前言
本文的中文注释代码demo更新在我的github上。
上篇 YYModel源代码分析（二）YYClassInfo
主要分析了YYClassInfo文件。本篇会主要集中在NSObject+YYModel文件上。文章内容会包含一些与JSONModel的比较，想了解JSONModel，可以参考JSONModel源代码解析。
主体分层
NSObject+YYModel主要分为以下几个部分：
- 内部使用的C函数部分
@interface _YYModelPropertyMeta : NSObject@interface _YYModelMeta : NSObject@interface NSObject (YYModel) : NSObject@interface NSArray (YYModel) : NSObject@interface NSDictionary (YYModel) : NSObject-
@protocol YYModel:接口YYModel
由于代码较多，所以会挑重点的部分进行介绍。
NSObject+YYModel源代码
@interface _YYModelPropertyMeta : NSObject
声明
/// A property info in object model.
// model property的进一步分装
@interface _YYModelPropertyMeta : NSObject {
@package
NSString *_name; ///< property's name //property名
YYEncodingType _type; ///< property's type //property的encode解析值
YYEncodingNSType _nsType; ///< property's Foundation type //property的foundation类型
BOOL _isCNumber; ///< is c number type //是不是c语言的数字
Class _cls; ///< property's class, or nil //property的class
Class _genericCls; ///< container's generic class, or nil if threr's no generic class //property内包含的类class
SEL _getter; ///< getter, or nil if the instances cannot respond //property getter方法
SEL _setter; ///< setter, or nil if the instances cannot respond //property setter方法
BOOL _isKVCCompatible; ///< YES if it can access with key-value coding //是否可以使用KVC
BOOL _isStructAvailableForKeyedArchiver; ///< YES if the struct can encoded with keyed archiver/unarchiver //是否是struct并且可以archiver/unarchiver
BOOL _hasCustomClassFromDictionary; ///< class/generic class implements +modelCustomClassForDictionary: //是否包含本本地的class转换
/*
property->key: _mappedToKey:key _mappedToKeyPath:nil _mappedToKeyArray:nil
property->keyPath: _mappedToKey:keyPath _mappedToKeyPath:keyPath(array) _mappedToKeyArray:nil
property->keys: _mappedToKey:keys[0] _mappedToKeyPath:nil/keyPath _mappedToKeyArray:keys(array)
*/
NSString *_mappedToKey; ///< the key mapped to //property本地的key mapper的key
NSArray *_mappedToKeyPath; ///< the key path mapped to (nil if the name is not key path) //property本地的key mapper的key path列表
NSArray *_mappedToKeyArray; ///< the key(NSString) or keyPath(NSArray) array (nil if not mapped to multiple keys) /property本地的key mapper的key列表
YYClassPropertyInfo *_info; ///< property's info //property的YYClassPropertyInfo info
_YYModelPropertyMeta *_next; ///< next meta if there are multiple properties mapped to the same key. //同个key的多个property的映射next指针
}
@end
其中需要理解一下的包括：
1._hasCustomClassFromDictionary就是判断是否有本地的不同class的映射
如下例子，当dictionary包含不同的值的时候，映射的model类型不同
@implementation YYBaseUser
+ (Class)modelCustomClassForDictionary:(NSDictionary*)dictionary {
if (dictionary[@"localName"]) {
return [YYLocalUser class];
} else if (dictionary[@"remoteName"]) {
return [YYRemoteUser class];
}
return [YYBaseUser class];
}
2.keyMapper相关内容
如下例子，dictionary中不同的key，对应的model的property有一个映射关系
其中对于包含"."的映射，则是一种多层的映射关系
+ (NSDictionary *)modelCustomPropertyMapper {
return @{ @"name" : @"n",
@"count" : @"ext.c",
