保留完成块中的周期 [英] Retain cycle in completion block

问题描述

在我的类中，我创建了此方法。

In my class i have created this method.

-(void) refreshDatasourceWithSuccess:(CreateDataSourceSuccessBlock) successBlock 
                         failure:(CreateDataSourceFailureBlock) failureBlock;

然后我这样调用：

[self refreshDatasourceWithSuccess:^(NSArray* array){
    //Success block 
    [self setDataSource:array];
    [self.tableView reloadData];

} failure:^(NSError* error){
    // failure block 
    [self showConnnectionError];
}];

这是一个保留周期，因为我引用 self 在完成块中？
（我没有收到任何警告）

Is this a retain cycle because I reference self inside the completion block? (I do not get any warning)

更新：

UPDATE:

IN另一个类在这种情况下，我得到一个警告为保留周期

IN Another class in this case I get a warning for retain cycles

typedef void (^SetFavoriteCompletionBlock)(NSError*);

-(void)setFavoriteFriend:(BOOL)pSetFavorite
          completion:(SetFavoriteCompletionBlock)completionBlock
{
   //....
   completionBlock(error);
}

然后在此调用中我收到警告

And then in this call I get the warning

[self setFavoriteFriend:setFavorite 
             completion:^(NSError *error){
                 [self.tableView reloadData];
             }];

推荐答案

假设你的类中没有变量存储该块，则这两个示例都不是保留周期。该块具有对self的引用，但self不保留对块的引用。

Assuming you do not have a variable in your class that stores the block, then neither examples are retain cycles. The block has a reference to self, but self does not keep a reference to the block.

在第二种情况下，由于方法的命名，您会收到警告。它以set开头，因此代码分析器假定它正在设置类的变量。给它一个不同的名称，警告应该消失。

You get the warning in the second case because of the naming of the method. It starts with "set", and therefore the code analyzer assumes it is setting a variable of your class. Give it a different name, and the warning should go away.

但是，这是一个奇怪的编码完成块的方式，如果你只从方法同步调用。因此，我怀疑你实际上将块存储在某个地方，然后异步调用它们。在这种情况下，它可能是一个保留周期，具体取决于您如何和在哪里存储它们。

However, it is a strange way of coding with the completion blocks if you only call them synchronously from the method. Therefore, I suspect you actually do store the blocks somewhere, and then call them asynchronously. In that case it might be a retain cycle, depending on how and where you store them.

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