Re: [cp-patches] Bug in java_nio_VMDirectByteBuffer.c

[Archie Cobbs]

Archie Cobbs wrote:
> Another common problem is using too many local native references, e.g.,
> when creating and populating an array. You only get 16, and have to use
> DeleteLocalRef() to free up the ones you don't need anymore.

Well, soon as I sent that I ran into exactly this problem. Don't have
time to fix it right now (and I'm sure there are others...)

In gnu_java_awt_peer_gtk_GdkPixbufDecoder.c, in the function
query_formats(), there is a loop where (*env)->NewStringUTF()
is invoked over and over again. There are two bugs actually:

1- The function exhausts the pool of local native references.
   It should use DeleteLocalRef() to free them as it goes along.
2- It doesn't check for exceptions from any of the JNI functions
   it invokes.

In my case, (*env)->NewStringUTF() threw an exception because of #1,
but the exception was not checked for because of #2, causing an
assertion failure. So just fixing #1 would fix the crash in practice.

For #2 it probably suffices for now to use assert() like is done earlier
in the function after the FindClass() call.

-Archie

__________________________________________________________________________
Archie Cobbs      *        CTO, Awarix        *      http://www.awarix.com