『iOS』_block在各种情况下的源码表现

作者: butterflyer | 来源:发表于2022-01-15 11:20 被阅读0次

『iOS』_block在各种情况下的源码表现
『iOS』各种不同情况下block相关的源码表现
iOS源码解析：Block的本质<一>
block系列文章总结
block
Block
探究Block之MethodSignature
block的内存存储
iOS-2 Block
iOS block底层分析(2)--源码探索

整理了_block在各种情况下的源码表现，目的是帮助自己加深对_block的理解。

1.

typedef void (^MJBlock)(void);

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        
        __block __weak int age = 10;
        
        MJBlock block2 = ^{
            age = 30;
            NSLog(@"age is %d", age);
        };
        block2();
        
    }
    return 0;
}

源码


typedef void (*MJBlock)(void);
struct __block_impl {
  void *isa;
  int Flags;
  int Reserved;
  void *FuncPtr;
};
struct __Block_byref_age_0 {
  void *__isa;
__Block_byref_age_0 *__forwarding;
 int __flags;
 int __size;
 int age;
};

struct __main_block_impl_0 {
  struct __block_impl impl;
  struct __main_block_desc_0* Desc;
  __Block_byref_age_0 *age; // by ref
  __main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, __Block_byref_age_0 *_age, int flags=0) : age(_age->__forwarding) {
    impl.isa = &_NSConcreteStackBlock;
    impl.Flags = flags;
    impl.FuncPtr = fp;
    Desc = desc;
  }
};
static void __main_block_func_0(struct __main_block_impl_0 *__cself) {
  __Block_byref_age_0 *age = __cself->age; // bound by ref

            (age->__forwarding->age) = 30;
            NSLog((NSString *)&__NSConstantStringImpl__var_folders_mm_hfgvs481081__0wdsw776zfh0000gn_T_main_419699_mi_0, (age->__forwarding->age));
        }
static void __main_block_copy_0(struct __main_block_impl_0*dst, struct __main_block_impl_0*src) {_Block_object_assign((void*)&dst->age, (void*)src->age, 8/*BLOCK_FIELD_IS_BYREF*/);}

static void __main_block_dispose_0(struct __main_block_impl_0*src) {_Block_object_dispose((void*)src->age, 8/*BLOCK_FIELD_IS_BYREF*/);}

static struct __main_block_desc_0 {
  size_t reserved;
  size_t Block_size;
  void (*copy)(struct __main_block_impl_0*, struct __main_block_impl_0*);
  void (*dispose)(struct __main_block_impl_0*);
} __main_block_desc_0_DATA = { 0, sizeof(struct __main_block_impl_0), __main_block_copy_0, __main_block_dispose_0};
int main(int argc, const char * argv[]) {
    /* @autoreleasepool */ { __AtAutoreleasePool __autoreleasepool; 

        __attribute__((__blocks__(byref))) __attribute__((objc_ownership(weak))) __Block_byref_age_0 age = {(void*)0,(__Block_byref_age_0 *)&age, 0, sizeof(__Block_byref_age_0), 10};


        MJBlock block2 = ((void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA, (__Block_byref_age_0 *)&age, 570425344));


        ((void (*)(__block_impl *))((__block_impl *)block2)->FuncPtr)((__block_impl *)block2);

    }
    return 0;
}

2.

typedef void (^MJBlock)(void);

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        
        __block __weak int age = 10;
        
        MJBlock block1 = ^{
            __strong int myage = age;
            age = 20;
            NSLog(@"age is %d", age);
        };
        
        block1();
        
    }
    return 0;
}

源码


typedef void (*MJBlock)(void);
struct __block_impl {
  void *isa;
  int Flags;
  int Reserved;
  void *FuncPtr;
};

struct __Block_byref_age_0 {
  void *__isa;
__Block_byref_age_0 *__forwarding;
 int __flags;
 int __size;
 int age;
};

struct __main_block_impl_0 {
  struct __block_impl impl;
  struct __main_block_desc_0* Desc;
  __Block_byref_age_0 *age; // by ref
  __main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, __Block_byref_age_0 *_age, int flags=0) : age(_age->__forwarding) {
    impl.isa = &_NSConcreteStackBlock;
    impl.Flags = flags;
    impl.FuncPtr = fp;
    Desc = desc;
  }
};
static void __main_block_func_0(struct __main_block_impl_0 *__cself) {
  __Block_byref_age_0 *age = __cself->age; // bound by ref

            __attribute__((objc_ownership(strong))) int myage = (age->__forwarding->age);
            (age->__forwarding->age) = 20;
            NSLog((NSString *)&__NSConstantStringImpl__var_folders_mm_hfgvs481081__0wdsw776zfh0000gn_T_main_05aebe_mi_0, (age->__forwarding->age));
        }
static void __main_block_copy_0(struct __main_block_impl_0*dst, struct __main_block_impl_0*src) {_Block_object_assign((void*)&dst->age, (void*)src->age, 8/*BLOCK_FIELD_IS_BYREF*/);}

static void __main_block_dispose_0(struct __main_block_impl_0*src) {_Block_object_dispose((void*)src->age, 8/*BLOCK_FIELD_IS_BYREF*/);}

static struct __main_block_desc_0 {
  size_t reserved;
  size_t Block_size;
  void (*copy)(struct __main_block_impl_0*, struct __main_block_impl_0*);
  void (*dispose)(struct __main_block_impl_0*);
} __main_block_desc_0_DATA = { 0, sizeof(struct __main_block_impl_0), __main_block_copy_0, __main_block_dispose_0};
int main(int argc, const char * argv[]) {
    /* @autoreleasepool */ { __AtAutoreleasePool __autoreleasepool; 

