RFR: 8360037: Refactor ImageReader in preparation for Valhalla support [v13]

[David Beaumont]

On Wed, 23 Jul 2025 06:58:42 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> David Beaumont has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Feedback changes.
>
> src/java.base/share/classes/jdk/internal/jimage/ImageReader.java line 51:
> 
>> 49:  * file system friendly way. The jimage entries (resources, module and package
>> 50:  * information) are mapped into a unified hierarchy of named nodes, which serve
>> 51:  * as the underlying structure for the {@code JrtFileSystem} and other utilities.
> 
> I think it's a bit confusing to document this class as an adapter for a BasicImageReader because you obtain one with static open methods that specify the file path to the jimage file. So I think better to start out in the class description by saying that it provide an API that can be used to create file system and other views over the contents of the jimage file.

Except it's not *quite* a view over the contents. The change in namespace (resources now get the same "/modules" prefix as resources, and that namespace unification that is one of the key benefits of this class because it's suddenly compatible with the notion of paths in a filesystem. That's why I refer to the JRT filesystem (which is almost the only thing that actually uses this class).

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PR Review Comment: https://git.openjdk.org/jdk/pull/26054#discussion_r2231606406