同时访问0x10f10df48，但修改需要独占访问 [英] Simultaneous accesses to 0x10f10df48, but modification requires exclusive access

问题描述

我正在进行SWIFT4迁移，出现此警告(这会使我的应用非常慢)。

同时访问0x10f10df48，但修改需要独占访问。

在线

else if (context == &KVOContext && keyPath == contentSizeKeyPath && object as? UIScrollView == scrollView) {

找不到如何解决此问题。

推荐答案

https://github.com/apple/swift-evolution/blob/master/proposals/0176-enforce-exclusive-access-to-memory.md 在此链接中，您可以看到&；KVOContext

的冲突

这样：

// CONFLICT.  Passing 'x' as an inout argument is a write access for the
// duration of the call.  Passing the same variable twice means performing
// two overlapping write accesses to that variable, which therefore conflict.
swap(&x, &x)

extension Int {
  mutating func assignResultOf(_ function: () -> Int) {
    self = function()  
  }
} 

我用

解了它

struct Pair {
  var x: Int
  var y: Int
}

class Paired {
  var pair = Pair(x: 0, y: 0)
}

let object = Paired()
swap(&object.pair.x, &object.pair.y)

我的代码是

    class Paired {
        var pair = Pair(x : "PullToRefreshKVOContext")
    }

    let objects = Paired()
    override open func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        if (context == &objects.pair.x && keyPath == contentOffsetKeyPath && object as? UIScrollView == scrollView) {
...
}

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