RFR 8023173: FileDescriptor should respect append flag
ivan.gerasimov at oracle.com
Tue Oct 7 08:08:20 UTC 2014
Thanks Martin for the comments!
On 06.10.2014 21:22, Martin Buchholz wrote:
> Thanks for tackling this difficult area!
> Alan is the most qualified to review, but I'll throw in some comments.
> The title of the bug in jira doesn't match the one in the webrev -
> they should be the same.
Do you mean the summary in the regression test?
I'll update the Jira bug's title, the thread subject and the summary to
be the same.
> I'm not sure, but it looks like getAppend is called even on
> non-Windows platforms, but there should be no need?
There is one place where we need it: in FileChannelImpl.position(), if
in append mode, we should return the file size (see JDK-6526860).
As the append flag was moved from FileChannelImpl down to
FileDescriptor, we need a way to retrieve this information back, so
getAppend() had to be introduced.
This is applicable to both Windows and Unix.
This code seems already to be covered by
java/nio/channels/FileChannel/AtomicAppend.java, so I'm not introducing
a new test for it.
> On Mon, Oct 6, 2014 at 3:41 AM, Ivan Gerasimov
> <ivan.gerasimov at oracle.com <mailto:ivan.gerasimov at oracle.com>> wrote:
> Hello everybody!
> The append mode is emulated on Windows, therefore we have to keep
> a flag indicating that.
> With the current implementation, the FileDescriptor does not know
> if the file were opened with O_APPEND, and the flag is maintained
> at the upper level.
> This can cause inconsistency, when the FileDescriptor is reused to
> construct a new FileOutputStream, as there is no information
> available about the append/non-append mode.
> Even though the solution is quite straight-forward: moving the
> flag from FileOutputStream, FileDispatcherImpl and
> FileChannelImpl to the lower level of FileDescriptor, it touches
> 20 files across the source-code base.
> BUGURL: https://bugs.openjdk.java.net/browse/JDK-8023173
> WEBREV: http://cr.openjdk.java.net/~igerasim/8023173/0/webrev/
> With the fix, all the io/nio tests, including the new one, pass on
> all available platforms.
> Would you please help review this fix?
> Sincerely yours,
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