/// A class info in object model.
/// 模型对象的 “元类” 信息
@interface _YYModelMeta : NSObject {
@package
// 记录的类信息
YYClassInfo *_classInfo;
/// Key:mapped key and key path, Value:_YYModelPropertyMeta.
NSDictionary *_mapper;
/// Array<_YYModelPropertyMeta>, all property meta of this model.
/// 一个类的所有 属性 元
NSArray *_allPropertyMetas;
/// Array<_YYModelPropertyMeta>, property meta which is mapped to a key path.
NSArray *_keyPathPropertyMetas;
/// Array<_YYModelPropertyMeta>, property meta which is mapped to multi keys.
NSArray *_multiKeysPropertyMetas;
/// The number of mapped key (and key path), same to _mapper.count.
NSUInteger _keyMappedCount;
/// Model class type.
YYEncodingNSType _nsType;
BOOL _hasCustomWillTransformFromDictionary;
BOOL _hasCustomTransformFromDictionary;
BOOL _hasCustomTransformToDictionary;
BOOL _hasCustomClassFromDictionary;
}
@end
// 模型元
@implementation _YYModelMeta
- (instancetype)initWithClass:(Class)cls {
// 获取类信息
/*
在这一步已经对类的进行了处理，获取了属性列表，变量列表，方法列表。处理的属性和变量的类型编码格式。
并将 class 的这些信息都添加到了 缓存池中。
*/
YYClassInfo *classInfo = [YYClassInfo classInfoWithClass:cls];
// 初始化失败就直接返回 nil
if (!classInfo) return nil;
// 初始化父类信息
self = [super init];
// Get black list 获取黑名单 （NSSet 可以去重）
NSSet *blacklist = nil;
// 查看当前类是否实现了黑名单方法
if ([cls respondsToSelector:@selector(modelPropertyBlacklist)]) {
// 获取黑名单
NSArray *properties = [(id<YYModel>)cls modelPropertyBlacklist];
if (properties) {
blacklist = [NSSet setWithArray:properties];
}
}
// Get white list 获取白名单
// 查看当前类是否实现了白名单方法
NSSet *whitelist = nil;
if ([cls respondsToSelector:@selector(modelPropertyWhitelist)]) {
NSArray *properties = [(id<YYModel>)cls modelPropertyWhitelist];
if (properties) {
whitelist = [NSSet setWithArray:properties];
}
}
// Get container property's generic class 获取 容器属性 泛类
/*
容器： dict ， array ，set
Example:
@class YYShadow, YYBorder, YYAttachment;
@interface YYAttributes
@property NSString *name;
@property NSArray *shadows;
@property NSSet *borders;
@property NSDictionary *attachments;
@end
@implementation YYAttributes
+ (NSDictionary *)modelContainerPropertyGenericClass {
return @{@"shadows" : [YYShadow class],
@"borders" : YYBorder.class,
@"attachments" : @"YYAttachment" };
}
@end
*/
// 泛型映射
NSDictionary *genericMapper = nil;
if ([cls respondsToSelector:@selector(modelContainerPropertyGenericClass)]) {
// 获取映射的 class 字典
genericMapper = [(id<YYModel>)cls modelContainerPropertyGenericClass];
if (genericMapper) {
NSMutableDictionary *tmp = [NSMutableDictionary new];
// 泛型映射便利
[genericMapper enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
// key 为 非字符串 直接返回
if (![key isKindOfClass:[NSString class]]) return;
// 获取对象的类
Class meta = object_getClass(obj);
// 获取失败直接返回
if (!meta) return;
// 判断是否是 元 类
/*
关乎为什么要判断是否是 元 类
http://stackoverflow.com/questions/6536244/check-if-object-is-class-type
*/
if (class_isMetaClass(meta)) { // 确定传入的是一个 类， 不是一个实例对象
// 添加进字典
tmp[key] = obj;
// objc 是 string ， 将 objc 转换为 class 加入到字典
} else if ([obj isKindOfClass:[NSString class]]) {
Class cls = NSClassFromString(obj);
if (cls) {
tmp[key] = cls;
}
}
}];
genericMapper = tmp;
}
}
// Create all property metas. 获取所有的 “元” 属性
NSMutableDictionary *allPropertyMetas = [NSMutableDictionary new];
YYClassInfo *curClassInfo = classInfo;
while (curClassInfo && curClassInfo.superCls != nil) {
// recursive parse super class, but ignore root class (NSObject/NSProxy)
// 递归解析父类，但是会忽略根类
// 便利当前类的属性信息
for (YYClassPropertyInfo *propertyInfo in curClassInfo.propertyInfos.allValues) {
// 属性名为 nil 就直接进入下一次循环
if (!propertyInfo.name) continue;
// 这下面要做的就是 剔除黑名单，剔除非白名单。
// 黑名单有值，并属性名称包含在黑名单中就直接进入下一次循环
if (blacklist && [blacklist containsObject:propertyInfo.name]) continue;
// 白名单有值 ，请属性不在白名单中就直接进入下一次循环
if (whitelist && ![whitelist containsObject:propertyInfo.name]) continue;
// 包含属性的处理
// 模型属性 “元”
_YYModelPropertyMeta *meta = [_YYModelPropertyMeta metaWithClassInfo:classInfo
propertyInfo:propertyInfo
generic:genericMapper[propertyInfo.name]];
if (!meta || !meta->_name) continue;
if (!meta->_getter || !meta->_setter) continue;
if (allPropertyMetas[meta->_name]) continue;
allPropertyMetas[meta->_name] = meta;
}
