On Mon, 29 Sep 2025 01:50:01 GMT, Roger Riggs <[email protected]> wrote:
>> C++ changes for supporting preview mode when preview mode resources (with
>> new location flags) are available.
>>
>> At the moment, this code will operate on non-preview jimage files (1.0) and
>> act as if no preview resources are available by virtue of the default value
>> for missing attributes being zero (which matches location flags for "normal"
>> entries).
>
> src/java.base/share/native/libjimage/imageFile.hpp line 259:
>
>> 257: // it exists in the same module.
>> 258: FLAGS_IS_PREVIEW_ONLY = 0x4
>> 259: };
>
> A refactoring of the flags can avoid conflicting states.
> FLAGS_IS_PREVIEW_VERSION = 2; // set for preview version
> FLAGS_NO_NORMAL_VERSION = 1; // preserving the zero value for normal and
> no preview.
>
> Create static methods in ImageLocation to perform the desired tests on flags.
> The utility methods make the code easier to read.
> Also define macros/function in the native code in ImageFile and jimage.
>
> isPreviewVersion(flags) { return (flags & FLAGS_IS_PREVIEW_VERSION) != 0)}
> isPreviewOnly(flags) { return (flags & FLAGS_IS_REVIEW_VERSION |
> FLAGS_NO_NORMAL_VERSION) == FLAGS_NO_NORMAL_VERSION}
Reprise:
Your name FLAGS_IS_PREVIEW_ONLY probably better than FLAGS_NO_NORMAL_VERSION
and has the same semantics.
FLAGS_HAS_PREVIEW_VERSION means that there is a preview version and it will be
found in the <META-INF/Preview> hierarchy. if the flag is in the preview node
then this is it. If found in the normal hierarchy, the preview class is found
in the <META-INF/Preview> hierarchy.
-------------
PR Review Comment:
https://git.openjdk.org/valhalla/pull/1618#discussion_r2388252261
