Question

I have a method that returns a CGPath and is generating analyzer warnings. The method is declared in a protocol. Here is an example implementation that is generating the warning:

“Potential leak of an object allocated on line 47 and stored into ‘path'”:

- (CGPathRef)createPathForBounds:(CGRect)bounds key:(NSString *)key;
{
    if ([key isEqualToString:OvalColumn])
    {
        CGPathRef path = CGPathCreateWithEllipseInRect(bounds, NULL);
        return path;
    }

    return NULL;
}

Here is example usage that is generating the warning, “Incorrect decrement of the reference count of an object that is not owned at this point by the caller”

CGPathRef path = [self.delegate createPathForBounds:bounds key:someKey];

// Use the path to do some drawing

CGRelease(path);

My memory management is correct; I’m passing back a retained CGPath from my protocol method and I’m releasing it in the calling block, so I know the warnings can be ignored, but I’d like to remove them altogether.

Am I missing a naming convention that will make the analyzer happy?
Can functions be defined in protocols?
How will subclassing work?

Answer 1

- (CGPathRef)newPathForBounds:(CGRect)bounds key:(NSString *)key

a detailed note on the topic can be found here

alternatively, you could have chosen to use the attribute cf_returns_retained, but it’s best (imo) to favor naming conventions.