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
