RFR: 8313452: Improve Classfile API attributes handling safety [v3]

[Adam Sotona]

On Wed, 6 Sep 2023 13:54:28 GMT, ExE Boss <duke at openjdk.org> wrote:

>> Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   magic moved to Util::isAttributeAllowed and fixed possible NPE
>
> src/java.base/share/classes/jdk/internal/classfile/impl/AbstractDirectBuilder.java line 59:
> 
>> 57:         if (a instanceof UnboundAttribute ||
>> 58:             5 - a.attributeMapper().attributeStability().ordinal()
>> 59:                     > context.attributesProcessingOption().ordinal()) {
> 
> Maybe extract the `5 - a.attributeMapper().attributeStability().ordinal() > context.attributesProcessingOption().ordinal()` check into a helper method, as the current expression is too noisy:
> 
> import jdk.internal.classfile.AttributeMapper.AttributeStability;
> import jdk.internal.classfile.Classfile.AttributesProcessingOption;
> 
> private static final int ATTRIBUTE_STABILITY_COUNT = AttributeStability.values().length;
> public static boolean isAttributeAllowed(
> 	final AttributeStability stability,
> 	final AttributesProcessingOption processingOption
> ) {
> 	return ATTRIBUTE_STABILITY_COUNT - stability.ordinal() > processingOption.ordinal();
> }
> 
> 
> Also, the magic number should probably be replaced with a constant storing the value of `AttributeStability.values().length`.

Fixed, thanks!

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PR Review Comment: https://git.openjdk.org/jdk/pull/15101#discussion_r1317422600