@"desc1" : @"ext.d", // mapped to same key path
@"desc2" : @"ext.d", // mapped to same key path
@"desc3" : @"ext.d.e",
@"desc4" : @".ext",
@"modelID" : @[@"ID", @"Id", @"id", @"ext.id"]};
}
3._YYModelPropertyMeta *_next同一个key的下一个meta解析类型
因为有了key mapper，所以会出现同一个mapper的key值，可能会一对多个model的property值，这边设计了一个_next指针进行链接
4.Class _genericCls包含的类型
如下例子，property会有NSArray\NSDictionary\NSSet类型，内部的类型就通过该参数表示
@interface YYTestCustomClassModel : NSObject
@property (nonatomic, strong) NSArray *users;
@property (nonatomic, strong) NSDictionary *userDict;
@property (nonatomic, strong) NSSet *userSet;
@end
+ (NSDictionary *)modelContainerPropertyGenericClass {
return @{@"users" : YYBaseUser.class,
@"userDict" : YYBaseUser.class,
@"userSet" : YYBaseUser.class};
}
实现
//通过YYClassInfo，YYClassPropertyInfo，Class对象解析成_YYModelPropertyMeta
+ (instancetype)metaWithClassInfo:(YYClassInfo *)classInfo propertyInfo:(YYClassPropertyInfo *)propertyInfo generic:(Class)generic {
// support pseudo generic class with protocol name
// 这边也考虑了，某些类型写在protocol中，包含在<>中，和JSONModel一样进行一下protocol的类型判断
// 比如NSArray xxx
if (!generic && propertyInfo.protocols) {
for (NSString *protocol in propertyInfo.protocols) {
Class cls = objc_getClass(protocol.UTF8String);
if (cls) {
generic = cls;
break;
}
}
}
//构造_YYModelPropertyMeta对象
_YYModelPropertyMeta *meta = [self new];
meta->_name = propertyInfo.name; //设置名
meta->_type = propertyInfo.type; //设置encode type
meta->_info = propertyInfo; //设置YYClassPropertyInfo
meta->_genericCls = generic; //设置可能有的包含类
if ((meta->_type & YYEncodingTypeMask) == YYEncodingTypeObject) { //如果是OC对象，则判断是不是标准oc foundation类型
meta->_nsType = YYClassGetNSType(propertyInfo.cls);
} else {
meta->_isCNumber = YYEncodingTypeIsCNumber(meta->_type); //判断是否是c 数字
}
if ((meta->_type & YYEncodingTypeMask) == YYEncodingTypeStruct) { //判断和是否是struct
/*
It seems that NSKeyedUnarchiver cannot decode NSValue except these structs:
*/
//NSKeyedUnarchiver只可以解析以下的struct
static NSSet *types = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
NSMutableSet *set = [NSMutableSet new];
// 32 bit
[set addObject:@"{CGSize=ff}"];
[set addObject:@"{CGPoint=ff}"];
[set addObject:@"{CGRect={CGPoint=ff}{CGSize=ff}}"];
[set addObject:@"{CGAffineTransform=ffffff}"];
[set addObject:@"{UIEdgeInsets=ffff}"];
[set addObject:@"{UIOffset=ff}"];
// 64 bit
[set addObject:@"{CGSize=dd}"];
[set addObject:@"{CGPoint=dd}"];
[set addObject:@"{CGRect={CGPoint=dd}{CGSize=dd}}"];
[set addObject:@"{CGAffineTransform=dddddd}"];
[set addObject:@"{UIEdgeInsets=dddd}"];
[set addObject:@"{UIOffset=dd}"];
types = set;
});
if ([types containsObject:propertyInfo.typeEncoding]) {
meta->_isStructAvailableForKeyedArchiver = YES;
}
}
meta->_cls = propertyInfo.cls; //设置类
if (generic) { //如果是包含类的话，用包含类去判断是否需要类型转换
meta->_hasCustomClassFromDictionary = [generic respondsToSelector:@selector(modelCustomClassForDictionary:)];
} else if (meta->_cls && meta->_nsType == YYEncodingTypeNSUnknown) { //如果是其它oc类型，用类型去判断是否需要类型转换
