[Mono-list] Mono.Unix.Native.Syscall.(l)stat weirdness

[László Monda]

On Thu, 2006-02-23 at 07:50 -0500, Jonathan Pryor wrote:
> On Wed, 2006-02-22 at 19:52 +0100, László Monda wrote:
> > On Fri, 2006-02-17 at 06:28 -0500, Jonathan Pryor wrote:
> > > On Fri, 2006-02-17 at 00:36 +0100, László Monda wrote:
> > > > UnixFileSystemInfo seems to be a well-designed abstraction on top of the
> > > > Unix VFS API, but I'll stick with syscalls, because I don't like
> > > > UnixFileSystemInfo's exception policy.
> > > 
> > > What don't you like about its exception policy?
> > 
> > It was something to do with dangling links.  If I remember correctly,
> > UnixFileSystemInfo throwed an exception on dangling links.  I wanted to
> > subclass this class, but this policy made it unconvenient for me.  Of
> > course, my scenario is rather unusual, because I'm writing a file
> > manager application and the File class is a critical part of it.
> 
> UnixFileSystemInfo's exception policy is to throw an exception if the
> file doesn't exist.  You were probably using the UnixFileInfo subclass,
> which uses Syscall.stat, which would generate an exception when trying
> to access the UnixFileSystemInfo members.

Yeah, I've probably used UnixFileInfo.  Its name sounded more
appropriate to me (without looking up its API), I guess.

> One issue that I've just found is that for dangling symlinks HasContents
> will return true while Contents will generate a FileNotFoundException
> exception.  This is obviously bad (as there's no way to avoid the
> exception), and I will fix this.

Then this discussion wasn't futile, for sure.  ;-)

> I need to make a public UnixFileSystemInfo.CreateInfo() method which
> looks at an existing file and creates a UnixFileInfo, UnixDirectoryInfo,
> or UnixSymbolicLinkInfo instance as appropriate for the specified file.

That's actually a great idea, I think.

> > I probably had some other minor issues with UnixFileSystemInfo, but the
> > above behaviour was the showstopper.
> > 
> > In the end, I implemented my own File class.  You may want to take a
> > look at it:
> > 
> > http://cvs.sourceforge.net/viewcvs.py/ulc/uc/File.cs?view=markup
> 
> FYI, your SymbolicPermissions property could be replaced with
> Mono.Unix.Native.NativeConvert.ToUnixPermissionString().

Thanks Jon, I'll give it a try soon.

-- 
Laci

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