Am Montag, 5. April 2004 15:10 schrieb Andrew Haley: > Michael Koch writes: > > > To be honest I think we should not have RawData in Classpath. > > The trouble with RawData (as it is used in gcj) is that it breaks the > Java type system. Its bizarre semantics mean that you have something > that looks like an object reference but you can't use it as one. You > can't convert it to an instance of Object, for example. A garbage > collector can't inspect it. A VM that doesn't expect this behaviour > might crash. If we use RawData like that in Classpath, a VM may need > to be modified. It might not even be possible. For that reason, I > believe that we should not use RawData in Classpath, although some VM > implementors might choose to. > > I think we need a better abstraction. Perhaps a Pointer class that > may be subclassed to swtPeerPointer, nativeIntPointer, and so on. > That will get over the enormous and painful maintenance problem with > SWT, where you have no idea what type a pointer is, because > everything is implicily void*. This is truly Evil. > > If some VM implementers want to use a RawData reference as a raw > pointer, fine. But IMO our reference JNI shouldn't. > > > > It is used in VMClass, but it seems no VM implementor actually > > > likes how that is setup now. And it is used in some of the new > > > nio implementation classes. But I have a hard time seeing how > > > our reference JNI implementation will make use of it. All places > > > where it is used have unimplemented native jni parts. How are > > > you planning to use this? Maybe we could add state (a Object or > > > byte[] field to the class) that holds the real data (== > > > address). > > Better. > > > > And some access method to get add the address it represents > > > (that then might be optimized by a particular VM). But that > > > would mean that it isn't the same type as the one from libgcj > > > (or Ptr from kaffe) since those classes are not actually > > > accessed through normal java code or through JNI, but handled > > > specially through CNI or Kaffe native/vm code. > > > > > > As Andrew says we could maybe just use long if we want to store > > > an address. Andrew also worked hard on getting SWT (Eclipse) 64 > > > bit clean. What I have seen from the (huge) patch this was > > > mainly done by turning addresses as stored by JNI from int to > > > long. BTW, was this work ever accepted into Eclipse? > > > > The RawData pointer will get the real address to a native memory > > region. It can be directly used and has always the pointer size of > > the platform. > > Uh, I don't understand what you mean, sorry. Why is a Java reference > the same size as a native pointer? Perhaps I misunderstood you.
AFAIK a java refernce is a pointer and this pointer can point everywhere. Right ? Tell me when I'm wrong. Michael _______________________________________________ Classpath mailing list [EMAIL PROTECTED] http://mail.gnu.org/mailman/listinfo/classpath
