ScriptOrigin::text duplicates the string contents

[jdm]

Since these scripts can be large minified scripts, if there's a way to borrow the result instead that would be preferable.

[camelid]

I don't know the context, but what about a Cow?

[jdm]

I don't think we ever need to mutate the contents of the string, so a straight borrow is probably all that would be required.

[camelid]

So this would just entail updating all the usages so that it works with a reference instead of an owned value then?

[jdm]

Yes, this would require investigating whether it's possible to avoid using an owned value in the code that relies on this method.

[camelid]

Is it okay to introduce a lifetime to ModuleTree so that the text field can be DomRefCell<&'a DOMString> instead of DomRefCell<DOMString>? Or is there a better way to do it that won't affect other code?

[jdm]

One other option would be storing Rc<DOMString>. I suspect introducing a lifetime might be tricky.

[camelid]

Yeah, that's kind of what I was thinking. I think I'll try that later today :)

[camelid]

@jdm I changed ScriptOrigin.text to be an Rc<DOMString>, but I'm getting this (among other) errors:

error[E0277]: the trait bound `std::rc::Rc<dom::bindings::str::DOMString>: malloc_size_of::MallocSizeOf` is not satisfied
   --> components/script/dom/htmlscriptelement.rs:152:23
    |
152 | #[derive(JSTraceable, MallocSizeOf)]
    |                       ^^^^^^^^^^^^ the trait `malloc_size_of::MallocSizeOf` is not implemented for `std::rc::Rc<dom::bindings::str::DOMString>`
    |
    = note: required by `malloc_size_of::MallocSizeOf::size_of`
    = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)

What should I do?

[CYBAI]

In this case, I think you can add use ignore_malloc_size_ofattribute to the text property so that compiler will ignore MallocSizeOf for it.

For example, the external_underlying_source property of ReadableStream 👇

servo/components/script/dom/readablestream.rs

Lines 49 to 59 in 12d4c0d

	#[dom_struct]
	pub struct ReadableStream {
	reflector_: Reflector,
	#[ignore_malloc_size_of = "SM handles JS values"]
	js_stream: Heap<*mut JSObject>,
	#[ignore_malloc_size_of = "SM handles JS values"]
	js_reader: Heap<*mut JSObject>,
	has_reader: Cell<bool>,
	#[ignore_malloc_size_of = "Rc is hard"]
	external_underlying_source: Option<Rc<ExternalUnderlyingSourceController>>,
	}

[camelid]

Thanks! What reason should I put for the macro?

EDIT: Never mind, just saw the reason in your example :)