[foreign-memaccess+abi] RFR: 8291639: Improve the ability to visualize a MemorySegment in human readable forms [v22]

[ExE Boss]

On Tue, 13 Jun 2023 14:01:28 GMT, Per Minborg <pminborg at openjdk.org> wrote:

>> This PR proposes to add a "Record Mapper" that allows `MemorySegment` instances to be projected onto `Record` types given `GroupLayout` instances.
>> 
>> Here is a simple example of how to use the mapper:
>> 
>> 
>>     private static final GroupLayout POINT_LAYOUT = MemoryLayout.structLayout(
>>             JAVA_INT.withName("x"),
>>             JAVA_INT.withName("y"));
>> 
>>     MemorySegment segment =  MemorySegment.ofArray(new int[]{3, 4});
>> 
>>     Point point = POINT_LAYOUT.recordMapper(Point.class)
>>           .apply(segment); // Point[x=3, y=4]
>> 
>> 
>> I think the implementation can be improved later, for example by de-duplicating handling of arrays and maybe add recursive "un-pealing" of multidimensional arrays.
>
> Per Minborg has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Change to TypeMapper

src/java.base/share/classes/java/lang/foreign/GroupLayout.java line 110:

> 108:          *                                  example, if the provided segment is too small.
> 109:          */
> 110:         default T apply(MemorySegment segment) {

Suggestion:

         */
        @Override
        default T apply(MemorySegment segment) {

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PR Review Comment: https://git.openjdk.org/panama-foreign/pull/833#discussion_r1315668522