> If originalContentsURL is supplied, a directory wrapper checks its child > wrappers against that directory. If a file exists there by the same name and > with the same modification date, it gets hardlinked, rather than written out > from scratch. > Certainly as of 10.8, NSDocument cunningly makes use of the previous version > of the document, rather than writing it out anew. But I believe Versions then > copies that whole doc regardless. > Versions has no knowledge of your file wrapper I suspect. You may well be > into DTS incident territory looking for a way to speed this up. After thinking about it, I also suspect Versions to be the culprit. I will ask DTS about that issue.
Thanks, Thomas > > On 5 Feb 2013, at 10:38, Thomas Zoechling <thomas.zoechl...@gmx.at> wrote: > >> >> Thanks for your response, >>> Given the right conditions, NSFileWrapper can make writing vastly more >>> efficient by writing hard links for unchanged files, rather than recreating >>> them afresh. Have you determined whether this is happening at all? >> Currently I am trying to figure out what those conditions are :) > > If originalContentsURL is supplied, a directory wrapper checks its child > wrappers against that directory. If a file exists there by the same name and > with the same modification date, it gets hardlinked, rather than written out > from scratch. >> >>> In my experience Versions tends to be pretty inefficient about its work. >> I wonder what NSDocument's private _preserveContentsIfNecessaryAfterWriting >> (see above call stack) uses to determine whether a file has to be copied or >> not. > > Certainly as of 10.8, NSDocument cunningly makes use of the previous version > of the document, rather than writing it out anew. But I believe Versions then > copies that whole doc regardless. >> >>> Are you seeing it block the main thread though? That can generally be >>> avoided. >> No. Saving and Version preservation are off the main thread. >> That's why I almost didn't notice the vast amount of copying that's going on >> after each save. >> >> My usage of NSDocument & file packages seems to be straightforward. >> I didn't overwrite any of the write* methods, I keep a root file wrapper for >> the lifetime of each NSDocument instance, ... >> >> What am I doing wrong? There must be a way to avoid this unnecessary >> copying... > > Versions has no knowledge of your file wrapper I suspect. You may well be > into DTS incident territory looking for a way to speed this up. > _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
