This algorithm is quite straightforward written in the specification,
but leads to some type awkwardness in Rust. Most notably, the callbacks
have different types and cannot be unified easily. They also return
different string types. Similarly, the returning objects are all unique
types and don't have a common denominator.
Therefore, rather than implementing it in 1-to-1 fashion with the
specification text, it instead uses callbacks to instruct the type
system of what to call when.
This is further complicated by the fact that the callback can exist
or not, as well as return a value or not. This requires multiple
unwrangling, combined with the fact that the algorithm should throw
or not.
All in all, the number of lines is relatively low compared to the
specification algorithm and the Rust compiler does a lot of heavy
lifting figuring out which type is what.
Part of https://github.com/servo/servo/issues/36258
Signed-off-by: Tim van der Lippe <tvanderlippe@gmail.com>
Co-authored-by: Josh Matthews <josh@joshmatthews.net>
This is the final step of #1799, where the majority of the generated
code for the JS bindings is now compiled as part of the script_bindings
build step. The remaining pieces in script must live there because they
refer to concrete DOM types; all code in script_bindings is generic over
the
[DomTypes](https://doc.servo.org/script/dom/bindings/codegen/DomTypes/trait.DomTypes.html)
trait.
My testing with incremental builds shows me a 12 second reduction in
build times on my 2024 M4 Macbook Pro when modifying code in the script
crate after these changes. Before this PR those changes took 20 seconds
to rebuild Servo, and now they take 8 seconds.
Testing: Existing WPT tests ensure no regressions.
Fixes: #1799
---------
Signed-off-by: Josh Matthews <josh@joshmatthews.net>