meta->_hasCustomClassFromDictionary = [meta->_cls respondsToSelector:@selector(modelCustomClassForDictionary:)];
}
//设置getter方法
if (propertyInfo.getter) {
if ([classInfo.cls instancesRespondToSelector:propertyInfo.getter]) {
meta->_getter = propertyInfo.getter;
}
}
//设置setter方法
if (propertyInfo.setter) {
if ([classInfo.cls instancesRespondToSelector:propertyInfo.setter]) {
meta->_setter = propertyInfo.setter;
}
}
//如果包含getter和setter方法
if (meta->_getter && meta->_setter) {
/*
KVC invalid type:
long double
pointer (such as SEL/CoreFoundation object)
*/
//以下代表可以使用kvc进行附值
switch (meta->_type & YYEncodingTypeMask) {
case YYEncodingTypeBool:
case YYEncodingTypeInt8:
case YYEncodingTypeUInt8:
case YYEncodingTypeInt16:
case YYEncodingTypeUInt16:
case YYEncodingTypeInt32:
case YYEncodingTypeUInt32:
case YYEncodingTypeInt64:
case YYEncodingTypeUInt64:
case YYEncodingTypeFloat:
case YYEncodingTypeDouble:
case YYEncodingTypeObject:
case YYEncodingTypeClass:
case YYEncodingTypeBlock:
case YYEncodingTypeStruct:
case YYEncodingTypeUnion: {
meta->_isKVCCompatible = YES;
} break;
default: break;
}
}
return meta;
}
实现部分还是容易理解，主要还是通过YYClassInfo，YYClassPropertyInfo，Class对象解析成_YYModelPropertyMeta。
@interface _YYModelMeta : NSObject
声明
/// A class info in object model.
// model class的进一层封装
@interface _YYModelMeta : NSObject {
@package
YYClassInfo *_classInfo; //YYClassInfo类型
/// Key:mapped key and key path, Value:_YYModelPropertyMeta.
NSDictionary *_mapper; //key mapper的值，key是mapped key and key path，Value是_YYModelPropertyMeta类型
/// Array<_YYModelPropertyMeta>, all property meta of this model.
NSArray *_allPropertyMetas; //所有的_YYModelPropertyMeta列表
/// Array<_YYModelPropertyMeta>, property meta which is mapped to a key path.
NSArray *_keyPathPropertyMetas; //所有的路径映射property缓存
/// Array<_YYModelPropertyMeta>, property meta which is mapped to multi keys.
NSArray *_multiKeysPropertyMetas; //所有的多层映射property缓存
/// The number of mapped key (and key path), same to _mapper.count.
NSUInteger _keyMappedCount; //key mapper数量
/// Model class type.
YYEncodingNSType _nsType; //model class的oc类型
BOOL _hasCustomWillTransformFromDictionary; //是否包含本地的某些值进行替换
BOOL _hasCustomTransformFromDictionary; //是否有本地的值的类型判断
BOOL _hasCustomTransformToDictionary; //与上个相反，当转成dictionary的时候，转换的方式
BOOL _hasCustomClassFromDictionary; //是否有本地的类型的转换
}
@end
其中，需要理解的包括：
NSDictionary *_mapper;
NSArray *_allPropertyMetas;
NSArray *_keyPathPropertyMetas;
NSArray *_multiKeysPropertyMetas;
_mapper是包括了所有class和superclass的property的key value缓存，其中的key是所有已经映射过key name和不需要映射的property name组成。
_allPropertyMetas是所有class和superclass的property解析_YYModelPropertyMeta列表。
_keyPathPropertyMetas是表示映射如果是一个路径比如@"count" : @"ext.c"下的_YYModelPropertyMeta列表。
_multiKeysPropertyMetas是表示映射如果是一个NSArray比如@"modelID" : @[@"ID", @"Id", @"id", @"ext.id"]下的_YYModelPropertyMeta列表。
BOOL _hasCustomWillTransformFromDictionary; //是否包含本地的某些值进行替换
BOOL _hasCustomTransformFromDictionary; //是否有本地的值的类型判断
BOOL _hasCustomTransformToDictionary; //与上个相反，当转成dictionary的时候，转换的方式
