共享引用和循环引用

Swift 引用跟踪由 Config.trackRef 控制。

启用引用跟踪

let fory = Fory(ref: true)

启用后，可跟踪引用的类型会保留对象标识和循环关系。

共享引用示例

import Fory

@ForyStruct
final class Animal {
    var name: String = ""

    required init() {}

    init(name: String) {
        self.name = name
    }
}

@ForyStruct
final class AnimalPair {
    var first: Animal? = nil
    var second: Animal? = nil

    required init() {}

    init(first: Animal? = nil, second: Animal? = nil) {
        self.first = first
        self.second = second
    }
}

let fory = Fory(ref: true)
try fory.register(Animal.self, id: 200)
try fory.register(AnimalPair.self, id: 201)

let shared = Animal(name: "cat")
let input = AnimalPair(first: shared, second: shared)

let data = try fory.serialize(input)
let decoded: AnimalPair = try fory.deserialize(data)

assert(decoded.first === decoded.second)

循环引用示例（使用 weak）

trackRef 会保留引用图，但不会改变 ARC 所有权。为避免内存泄漏，请在循环中至少一条边上 使用 weak。

import Fory

@ForyStruct
final class Node {
    var value: Int32 = 0
    weak var next: Node? = nil

    required init() {}

    init(value: Int32, next: Node? = nil) {
        self.value = value
        self.next = next
    }
}

let fory = Fory(ref: true)
try fory.register(Node.self, id: 300)

let node = Node(value: 7)
node.next = node

let data = try fory.serialize(node)
let decoded: Node = try fory.deserialize(data)

assert(decoded.next === decoded)

注意事项

• 值类型（struct、基本类型值）不具有对象标识语义
• trackRef 控制序列化图的对象标识，而不是 ARC 内存所有权
• 对纯值载荷使用 trackRef=false 以降低开销