On Thu, 9 May 2024 15:00:35 GMT, Maurizio Cimadamore <mcimadam...@openjdk.org>
wrote:
> Consider this layout:
>
>
> MemoryLayout SEQ = MemoryLayout.sequenceLayout(5,
> MemoryLayout.sequenceLayout(10, JAVA_INT));
>
>
> And the corresponding offset handle:
>
>
> MethodHandle offsetHandle = SEQ.offsetHandle(PathElement.sequenceLayout(),
> PathElement.sequenceLayout());
>
>
> The resulting method handle takes two additional `long` indices. The
> implementation checks that the dynamically provided indices conform to the
> bound available at construction: that is, the first index must be < 5, while
> the second must be < 10. If this is not true, an `IndexOutOfBoundException`
> is thrown.
>
> However, the javadoc for `MemoryLayout::byteOffsetHandle` doesn't claim
> anything in this direction. There are only some vague claims in the javadoc
> for `PathElement::sequenceElement()` and `PathElement::sequenceElement(long,
> long, long)` which make some claims on which indices are actually allowed,
> but the text seems more in the tone of a discussion, rather than actual
> normative text.
>
> I've tweaked the javadoc for `MemoryLayout::byteOffsetHandle` to actually
> state that the indices will be checked against the "size" of the
> corresponding open path element (this is a new concept that I also have
> defined in the javadoc).
>
> I also added a test for `byteOffsetHandle` as I don't think we had a test for
> that specifically (although this method is tested indirectly, via
> `MemoryLayout::varHandle`).
src/java.base/share/classes/java/lang/foreign/MemoryLayout.java line 616:
> 614: *
> 615: * {@snippet lang = "java":
> 616: * O = this.byteOffsetHandle(P).invokeExact(B, I1, I2, ... In);
Good catch
test/jdk/java/foreign/TestLayoutPaths.java line 36:
> 34:
> 35: import java.lang.invoke.MethodHandle;
> 36: import java.lang.invoke.VarHandle;
Nit: Copyright year
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/19158#discussion_r1595624831
PR Review Comment: https://git.openjdk.org/jdk/pull/19158#discussion_r1595624353
