The Rust API has so far grown somewhat organically driven by the needs of the
javascript implementation. This has led to an API which is quite awkward and
unfamiliar to Rust programmers. Additionally there is no documentation to speak
of. This commit is the first movement towards cleaning things up a bit. We touch
a lot of files but the changes are all very mechanical. We introduce a few
traits to abstract over the common operations between `Automerge` and
`AutoCommit`, and add a whole bunch of documentation.
* Add a `ReadDoc` trait to describe methods which read value from a document.
make `Transactable` extend `ReadDoc`
* Add a `SyncDoc` trait to describe methods necessary for synchronizing
documents.
* Put the `SyncDoc` implementation for `AutoCommit` behind `AutoCommit::sync` to
ensure that any open transactions are closed before taking part in the sync
protocol
* Split `OpObserver` into two traits: `OpObserver` + `BranchableObserver`.
`BranchableObserver` captures the methods which are only needed for observing
transactions.
* Add a whole bunch of documentation.
The main changes Rust users will need to make is:
* Import the `ReadDoc` trait wherever you are using the methods which have been
moved to it. Optionally change concrete paramters on functions to `ReadDoc`
constraints.
* Likewise import the `SyncDoc` trait wherever you are doing synchronisation
work
* If you are using the `AutoCommit::*_sync_message` methods you will need to add
a call to `AutoCommit::sync()` first. E.g. `doc.generate_sync_message` becomes
`doc.sync().generate_sync_message`
* If you have an implementation of `OpObserver` which you are using in an
`AutoCommit` then split it into an implementation of `OpObserver` and
`BranchableObserver`
The assert_doc and assert_obj macros in automerge/tests::helpers are
useful for writing tests for any application working with automerge
documents. Typically however, you only want these utilities in tests so
rather than packaging them in the main `automerge` crate move them to a
new crate (in the spirit of `tokio_test`)
