ios - 同步线程中的同步问题

Question

很抱歉提前发布了这么多代码。我似乎有同步问题导致我的应用程序崩溃。我将所有代码放在 sync 线程中，所以我不确定这是怎么可能的。根据调用函数的频率，它会在两个不同的地方崩溃，但我怀疑问题的根源是相同的。如果您有任何建议，请告诉我。

代码

var curCollisionChecks = 0

func okToCheckForCollision() -> Bool {
    
    print(curCollisionChecks)
    
    if (curCollisionChecks < 4) {
        let collisionQueue = DispatchQueue(label: "collisionQueue")
        collisionQueue.sync {
            curCollisionChecks += 1
        }
        return true
    }
    
    logText(text: "WARNING: Checking too many collisions")
    logText(text: "WARNING: Some may be ignored")
    
    return false
}


func checkColision(object: UIView) {
    
    if (!viewThatRequireChecking.contains((objectToFO[object]?.name)!)){
        return
    }
    
    let collisionQueue = DispatchQueue(label: "collisionQueue")
    collisionQueue.sync {
        
        if (!okToCheckForCollision()) {
            return
        }
        
        for view in objectToFO.keys {
            
            if (!viewThatRequireChecking.contains((objectToFO[view]?.name)!)){
                continue
            }
            
            let s0 = [object,view]
            let s1 = [view,object]
            
            if (view.frame.intersects(object.frame)) {
                
                if (view == object) {
                    continue
                }
                
                var shouldContinue = false
                
                for combo in collisionsStatus {
                    if (combo == s0) {
                        shouldContinue = true
                        break
                    }
                    if (combo == s1) {
                        shouldContinue = true
                        break
                    }
                }
                
                if (shouldContinue) {
                    continue
                }
                
                collisionsStatus.append(s0) // SOMETIMES BREAKS HERE
                collisionsStatus.append(s1)
                
                let fo1 = objectToFO[view]
                let fo2 = objectToFO[object]
                
                if (viewToCollisionParents.keys.contains(view)) {
                    
                    let script1 = ScriptObjects[(fo1?.name)!]
                    for curParent in viewToCollisionParents[view]! {
                        
                        let deplexed = deplex(snap: curParent, object: view)
                        
                        if ((deplexed[0] as! String) == "Myself") {
                            if (fo2?.name == fo1?.name) {
                                run(sender: view, curScript: script1!, parent: curParent)
                            }
                        }
                        else {
                            if (fo2?.name == (deplexed[0] as! String)) {
                                run(sender: view, curScript: script1!, parent: curParent)
                            }
                        }
                        
                    }
                }
                
                if (viewToCollisionParents.keys.contains(object)) {
                    let script2 = ScriptObjects[(fo2?.name)!]
                    for curParent in viewToCollisionParents[object]! {
                        
                        let deplexed = deplex(snap: curParent, object: object)
                        
                        if ((deplexed[0] as! String) == "Myself") {
                            if (fo2?.name == fo1?.name) {
                                run(sender: object, curScript: script2!, parent: curParent)
                            }
                        }
                        else {
                            if (fo1?.name == (deplexed[0] as! String)) {
                                run(sender: object, curScript: script2!, parent: curParent)
                            }
                        }
                        
                    }
                }
                
            }
            else {
                var newCollisionsStatus = [[UIView]]()
                // SOMETIMES BREAKS HERE
                for combo in collisionsStatus {
                    if (combo != s0 && combo != s1) {
                        newCollisionsStatus.append(combo)
                    }
                }
                collisionsStatus = newCollisionsStatus
            }
        }
        
        if (curCollisionChecks > 0) {
            curCollisionChecks -= 1
        }
    }
    
}

错误信息的类型

fatal error: Index out of range

fatal error: UnsafeMutablePointer.deinitialize with negative count

Answer 1

一个明显的问题是您滥用了 DispatchQueue 和 sync。您每次都创建一个新队列，因此它不会保护对属性的访问。创建单个队列作为实例属性并每次都使用它。这将确保一次只有一个线程可以访问 sync block 中的代码。