On Wed, 5 Nov 2025 15:07:12 GMT, David Beaumont <[email protected]> wrote:
>> Adds support for writing preview related flags into jimage files.
>>
>> Preview mode is complex. It's not nearly as simple as "does something in
>> /modules/xxx/... have an entry in /modules/xxx/META-INF/preview/...".
>>
>> Specific issues include:
>>
>> Supporting preview-only resources without forcing a double lookup on
>> everything.
>> Changing the set of entries in /packages/xxx directories to account for
>> preview only packages in some modules.
>> Minimising the work done during image reader initialization to only need to
>> process the small number of preview resources (rather than scanning the
>> whole file to look for them).
>> The new flags added by this code address these issues, but calculating them
>> correctly with only minor adjustments to the existing code was not feasible,
>> it just became a lot larger and very complex.
>>
>> To address this, a new type (ModuleReference) is introduced to track and
>> then merge information about packages seen in each module. This allows a
>> much simpler inner loop for processing resource paths when building the node
>> tree, combined with a subsequent merging stage to produce the final package
>> information for each module.
>>
>> Not that since ModuleReference is needed during jimage reading, that class
>> is already present in the previous PR on which this is based, but it starts
>> to be used to calculate the module flags in this PR.
>>
>> This PR can also adds the ImageReader unit tests for preview mode, which
>> rely on being able to generate jimage files with preview mode flags in.
>
> David Beaumont has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Minor feedback changes
Changes requested by rriggs (Committer).
test/jdk/jdk/internal/jimage/ImageLocationTest.java line 92:
> 90: public void getPackageFlags_noPreview() {
> 91: List<ModuleReference> refs = List.of(
> 92: ModuleReference.forPackage("modfoo", false),
Rename the method in ModuleReference back to "forPackage".
-------------
PR Review:
https://git.openjdk.org/valhalla/pull/1718#pullrequestreview-3423305568
PR Review Comment:
https://git.openjdk.org/valhalla/pull/1718#discussion_r2495373320
