[foreign-memaccess+abi] RFR: 8294621: Copying from a StringCharBuffer-backed MemorySegment results in crash [v3]

[Jorn Vernee]

On Fri, 14 Oct 2022 18:36:12 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

>> src/java.base/share/classes/jdk/internal/foreign/AbstractMemorySegmentImpl.java line 473:
>> 
>>> 471:         Objects.requireNonNull(bb);
>>> 472:         // StringCharBuffer is packet-private
>>> 473:         if ("java.nio.StringCharBuffer".equals(bb.getClass().getName())) {
>> 
>> IMHO would be better to call Buffer::isDirect, and then check if Buffer::array is == null.
>
> Nevermind, the array is not given away for read-only buffers... grrr

We get the array in the code below. I guess we can check if it's `null` there?

i.e.

if (!buffer.isDirect()) {
    // heap
    if (base == null) throw ...;
    // wrap
}

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PR: https://git.openjdk.org/panama-foreign/pull/741