* Shard the `convert.rs` module into sub-modules
Hopefully this'll make the organization a little nicer over time!
* Start adding support for optional types
This commit starts adding support for optional types to wasm-bindgen as
arguments/return values to functions. The strategy here is to add two new
traits, `OptionIntoWasmAbi` and `OptionFromWasmAbi`. These two traits are used
as a blanket impl to implement `IntoWasmAbi` and `FromWasmAbi` for `Option<T>`.
Some consequences of this design:
* It should be possible to ensure `Option<SomeForeignType>` implements to/from
wasm traits. This is because the option-based traits can be implemented for
foreign types.
* A specialized implementation is possible for all types, so there's no need for
`Option<T>` to introduce unnecessary overhead.
* Two new traits is a bit unforutnate but I can't currently think of an
alternative design that works for the above two constraints, although it
doesn't mean one doesn't exist!
* The error messages for "can't use this type here" is actually halfway decent
because it says these new traits need to be implemented, which provides a good
place to document and talk about what's going on here!
* Nested references like `Option<&T>` can't implement `FromWasmAbi`. This means
that you can't define a function in Rust which takes `Option<&str>`. It may be
possible to do this one day but it'll likely require more trait trickery than
I'm capable of right now.
* Add support for optional slices
This commit adds support for optional slice types, things like strings and
arrays. The null representation of these has a pointer value of 0, which should
never happen in normal Rust. Otherwise the various plumbing is done throughout
the tooling to enable these types in all locations.
* Fix `takeObject` on global sentinels
These don't have a reference count as they're always expected to work, so avoid
actually dropping a reference on them.
* Remove some no longer needed bindings
* Add support for optional anyref types
This commit adds support for optional imported class types. Each type imported
with `#[wasm_bindgen]` automatically implements the relevant traits and now
supports `Option<Foo>` in various argument/return positions.
* Fix building without the `std` feature
* Actually fix the build...
* Add support for optional types to WebIDL
Closes#502
Awhile back slices switched to being raw views into wasm memory, but this
doens't work if we free the underlying memory unconditionally! Moving around a
`Vec` is already moving a lot of data, so let's copy it onto the JS heap instead
of leaving it in the wasm heap.
This commit is an implementation of mapping u64/i64 to `BigInt` in JS through
the unstable BigInt APIs. The BigInt type will ship soon in Chrome and so this
commit builds out the necessary support for wasm-bindgen to use it!
When adding support for mutable slices I was under the impression that if the
wasm memory was reallocated while we were using it then we'd have to commit the
changes from the original buffer back to the new buffer. What I didn't know,
however, is that once the wasm memory is reallocated then all views into it are
supposed to be defunkt.
It looks like node 9 didn't have this implementation quite right and it appears
fixed in node 10, causing the deleted test here to fail. While this commit does
raise the question of whether this is the right approach to interact with slices
in JS I think the answer is still "yes". The user can always initiate the copy
if need be and that seems strictly better than copying 100% of the time.
This commit updates the `Abi` associated type for all slice types to a
`WasmSlice` type, an aggregate of two `u32` integers. This translates to an ABI
where when passed as a function argument it expands to two integer arguments,
and when passed as a return value it passes a return pointer as the first
argument to get filled in.
This is hopefully more forwards-compatible with the host bindings proposal which
uses this strategy for passing string arguments at least. It's a little sketchy
what we're doing as there's not really a stable ABI yet, but hopefully this'll
all be relatively stable for awhile!
This commit adds support for mutable slices to pass the boundary between JS and
Rust. While mutable slices cannot be used as return values they can be listed as
arguments to both exported functions as well as imported functions.
When passing a mutable slice into a Rust function (aka having it as an argument
to an exported Rust function) then like before with a normal slice it's copied
into the wasm memory. Afterwards, however, the updates in the wasm memory will
be reflected back into the original slice. This does require a lot of copying
and probably isn't the most efficient, but it should at least work for the time
being.
The real nifty part happens when Rust passes a mutable slice out to JS. When
doing this it's a very cheap operation that just gets a subarray of the main
wasm memory. Now the wasm memory's buffer can change over time which can produce
surprising results where memory is modified in JS but it may not be reflected
back into Rust. To accomodate this when a JS imported function returns any
updates to the buffer are copied back to Rust if Rust's memory buffer has
changed in the meantime.
Along the way this fixes usage of `slice` to instead use `subarray` as that's
what we really want, no copying. All methods have been updated to use `subarray`
accessors instead of `slice` or constructing new arrays.
Closes#53
Currently errors are reported via Rust panics but there's lots more errors being
added over time so this commit starts the movement towards the `failure` crate
to more idiomatically report errors as well as provide better error messages
over time.
This commit adds support for both `#![no_std]` in the wasm-bindgen runtime
support (disabled by default with an on-by-default `std` feature). This also
adds support to work and compile in the context of `#![no_std]` crates.
Closes#146