        __attribute__((__blocks__(byref))) __attribute__((objc_ownership(weak))) __Block_byref_age_0 age = {(void*)0,(__Block_byref_age_0 *)&age, 0, sizeof(__Block_byref_age_0), 10};

        MJBlock block1 = ((void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA, (__Block_byref_age_0 *)&age, 570425344));

        ((void (*)(__block_impl *))((__block_impl *)block1)->FuncPtr)((__block_impl *)block1);


    }
    return 0;
}

3.

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        
       __block MJPerson *person = [[MJPerson alloc] init];
        
        MJBlock block = [^{
            NSLog(@"%p", person);
        } copy];
        
        NSLog(@"%@",[block class]);
        block();
    }
    return 0;
}

源码


typedef void (*MJBlock) (void);

struct __Block_byref_age_0 {
    void *__isa;
    struct __Block_byref_age_0 *__forwarding;
    int __flags;
    int __size;
    int age;
};

struct __main_block_desc_0 {
    size_t reserved;
    size_t Block_size;
    void (*copy)(void);
    void (*dispose)(void);
};

struct __block_impl {
    void *isa;
    int Flags;
    int Reserved;
    void *FuncPtr;
};

struct __main_block_impl_0 {
    struct __block_impl impl;
    struct __main_block_desc_0* Desc;
    struct __Block_byref_age_0 *age;
};

struct __Block_byref_person_0 {
  void *__isa;
__Block_byref_person_0 *__forwarding;
 int __flags;
 int __size;
 void (*__Block_byref_id_object_copy)(void*, void*);
 void (*__Block_byref_id_object_dispose)(void*);
 MJPerson *__strong person;
};

struct __main_block_impl_0 {
  struct __block_impl impl;
  struct __main_block_desc_0* Desc;
  __Block_byref_person_0 *person; // by ref
  __main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, __Block_byref_person_0 *_person, int flags=0) : person(_person->__forwarding) {
    impl.isa = &_NSConcreteStackBlock;
    impl.Flags = flags;
    impl.FuncPtr = fp;
    Desc = desc;
  }
};
static void __main_block_func_0(struct __main_block_impl_0 *__cself) {
  __Block_byref_person_0 *person = __cself->person; // bound by ref

            NSLog((NSString *)&__NSConstantStringImpl__var_folders_mm_hfgvs481081__0wdsw776zfh0000gn_T_main_48cd6f_mi_0, (person->__forwarding->person));
        }
static void __main_block_copy_0(struct __main_block_impl_0*dst, struct __main_block_impl_0*src) {_Block_object_assign((void*)&dst->person, (void*)src->person, 8/*BLOCK_FIELD_IS_BYREF*/);}

static void __main_block_dispose_0(struct __main_block_impl_0*src) {_Block_object_dispose((void*)src->person, 8/*BLOCK_FIELD_IS_BYREF*/);}

static struct __main_block_desc_0 {
  size_t reserved;
  size_t Block_size;
  void (*copy)(struct __main_block_impl_0*, struct __main_block_impl_0*);
  void (*dispose)(struct __main_block_impl_0*);
} __main_block_desc_0_DATA = { 0, sizeof(struct __main_block_impl_0), __main_block_copy_0, __main_block_dispose_0};
int main(int argc, const char * argv[]) {
    /* @autoreleasepool */ { __AtAutoreleasePool __autoreleasepool; 

       __attribute__((__blocks__(byref))) __Block_byref_person_0 person = {(void*)0,(__Block_byref_person_0 *)&person, 33554432, sizeof(__Block_byref_person_0), __Block_byref_id_object_copy_131, __Block_byref_id_object_dispose_131, ((MJPerson *(*)(id, SEL))(void *)objc_msgSend)((id)((MJPerson *(*)(id, SEL))(void *)objc_msgSend)((id)objc_getClass("MJPerson"), sel_registerName("alloc")), sel_registerName("init"))};

        MJBlock block = (__strong MJBlock)((id (*)(id, SEL))(void *)objc_msgSend)((id)((void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA, (__Block_byref_person_0 *)&person, 570425344)), sel_registerName("copy"));

        NSLog((NSString *)&__NSConstantStringImpl__var_folders_mm_hfgvs481081__0wdsw776zfh0000gn_T_main_48cd6f_mi_1,((Class (*)(id, SEL))(void *)objc_msgSend)((id)block, sel_registerName("class")));


        ((void (*)(__block_impl *))((__block_impl *)block)->FuncPtr)((__block_impl *)block);


    }
    return 0;
}

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