BOOL _hasCustomClassFromDictionary; //是否有本地的类型的转换
判断方式：
_hasCustomWillTransformFromDictionary = ([cls instancesRespondToSelector:@selector(modelCustomWillTransformFromDictionary:)]);
_hasCustomTransformFromDictionary = ([cls instancesRespondToSelector:@selector(modelCustomTransformFromDictionary:)]);
_hasCustomTransformToDictionary = ([cls instancesRespondToSelector:@selector(modelCustomTransformToDictionary:)]);
_hasCustomClassFromDictionary = ([cls respondsToSelector:@selector(modelCustomClassForDictionary:)]);
对应的实际例子：
@interface YYTestCustomTransformModel : NSObject
@property uint64_t id;
@property NSString *content;
@property NSDate *time;
@end
-(NSDictionary *)modelCustomWillTransformFromDictionary:(NSDictionary *)dic{
if (dic) {
NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithDictionary:dic];
if (dict[@"date"]) {
dict[@"time"] = dict[@"date"];
}
return dict;
}
return dic;
}
- (BOOL)modelCustomTransformFromDictionary:(NSDictionary *)dic {
NSNumber *time = dic[@"time"];
if ([time isKindOfClass:[NSNumber class]] && time.unsignedLongLongValue != 0) {
_time = [NSDate dateWithTimeIntervalSince1970:time.unsignedLongLongValue / 1000.0];
return YES;
} else {
return NO;
}
}
- (BOOL)modelCustomTransformToDictionary:(NSMutableDictionary *)dic {
if (_time) {
dic[@"time"] = @((uint64_t)(_time.timeIntervalSince1970 * 1000));
return YES;
} else {
return NO;
}
}
最后一个在_YYModelPropertyMeta已经提过，这里不再提。
实现
- (instancetype)initWithClass:(Class)cls {
YYClassInfo *classInfo = [YYClassInfo classInfoWithClass:cls]; //构造 YYClassInfo结构体
if (!classInfo) return nil;
self = [super init];
// Get black list
NSSet *blacklist = nil;
if ([cls respondsToSelector:@selector(modelPropertyBlacklist)]) { //黑名单，不解析的property
NSArray *properties = [(id)cls modelPropertyBlacklist];
if (properties) {
blacklist = [NSSet setWithArray:properties];
}
}
// Get white list
NSSet *whitelist = nil;
if ([cls respondsToSelector:@selector(modelPropertyWhitelist)]) { //白名单，只解析的property
NSArray *properties = [(id)cls modelPropertyWhitelist];
if (properties) {
whitelist = [NSSet setWithArray:properties];
}
}
// Get container property's generic class
//获得包含的类的类型
NSDictionary *genericMapper = nil;
if ([cls respondsToSelector:@selector(modelContainerPropertyGenericClass)]) {
genericMapper = [(id)cls modelContainerPropertyGenericClass]; //获得包含类映射的dictionary
if (genericMapper) {
NSMutableDictionary *tmp = [NSMutableDictionary new];
[genericMapper enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) { //遍历dictionary
if (![key isKindOfClass:[NSString class]]) return;
Class meta = object_getClass(obj); //获得映射的类型
if (!meta) return; //不是类型返回
if (class_isMetaClass(meta)) { //如果是meta class的话,直接设置（因为是对象的类类型)
tmp[key] = obj;
} else if ([obj isKindOfClass:[NSString class]]) { //如果是string的话，转成class，设置
Class cls = NSClassFromString(obj);
if (cls) {
tmp[key] = cls;
}
}
}];
genericMapper = tmp; //获得包含类的映射dictionary
}
}
// Create all property metas.
