Re: [stellation-res] File.renameTo()

["Mark C. Chu-Carroll" <mcc@xxxxxxxxxxxxxx>]

On Saturday 24 August 2002 03:32 pm, Florin Iucha wrote:
> On Sat, Aug 24, 2002 at 11:15:15AM +0000, Mark C. Chu-Carroll wrote:
> > On Saturday 24 August 2002 12:42 pm, Jonathan Gossage wrote:
> > > This API is not safe to use on any platform. It will never succeed when
> > > a move across file system boundaries is required (e.g. between a local
> > > file system and NFS)and on Windows it will fail when trying to move a
> > > file from one directory to another. The failure is reported, not by an
> > > exception, but simply by returning "false".
> >
> > I knew about the filesystem restriction, but not the windows restriction.
> >
> > We didn't consider the filesystem restriction to be a big deal. Since the
> > workspace is created and maintained by Stellation, it shouldn't ever
> > be crossing filesystems. So moving things around within the workspace
> > should never cause a problem.
> >
> > Windows is a different situation apparently.
> >
> > > One solution would be to use the Unix mv command, natively under Unix
> > > and under Cygwin under Windows. Another, and I feel better solution,
> > > would be to implement an internal method that provides the necessary
> > > subset of functionality of the mv command.
> >
> > One solution would be to replace the File.rename with a copy to
> > the new location, and delete from the old.
>
> And penalize the sane architectures that can do that efficiently?

Well, we can do the copy/delete when rename returns false, thus making it
work everywhere, but not penalizing places where the simple rename
works.

> Uh-oh... java sucks for I/O more and more...
> They rush to add mmap io but cannot provide a sane api to access the
> directory structure.

Java I/O truly sucks. They've never admitted that a very poor
implementation of the lowest-common-denominator of filesystem
functionality isn't really good enough. That's part of why we
sometimes spawn commands to run external file operations -
Java IO just isn't good enough for everything we need.

	-Mark


-- 
Mark Craig Chu-Carroll,  IBM T.J. Watson Research Center  
*** The Stellation project: Advanced SCM for Collaboration
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