Every field of Peer now has a corresponding unit struct defined in the
`peer_field` module, which implements the `PeerFieldDef` trait which in
turn contains information about the field's name, tarantool type and
rust type.

This information currently is used in the `field_by_raft_id` method
and is generated by the `define_peer_fields` macro, which also
automates the generation of the format (`peer_format` function) for the
"raft_group" space.

Yaroslav Dynnikov authored 2 years ago and Yaroslav Dynnikov committed 2 years ago

Exit only after processing `light_ready`. It doesn't affect much the
behavior, but simplifies main_loop decomposition.

`KVCell` contains an optional value and provides access by key in two
flavors:

```rust
fn take_or_drop(&mut self, key: &K) -> Option<T>
fn take_or_keep(&mut self, key: &K) -> Option<T>
```

Both return `Some` value only if provided key matches the contained one.

The behavior differs when the provided key doesn't match:
- `take_or_drop` always leaves the cell empty. It supersedes
  `CachedCell` and copies its behavior.
- `take_or_keep` retains contained value. It's a replacement for
  `JointStateLatch`.

Single-out ConfChange generation logics into a separate clean function.

Georgy Moshkin authored 2 years ago and Georgy Moshkin committed 2 years ago

replication_factor now goes into cluster_state

Yaroslav Dynnikov authored 2 years ago and Georgy Moshkin committed 2 years ago

The final goal is to encapsulate access to Storage, but at first we split it
into two parts - one for raft data, and another one for picodata stuff.

This patch introduces the first one - RaftSpaceAccess. It isn't used in
code yet, but already displays the future API.

If makes the code neater.