NSMutableDictionary *allPropertyMetas = [NSMutableDictionary new];
YYClassInfo *curClassInfo = classInfo;
//递归class和superclass，但忽略nsobject/nsproxy
while (curClassInfo && curClassInfo.superCls != nil) { // recursive parse super class, but ignore root class (NSObject/NSProxy)
//获得class的所有YYClassPropertyInfo缓存
for (YYClassPropertyInfo *propertyInfo in curClassInfo.propertyInfos.allValues) {
if (!propertyInfo.name) continue;
if (blacklist && [blacklist containsObject:propertyInfo.name]) continue; //跳过黑名单
if (whitelist && ![whitelist containsObject:propertyInfo.name]) continue; //只判断拍名单
//构造_YYModelPropertyMeta结构体
_YYModelPropertyMeta *meta = [_YYModelPropertyMeta metaWithClassInfo:classInfo
propertyInfo:propertyInfo
generic:genericMapper[propertyInfo.name]];
if (!meta || !meta->_name) continue; //没有名字跳过
if (!meta->_getter || !meta->_setter) continue; //没有getter或者setter方法跳过
if (allPropertyMetas[meta->_name]) continue; //已经解析过的跳过
allPropertyMetas[meta->_name] = meta; //将解析通过dictionary缓存
}
curClassInfo = curClassInfo.superClassInfo; //递归super class
}
if (allPropertyMetas.count) _allPropertyMetas = allPropertyMetas.allValues.copy; //复制一份解析出来的所有allPropertyMetas
// create mapper
//开始key mapper映射
NSMutableDictionary *mapper = [NSMutableDictionary new];
NSMutableArray *keyPathPropertyMetas = [NSMutableArray new];
NSMutableArray *multiKeysPropertyMetas = [NSMutableArray new];
//如果有key mapper 映射
if ([cls respondsToSelector:@selector(modelCustomPropertyMapper)]) {
NSDictionary *customMapper = [(id )cls modelCustomPropertyMapper];
[customMapper enumerateKeysAndObjectsUsingBlock:^(NSString *propertyName, NSString *mappedToKey, BOOL *stop) {
_YYModelPropertyMeta *propertyMeta = allPropertyMetas[propertyName]; //找到映射值的_YYModelPropertyMeta
if (!propertyMeta) return; //没有直接返回
[allPropertyMetas removeObjectForKey:propertyName]; //有映射所以从原来的列表删除
if ([mappedToKey isKindOfClass:[NSString class]]) { //如果是NSString映射
if (mappedToKey.length == 0) return;
propertyMeta->_mappedToKey = mappedToKey; //设置mapper key
NSArray *keyPath = [mappedToKey componentsSeparatedByString:@"."]; //如果是包含"."代表key的路径映射
for (NSString *onePath in keyPath) {
if (onePath.length == 0) {
NSMutableArray *tmp = keyPath.mutableCopy;
[tmp removeObject:@""];
keyPath = tmp;
break;
}
}
if (keyPath.count > 1) { //>1说明有路径映射
propertyMeta->_mappedToKeyPath = keyPath; //设置_mappedToKeyPath
[keyPathPropertyMetas addObject:propertyMeta]; //添加路径映射对象
}
propertyMeta->_next = mapper[mappedToKey] ?: nil; //如果包含上一个同样key值的_YYModelPropertyMeta对象，则设置next指针
mapper[mappedToKey] = propertyMeta;
} else if ([mappedToKey isKindOfClass:[NSArray class]]) { //如果是nsarray映射
NSMutableArray *mappedToKeyArray = [NSMutableArray new];
for (NSString *oneKey in ((NSArray *)mappedToKey)) { //多一级nsarray的遍历，内容与nsstring相同
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; //多级的映射值会存到_mappedToKeyArray
[multiKeysPropertyMetas addObject:propertyMeta];
propertyMeta->_next = mapper[mappedToKey] ?: nil; //同样，如果包含上一个同样key值的_YYModelPropertyMeta对象，则设置next指针
