nsdictionary中的块？

Question

所以我将块动作存储到一个nsmutabledictionary中,然后当一个响应返回到websocket时调用它们.这会将异步请求转换为块语法.这是精简代码:

- (void)sendMessage:(NSString*)message responseAction:(void (^)(id))responseAction
{ 
    NSString *correlationID =  (NSString*)[[message JSONValue] objectForKey:@"correlationId"];

    [self.messageBlocks setObject:responseAction forKey:correlationID];

    NSLog(@"Sending message: %@", correlationID);
   [webSocket send:message];
}

- (void)webSocket:(SRWebSocket *)wsocket didReceiveMessage:(id)message;
{
    NSString *correlationID = (NSString*)[[message JSONValue] objectForKey:@"correlationId"];
    NSLog(@"Incoming message. CorrelationID: %@", correlationID);
    void (^action)(id) = nil;
    if (correlationID) {
        action = [messageBlocks objectForKey:correlationID];
        if (action) action([message JSONValue]);
        [messageBlocks removeObjectForKey:correlationID];
    }
}

注意:服务器使用随请求发送的correlationID进行响应.因此,每个响应都通过该ID链接到每个请求.

这完美,比我预期的更好.我的问题是以这种方式运行块是否安全？正在调用[messageBlocks removeObjectForKey:correlationID]; 足以将其从内存中删除.我记得pre-ARC,block_release是一个选项.

Answer 1

您需要复制基于堆栈的块才能将它们安全地存储在容器中.

[self.messageBlocks setObject:[responseAction copy] forKey:correlationID];

对于非ARC代码,您也需要-autorelease它.

[self.messageBlocks setObject:[[responseAction copy] autorelease] forKey:correlationID];

希望有所帮助.