Platform/XML Rewrite: Difference between revisions

In the HTML case, the only thing that can cause a speculation fail is document.write. Since XML has no document.write, the off-the-main-thread XML parser can parse its input to completion and doesn't need to support stream rewinding. All the tree ops can be queued up and they just need to be executed in chunks that end at a script execution op so that the world experienced by scripts looks as though the parts of the document after the current script didn't exist yet.

Chrome documents in Firefox are localized using external DTDs that define named entities. This needs to work with the new implementation. Since initiating DTD IO from off the main thread is trouble, chrome: documents should be parsed on the main thread. To enable this, there should be an on-the-main-thread alternative for mozilla::parser::xml::StreamParser: mozilla::parser::xml::MainThreadStreamParser. To get assertions about which methods should run on which thread right, it is probably useful to actually have two classes instead of having one class with a flag that picks different code paths within the class. The two classes should probably share encoding sniffing code in a common superclass.

Since chrome: documents can be XHTML, it follows that mozilla::parser::xml::TreeOpGenerator needs to work on the main thread, too. This shouldn't be a big deal considering that tree op generation in the HTML case can run on either thread.