mapper[mappedToKey] = propertyMeta;
}
}];
}
//映射完后，遍历所有的allPropertyMetas，设置mapper和next指针
[allPropertyMetas enumerateKeysAndObjectsUsingBlock:^(NSString *name, _YYModelPropertyMeta *propertyMeta, BOOL *stop) {
propertyMeta->_mappedToKey = name;
propertyMeta->_next = mapper[name] ?: nil;
mapper[name] = propertyMeta;
}];
//如果有映射值，则缓存
if (mapper.count) _mapper = mapper;
//如果路径映射值，则缓存
if (keyPathPropertyMetas) _keyPathPropertyMetas = keyPathPropertyMetas;
//如果有多映射值，则缓存
if (multiKeysPropertyMetas) _multiKeysPropertyMetas = multiKeysPropertyMetas;
_classInfo = classInfo; //设置classinfo
_keyMappedCount = _allPropertyMetas.count; //设置property数量
_nsType = YYClassGetNSType(cls); //获得本类的oc foundation类型
_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
//返回缓存的model class meta
+ (instancetype)metaWithClass:(Class)cls {
if (!cls) return nil;
static CFMutableDictionaryRef cache; //class的_YYModelMeta缓存
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);
_YYModelMeta *meta = CFDictionaryGetValue(cache, (__bridge const void *)(cls));
dispatch_semaphore_signal(lock);
if (!meta || meta->_classInfo.needUpdate) { //利用
meta = [[_YYModelMeta alloc] initWithClass:cls]; //重新构造 _YYModelMeta缓存
if (meta) { //设置缓存
dispatch_semaphore_wait(lock, DISPATCH_TIME_FOREVER);
CFDictionarySetValue(cache, (__bridge const void *)(cls), (__bridge const void *)(meta));
dispatch_semaphore_signal(lock);
}
}
return meta;
}
实现处理了很多key mapper的映射问题，但本身逻辑并不复杂。
解析逻辑
//id json对象转化为 dictioanry的方法
+ (NSDictionary *)_yy_dictionaryWithJSON:(id)json {
if (!json || json == (id)kCFNull) return nil;
NSDictionary *dic = nil;
NSData *jsonData = nil;
if ([json isKindOfClass:[NSDictionary class]]) {
dic = json;
} else if ([json isKindOfClass:[NSString class]]) {
jsonData = [(NSString *)json dataUsingEncoding : NSUTF8StringEncoding];
} else if ([json isKindOfClass:[NSData class]]) {
jsonData = json;
}
if (jsonData) {
dic = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:NULL];
if (![dic isKindOfClass:[NSDictionary class]]) dic = nil;
}
return dic;
}
//先转化json对象到dictionary，再调用yy_modelWithDictionary
+ (instancetype)yy_modelWithJSON:(id)json {
NSDictionary *dic = [self _yy_dictionaryWithJSON:json];
return [self yy_modelWithDictionary:dic];
}
//解析model属性并附值
+ (instancetype)yy_modelWithDictionary:(NSDictionary *)dictionary {
if (!dictionary || dictionary == (id)kCFNull) return nil;
if (![dictionary isKindOfClass:[NSDictionary class]]) return nil;
Class cls = [self class];
//解析class得到modelmeta对象
_YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:cls];
//本地class类型映射
if (modelMeta->_hasCustomClassFromDictionary) {
cls = [cls modelCustomClassForDictionary:dictionary] ?: cls;
}
NSObject *one = [cls new];
//附值函数
if ([one yy_modelSetWithDictionary:dictionary]) return one;
return nil;
}
//附值函数
- (BOOL)yy_modelSetWithDictionary:(NSDictionary *)dic {
if (!dic || dic == (id)kCFNull) return NO;
if (![dic isKindOfClass:[NSDictionary class]]) return NO;
