Request for breaking hard feature freeze for an important Nepomuk service

[Sebastian Trüg]

Thanks for the hint. Now all I need is someone to implement it. I never hacked 
on Win or MAC and cannot test it properly anyway....

On Tuesday 01 July 2008 02:19:51 Martin Konold wrote:
> Am Montag 30 Juni 2008 schrieb Sebastian Trüg:
>
> Hi Sebastian,
>
> > * I have no replacement for inotify on Windows or MAC yet (KDirWatch
> > cannot be used for the same reason as FAM)
>
> are you aware of
> http://msdn.microsoft.com/en-us/library/aa364417(VS.85).aspx
> FindFirstChangeNotification(__in  LPCTSTR lpPathName, __in  BOOL
> bWatchSubtree, __in  DWORD dwNotifyFilter); ?
>
> To my knowledge this feature depends on support from the underlying
> filesystem though NTFS is well supported. I verified it once that it works
> with local NTFS. Networked drives need to be investigated (maybe check with
> Samba).
>
> http://www.snia.org/tech_activities/CIFS/CIFS-TR-1p00_FINAL.pdf
> gives a hint that notification is actually part of the CIFS API.
>
> The well known FileMon for Windows Utility (from former Sysinternals)
> http://technet.microsoft.com/de-de/sysinternals/bb896642(en-us).aspx
> is able to watch local and networked resources including UNC resources.
>
> IIRC FileMon needs Administrator privileges though.
>
> It must be noted that certain versions of Microsoft Windows already provide
> analogous features, with some differing aspects. The NTFS Change Journal
> provides a persistent file system change log. When file system objects are
> added, deleted, or modified, the change is recorded in a per-volume
> journal. In particular, Microsoft uses this mechanism for implementing the
> Indexing Service feature of Windows XP Professional.
>
> http://msdn.microsoft.com/en-us/library/aa363798(VS.85).aspx
>
> http://www.microsoft.com/msj/0999/journal/journal.aspx
> "The Windows 2000 Change Journal is a database that contains a list of
> every change made to the files or directories on an NTFS 5.0 volume. Each
> volume has its own Change Journal database that contains records reflecting
> the changes occurring to that volume's files and directories."
>
> For Macs there is a similiar mechanism which needs also root permissions
> and which is used by Spotlight. To my knowledge the Mac API to this kernel
> functionality is not published. AFAIK it is subject to change in the future
> (a more mature API is planned)
>
> see also:
> http://fxr.watson.org/fxr/source/bsd/vfs/vfs_fsevents.c?v=DARWIN8
> http://kernelthread.com/forums/viewtopic.php?t=155
>
> An older Mac method is to use kqueue, kevent -- kernel event notification
> mechanism.
>
> http://developer.apple.com/documentation/Darwin/Reference/ManPages/man2/kqu
>eue.2.html
>
> IMHO the kqueue approach is really inefficient for your purposes as it
> requires to keep to many filedescriptors open and does not really provide
> the required information in order to figure out the real cause for the
> event without scanning.
>
> Yours,
> -- martin