* Add the `snapshot` crate, which implements snapshotting at a low level
- Requires making `BlobHash` be `Serialize` and `Deserialize`.
For arcane macro-ology reasons, this requires writing `BlobHash::SIZE`
instead of `Self::SIZE` (it gets embedded in a visitor struct or something).
- Requires adding two new operators to `BlobStore`.
- Adds a return value to `Page::save_content_hash`, for convenience.
- Impls `DerefMut` for `Pages`.
- **Scary change:** adds `Table::pages_mut`.
I think possibly this operator should be `unsafe`,
since write access to the `Pages` allows an undisciplined caller
to violate the `Table`'s assumptions by corrupting a `Page`.
It seems like an anti-pattern to mark a method `unsafe` on the grounds that
misusing its return value can cause UB,
but I don't see a plausible alternative
without making most methods on `Page` unsafe.
Open to feedback on this one!
* Nix `Table::pages_mut`
* Address Mazdak's feedback
* Use `thiserror` rather than `anyhow` for better error hygiene
* Create new crate `fs-utils`; move `Lockfile` and `create_parent_dir`
The snapshot crate will need to create lockfiles.
Rather than duplicating code to do so, we choose to move our definition of `Lockfile`
into a crate that can be depended on by both `cli` and `snapshot`.
No existing crate seems like an obvious choice for this
-- a `Lockfile` is not really a data structure, so `data-structures` seems wrong --
so we add a new crate, `fs-utils`.
Currently this contains only `Lockfile` and `create_parent_dir`,
but a follow-up PR will add `DirTrie`, a Git-like on-disk object store.
* Deduplicate `map_err` closure
* Zeke's nit: simplify control flow
Co-authored-by: Zeke Foppa <196249+bfops@users.noreply.github.com>
Signed-off-by: Phoebe Goldman <phoebe@goldman-tribe.org>
---------
Signed-off-by: Phoebe Goldman <phoebe@goldman-tribe.org>
Co-authored-by: Zeke Foppa <196249+bfops@users.noreply.github.com>
Noa