On 1 Mar 2014, at 19:11, Trygve Inda <cocoa...@xericdesign.com> wrote:
>> On Mar 1, 2014, at 07:23 , Trygve Inda <cocoa...@xericdesign.com> wrote: >> >>> The problem is that when there is a very small change (just adding or >>> removing one of the files in the package), the system does not save in >>> place. >>> >>> Rather it reads the previous package file completely, writes out a copy of >>> the package (400 MB) and then renames it. >>> >>> How can I get it to save in place? >> >> AFAIK, NSDocument never saves in place, and isn’t intended to (for safety >> reasons — what happens if your app crashes after some of the files have been >> updated but not others?). >> >> Instead, it achieves its package performance optimization by hard-linking >> unchanged files in the new (saved) package to files in the old (original) >> package. If your save is taking 40 seconds, that could mean: >> >> — The document is on a file system that doesn’t support hard linking. >> >> — The document is on a file system where hard linking 7500 files takes 40 >> seconds. >> >> — You didn’t preserve the original file sub-wrappers from the directory >> wrapper created when the document was opened, so NSDocument thinks all the >> files have changed. Note that it’s undocumented (again, AFAIK) what criteria >> NSDocument uses** to decide when a particular file wrapper represents “no >> change”, so it’s safest to keep the original NSFileWrapper objects from open >> time until save time. >> >> >> >> ** The most likely possibilities are ‘==’ on file wrappers, ‘isEqual:’ on >> file >> wrappers, or comparison of mod date and/or size of the actual files, but it >> could be something more obscure. >> > > > When a file is opened, my NSDocument subclass uses > > -(BOOL)readFromFileWrapper:(NSFileWrapper *)fileWrapper ofType:(NSString > *)typeName error:(NSError **)outError > > After loading it, I call > > [self setDocumentFileWrapper:fileWrapper]; > > Which stores the fileWrapper in my Document object for later use. > > > Later, when saving I use > > -(NSFileWrapper *)fileWrapperOfType:(NSString *)typeName error:(NSError > **)outError > > Even if I only call > > return documentFileWrapper; > > So the document is saved with zero changes, it takes 40 seconds on my > package with 7500 sub-items. It should happen almost instantly, but it > doesn't. > > I am using a normal Mac HFS system. > > I really need this to be faster. It is -[NSFileWrapper writeToURL:options:originalContentsURL:error:] which has the feature of writing out hard links for efficiency. But it only does it if requested, by passing a suitable URL as the original contents URL. It is my suspicion that NSDocument does not do this for you. You could set a breakpoint to test this. If so, it becomes your responsibility to override -writeToURL:… in your document subclass and write the file wrapper yourself. _______________________________________________ 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