curClassInfo = curClassInfo.superClassInfo;
}
if (allPropertyMetas.count) _allPropertyMetas = allPropertyMetas.allValues.copy;
// create mapper 创建映射
NSMutableDictionary *mapper = [NSMutableDictionary new];
NSMutableArray *keyPathPropertyMetas = [NSMutableArray new];
NSMutableArray *multiKeysPropertyMetas = [NSMutableArray new];
// 自定义属性映射
if ([cls respondsToSelector:@selector(modelCustomPropertyMapper)]) {
NSDictionary *customMapper = [(id <YYModel>)cls modelCustomPropertyMapper];
[customMapper enumerateKeysAndObjectsUsingBlock:^(NSString *propertyName, NSString *mappedToKey, BOOL *stop) {
_YYModelPropertyMeta *propertyMeta = allPropertyMetas[propertyName];
if (!propertyMeta) return;
[allPropertyMetas removeObjectForKey:propertyName];
if ([mappedToKey isKindOfClass:[NSString class]]) {
if (mappedToKey.length == 0) return;
propertyMeta->_mappedToKey = mappedToKey;
NSArray *keyPath = [mappedToKey componentsSeparatedByString:@"."];
for (NSString *onePath in keyPath) {
if (onePath.length == 0) {
NSMutableArray *tmp = keyPath.mutableCopy;
[tmp removeObject:@""];
keyPath = tmp;
break;
}
}
if (keyPath.count > 1) {
propertyMeta->_mappedToKeyPath = keyPath;
[keyPathPropertyMetas addObject:propertyMeta];
}
propertyMeta->_next = mapper[mappedToKey] ?: nil;
mapper[mappedToKey] = propertyMeta;
} else if ([mappedToKey isKindOfClass:[NSArray class]]) {
NSMutableArray *mappedToKeyArray = [NSMutableArray new];
for (NSString *oneKey in ((NSArray *)mappedToKey)) {
if (![oneKey isKindOfClass:[NSString class]]) continue;
if (oneKey.length == 0) continue;
NSArray *keyPath = [oneKey componentsSeparatedByString:@"."];
if (keyPath.count > 1) {
[mappedToKeyArray addObject:keyPath];
} else {
[mappedToKeyArray addObject:oneKey];
}
if (!propertyMeta->_mappedToKey) {
propertyMeta->_mappedToKey = oneKey;
propertyMeta->_mappedToKeyPath = keyPath.count > 1 ? keyPath : nil;
}
}
if (!propertyMeta->_mappedToKey) return;
propertyMeta->_mappedToKeyArray = mappedToKeyArray;
[multiKeysPropertyMetas addObject:propertyMeta];
propertyMeta->_next = mapper[mappedToKey] ?: nil;
mapper[mappedToKey] = propertyMeta;
}
}];
}
[allPropertyMetas enumerateKeysAndObjectsUsingBlock:^(NSString *name, _YYModelPropertyMeta *propertyMeta, BOOL *stop) {
propertyMeta->_mappedToKey = name;
propertyMeta->_next = mapper[name] ?: nil;
mapper[name] = propertyMeta;
}];
if (mapper.count) _mapper = mapper;
if (keyPathPropertyMetas) _keyPathPropertyMetas = keyPathPropertyMetas;
if (multiKeysPropertyMetas) _multiKeysPropertyMetas = multiKeysPropertyMetas;
_classInfo = classInfo;
_keyMappedCount = _allPropertyMetas.count;
_nsType = YYClassGetNSType(cls);
_hasCustomWillTransformFromDictionary = ([cls instancesRespondToSelector:@selector(modelCustomWillTransformFromDictionary:)]);
_hasCustomTransformFromDictionary = ([cls instancesRespondToSelector:@selector(modelCustomTransformFromDictionary:)]);
_hasCustomTransformToDictionary = ([cls instancesRespondToSelector:@selector(modelCustomTransformToDictionary:)]);
_hasCustomClassFromDictionary = ([cls respondsToSelector:@selector(modelCustomClassForDictionary:)]);
return self;
}
/// Returns the cached model class meta
/// 返回缓存 元类 模型
+ (instancetype)metaWithClass:(Class)cls {
// 传入的类型为空直接返回 nil
if (!cls) return nil;
// 缓存池
static CFMutableDictionaryRef cache;
// 保证缓存池只被初始化一次
static dispatch_once_t onceToken;
static dispatch_semaphore_t lock;
dispatch_once(&onceToken, ^{
cache = CFDictionaryCreateMutable(CFAllocatorGetDefault(), 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
lock = dispatch_semaphore_create(1);
});
dispatch_semaphore_wait(lock, DISPATCH_TIME_FOREVER);
// 获取字典缓存的数据
_YYModelMeta *meta = CFDictionaryGetValue(cache, (__bridge const void *)(cls));
dispatch_semaphore_signal(lock);
// 没有缓存数据 或者 缓存数据需要根系
if (!meta || meta->_classInfo.needUpdate) {
// 实例化 元 数据模型
meta = [[_YYModelMeta alloc] initWithClass:cls];
if (meta) {
dispatch_semaphore_wait(lock, DISPATCH_TIME_FOREVER);
// 保存到缓存池
CFDictionarySetValue(cache, (__bridge const void *)(cls), (__bridge const void *)(meta));
dispatch_semaphore_signal(lock);
}
}
return meta;
}
@end
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