RFR JDK-8234049: Implementation of Memory Access API (Incubator)

[Maurizio Cimadamore]

On 10/12/2019 18:45, Paul Sandoz wrote:
> MemoryScope changes look good.
>
> In j.u.concurrent we use ExceptionInInitializerError in the static blocks when there is an error looking up the VH,
>
> FWIW close can also fail because it has already been closed but the exception message does not distinguish between the two states (active or already closed).
>   
> Paul.
>
Hi Paul,

would something like this be satisfactory?


diff -r 50ef46599c56 
src/jdk.incubator.foreign/share/classes/jdk/internal/foreign/MemoryScope.java
--- 
a/src/jdk.incubator.foreign/share/classes/jdk/internal/foreign/MemoryScope.java 
Tue Dec 10 16:28:03 2019 +0000
+++ 
b/src/jdk.incubator.foreign/share/classes/jdk/internal/foreign/MemoryScope.java 
Wed Dec 11 00:12:20 2019 +0000
@@ -48,7 +48,7 @@
          try {
              COUNT_HANDLE = 
MethodHandles.lookup().findVarHandle(MemoryScope.class, "activeCount", 
int.class);
          } catch (Throwable ex) {
-            throw new IllegalStateException(ex);
+            throw new ExceptionInInitializerError(ex);
          }
      }

@@ -107,6 +107,9 @@

      void close() {
          if (!COUNT_HANDLE.compareAndSet(this, UNACQUIRED, CLOSED)) {
+            //first check if already closed...
+            checkAliveConfined();
+            //...if not, then we have acquired views that are still active
              throw new IllegalStateException("Cannot close a segment 
that has active acquired views");
          }
          if (cleanupAction != null) {



If you need a full webrev please let me know.

Thanks
Maurizio