The "list of available images" and origin

[yutakahirano]

Hi,

Currently https://html.spec.whatwg.org/multipage/images.html#the-list-of-available-images says:

Each Document object must have a list of available images. Each image in this list is identified by a tuple consisting of an absolute URL, a CORS settings attribute mode, and, if the mode is not No CORS, an origin.

I think we should always attach the origin to the matching key, because that information is pretty important even for No CORS images - CORS-sameoriginness is one example.

cc: @domfarolino

[domfarolino]

This seems reasonable. Any objections?

[annevk]

Is this a general property of "memory cache" keys? It makes sense to me it cannot span origins. It should not be able to span top-level sites either, but that's probably best tackled separately.

cc @emilio

[domfarolino]

Chrome's memory cache is effectively keyed by requestor origin as well, so I think this is general property for us at least.

[emilio]

Sure, but I don't get why the key needs to be in the document's "list of available images". Why is that desirable? For a given document, the origin is always the same, right? (maybe modulo document.domain shenanigans). If so I don't get how it is useful.

[domfarolino]

I believe the spec allows for a document’s list of available images to be shared with any other document at any time

[emilio]

Yeah, it seems like then we should key off the origin then.