This commit adds support for generating bindings for dictionaries defined in
WebIDL. Dictionaries are associative arrays which are simply objects in JS with
named keys and some values. In Rust given a dictionary like:
dictionary Foo {
long field;
};
we'll generate a struct like:
pub struct Foo {
obj: js_sys::Object,
}
impl Foo {
pub fn new() -> Foo { /* make a blank object */ }
pub fn field(&mut self, val: i32) -> &mut Self {
// set the field using `js_sys::Reflect`
}
}
// plus a bunch of AsRef, From, and wasm abi impls
At the same time this adds support for partial dictionaries and dictionary
inheritance. All dictionary fields are optional by default and hence only have
builder-style setters, but dictionaries can also have required fields. Required
fields are exposed as arguments to the `new` constructor.
Closes#241
I think these might all be from before WebIDL mixins existed. Either way,
multiple inheritance of interfaces that don't have exposed interface objects is
equivalent to mixins.
This commit makes these changes:
* Unsupported constructs always log "unsupported" for easy `grep`ing
* There is always a "<generic message> : <details>" format now, so we can easily
use `cut` to grab the generic message and count which kinds of things are our
biggest missing features.
* Make sure that we have different `warn!` logs for each kind of unsupported
thing, instead of grouping them together.
Put all that together and this is the current state of `wasm-bindgen-webidl` and
`web-sys`:
```
$ grep WARN stderr.txt | grep wasm_bindgen_webidl | grep -i unsupported | cut -d ' ' -f5- | cut -d ':' -f 1 | sort | uniq -c | sort -rn
387 Unsupported WebIDL Dictionary definition
139 Unsupported argument type
70 Unsupported return type
47 Unsupported WebIDL Callback definition
22 Unsupported WebIDL extended attribute
18 Unsupported unnamed operation
9 Unsupported WebIDL CallbackInterface definition
7 Unsupported WebIDL Stringifier interface member
7 Unsupported WebIDL Maplike interface member
2 Unsupported webidl stringifier
2 Unsupported WebIDL Setlike interface member
2 Unsupported stringifier on type
```
This does involve us losing the type argument present in the WebIDL, but for now
that should be fine as we're exposing low-level bindings and it's not otherwise
clear whether having a typed wrapper is a great option. Usage of `JsCast` can
convert the incoming value to a different object fairly easily.
The purpose of the `web-sys` crate is to expose functionality of the web, not
necessarily take an opinionated stance on how it should be exposed. In that
sense it should be able to work with the `Promise` as you would a typed promise
in terms of no functionality is left out. That being said we'll likely want to
be sure to reconsider this before 1.0-stabilizing the `web-sys` crate!
This commit adds support for two different features of the "special" operations
in WebIDL. First, it implements the desugaring [described by WebIDL][1] where
this:
interface Dictionary {
getter double getProperty(DOMString propertyName);
setter void setProperty(DOMString propertyName, double propertyValue);
};
becomes ...
interface Dictionary {
double getProperty(DOMString propertyName);
void setProperty(DOMString propertyName, double propertyValue);
getter double (DOMString propertyName);
setter void (DOMString propertyName, double propertyValue);
};
where specifically a named `getter` generates both a getter and a named
function.
Second it implements the distinction between two different types of getters in
WebIDL, described as:
> Getters and setters come in two varieties: ones that take a DOMString as a
> property name, known as named property getters and named property setters, and
> ones that take an unsigned long as a property index, known as indexed property
> getters and indexed property setters.
The name `get` is given to DOMString arguments, and the name `get_idx` is given
to index property getters.
[1]: https://heycam.github.io/webidl/#idl-special-operations
