这篇文章主要记录下，block在不同情况下的源码表现，目的在于加深自己对于block理解
相关命令
xcrun -sdk iphoneos clang -arch arm64 -rewrite-objc OC源文件 -o 输出的CPP文件
__weak无法生成源码的问题
clang -rewrite-objc -fobjc-arc -fobjc-runtime=macosx-10.14 main.m -o main1.cpp
1.
void (^block)(void);
void test()
{
int age = 10;
static int height = 10;
block = ^{
// age的值捕获进来（capture）
NSLog(@"age is %d, height is %d", age, height);
};
age = 20;
height = 20;
}
int main(int argc, const char * argv[]) {
@autoreleasepool {
test();
block();
}
return 0;
}
源码
void (*block)(void);
struct __test_block_impl_0 {
struct __block_impl impl;
struct __test_block_desc_0* Desc;
int age;
int *height;
__test_block_impl_0(void *fp, struct __test_block_desc_0 *desc, int _age, int *_height, int flags=0) : age(_age), height(_height) {
impl.isa = &_NSConcreteStackBlock;
impl.Flags = flags;
impl.FuncPtr = fp;
Desc = desc;
}
};
static void __test_block_func_0(struct __test_block_impl_0 *__cself) {
int age = __cself->age; // bound by copy
int *height = __cself->height; // bound by copy
NSLog((NSString *)&__NSConstantStringImpl__var_folders_2r__m13fp2x2n9dvlr8d68yry500000gn_T_main_d2875b_mi_0, age, (*height));
}
static struct __test_block_desc_0 {
size_t reserved;
size_t Block_size;
} __test_block_desc_0_DATA = { 0, sizeof(struct __test_block_impl_0)};
void test()
{
int age = 10;
static int height = 10;
block = ((void (*)())&__test_block_impl_0((void *)__test_block_func_0, &__test_block_desc_0_DATA, age, &height));
age = 20;
height = 20;
}
int main(int argc, const char * argv[]) {
/* @autoreleasepool */ { __AtAutoreleasePool __autoreleasepool;
test();
((void (*)(__block_impl *))((__block_impl *)block)->FuncPtr)((__block_impl *)block);
}
return 0;
}
2.
void (^block)(void);
int main(int argc, const char * argv[]) {
@autoreleasepool {
void (^block)(void) = ^{
NSLog(@"Hello, World!");
};
block();
}
return 0;
}
源码
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;
// 构造函数（类似于OC的init方法），返回结构体对象
__main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, int flags=0) {
impl.isa = &_NSConcreteStackBlock;
impl.Flags = flags;
impl.FuncPtr = fp;
Desc = desc;
}
};
// 封装了block执行逻辑的函数
static void __main_block_func_0(struct __main_block_impl_0 *__cself) {
NSLog((NSString *)&__NSConstantStringImpl__var_folders_2r__m13fp2x2n9dvlr8d68yry500000gn_T_main_c60393_mi_0);
}
static struct __main_block_desc_0 {
size_t reserved;
size_t Block_size;
} __main_block_desc_0_DATA = { 0, sizeof(struct __main_block_impl_0)};
int main(int argc, const char * argv[]) {
/* @autoreleasepool */ { __AtAutoreleasePool __autoreleasepool;
// 定义block变量
void (*block)(void) = &__main_block_impl_0(
__main_block_func_0,
&__main_block_desc_0_DATA
);
// 执行block内部的代码
block->FuncPtr(block);
}
return 0;
}
3.
