Objective-C 浅拷贝、深拷贝、完全拷贝

在Objective-C中，对对象的拷贝可分为浅拷贝、深拷贝和完全拷贝。

copy、mutableCopy和容器拷贝总结：

1. copy对于可变对象为深拷贝，对于不可变对象为浅拷贝。
2. mutableCopy始终是深拷贝。
3. 对容器进行拷贝，容器内元素始终为浅拷贝。

浅拷贝、深拷贝和完全拷贝总结：

1. 浅拷贝(shallow copy)：仅仅对内存地址进行了拷贝，并没有对源对象进行拷贝；对于被复制对象的每一层都是指针复制。
2. 深拷贝(one-level-deep copy)：不仅对内存地址进行拷贝，而且对源对象进行拷贝；对于被复制对象，至少有一层是深复制。
3. 完全深拷贝(real-deep copy)：在拷贝的时候，对于被拷贝对象的每一层都进行了拷贝。

image.png image.png 未命名文件(4).png eg1. 不可变原数据执行 copy，mutableCopy操作： image.png eg2. 可变原数据执行 copy，mutableCopy操作： image.png eg3. 自定义模型(YYModel)数据执行 copy，mutableCopy操作： image.png eg4. 自定义模型(NSCoding,NSCopying)数据归档解档、initWithArray:copyItems:操作： image.png

eg5. 自定义模型嵌套自定义模型(NSCoding,NSCopying)数据归档解档、initWithArray:copyItems:操作：

NSMutableArray *array = [[NSMutableArray alloc] init];
Person *person = [[Person alloc] init];
person.name = [NSString stringWithFormat:@"张三"];
person.age = 18;
[array addObject:person];

// 不完全深拷贝
NSArray *arrCopy = [array copy];
NSMutableArray *arrMCopy = [array mutableCopy];
Person *person1 = [array firstObject];
Person *perCopy = arrCopy.firstObject;
Person *perMCopy =arrMCopy.firstObject;
perCopy.name = @"李四";
perMCopy.name = @"王五";

NSLog(@"不完全深拷贝");
NSLog(@"array= %p, person= %@, name= %@", array, person1, person1.name);
NSLog(@"arrCopy= %p, person= %@, name= %@", arrCopy, perCopy, perCopy.name);
NSLog(@"arrMCopy= %p, person= %@, name= %@", arrMCopy, perMCopy, perMCopy.name);

//方式1 要在集合对象中实现NSCoding协议
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:array];
NSArray *array2 = [NSKeyedUnarchiver unarchiveTopLevelObjectWithData:data error:nil];

    
//方式2 要在集合对象中实现NSCopying协议
NSMutableArray *array3 = [[NSMutableArray alloc] initWithArray:array copyItems:YES];

Person *person2 = [array2 firstObject];
Person *person3 = [array3 firstObject];
person2.name = @"李四一";
person3.name = @"王五一";
NSLog(@"完全深拷贝");
NSLog(@"array= %p, person= %@, name= %@", array, person1, person1.name);
NSLog(@"array2= %p, person= %@, name= %@", array2, person2, person2.name);
NSLog(@"array3= %p, person= %@, name= %@", array3, person3, person3.name);

/*
2022-10-12 14:41:37.732284+0800 OC深浅拷贝[52457:290164] 不完全深拷贝
2022-10-12 14:41:37.732661+0800 OC深浅拷贝[52457:290164] array= 0x10120e030, person= <Person: 0x10073c1e0>, name= 王五
2022-10-12 14:41:37.732744+0800 OC深浅拷贝[52457:290164] arrCopy= 0x10073a360, person= <Person: 0x10073c1e0>, name= 王五
2022-10-12 14:41:37.732798+0800 OC深浅拷贝[52457:290164] arrMCopy= 0x10073c1b0, person= <Person: 0x10073c1e0>, name= 王五
2022-10-12 14:41:37.733398+0800 OC深浅拷贝[52457:290164] 完全深拷贝
2022-10-12 14:41:37.733525+0800 OC深浅拷贝[52457:290164] array= 0x10120e030, person= <Person: 0x10073c1e0>, name= 王五
2022-10-12 14:41:37.733596+0800 OC深浅拷贝[52457:290164] array2= 0x10140b8e0, person= <Person: 0x10140b560>, name= 李四一
2022-10-12 14:41:37.733657+0800 OC深浅拷贝[52457:290164] array3= 0x10140a280, person= <Person: 0x10140a330>, name= 王五一
**/

@interface Person : NSObject <NSCoding,NSCopying, NSMutableCopying>

@property NSString *name;
@property NSInteger  age;

@end

@interface Worker : Person <NSCoding,NSCopying>

@property NSString *salary;
@property Person *leader;

@end

@implementation Person
 
- (id)copyWithZone:(nullable NSZone *)zone{
 
    Person *copy = [[[self class] allocWithZone:zone] init];
    copy.name = [self.name copy];
    copy.name = [self.name mutableCopy];// copy，mutableCopy二选一
    copy.age = self.age;
    return copy;
}

- (id)mutableCopyWithZone:(NSZone *)zone {
    
   Person *copy = [[[self class] allocWithZone:zone] init];
    copy.name = [self.name copy];
   copy.name = [self.name mutableCopy];// copy，mutableCopy二选一
   copy.age = self.age;
   return copy;
}

- (void)encodeWithCoder:(NSCoder *)aCoder{

    [aCoder encodeObject:self.name forKey:@"name"];
    [aCoder encodeInteger:self.age forKey:@"age"];
}

- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder{

    _name = [aDecoder decodeObjectForKey:@"name"];
    _age = [aDecoder decodeIntegerForKey:@"age"];
    return self;
}

@end


@implementation Worker
 
- (id)copyWithZone:(nullable NSZone *)zone{
 
    Worker *copy = [[[self class] allocWithZone:zone] init];
    copy.salary = [self.salary copy];
    copy.salary = [self.salary mutableCopy];// copy，mutableCopy二选一
    copy.leader = [self.leader copy];
    copy.leader = [self.leader mutableCopy];// 注意要实现NSMutableCopying; copy，mutableCopy二选一
    return copy;
}
 
- (void)encodeWithCoder:(NSCoder *)aCoder{

    [aCoder encodeObject:self.salary forKey:@"salary"];
    [aCoder encodeObject:self.leader forKey:@"leader"];
}

- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder{

    _salary = [aDecoder decodeObjectForKey:@"salary"];
    _leader = [aDecoder decodeObjectForKey:@"leader"];
    return self;
}

NSMutableArray *array = [[NSMutableArray alloc] init];
Worker *worker = [[Worker alloc] init];
worker.name = [NSString stringWithFormat:@"张三"];
worker.age = 25;
worker.salary = @"200";
Person *leader = [[Person alloc] init];
leader.name = [NSString stringWithFormat:@"领导"];
leader.age = 30;
worker.leader = leader;

[array addObject:worker];

// 不完全深拷贝
NSArray *arrCopy = [array copy];
NSMutableArray *arrMCopy = [array mutableCopy];
Worker *worker1 = [array firstObject];
Worker *wkrCopy = arrCopy.firstObject;
Worker *wkrMCopy =arrMCopy.firstObject;
wkrCopy.name = @"李四";
wkrMCopy.name = @"王五";
wkrCopy.leader.name = @"李四的领导";
wkrMCopy.leader.name = @"王五的领导";

NSLog(@"不完全深拷贝");
NSLog(@"array= %p, person= %@, name= %@, leader= %p, %@, name= %@", array, worker1, worker1.name, worker1.leader, worker1.leader, worker1.leader.name);
NSLog(@"arrCopy= %p, person= %@, name= %@, leader= %p, %@, name= %@", arrCopy, wkrCopy, wkrCopy.name, wkrCopy.leader, wkrCopy.leader, wkrCopy.leader.name);
NSLog(@"arrMCopy= %p, person= %@, name= %@, leader= %p, %@, name= %@", arrMCopy, wkrMCopy, wkrMCopy.name, wkrMCopy.leader, wkrMCopy.leader, wkrMCopy.leader.name);

//方式1 要在集合对象中实现NSCoding协议
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:array];
NSArray *array2 = [NSKeyedUnarchiver unarchiveTopLevelObjectWithData:data error:nil];

    
//方式2 要在集合对象中实现NSCopying协议
NSMutableArray *array3 = [[NSMutableArray alloc] initWithArray:array copyItems:YES];

Worker *worker2 = [array2 firstObject];
Worker *worker3 = [array3 firstObject];
worker2.name = @"李四一";
worker3.name = @"王五一";
worker2.leader.name = @"李四一的领导";
worker3.leader.name = @"王五一的领导";
NSLog(@"完全深拷贝");
NSLog(@"array= %p, person= %@, name= %@, leader= %p, %@, name= %@", array, worker1, worker1.name, worker1.leader, worker1.leader, worker1.leader.name);
NSLog(@"array2= %p, person= %@, name= %@, leader= %p, %@, name= %@", array2, worker2, worker2.name, worker2.leader, worker2.leader, worker2.leader.name);
NSLog(@"array3= %p, person= %@, name= %@, leader= %p, %@, name= %@", array3, worker3, worker3.name, worker3.leader, worker3.leader, worker3.leader.name);

/*
2022-10-12 14:41:37.733737+0800 OC深浅拷贝[52457:290164] 不完全深拷贝
2022-10-12 14:41:37.733809+0800 OC深浅拷贝[52457:290164] array= 0x10140a280, person= <Worker: 0x10140a630>, name= 王五, leader= 0x10140ac80, <Person: 0x10140ac80>, name= 王五的领导
2022-10-12 14:41:37.733867+0800 OC深浅拷贝[52457:290164] arrCopy= 0x10140a6e0, person= <Worker: 0x10140a630>, name= 王五, leader= 0x10140ac80, <Person: 0x10140ac80>, name= 王五的领导
2022-10-12 14:41:37.735200+0800 OC深浅拷贝[52457:290164] arrMCopy= 0x10140b070, person= <Worker: 0x10140a630>, name= 王五, leader= 0x10140ac80, <Person: 0x10140ac80>, name= 王五的领导
2022-10-12 14:41:37.735675+0800 OC深浅拷贝[52457:290164] 完全深拷贝
2022-10-12 14:41:37.735798+0800 OC深浅拷贝[52457:290164] array= 0x10140a280, person= <Worker: 0x10140a630>, name= 王五, leader= 0x10140ac80, <Person: 0x10140ac80>, name= 王五的领导
2022-10-12 14:41:37.735899+0800 OC深浅拷贝[52457:290164] array2= 0x101039ad0, person= <Worker: 0x10103a650>, name= 李四一, leader= 0x101038fe0, <Person: 0x101038fe0>, name= 李四一的领导
2022-10-12 14:41:37.735977+0800 OC深浅拷贝[52457:290164] array3= 0x101608210, person= <Worker: 0x101039b80>, name= 王五一, leader= 0x101605d60, <Person: 0x101605d60>, name= 王五一的领导
**/