RunTime实现无侵入全局埋点

无埋点，不是不需要埋点，更确切地说是“全埋点”，只是埋点代码不会出现在业务代码中
优点：容易管理和维护。并且可移植性高。
缺点：埋点成本高，后期的解析也比较复杂，再加上 view_path 的不确定性。所以，这种方案并不能解决所有的埋点需求，但对于大量通用的埋点需求来说，能够节省大量的开发和维护成本。

废话不多说直接上代码
1.创建一个Hook类用于方法替换
.h文件如下

@interface Hook : NSObject
+ (void)hookClass:(Class)classObject fromSelector:(SEL)fromSelector toSelector:(SEL)toSelector;
@end

.m文件如下

#import "Hook.h"
#import 
@implementation Hook
+ (void)hookClass:(Class)classObject fromSelector:(SEL)fromSelector toSelector:(SEL)toSelector {
    Class class = classObject;
    // 得到被替换类的实例方法
    Method fromMethod = class_getInstanceMethod(class, fromSelector);
    // 得到替换类的实例方法
    Method toMethod = class_getInstanceMethod(class, toSelector);
    
    // class_addMethod 返回成功表示被替换的方法没实现，然后会通过 class_addMethod 方法先实现；返回失败则表示被替换方法已存在，可以直接进行 IMP 指针交换
    if(class_addMethod(class, fromSelector, method_getImplementation(toMethod), method_getTypeEncoding(toMethod))) {
      // 进行方法的替换
        class_replaceMethod(class, toSelector, method_getImplementation(fromMethod), method_getTypeEncoding(fromMethod));
    } else {
      // 交换 IMP 指针
        method_exchangeImplementations(fromMethod, toMethod);
    }

}
@end

写一个UIViewcontroller的分类

@interface UIViewController (HookBuriedPoint)

@end

分类.m文件代码如下

#import "UIViewController+HookBuriedPoint.h"
#import "Hook.h"
@implementation UIViewController (HookBuriedPoint)
+ (void)load {
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        // 通过 @selector 获得被替换和替换方法的 SEL，作为 ViewHook:hookClass:fromeSelector:toSelector 的参数传入
        SEL fromSelectorAppear = @selector(viewWillAppear:);
        SEL toSelectorAppear = @selector(hook_viewWillAppear:);
        [Hook hookClass:self fromSelector:fromSelectorAppear toSelector:toSelectorAppear];
        
        SEL fromSelectorDisappear = @selector(viewWillDisappear:);
        SEL toSelectorDisappear = @selector(hook_viewWillDisappear:);
        
        [Hook hookClass:self fromSelector:fromSelectorDisappear toSelector:toSelectorDisappear];
    });
}

- (void)hook_viewWillAppear:(BOOL)animated {
    // 先执行插入代码，再执行原 viewWillAppear 方法
    [self insertToViewWillAppear];
    [self hook_viewWillAppear:animated];
}
- (void)hook_viewWillDisappear:(BOOL)animated {
    // 执行插入代码，再执行原 viewWillDisappear 方法
    [self insertToViewWillDisappear];
    [self hook_viewWillDisappear:animated];
}

- (void)insertToViewWillAppear {
    // 在 ViewWillAppear 时进全局无侵入埋点
    NSLog(@"hook-%@",[NSString stringWithFormat:@"%@ Appear",NSStringFromClass([self class])]);
}
- (void)insertToViewWillDisappear {
    // 在 ViewWillDisappear 时进全局无侵入埋点
}
@end