Question

I am new to iPhone objectiveC development. I am getting memory leaks when I run the following method.

- (NSString *) getDBPath {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
    NSString *documentsDir = [paths objectAtIndex:0];
    return [documentsDir stringByAppendingPathComponent:@"dbname.sqlite"];
}

and I have found that if I trim it down to just the following… it still leaks

 - (NSString *) getDBPath {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
    return nil;
}

so i tried releasing the paths variable with the following, which still leaks memory.

 - (NSString *) getDBPath {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
    [paths release];
    return nil;
}

To detect the leak, I am running it in the profiler with the following loop:

for (int iLoop = 0; iLoop < 30; iLoop++) {
    NSString *dbPath = [self getDBPath];
    [dbPath release];
    sleep(1);
}

The amount of memory associated with NSPathStore2 and NSArrayM continues to grow.

Any suggestions on what I a might be doing wrong?
thanks!

Answer 1

Your code for getDBPath is fine, but it is probably called from a context without any autorelease pool.

Fix it by allocating your own pool in the loop code:

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
for (int iLoop = 0; iLoop < 30; iLoop++) {
    NSString *dbPath = [self getDBPath];
    // [dbPath release]; // do not release! dbPath will be autoreleased
    sleep(1);
}
[pool drain];