Re: Storing NSDocument data in packages/bundles
Re: Storing NSDocument data in packages/bundles
- Subject: Re: Storing NSDocument data in packages/bundles
- From: Markus Spoettl <email@hidden>
- Date: Wed, 31 Dec 2008 10:08:37 -0800
On Dec 31, 2008, at 1:32 AM, Kyle Sluder wrote:
On Wed, Dec 31, 2008 at 4:16 AM, Markus Spoettl
<email@hidden> wrote:
No I have not, but I have a feeling that it wouldn't be suitable.
The data I
store contains (when the document is big) millions of double values
(amongst
other things) spread across hundreds of thousands of objects. If the
performance of NSKeyedArchiver is any indication the system
wouldn't scale
very well. It is an assumption and it might be totally wrong but I
guess the
overhead of keyed archiving is significantly less than that of Core
Data.
Quite the contrary, I'm afraid. Although without actually testing it,
you can't know for sure.
OK, I wouldn't have expected that. The question is rather academic for
me anyway as the application is existing and using non-Core Data
objects already. Changing all the innards of the application is not an
option at this point. Unless of course this is a lot less painfull
than it sounds.
That's no problem, that information is available. The documentation
for
-writeToURL:ofType:forSaveOperation:originalContentsURL:error:
states:
----------
The value of absoluteURL is often not the same as [self fileURL].
Other
times it is not the same as the URL for the final save destination.
Likewise, absoluteOriginalContentsURL is often not the same value
as [self
fileURL].
----------
which is a little problem because to update my packages I need to
original
location. Do you have any insights as to what "often not the same"
in this
context might mean? To write the diff into the package I'd have to
have
access to the package. It doesn't sounds as it that's guaranteed.
For safe save operations, AppKit writes the data to a temporary file
on the same volume, and then swaps the old file with the new, which is
an atomic operation. If it can't do that, it will rename the original
file and write the new one with the old name. This is why absoluteURL
or absoluteOriginalContentsURL won't necessarily jive with -fileURL
(see the comment header for -[NSDocument
writeSafelyToURL:ofType:forSaveOperation:error:] for more details).
The upshot is that absoluteOriginalContentsURL will be a URL which you
can use to access your existing on-disk data, whether or not AppKit
has temporarily renamed it.
That would not help a lot because I'd have to copy the unchanged parts
or the old package into the new package. The whole idea was not to re-
write data that hasn't changed.
Thanks for the ideas though, I'll definitely investigate this further.
Regards
Markus
--
__________________________________________
Markus Spoettl
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