Re: NSDocument save incremental file package in-place
Re: NSDocument save incremental file package in-place
- Subject: Re: NSDocument save incremental file package in-place
- From: Markus Spoettl <email@hidden>
- Date: Sun, 02 Mar 2014 10:13:47 +0100
On 3/2/14 12:06 AM, Quincey Morris wrote:
> I’ve never used this, but I *have* seen documents use hard linking anyway
> (though, on reflection, that might have been UIDocument, not NSDocument — I’m
> not sure now).
No, it is NSDocument/NSFileWrapper, UIDocument/NSFileWrapper doesn't know this
kind of trick.
Not sure why it's not working for the OP it certainly works fine for my app.
Works fine meaning it saves package files containing hundreds of megabytes of
data with thousands of files and folders in a fraction of a second (depending on
how much content changed, of course):
You basically need to overwrite:
- (BOOL)readFromFileWrapper:(NSFileWrapper *)fileWrapper ofType:(NSString
*)typeName error:(NSError **)outError
for loading (and stashing the original wrapper reference) and
- (NSFileWrapper *)fileWrapperOfType:(NSString *)typeName error:(NSError **)outError
to return the original wrapper with all necessary changes to its subwrappers
applied.
You also need to overwrite
- (void)setFileURL:(NSURL *)absoluteURL
in which you call super and then update your stored wrapper (if you have one
already) using -[NSFileWrapper readFromURL:options:error:].
You need to do this because the filewrapper you return in -fileWrapperOfType::
gets written to a temp location and moved in place. That causes all references
to all the files and folders the wrapper and its subwrappers point to to move
and to become invalid as a result, once the save is complete. Updating ensures
the references are valid for the next go.
Regards
Markus
--
__________________________________________
Markus Spoettl
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