_YYModelMeta *modelMeta = [_YYModelMeta metaWithClass:object_getClass(self)];
if (modelMeta->_keyMappedCount == 0) return NO;
//本地dictionary值替换
if (modelMeta->_hasCustomWillTransformFromDictionary) {
dic = [((id)self) modelCustomWillTransformFromDictionary:dic];
if (![dic isKindOfClass:[NSDictionary class]]) return NO;
}
ModelSetContext context = {0};
context.modelMeta = (__bridge void *)(modelMeta);
context.model = (__bridge void *)(self);
context.dictionary = (__bridge void *)(dic);
//遍历dictioanry并附值
if (modelMeta->_keyMappedCount >= CFDictionaryGetCount((CFDictionaryRef)dic)) {
CFDictionaryApplyFunction((CFDictionaryRef)dic, ModelSetWithDictionaryFunction, &context);
if (modelMeta->_keyPathPropertyMetas) {
CFArrayApplyFunction((CFArrayRef)modelMeta->_keyPathPropertyMetas,
CFRangeMake(0, CFArrayGetCount((CFArrayRef)modelMeta->_keyPathPropertyMetas)),
ModelSetWithPropertyMetaArrayFunction,
&context);
}
if (modelMeta->_multiKeysPropertyMetas) {
CFArrayApplyFunction((CFArrayRef)modelMeta->_multiKeysPropertyMetas,
CFRangeMake(0, CFArrayGetCount((CFArrayRef)modelMeta->_multiKeysPropertyMetas)),
ModelSetWithPropertyMetaArrayFunction,
&context);
}
} else {
CFArrayApplyFunction((CFArrayRef)modelMeta->_allPropertyMetas,
CFRangeMake(0, modelMeta->_keyMappedCount),
ModelSetWithPropertyMetaArrayFunction,
&context);
}
//本地property验证
if (modelMeta->_hasCustomTransformFromDictionary) {
return [((id)self) modelCustomTransformFromDictionary:dic];
}
return YES;
}
附值这块，就只取ModelSetWithDictionaryFunction设置
static void ModelSetWithDictionaryFunction(const void *_key, const void *_value, void *_context) {
ModelSetContext *context = _context;
__unsafe_unretained _YYModelMeta *meta = (__bridge _YYModelMeta *)(context->modelMeta); //取_YYModelMeta
__unsafe_unretained _YYModelPropertyMeta *propertyMeta = [meta->_mapper objectForKey:(__bridge id)(_key)]; //取_YYModelPropertyMeta
__unsafe_unretained id model = (__bridge id)(context->model);
while (propertyMeta) { //循环遍历propertyMeta
if (propertyMeta->_setter) {
ModelSetValueForProperty(model, (__bridge __unsafe_unretained id)_value, propertyMeta); //设置值
}
propertyMeta = propertyMeta->_next;
};
}
而ModelSetValueForProperty的设置函数，就是根据不同类型，去调用msgSend调用相应的meta->_setter方法，进行附值，代码较长，这里也不贴了。
至此，整个YYModel的解析就完成了。
总结
YYModel在整体的解析过程中，分三步：
- 先将Class的Method，Property，Ivar分别解析缓存，构成Class的缓存
- 构建
_YYModelPropertyMeta缓存Property结构体，再_YYModelMeta缓存_YYModelPropertyMeta结构。
3.根据解析出来的_YYModelPropertyMeta与相应的YYEncodingType等属性，进行相应值的设置
JSONModel与YYModel对比
| 对比 | JSONModel | YYModel |
|---|---|---|
| 解析方式 | 只解析property attribute encode string | 解析Class Method,Property,Ivar缓存，再构造_YYModelPropertyMeta与_YYModelMeta |
| 附值方式 | KVC | 先解析出property的类型，使用msgSend调用meta->setter方法分类型附值 |
| 缓存方式 | AssociatedObject | CFMutableDictionaryRef |
| 包含类型方式 | 定义同名protocol，声明protocol | 不仅可以声明protocol定义，还可以实现modelContainerPropertyGenericClass接口 |
| 映射值为路径解析 | 无 | 有 |
| model类型转换 | 无 | 有 |
| 懒加载 | 有 | 无 |
| 是否可以缺省 | 通过protocol optional | 黑名单\白名单 |
参考资料
CSDN地址
1.JSONModel源代码解析
2.郑钦洪_：YYModel 源码历险记