Provide a way to change path of common css/js paths in documentations

[onur]

I am asking this for docs.rs.

Currently docs.rs is leveraging browser cache by serving every common css/js file ("rustdoc.css", "main.css", "main.js", "normalize.css", "*.woff"]) from root of the docs.rs. Otherwise docs.rs would serve 60k different copies of this files since rustdoc is generating them for each crate. Docs.rs is only replacing this file paths in documentations to provide a better/faster browsing experience.

But unfortunately new theme picker did break this feature and causing me some trouble to update rustc on docs.rs since it's not compatible.

I did a small talk with @GuillaumeGomez (the guy behind theme picker). He came up with an idea of adding a --replace or --url argument to rustdoc so this files can be served from a desired path. For example running rustdoc lib.rs --url main.css /main-1.24.css --url light.css /light-1.24.css will replace this paths for the main.css and light.css.

This will make new theme picker compatible with docs.rs and also it will dramatically improve docs.rs by removing only necessary documentation change made by docs.rs.

[GuillaumeGomez]

The alternative with --replace is as follow:

rustdoc lib.rs --replace main.css ../../main-1.24.css

[QuietMisdreavus]

How about we add a hook for the entire html/static/ folder at once? That way, instead of having to hook each file individually, we can just dump those files into that folder (or assume you have it there) instead of putting them in the doc root every time.

[GuillaumeGomez]

It could as well. I don't have preference in here.

[GuillaumeGomez]

Another idea: --files-suffix="something which generates rustdoc-something.css.

[GuillaumeGomez]

The best option for the moment seems to be the one proposed by @QuietMisdreavus. We just need confirmation from @onur now.

[onur]

@GuillaumeGomez --files-suffix might not work, I am not just adding a suffix to common files. I am also moving them to out of target/doc directory. @QuietMisdreavus idea is great, a hook would solve this problem for me.

[GuillaumeGomez]

Then I'll implement @QuietMisdreavus' solution.

[onur]

#48511 fixed this issue