* 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
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!
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
This commit adds support for closures with arguments like strings and such. In
other words, closures passed to JS can now have the same suite of arguments as
all functions that can be exported from Rust, as one might expect!
At this time due to the way trait objects work closures still cannot use types
with references like `&str`, but bare values like `String` or `ImportedType`
should work just fine.
Closes#104
This commit adds support for passing `&mut FnMut(..)` to JS via imports. These
closures cannot be invoked recursively in JS (they invalidate themselves while
they're being invoked) and otherwise work the same as `&Fn(..)` closures.
Closes#123
This commit is a complete overhaul of how the `#[wasm_bindgen]` macro
communicates type information to the CLI tool, and it's done in a somewhat...
unconventional fashion.
Today we've got a problem where the generated JS needs to understand the types
of each function exported or imported. This understanding is what enables it to
generate the appropriate JS wrappers and such. We want to, however, be quite
flexible and extensible in types that are supported across the boundary, which
means that internally we rely on the trait system to resolve what's what.
Communicating the type information historically was done by creating a four byte
"descriptor" and using associated type projections to communicate that to the
CLI tool. Unfortunately four bytes isn't a lot of space to cram information like
arguments to a generic function, tuple types, etc. In general this just wasn't
flexible enough and the way custom references were treated was also already a
bit of a hack.
This commit takes a radical step of creating a **descriptor function** for each
function imported/exported. The really crazy part is that the `wasm-bindgen` CLI
tool now embeds a wasm interpreter and executes these functions when the CLI
tool is invoked. By allowing arbitrary functions to get executed it's now *much*
easier to inform `wasm-bindgen` about complicated structures of types. Rest
assured though that all these descriptor functions are automatically unexported
and gc'd away, so this should not have any impact on binary sizes
A new internal trait, `WasmDescribe`, is added to represent a description of all
types, sort of like a serialization of the structure of a type that
`wasm-bindgen` can understand. This works by calling a special exported function
with a `u32` value a bunch of times. This means that when we run a descriptor we
effectively get a `Vec<u32>` in the `wasm-bindgen` CLI tool. This list of
integers can then be parsed into a rich `enum` for the JS generation to work
with.
This commit currently only retains feature parity with the previous
implementation. I hope to soon solve issues like #123, #104, and #111 with this
support.
