Iroha squash and upgrade tool

For usage: cargo run help

Known limitations:

• Supported versions for squashing: pre-rc-9, pre-rc-11, pre-rc-13, pre-rc-16, pre-rc-19, pre-rc-20
• Supported upgrade paths: pre-rc-9 -> pre-rc-11, pre-rc-9 -> pre-rc-13, pre-rc-13 -> pre-rc-16 -> pre-rc-19 -> pre-rc-20
• Information about asset definition registrar is not retained after squash due to Iroha genesis limitations
• Build times (there's no easy way to do this without essentialy building all supported versions of iroha)
• WASM smartcontract upgrade UX: currently smartcontracts are replaced with value "NEEDSREBUILD++{hash}++", where hash is sha256 hash of original smartcontract.

Design

Every supported version of iroha is built as a separate library (found in versions/), which is loaded by cli. This is done because trying to depend all supported versions of iroha leads - understandably - to dependency resulution failures.

Every version defines two functions:

• extern "C" fn squash_store(path: *const libc::c_char) -> *mut libc::c_char, which takes a path to this version's blockstore, loads it and squashes into a single genesis.
• extern "C" fn upgrade(from: *const libc::c_char) -> *mut libc::c_char, which takes a path to a genesis.json (presumably squashed) for a previous supported version and upgrades it.

There is a macro crate with some utility macros, since most of the code is boilerplate that translates between two structurally identical types that Rust doesn't consider identical since they're from different iroha versions.

A lot of type conversions are not implemented, either because they're unlikely to be seen in actual blockchain and are mostly something you would see on a client running queries, or because there's no unambiguous mapping from previous version's concept to a new one's, in which case input from actual users needs to be considered.