On Sun, Jul 26, 2009 at 3:58 AM, Aaron Burghardt<abu...@mac.com> wrote:
> Why use Core Foundation? How about (written in Mail):
Thanks for your reply. I ran a test, and it seems CF is slightly faster:
2009-07-26 18:11:52.545 tst[31180:813] CF: Read 4611 tracks in 0.505728 seconds
2009-07-26 18:11:53.585 tst[31180:813] NS: Read 4611 tracks in 0.545601 seconds
2009-07-26 18:11:54.547 tst[31180:813] CF: Read 4611 tracks in 0.507425 seconds
2009-07-26 18:11:55.580 tst[31180:813] NS: Read 4611 tracks in 0.539849 seconds
2009-07-26 18:11:56.543 tst[31180:813] CF: Read 4611 tracks in 0.503465 seconds
2009-07-26 18:11:57.568 tst[31180:813] NS: Read 4611 tracks in 0.528393 seconds
2009-07-26 18:11:58.542 tst[31180:813] CF: Read 4611 tracks in 0.501907 seconds
2009-07-26 18:11:59.585 tst[31180:813] NS: Read 4611 tracks in 0.545226 seconds
2009-07-26 18:12:00.546 tst[31180:813] CF: Read 4611 tracks in 0.506640 seconds
2009-07-26 18:12:01.587 tst[31180:813] NS: Read 4611 tracks in 0.547467 seconds
2009-07-26 18:12:02.547 tst[31180:813] CF: Read 4611 tracks in 0.507250 seconds
2009-07-26 18:12:03.604 tst[31180:813] NS: Read 4611 tracks in 0.564047 seconds
Both methods seem robust, no crashes so far. So, I'm happy for now :)
>
> - (NSDictionary *)dictionaryFromPropertyListFile:(NSString *)path
> error:(NSError **)outError
> {
> NSData *data = [NSData dataWithContentsOfFile:path options:NULL
> error:&outError];
> if (!data) return nil;
>
> NSString *errorString;
> NSDictionary *plist = [NSPropertyListSerialization
> propertyListFromData:data
>
> mutabilityOption:NSPropertyListImmutable
>
> format:NULL
>
> errorDescription:&errorString];
> if (!plist) {
> NSDictionary *info = [NSDictionary
> dictionaryWithObject:errorString forKey:NSLocalizedDescriptionKey];
> *outError = [NSError errorWithDomain:@"MyAppDomain" code:-1
> userInfo:info];
> return nil;
> }
> return plist;
> }
>
> If there is a read error, the NSData method should be robust enough to catch
> it and just return a nil object. If the data is truncated, modified, or
> corrupted during the read, NSPropertyListSerialization should detect it and
> return nil. If you are really concerned, wrap it all up in a @try/@catch.
> Call it, if it fails, wait a couple seconds and try again. If it continues
> to fail for 2 to 4 attempts, give up and report an error to the user.
>
> Also, it should be faster to just read the content of the file into an
> NSData than to open the file, parse the contents into a plist, then close
> the file (assuming that is what your other approaches are doing.)
>
> Also also, I suggest a quick-and-dirty test. Write a simple command line
> tool that calls this method repeatedly as fast as possible and logs all
> errors. Start it up and modify your iTunes library to see if you can induce
> any failure points.
>
> Or use ScriptingBridge.
>
> Regards,
>
> Aaron
>
>
> On Jul 25, 2009, at 4:53 PM, slasktrattena...@gmail.com wrote:
>
>> On Sat, Jul 25, 2009 at 10:21 PM, Kyle Sluder<kyle.slu...@gmail.com>
>> wrote:
>>>
>>> Also not a safe option; other Apple apps can access the XML file,
>>> includeing
>>> CoreServices (for the media picker in the Open panel). Unfortunately we
>>> don't know how they do it and therefore can't be guaranteed that they
>>> won't
>>> also break if you have a lock on the database file.
>>
>> Thanks for the heads up. I'm afraid the end users would be upset if
>> the app required iTunes to be running all of a sudden, though. So I'll
>> try with the Core Foundation methods for now (without locking the
>> file). Hopefully it won't result in a crash if the file is modified
>> while read, just a NULL pointer or invalid data (which is fine
>> considering how often the data is read, I'll just rely on the last
>> valid object).
>>
>> CFPropertyListRef CreateMyPropertyListFromFile( CFURLRef fileURL ) {
>> CFPropertyListRef propertyList;
>> CFStringRef errorString;
>> CFDataRef resourceData;
>> Boolean status;
>> SInt32 errorCode;
>>
>> // Read the XML file.
>> status = CFURLCreateDataAndPropertiesFromResource(
>> kCFAllocatorDefault,
>> fileURL,
>> &resourceData, // place to put file data
>> NULL,
>> NULL,
>> &errorCode);
>>
>> // Reconstitute the dictionary using the XML data.
>> propertyList = CFPropertyListCreateFromXMLData( kCFAllocatorDefault,
>> resourceData,
>> kCFPropertyListImmutable,
>> &errorString);
>>
>> if (resourceData) {
>> CFRelease( resourceData );
>> } else {
>> CFRelease( errorString );
>> }
>>
>> return propertyList;
>> }
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>
>
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