* Use async_trait for SourceClient

* Use aync_trait for TargetClient

* Revert async_trait usage for Source/Target client

This reverts commit f636ffaf.
This reverts commit 2c15755e

.

I'm having a very hard time finding out what is causing compilation
issues, and I think it's best to start over again.

* Use async_trait for TargetClient

* Use async_trait for SourceClient

* Move where non-async methods are

* RustFmt

* QueuedHeader holds Arc to actual data

* Clean up async return type

Co-authored-by: Svyatoslav Nikolsky <[email protected]>

* Clean up async return type

Co-authored-by: Svyatoslav Nikolsky <[email protected]>

* Clean up async return type

Co-authored-by: Svyatoslav Nikolsky <[email protected]>

* Remove unused import

Co-authored-by: Svyatoslav Nikolsky <[email protected]>

* Substrate 606c56d2e2f69f68f3947551224be6a3515dff60

* update jsonrpsee

* Add diagrams from draw.io

I'm trying to figure out how best to share these in such a way that we
can all contribute to them easily. While integration between draw.io
and GitHub exists, it requires read/write permissions to all ParityTech
repos, which doesn't comfort me. I think having the .drawio file and
the corresponding pictures available in a folder is a good start.

I imagine the workflow would be something like this: Someone wants to
update a diagram, so they go to draw.io and upload the .drawio file
from the repo. They make their changes, download the new .drawio file
and corresponding SVG, and commit their changes to the repo.

* Make diagrams consistent with background/filling

The background for each diagram has been removed (now it's transparent)
and the boxes that make up the diagrams have gotten a filled in white
colour. This will make it possible to have these diagrams show up on
non-white backgrounds.

* Add file for describing diagram...

* removeInMemoryStorage + extract Kovan stuff to runtime

* removed comment from the future

* remove redundant conversions

* remove redundant `u8 as usize`

* remove redundant `u8 as usize`

* Update modules/ethereum/src/mock.rs

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

* use hex-literal in kovan config

* cargo fmt --all

* extracted insert_header

* cargo fmt --all

* finality cache

* cargo fmt --all

* cargo fmt --all

* impl Default for FinalityVotes

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

* Revert "Bump async-std from 1.5.0 to 1.6.0 (#126)"

This reverts commit a865976e.

* Add async-std=1.6 to ignore.

* Add descriptions for folder structure + node

* Beef up descriptions of project components

* Fix list formatting

* Add note about nightly Rust

* Update README.md

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

* Update README.md

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

* Reword Tomek's currency-exchange suggestion

* Add link to Substrate's installation guide

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

* ethereum exchange module

* continue

* continue

* added tests for exchange module

* moved

* remove println

* move again

* fixes

* removed redundant deps

* cargo fmt

* fund_locks_transaction_decode_works

* cargo fmt --all

* fix error processing

* added some tracing to bridge modules

* more tests

* more tests

* cargo fmt --all

* kovan.rs -> exchange.rs

* Update bin/node/runtime/src/exchange.rs

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

* added assumption doc

* Airdrop -> DepositInto

* AsIs -> Identity

* OnTransactionSubmitted

* Transfers::Key = Id

* typo

* Update bin/node/runtime/src/exchange.rs

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

* block+tx+proof -> proof { block, tx, proof }

* cargo fmt --all

* docs

* check <-> verify

* parse hex

* extracted exchange primitives to separate crate

* added docs to runtime::exchange module

* Update bin/node/runtime/src/exchange.rs

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

* typo

* Update modules/currency-exchange/Cargo.toml

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

* add docs to currency-exchange module

* change tests names

* cargo fmt --all

* Update bin/node/runtime/src/exchange.rs

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

* Update bin/node/runtime/src/exchange.rs

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

* Update bin/node/runtime/src/exchange.rs

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

* Update bin/node/runtime/src/exchange.rs

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

* Update bin/node/runtime/src/exchange.rs

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

* fixed verify_transaction_finalized for siblings of finalized blocks

* cargo fmt --all

* added double spend note

* cargo fmt --all

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

* bump substrate

* cargo fmt --all

* removeInMemoryStorage + extract Kovan stuff to runtime

* removed comment from the future

* limit number of headers that are pruned within single import Call

* verify that pruning range upper bottom is always-increasing

* Fix typo

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

* removeInMemoryStorage + extract Kovan stuff to runtime

* removed comment from the future

* remove redundant conversions

* remove redundant `u8 as usize`

* remove redundant `u8 as usize`

* Update modules/ethereum/src/mock.rs

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

* use hex-literal in kovan config

* cargo fmt --all

* extracted insert_header

* cargo fmt --all

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

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]>