* Pre: remove remnants of 'open_empty'
* Pre: Cleanup 'datoms' table after a timeline move
Since timeline move operations use a transactor, they generate a
"phantom" 'tx' and a 'txInstant' assertion. It is "phantom" in a sense
that it was never present in the 'transactions' table, and is entirely
synthetic as far as our database is concerned.
It's an implementational artifact, and we were not cleaning it up.
It becomes a problem when we start inserting transactions after a move.
Once the transactor clashes with the phantom 'tx', it will retract the
phantom 'txInstant' value, leaving the transactions log in an incorrect state.
This patch adds a test for this scenario and elects the easy way out: simply
remove the offending 'txInstant' datom.
* Part 1: Sync without support for side-effects
A "side-effect" is defined here as a mutation of a remote state as part
of the sync.
If, during a sync we determine that a remote state needs to be changed, bail out.
This generally supports different variations of "baton-passing" syncing, where clients
will succeed syncing if each change is non-conflicting.
* Part 2: Support basic "side-effects" syncing
This patch introduces a concept of a follow-up sync. If a sync generated
a "merge transaction" (a regular transaction that contains assertions
necessary for local and remote transaction logs to converge), then
this transaction needs to be uploaded in a follow-up sync.
Generated SyncReport indicates if a follow-up sync is required.
Follow-up sync itself is just a regular sync. If remote state did not change,
it will result in a simple RemoteFastForward. Otherwise, we'll continue
merging and requesting a follow-up.
Schema alterations are explicitly not supported.
As local transactions are rebased on top of remote, following changes happen:
- entids are changed into tempids, letting transactor upsert :db/unique values
- entids for retractions are changed into lookup-refs if we're confident they'll succeed
-- otherwise, retractions are dropped on the floor
* Post: use a macro for more readable tests
* Tolstoy README
There are a few tricky details to call out here. The first is the
`TransactableValueMarker` trait. This is strictly a marker (like
`Sized`, for example) to give some control over what types can be used
as value types in `Entity` instances. This expression is needed due
to the network of `Into` and `From` relations between the parts of
valid `Entity` instances. This allows to drop the `IntoThing`
work-around trait and use the established patterns. (Observe that
`KnownEntid` makes this a little harder, due to the cross-crate
consistency restrictions.)
The second is that we can get rid `{add,retract}_kw`, since the
network of relations expresses the coercions directly.
The third is that this commit doesn't change the name `TermBuilder`,
even though it is now building `Entity` instances. This is because
there's _already_ an `EntityBuilder` which fixes the `EntityPlace`.
It's not clear whether the existing entity building interface should
be removed or whether both should be renamed. That can be follow-up.
This is neat, because currently at the FFI boundary we're primarily concerned
with verbalizing our errors. It doesn't matter what 'error' that's wrapped by
Result is then, as long as it can be displayed.
Once we're past the prototyping stage, it might be a good idea to formalize this.
* Add an IntelliJ section to gitignore
* Add Android SDK sample project which exercises mentat SDK
* Symlink libmentat_ffi.so in Android SDK to the generated --release files
* README files for Android SDK and mentat_ffi
`CacheDirection` enum is used only on the Android side to provide a usable interface. FFI calls are more explicit.
Tests ensure that a cached query is faster than the uncached one.
This exposes an FFI function for each direction of caching, `Forward`, `Reverse` and `Both`. This is to make is as clear as possible to consumers which direction they are caching their attributes in. The original implementation exposed the `CacheDirection` enum over FFI and it made mistakes very easy to make. This is more explicit and therefore less prone to error.
There are two ways to create each builder, directly from a `Store` or from an `InProgress`. Creating from `Store` will perform two actions, creating a new `InProgress` and then returning a builder from that `InProgress`. In the case of `store_entity_builder_with_entid` and `store_entity_builder_from_tempid`, the function goes a step further and calls `describe` or `describe_tempid` from the created `InProgressBuilder` and returning the `EntityBuilder` that results. These two functions are replicated on `InProgress`. This has been done to reduce the overhead of objects being passed over the FFI boundary.
The decision to do this enables us to go from something like
```
in_progress = store_begin_transaction(store);
builder = in_progress_builder(in_progress);
entity_builder = in_progress_builder_describe(builder, entid);
```
to
```
entity_builder = store_entity_builder_from_entid(store);
```
There is an `add_*` and `retract_*` function specified for each `TypedValue` type for both `InProgressBuilder` and `EntityBuilder`.
To enable `transact` on `EntityBuilder` and `InProgressBuilder`, a new `repr(C)` struct has been created that contains a pointer to an `InProgress` and a pointer to a `Result<TxReport>` to allow passing the tuple result returned from `transact` on those types over the FFI.
Commit is possible from both builders and `InProgress`.
Documents the FFI layer for Mentat, and provides transaction functionality via an EDN string. Creates two native libraries for iOS (Swift) and Android (Java) and fully tests the FFI for both platforms.
Closes#619#614#611
* Make properties on NamespacedKeyword/NamespacedSymbol private
* Use only a single String for NamespacedKeyword/NamespacedSymbol
* Review comments.
* Remove unsafe code in namespaced_name.
Benchmarking shows approximately zero change.
* Allow the types of ns and name to differ when constructing a NamespacedName.
* Make symbol namespaces optional.
* Normalize names of keyword/symbol constructors.
This will make the subsequent refactor much less painful.
* Use expect not unwrap.
* Merge Keyword and NamespacedKeyword.
* Pre: eliminate some occurrences of Rc, largely through the magic of Into.
* Pre: introduce FromRc to convert between refcounted types.
* Introduce ValueRc as an abstraction over Rc/Arc choice.
* Move Cloned to core.
* Move CString-creation methods to TypedValue.
* Finish transition.
* Tidy up and add txid at beginning of transaction
* Add ffi crate and new_store function
* Add register and unregister observer FFI, Store and Conn functions.
Also add android logging facilities
* Add function for fetching entids for attribute strings
* Add functions for iterating through TxReports
* Add sync to ffi boundary
* Move Extern types from submodule to lib in FFI.
For some reason, if these types are in a submodule, even if they are publically used, the functions inside the FFI are not found in
Android. Works for iOS though. To be investigated later....
* Return to passing TxReports to observer function.
Also, remove some debug
* Expose DateTime and Utc publically
* Use Store in observer tests
