Bindings generation ignores Exposed annotations on members and partial interfaces

[jdm]

Despite #12414 being closed, exposed annotations do on members do not actually affect whether those members are exposed in the generated bindings. master...jdm:exposed-member contains an automated test that demonstrates this.

[highfive]

cc @wafflespeanut

[jdm]

This requires:

• adding a Exposed(Globals) variant to the Condition enum
• making Condition::is_satisfied call is_exposed_in for the new variant
• updating the code generator's MemberCondition to accept a new argument for exposed conditions and returning Condition::Exposed when appropriate
• updating getControllingCondition to pass a list of exposed globals when appropriate

Code: components/script/dom/bindings/guard.rs, components/script/dom/bindings/codegen/CodegenRust.py

[sreeise]

@highfive: assign me

I can work on this :)

[highfive]

Hey @sreeise! Thanks for your interest in working on this issue. It's now assigned to you!

[jdm]

Please let me know if anything is unclear!

[sreeise]

@jdm Hey, so I started on this in the commit here, but it doesn't compile yet so I didn't bother to make a pr.

The main issue currently is where the Exposed annotation could either be a list or it could be a string. When a match is found, in Guard.rs, and the is_exposed_in method is called it expects a single global to be passed as an argument which works only if the Exposed attribute in any given webidl has one member, i.e., Exposed=Window as opposed to Exposed=(Window, Worker). Because there is a possibility that the attribute is set to a list, compilation will fail because is_exposed_in does not expect a list.

For example, when the code is generated for a list the arguments don't get parsed correctly:

1349 |     Guard::new(Condition::Exposed(['Window', 'Worker']), sMethods_specs[1]),
     |                                              ^^^^^^^^
help: if you meant to write a `str` literal, use double quotes
     |
1349 |     Guard::new(Condition::Exposed(['Window', "Worker"]), sMethods_specs[1]),

The compiler complains about using double quotes for a string literal which really isn't the problem as is_exposed_in only accepts one InterfaceObjectMap::Globals argument anyway (I am assuming that globals is not an &str so I could be wrong).

I am honestly not sure where in CodgenRust.py to write a fix for this or if I am possibly missing something that should be changed. I havn't worked in the codegen section before so I figured I'd ask about this before attempting to find a solution. Thanks for your help :).

[jdm]

The Globals type is actually a bitset. I recommend using the following code as a model:

servo/components/script/dom/bindings/codegen/CodegenRust.py

Lines 2581 to 2583 in 8dc7a25

	bits = " | ".join(sorted(
	"InterfaceObjectMap::Globals::" + camel_to_upper_snake(i) for i in iface.exposureSet
	))

.

[jdm]

More specifically, returning Condition::Exposed(%s) with the Globals bitset value from MemberCondition seems like the right choice to me.

[jdm]

You can see the documentation for the Globals type at https://doc.servo.org/script/dom/bindings/codegen/InterfaceObjectMap/struct.Globals.html if that helps.