@implementation Person
int age_ = 10;
- (void)test
{
void (^block)(void) = ^{
NSLog(@"-------%d", [self name]);
};
block();
}
- (instancetype)initWithName:(NSString *)name
{
if (self = [super init]) {
self.name = name;
}
return self;
}
@end
源码
struct __MJPerson__test_block_impl_0 {
struct __block_impl impl;
struct __MJPerson__test_block_desc_0* Desc;
MJPerson *self;
__MJPerson__test_block_impl_0(void *fp, struct __MJPerson__test_block_desc_0 *desc, MJPerson *_self, int flags=0) : self(_self) {
impl.isa = &_NSConcreteStackBlock;
impl.Flags = flags;
impl.FuncPtr = fp;
Desc = desc;
}
};
static void __MJPerson__test_block_func_0(struct __MJPerson__test_block_impl_0 *__cself) {
MJPerson *self = __cself->self; // bound by copy
NSLog((NSString *)&__NSConstantStringImpl__var_folders_2r__m13fp2x2n9dvlr8d68yry500000gn_T_MJPerson_1027e6_mi_0, ((NSString *(*)(id, SEL))(void *)objc_msgSend)((id)self, sel_registerName("name")));
}
static void __MJPerson__test_block_copy_0(struct __MJPerson__test_block_impl_0*dst, struct __MJPerson__test_block_impl_0*src) {_Block_object_assign((void*)&dst->self, (void*)src->self, 3/*BLOCK_FIELD_IS_OBJECT*/);}
static void __MJPerson__test_block_dispose_0(struct __MJPerson__test_block_impl_0*src) {_Block_object_dispose((void*)src->self, 3/*BLOCK_FIELD_IS_OBJECT*/);}
static struct __MJPerson__test_block_desc_0 {
size_t reserved;
size_t Block_size;
void (*copy)(struct __MJPerson__test_block_impl_0*, struct __MJPerson__test_block_impl_0*);
void (*dispose)(struct __MJPerson__test_block_impl_0*);
} __MJPerson__test_block_desc_0_DATA = { 0, sizeof(struct __MJPerson__test_block_impl_0), __MJPerson__test_block_copy_0, __MJPerson__test_block_dispose_0};
static void _I_MJPerson_test(MJPerson * self, SEL _cmd) {
void (*block)(void) = ((void (*)())&__MJPerson__test_block_impl_0((void *)__MJPerson__test_block_func_0, &__MJPerson__test_block_desc_0_DATA, self, 570425344));
((void (*)(__block_impl *))((__block_impl *)block)->FuncPtr)((__block_impl *)block);
}
static instancetype _I_MJPerson_initWithName_(MJPerson * self, SEL _cmd, NSString *name) {
if (self = ((MJPerson *(*)(__rw_objc_super *, SEL))(void *)objc_msgSendSuper)((__rw_objc_super){(id)self, (id)class_getSuperclass(objc_getClass("MJPerson"))}, sel_registerName("init"))) {
((void (*)(id, SEL, NSString *))(void *)objc_msgSend)((id)self, sel_registerName("setName:"), (NSString *)name);
}
return self;
}
4.
typedef void (^MJBlock)(void);
int main(int argc, const char * argv[]) {
@autoreleasepool {
MJBlock block;
{
MJPerson *person = [[MJPerson alloc] init];
person.age = 10;
int age = 10;
block = ^{
NSLog(@"---------%d", person.age);
};
}
NSLog(@"------");
}
return 0;
}
源码
typedef void (*MJBlock)(void);
struct __main_block_impl_0 {
struct __block_impl impl;
struct __main_block_desc_0* Desc;
MJPerson *__strong person;
__main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, MJPerson *__strong _person, int flags=0) : person(_person) {
impl.isa = &_NSConcreteStackBlock;
impl.Flags = flags;
impl.FuncPtr = fp;
Desc = desc;
}
};
static void __main_block_func_0(struct __main_block_impl_0 *__cself) {
MJPerson *__strong person = __cself->person; // bound by copy
NSLog((NSString *)&__NSConstantStringImpl__var_folders_mm_hfgvs481081__0wdsw776zfh0000gn_T_main_13ee9c_mi_0, ((int (*)(id, SEL))(void *)objc_msgSend)((id)person, sel_registerName("age")));
}
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, 3/*BLOCK_FIELD_IS_OBJECT*/);}
static void __main_block_dispose_0(struct __main_block_impl_0*src) {_Block_object_dispose((void*)src->person, 3/*BLOCK_FIELD_IS_OBJECT*/);}
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;
MJBlock block;
{
MJPerson *person = ((MJPerson *(*)(id, SEL))(void *)objc_msgSend)((id)((MJPerson *(*)(id, SEL))(void *)objc_msgSend)((id)objc_getClass("MJPerson"), sel_registerName("alloc")), sel_registerName("init"));
((void (*)(id, SEL, int))(void *)objc_msgSend)((id)person, sel_registerName("setAge:"), 10);
int age = 10;
block = ((void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA, person, 570425344));
}
NSLog((NSString *)&__NSConstantStringImpl__var_folders_mm_hfgvs481081__0wdsw776zfh0000gn_T_main_13ee9c_mi_1);
}
return 0;
}
5.
