NULL Issues in ABContact Open Source Project

I found a nice open source project for Mac/iOS Address Book data source. The project contains several key wrapper classes: ABContact, ABGroup, and ABContactsHeler. Mac OS/iOS has extensive APIs for accessing and editing AB records, but they are all C libraries. The project provides nice Objective-C wrapper classes for those libraries.

Today, I found several bugs with multi value properties. Some NULL issues in the wrapper class ABContact.m methods have not been handled. As a result, I got EXC_BAD_ACCESS exception. Basically, if a record has no multi-value property defined, for example address property, the CFTypeRef value will be NULL. The fix is very easy: checking NULL before using CFTypeRef value. Here are my updated codes:

#pragma mark -
#pragma mark Getting MultiValue Elements
- (NSArray *) arrayForProperty: (ABPropertyID) anID
{
  NSArray *items = [NSArray array];
  CFTypeRef theProperty = ABRecordCopyValue(record, anID);
  // the return value is NULL if no multi property is defined for the record.
  // therefore, check its NULL first before getting values
  // Updated by David Chu, same apply to the following methods
  if (theProperty != NULL ) {
    items = (NSArray *)ABMultiValueCopyArrayOfAllValues(theProperty);
    CFRelease(theProperty);
    [items autorelease];
  }
  return items;
}

- (NSArray *) labelsForProperty: (ABPropertyID) anID
{
  NSMutableArray *labels = [NSMutableArray array];
  CFTypeRef theProperty = ABRecordCopyValue(record, anID);
  if ( theProperty != NULL ) {
    for (int i = 0; i < ABMultiValueGetCount(theProperty); i++)
    {
      NSString *label = (NSString *)ABMultiValueCopyLabelAtIndex(theProperty, i);
      [labels addObject:label];
      [label release];
    }
    CFRelease(theProperty);
  }
  return labels;
}

+ (NSArray *) arrayForProperty: (ABPropertyID) anID inRecord: (ABRecordRef) record
{
  NSArray *items = [NSArray array];
  // Recover the property for a given record
  CFTypeRef theProperty = ABRecordCopyValue(record, anID);
  if (theProperty != NULL) {
    items = (NSArray *)ABMultiValueCopyArrayOfAllValues(theProperty);
    CFRelease(theProperty);
    [items autorelease];
  }
  return items;
}

The original codes do not check NULL cases. With those updates, my codes resume normal. In addition to NULL checking, I also make sure there is no memory leak, as the same way as the original codes do. All the copied NSArray result are set with autorelease.