> On 6 Feb 2016, at 4:00 AM, Dave <[email protected]> wrote:
>
> self.pNetworkNodeChildArray = [[NSMutableArray alloc] initWithArray:myArray
> copyItems:YES];
This is one reason why sometimes having explicit ivars for key parts of an
object will save you many hours of trouble.
If you had e.g:
@synthesize pNetworkChildArray = mChildArray; // mChildArray is an ivar
NSMutableArray*
your -initWithCoder: method could then do something simple like:
mChildArray = [[aDecoder decodeObjectForKey:@“children”] mutableCopy];
This will avoid all of the issues you’ve had and also give you better
performance, because it’s not invoking a setter method, nor allocating an
unneeded intermediate copy of the array. For large object graphs, (>10,000
nodes say) bypassing a property setter can end up shaving minutes off the time
to decode an archive. - initWithCoder: is an init method, it should be creating
the initial state of the object, incuding allocating its ivars. So you don’t
have to either a) allocate the ivars then copy the decoded array into them, nor
b) worry about a leak caused by simply assigning a mutable copy of a decoded
array to the ivar. Another benefit of this is that you could declare your
pNetworkChildArray property read-only and non-mutable in the public interface,
which would catch external abuses of the network - usually only the internals
of the tree itself have any business mutating this.
n.b. if you’d have shown your code rather than a long verbal description of
what you were doing, the problem would have been instantly obvious. For
comparison, here’s the -initWithCoder: method I have in a general purpose tree
node class. It has never given the slightest trouble:
#pragma mark - NSCoding
- (instancetype) initWithCoder:(NSCoder*) aDecoder
{
self = [super init];
if( self )
{
mChildNodes = [[aDecoder decodeObjectForKey:@"Node_children"]
mutableCopy];
mParentNode = [aDecoder decodeObjectForKey:@"Node_parent"];
mRepresentedObject = [[aDecoder
decodeObjectForKey:@"Node_payload"] retain];
}
return self;
}
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