracted solc compilation details to separate file

* removed (obsolete in future Vec<u8> justification)

* fixed cli option description

* fix typos

* fix grumble

* extracted constants

* log decoded header

* cargo fmt --all

* comment

* new substrate version + actually verify justification

* cargo update + fix remaining stuff

* add weight=0 comments

* cargo fmt --all

* fix hash types

* renamed to-be-generic files

* make everything required generic over source/target chains

* some more fixes

* cargo fmt --all

* trait functions -> trait constants

* cargo --fmt --all

* reward submitters on finalization

* PoA -> Substrate: unsigned_import_header API

* fix grumble

* make submitter part of ImportContext

* verify using next validators set + tests

* fix nostd compilation

* add sub-tx-mode argument

* support sub-tx-mode

* impl ValidateUnsigned for Runtime

* do not submit too much transactions to the pool

* cargo fmt

* fix bad merge

* revert license fix

* Update modules/ethereum/src/lib.rs

Co-Authored-By: Hernando Castano <[email protected]>

* Update modules/ethereum/src/verification.rs

Co-Authored-By: Hernando Castano <[email protected]>

* updated comment

* validate receipts before accepting unsigned tx to pool

* cargo fmt

* fix comment

* fix grumbles

* Update modules/ethereum/src/verification.rs

Co-Authored-By: Hernando Castano <[email protected]>

* cargo fmt --all

* struct ChangeToEnact

* updated doc

* fix doc

* add docs to the code method

* simplify fn ancestry

* finish incomplete docs

* Update modules/ethereum/src/lib.rs

Co-Authored-By: Tomasz Drwięga <[email protected]>

* Update modules/ethereum/src/lib.rs

Co-Authored-By: Tomasz Drwięga <[email protected]>

* return err from unsigned_import_header

* get header once

* Update relays/ethereum/src/ethereum_sync.rs

Co-Authored-By: Tomasz Drwięga <[email protected]>

* fix

* UnsignedTooFarInTheFuture -> Custom(err.code())

* updated ImportContext::last_signal_block

* cargo fmt --all

* rename runtime calls

Co-authored-by: Hernando Castano <[email protected]>
Co-authored-by: Tomasz Drwięga <[email protected]>

* add missing RPC required for relay

* cargo fmt --all