使用可编码的swift进行解析时，忽略数组中的空对象

struct Person: Codable {
    var name: String
    var age: Int
}

class IgnoreNullArrayDecoder: Decoder {
    var codingPath: [CodingKey] = []
    var userInfo: [CodingUserInfoKey : Any] = [:]
    
    // 实际的解码器
    private let decoder: Decoder
    
    init(decoder: Decoder) {
        self.decoder = decoder
    }
    
    func container<Key>(keyedBy type: Key.Type) throws -> KeyedDecodingContainer<Key> where Key : CodingKey {
        return try decoder.container(keyedBy: type)
    }
    
    func unkeyedContainer() throws -> UnkeyedDecodingContainer {
        // 获取原始的UnkeyedDecodingContainer
        let unkeyedContainer = try decoder.unkeyedContainer()
        
        return IgnoreNullArrayUnkeyedDecodingContainer(decoder: decoder, unkeyedContainer: unkeyedContainer)
    }
    
    func singleValueContainer() throws -> SingleValueDecodingContainer {
        return try decoder.singleValueContainer()
    }
}

class IgnoreNullArrayUnkeyedDecodingContainer: UnkeyedDecodingContainer {
    var codingPath: [CodingKey] = []
    var count: Int? = nil
    var isAtEnd: Bool { return currentIndex >= count! }
    var currentIndex: Int = 0
    
    // 实际的解码器和UnkeyedDecodingContainer
    private let decoder: Decoder
    private var unkeyedContainer: UnkeyedDecodingContainer
    
    init(decoder: Decoder, unkeyedContainer: UnkeyedDecodingContainer) {
        self.decoder = decoder
        self.unkeyedContainer = unkeyedContainer
    }
    
    func decodeNil() -> Bool {
        return unkeyedContainer.decodeNil()
    }
    
    func decode<T>(_ type: T.Type) throws -> T where T : Decodable {
        let value = try unkeyedContainer.decode(T.self)
        
        // 如果解析出的值是空对象，则跳过继续解析下一个
        if let optionalValue = value as? AnyOptional, optionalValue.isNil {
            currentIndex += 1
            return try decode(T.self)
        }
        
        currentIndex += 1
        return value
    }
    
    // 其他方法的实现省略...
}

let jsonString = """
[
    {"name": "Alice", "age": 25},
    null,
    {"name": "Bob", "age": 30},
    null,
    {"name": "Charlie", "age": 35}
]
"""

let data = jsonString.data(using: .utf8)!

let decoder = JSONDecoder()
decoder.userInfo[.jsonDecoder] = IgnoreNullArrayDecoder.self

do {
    let people = try decoder.decode([Person].self, from: data)
    
    for person in people {
        print(person)
    }
} catch {
    print("Error: \(error)")
}