Rewrite WebGLRenderingContext to use typed array APIs

[jdm]

We need to replace uses of array_buffer_view_data_checked, array_buffer_view_data, array_buffer_view_to_vec_checked, array_buffer_view_to_vec, and array_buffer_to_vec. This may mean adding an additional ArrayBufferViewU16 type to the list in rust-mozjs, but the rest should be straightforward replacements with things like ArrayBuffer::from and ArrayBufferView::from (after servo/rust-mozjs#323 merges).

Code: components/script/dom/webglrenderingcontext.rs
Tests: ./mach test-wpt tests/wpt/web-platform-tests/webgl/

[yysung1123]

I would like to work on this issue!

[yysung1123]

There is no JSContext in the fn validate_tex_image_2d_data which is required by ArrayBufferView::From.
How can I fix this problem? thx

[KiChjang]

Does self.global().get_cx() work?

[jdm]

You can add a *mut JSContext argument to the method, since all of the callers should have access to one already.

[yysung1123]

Sorry for that I was busy before.
I can work for it now!
It seems that there should be type ArrayBufferViewU16 in the rust/mozjs
Could you please create an issue on rust/mozjs for this? Thanks

[yysung1123]

Change
code

} else if array_buffer_view_data_checked::<u8>(data).is_some(){
    1
}

To

typedarray!(in(cx) let typedarray_u8: ArrayBufferView = data);
// some line
} else if typedarray_u8.is_ok() {
    1
}

Is it right?

[jdm]

That looks right.

[yysung1123]

@jdm

So I need ArrayBufferViewU16 in rust/mozjs to replace the function array_buffer_view_data_checked::<u16>.

But I don't know how to add this to rust/mozjs.

[jdm]

You can add it to the list of typed arrays at https://github.com/servo/rust-mozjs/blob/master/src/typedarray.rs#L272, and then use a Cargo override to use your locally-modified version inside Servo.

[yysung1123]

It seems that I need to write C++ functions which are binding with two Rust functions UnwrapUint16ArrayBufferView and GetUint16ArrayBufferViewLengthAndData.

Where can I implement these function?

[Ms2ger]

It look like we shouldn't be using ArrayBufferView for this at all, just Uint8Array and Uint16Array.

[yysung1123]

The trait bound in ArrayBufferViewContents is u8, u16, i8, i16, i32, f16, f32 primitive type.

It means that there would be some function calls like

typed_array_or_sequence_to_vec::<i32>(cx, data, ConversionBehavior::Default)

But I have to change them to Uint8, Uint16, Int8, Int16, Int32, Float16, Float32 which are TypedArrayElementType.

Therefore I can rewrite fn typed_array_or_sequence_to_vec with TypedArray.

[yysung1123]

TypedArray only uses TypedArrayElement type to be created.

But the generic type parameters of typed_array_or_sequence_to_vec:: are primitive type now.

How can I use primitive type to create an TypedArray? thx