simple thread safe token generator

gistfile1.m

// _requests is a dictionary that can be mutated on any thread
// __tokenLBCURLRequestMap is just a dictionary to check if the token already is being "processed"


-(NSString *)readyToken {
    if ([_requests count] == 0)
        return nil;

    NSMutableArray *tokens = [[[_requests allKeys] mutableCopy] autorelease];
    NSString *token = nil;
    
    while (YES) {
        if ([tokens count] == 0)
            return nil;
        
        token = [tokens objectAtIndex:0];
        [tokens removeObjectAtIndex:0];
        
        if ((![__tokenLBCURLRequestMap objectForKey:token]) && ([_requests objectForKey:token]))
            return token;
    }
    
    return nil;
}