This commit moves `wasm-bindgen` the CLI tool from internally using
`parity-wasm` for wasm parsing/serialization to instead use `walrus`.
The `walrus` crate is something we've been working on recently with an
aim to replace the usage of `parity-wasm` in `wasm-bindgen` to make the
current CLI tool more maintainable as well as more future-proof.
The `walrus` crate provides a much nicer AST to work with as well as a
structured `Module`, whereas `parity-wasm` provides a very raw interface
to the wasm module which isn't really appropriate for our use case. The
many transformations and tweaks that wasm-bindgen does have a huge
amount of ad-hoc index management to carefully craft a final wasm
binary, but this is all entirely taken care for us with the `walrus`
crate.
Additionally, `wasm-bindgen` will ingest and rewrite the wasm file,
often changing the binary offsets of functions. Eventually with DWARF
debug information we'll need to be sure to preserve the debug
information throughout the transformations that `wasm-bindgen` does
today. This is practically impossible to do with the `parity-wasm`
architecture, but `walrus` was designed from the get-go to solve this
problem transparently in the `walrus` crate itself. (it doesn't today,
but this is planned work)
It is the intention that this does not end up regressing any
`wasm-bindgen` use cases, neither in functionality or in speed. As a
large change and refactoring, however, it's likely that at least
something will arise! We'll want to continue to remain vigilant to any
issues that come up with this commit.
Note that the `gc` crate has been deleted as part of this change, as the
`gc` crate is no longer necessary since `walrus` does it automatically.
Additionally the `gc` crate was one of the main problems with preserving
debug information as it often deletes wasm items!
Finally, this also starts moving crates to the 2018 edition where
necessary since `walrus` requires the 2018 edition, and in general it's
more pleasant to work within the 2018 edition!
This commit implements the first half of [RFC #5] where the `Deref`
trait is implemented for all imported types. The target of `Deref` is
either the first entry of the list of `extends` attribute or `JsValue`.
All examples using `.as_ref()` with various `web-sys` types have been
updated to the more ergonomic deref casts now. Additionally the
`web-sys` generation of the `extends` array has been fixed slightly to
explicitly list implementatoins in the hierarchy order to ensure the
correct target for `Deref` is chosen.
[RFC #5]: https://github.com/rustwasm/rfcs/blob/master/text/005-structural-and-deref.md
Previously the "container attribute" were set to the attributes of the
mixin itself, but we want the container attributes to be that of the
type which includes the mixin (like `Window`) as those attributes
contain information about whether or not bindings are `structural`.
The end result with this is that the `structural` tag is now used for
properties on `Window`, correctly generating setters/getters.
Closes#904
* Tweak the implementation of heap closures
This commit updates the implementation of the `Closure` type to internally store
an `Rc` and be suitable for dropping a `Closure` during the execution of the
closure. This is currently needed for promises but may be generally useful as
well!
* Support asynchronous tests
This commit adds support for executing tests asynchronously. This is modeled
by tests returning a `Future` instead of simply executing inline, and is
signified with `#[wasm_bindgen_test(async)]`.
Support for this is added through a new `wasm-bindgen-futures` crate which is a
binding between the `futures` crate and JS `Promise` objects.
Lots more details can be found in the details of the commit, but one of the end
results is that the `web-sys` tests are now entirely contained in the same test
suite and don't need `npm install` to be run to execute them!
* Review tweaks
* Add some bindings for `Function.call` to `js_sys`
Name them `call0`, `call1`, `call2`, ... for the number of arguments being
passed.
* Use oneshots channels with `JsFuture`
It did indeed clean up the implementation!
