* Fix automerge-c tests on mac
* Generate significantly smaller automerge-c builds
This cuts the size of libautomerge_core.a from 25Mb to 1.6Mb on macOS
and 53Mb to 2.7Mb on Linux.
As a side-effect of setting codegen-units = 1 for all release builds the
optimized wasm files are also 100kb smaller.
The AMvalue union, AMlistItem struct, AMmapItem struct, and AMobjItem struct are gone, replaced by the AMitem struct.
The AMchangeHashes, AMchanges, AMlistItems, AMmapItems, AMobjItems, AMstrs, and AMsyncHaves iterators are gone, replaced by the AMitems iterator.
The AMitem struct is opaque, getting and setting values is now achieved exclusively through function calls.
The AMitemsNext(), AMitemsPrev(), and AMresultItem() functions return a pointer to an AMitem struct so you ultimately get the same thing whether you're iterating over a sequence or calling AMmapGet() or AMlistGet().
Calling AMitemResult() on an AMitem struct will produce a new AMresult struct referencing its storage so now the AMresult struct for an iterator can be subsequently freed without affecting the AMitem structs that were filtered out of it.
The storage for a set of AMitem structs can be recombined into a single AMresult struct by passing pointers to their corresponding AMresult structs to AMresultCat().
For C/C++ programmers, I've added AMstrCmp(), AMstrdup(), AM{idxType,objType,status,valType}ToString() and AM{idxType,objType,status,valType}FromString(). It's also now possible to pass arbitrary parameters through AMstack{Item,Items,Result}() to a callback function.
The wasm codebase assumed that clients want to represent text as a
string of characters. This is faster, but in order to enable backwards
compatibility we add a `TextRepresentation` argument to
`automerge_wasm::Automerge::new` to allow clients to choose between a
`string` or `Array<any>` representation. The `automerge_wasm::Observer`
will consult this setting to determine what kind of diffs to generate.
* Use AMbyteSpan for byte values
Before this change there was an inconsistency between AMmapPutString
(which took an AMbyteSpan) and AMmapPutBytes (which took a pointer +
length).
Either is fine, but we should do the same in both places. I chose this
path to make it clear that the value passed in was an automerge value,
and to be symmetric with AMvalue.bytes when you do an AMmapGet().
I did not update other APIs (like load) that take a pointer + length, as
that is idiomatic usage for C, and these functions are not operating on
byte values stored in automerge.
Transactions with no ops in them are generally undesirable. They take up
space in the change log but do nothing else. They are not useless
though, it may occasionally be necessary to create an empty change in
order to list all the current heads of the document as dependents of the
empty change.
The current API makes no distinction between empty changes and non-empty
changes. If the user calls `Transaction::commit` a change is created
regardless of whether there are ops to commit. To provide a more useful
API modify `commit` so that if there is a no-op transaction then no
changes are created, but provide explicit methods to create an empty
change via `Transaction::empty_change`, `Automerge::empty_change` and
`Autocommit::empty_change`. Also make these APIs available in Javascript
and C.
After some discussion with PVH I realise that the repo structure in the
last reorg was very rust-centric. In an attempt to put each language on
a level footing move the rust code and project files into ./rust