typedef void (^MJBlock)(void);
int main(int argc, const char * argv[]) {
@autoreleasepool {
MJBlock block;
{
MJPerson *person = [[MJPerson alloc] init];
person.age = 10;
__weak MJPerson *weakPerson = person;
int age = 10;
block = ^{
NSLog(@"---------%d", weakPerson.age);
};
}
NSLog(@"------");
}
return 0;
}
源码
typedef void (*MJBlock)(void);
struct __main_block_impl_0 {
struct __block_impl impl;
struct __main_block_desc_0* Desc;
MJPerson *__weak weakPerson;
__main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, MJPerson *__weak _weakPerson, int flags=0) : weakPerson(_weakPerson) {
impl.isa = &_NSConcreteStackBlock;
impl.Flags = flags;
impl.FuncPtr = fp;
Desc = desc;
}
};
static void __main_block_func_0(struct __main_block_impl_0 *__cself) {
MJPerson *__weak weakPerson = __cself->weakPerson; // bound by copy
NSLog((NSString *)&__NSConstantStringImpl__var_folders_mm_hfgvs481081__0wdsw776zfh0000gn_T_main_1cad2d_mi_0, ((int (*)(id, SEL))(void *)objc_msgSend)((id)weakPerson, sel_registerName("age")));
}
static void __main_block_copy_0(struct __main_block_impl_0*dst, struct __main_block_impl_0*src) {_Block_object_assign((void*)&dst->weakPerson, (void*)src->weakPerson, 3/*BLOCK_FIELD_IS_OBJECT*/);}
static void __main_block_dispose_0(struct __main_block_impl_0*src) {_Block_object_dispose((void*)src->weakPerson, 3/*BLOCK_FIELD_IS_OBJECT*/);}
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;
MJBlock block;
{
MJPerson *person = ((MJPerson *(*)(id, SEL))(void *)objc_msgSend)((id)((MJPerson *(*)(id, SEL))(void *)objc_msgSend)((id)objc_getClass("MJPerson"), sel_registerName("alloc")), sel_registerName("init"));
((void (*)(id, SEL, int))(void *)objc_msgSend)((id)person, sel_registerName("setAge:"), 10);
__attribute__((objc_ownership(weak))) MJPerson *weakPerson = person;
int age = 10;
block = ((void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA, weakPerson, 570425344));
}
NSLog((NSString *)&__NSConstantStringImpl__var_folders_mm_hfgvs481081__0wdsw776zfh0000gn_T_main_1cad2d_mi_1);
}
return 0;
}
6.
typedef void (^MJBlock)(void);
int main(int argc, const char * argv[]) {
@autoreleasepool {
MJBlock block;
{
MJPerson *person = [[MJPerson alloc] init];
person.age = 10;
__weak MJPerson *weakPerson = person;
block = ^{
__strong MJPerson *strongPerson =weakPerson;
NSLog(@"---------%d", strongPerson.age);
};
}
NSLog(@"------");
}
return 0;
}
源码
typedef void (*MJBlock)(void);
struct __main_block_impl_0 {
struct __block_impl impl;
struct __main_block_desc_0* Desc;
MJPerson *__weak weakPerson;
__main_block_impl_0(void *fp, struct __main_block_desc_0 *desc, MJPerson *__weak _weakPerson, int flags=0) : weakPerson(_weakPerson) {
impl.isa = &_NSConcreteStackBlock;
impl.Flags = flags;
impl.FuncPtr = fp;
Desc = desc;
}
};
static void __main_block_func_0(struct __main_block_impl_0 *__cself) {
MJPerson *__weak weakPerson = __cself->weakPerson; // bound by copy
__attribute__((objc_ownership(strong))) MJPerson *strongPerson =weakPerson;
NSLog((NSString *)&__NSConstantStringImpl__var_folders_mm_hfgvs481081__0wdsw776zfh0000gn_T_main_47b66f_mi_0, ((int (*)(id, SEL))(void *)objc_msgSend)((id)strongPerson, sel_registerName("age")));
}
static void __main_block_copy_0(struct __main_block_impl_0*dst, struct __main_block_impl_0*src) {_Block_object_assign((void*)&dst->weakPerson, (void*)src->weakPerson, 3/*BLOCK_FIELD_IS_OBJECT*/);}
static void __main_block_dispose_0(struct __main_block_impl_0*src) {_Block_object_dispose((void*)src->weakPerson, 3/*BLOCK_FIELD_IS_OBJECT*/);}
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;
MJBlock block;
{
MJPerson *person = ((MJPerson *(*)(id, SEL))(void *)objc_msgSend)((id)((MJPerson *(*)(id, SEL))(void *)objc_msgSend)((id)objc_getClass("MJPerson"), sel_registerName("alloc")), sel_registerName("init"));
((void (*)(id, SEL, int))(void *)objc_msgSend)((id)person, sel_registerName("setAge:"), 10);
__attribute__((objc_ownership(weak))) MJPerson *weakPerson = person;
block = ((void (*)())&__main_block_impl_0((void *)__main_block_func_0, &__main_block_desc_0_DATA, weakPerson, 570425344));
}
NSLog((NSString *)&__NSConstantStringImpl__var_folders_mm_hfgvs481081__0wdsw776zfh0000gn_T_main_47b66f_mi_1);
}
return 0;
}
7.
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