I see. So we will need clarify the spec and make corresponding changes.
I think as long as we don't trigger exceptions and just return 0 will be
backward-compatible, right?
-Dan
On 03/30/2013 10:23 AM, Alan Bateman wrote:
On 26/03/2013 19:29, Dan Xu wrote:
Hi All,
In the old JVM function, os::available, it could return negative
values because lseek() allows the file offset to be set beyond the
end of a file. In the previous change of removing jvm functions, I
wasn't aware of that and regardnegative values as invalid and return
0, which causes this test failed if it handles negative values. This
fixaddressedthis problem and added a new testcase to ensure the
correctbehaviour when available() encounters negative values.
Webrev: http://cr.openjdk.java.net/~dxu/8010837/webrev/
Thanks,
-Dan
I see this has already been pushed but I think it requires further
discussion. I think it would be surprising if available() returned
anything other than 0 for this case. You can't read a negative number
of bytes, and with a normal InputStream then a negative skip is a
no-op. So minimally we will need a spec clarification to make it clear
how available() should behave when the file position is beyond the
current file size. I just checked Channels.newInputStream and it does
return 0 for this case. I also checked the FileInputStream.skip method
and it seems to differ from its spec in that it allows a negative skip
if the resulting file position is >= 0. I'll create bugs for these
issues (assuming there aren't existing bugs on these topics area).
-Alan.
