Thank you Jens. I have found the proper way to manage that. When the user imports a new image, I quickly copy the image to a temporary folder, then I add this latest file reference to the document¹s NSFileWrapper. I just create the file¹s fileWrapper using its URL, so I do not read its content and create the fileWrapper by the NSData. When the users saves the document, automatically the filesWrappers get written to the disk, within the document filePackage. And when I close the document, I remove the temp folder. That¹s fine.
I had to scratch my head at managing the undo, but I found a solution here too. When the user undo the import of an image, if the images has been never saved, so it is still within the temporary folder, I just remove the image file reference from the fileWrapper. Instead, if the image has already been saved, so it is within the file package, I copy its file to the temporary folder and remove its reference from the fileWrapper. So when the user saves the doc, the image file get removed from the doc filePackage. And if the user invokes the undo, I add the temp image file to the fileWrapper. It sounds complicated but it works well. Why do I use a temporary folder? Because if the user imports an image file then he tries to delete the original image file, the OS tells him that he can¹t delete that file in use. That could be annoying. Why don¹t I add the file¹s NSData to the fileWrapper but I add just its URL reference? Because I don¹t really know whether the fileWrapper uses the disk or keeps the NSData in memory. So in case of a 1GB file I do not engulf the app. I hope I have designed a good architecture. Regards -- Leonardo Da: Jens Alfke <j...@mooseyard.com> Data: Tue, 4 Feb 2014 11:47:35 -0800 A: Leonardo <mac.iphone....@gmail.com> Cc: <cocoa-dev@lists.apple.com> Oggetto: Re: Managing image loading On Feb 4, 2014, at 9:03 AM, Leonardo <mac.iphone....@gmail.com> wrote: > - When the user imports a new image, I add its NSData to the NSFileWrapper > [docFileWrapper addRegularFileWithContents:imgData > preferredFilename:@"image.png"]; > and retain the NSImage. So I can draw the NSImage at any time. You don't need an NSFileWrapper for that. I would just use NSFileManager to copy the file, and NSData methods to read/write the file. I have no idea whether NSFileWrapper caches the file contents in memory or not. Jens _______________________________________________ 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
