[classlib][luni] Problem with java.io.OutputStream

[Geir Magnusson Jr <ge...@pobox.com>]

When looking at HARMONY-1156, it became clear that our
java.io.OutputStream isn't right.

I'd like to make the following changes :

Follow the spec so that an IndexOOBE is thrown when :

a) offset is negative or
b) len is negative or
c) off + len > buff.length

So in the case of

   write( byte[count], count, 0);

for any value of count >= 0, then none of the conditions are true, and
it should simply [quickly] return.

Now, the spec says that if the array is null, then a NPE should be
thrown, but this doesn't happen in the RI when len = 0.

This seems to be a reasonable thing to do, and therefore I think that we
should match the RI here, and not the spec.

Comments?

geir


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Re: [classlib][luni] Problem with java.io.OutputStream

["Jimmy, Jing Lv" <fi...@gmail.com>]

Geir Magnusson Jr wrote:
> When looking at HARMONY-1156, it became clear that our
> java.io.OutputStream isn't right.
> 
> I'd like to make the following changes :
> 
> Follow the spec so that an IndexOOBE is thrown when :
> 
> a) offset is negative or
> b) len is negative or
> c) off + len > buff.length
> 
> So in the case of
> 
>    write( byte[count], count, 0);
> 
> for any value of count >= 0, then none of the conditions are true, and
> it should simply [quickly] return.
> 
> Now, the spec says that if the array is null, then a NPE should be
> thrown, but this doesn't happen in the RI when len = 0.
> 
> This seems to be a reasonable thing to do, and therefore I think that we
> should match the RI here, and not the spec.
> 
> Comments?
> 

Hi Geir,

    Sorry I don't catch well here. I write a test[1], extends 
OutputStream and try passing a null byte and len = 0, RI and Harmony 
both throw NPE(windows XP sp2, RI 1.5.06, the lastest Harmony,J9/DRLVM).

    And HARMONY-1156 only asks if given "write( byte[count], count, 0);" 
the write operation quickly returns. And we see it is better to fix in 
JNI, am I right?
    In fact, IMHO we are NOT breaking spec in return quickly as spec 
does not tell clear what "indexes in the region is not valid"? :)

[1]
     public void  test_OutputStream () throws IOException {
         try {
             new MockOutputStream().write(null, 0, 0);
             fail("should throw NPE");
         } catch (NullPointerException e) {
             // expected
         }
     }

     class MockOutputStream extends OutputStream {

         public void write(int oneByte) throws IOException {
             throw new NotYetImplementedException();
         }
     }
> geir
> 
> 
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> 


-- 

Best Regards!

Jimmy, Jing Lv
China Software Development Lab, IBM

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Re: [classlib][luni] Problem with java.io.OutputStream

[Andrew Zhang <zh...@gmail.com>]

On 8/15/06, Geir Magnusson Jr <ge...@pobox.com> wrote:
>
> When looking at HARMONY-1156, it became clear that our
> java.io.OutputStream isn't right.
>
> I'd like to make the following changes :
>
> Follow the spec so that an IndexOOBE is thrown when :
>
> a) offset is negative or
> b) len is negative or
> c) off + len > buff.length
>
> So in the case of
>
>   write( byte[count], count, 0);
>
> for any value of count >= 0, then none of the conditions are true, and
> it should simply [quickly] return.
>
> Now, the spec says that if the array is null, then a NPE should be
> thrown, but this doesn't happen in the RI when len = 0.


Yes. It's a common exception throw sequence of RI.
Vladimir Ivanov has provided a util patch for such exception check, iirc.
For detail, please refer to Harmony-942 (
http://issues.apache.org/jira/browse/HARMONY-942).
Following code snippet is copied from Harmony-942 patch. Does it work for
this problem?
public static void assertArrayIndex(byte[] array, int offset, int length) {
  if (offset < 0 || length < 0) {
   throw new IndexOutOfBoundsException(Msg.getString("K0006"));
  }
  if ((long)offset+(long)length >  array.length) {
   throw new IndexOutOfBoundsException(Msg.getString("K00ae"));
  }
 }

Of course, If long cast looks not elegant, we can change the code as
following:
 "if (offset >  array.length-length) ".


This seems to be a reasonable thing to do, and therefore I think that we
> should match the RI here, and not the spec.
>
> Comments?
>
> geir
>
>
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>
>


-- 
Andrew Zhang
China Software Development Lab, IBM