Should handle classloader URI as an absolute path when running on JRuby

[mojavelinux]

The virtual path represented by a classloader URI should be respected when running on JRuby. This means normalize_system_path should pass it through and is_uri? should return false.

[mojavelinux]

ex. uri:classloader:/path/to/image

Note that ::File.absolute_path? (as well as Pathname#absolute?) recognizes this as an absolute path.

[mojavelinux]

There are several cases to consider here, not all of which go through normalize_system_path

• read a stylesheet (to copy or embed)
• read an image to embed
• read an include file

[mojavelinux]

read a stylesheet (to copy or embed)

This one is tougher. The reason is, the dest will end up being the src, and thus the stylesheet won't be copied. Dedicated logic will be required.

[mojavelinux]

This one is tougher. The reason is, the dest will end up being the src, and thus the stylesheet won't be copied. Dedicated logic will be required.

Actually, it's no problem after all. If stylesheet is a classloader URI, and linkcss is not set, it will be read and embedded. If linkcss and copycss are set, copycss must be the classloader URI and stylesheet must be the destination path. I'll make sure there are tests to cover these scenarios.

[mojavelinux]

The one outstanding restriction is that if the safe mode is safe or greater, the resources will only be read if the base/jail is a parent classloader URI. We can revisit this restriction in a separate issue. The simplest workaround when mixing local paths and classloader URIs is to set the safe mode to unsafe.

[mojavelinux]

This fix will also prevent the following warning when including a file from the classloader:

cannot include contents of URI: uri:classloader:/path/to/include/file.adoc (allow-uri-read attribute not enabled)