iOS调试——Chisel

Chisel是facebook开源的辅助xcode进行iOS开发调试的工具，包含一系列更加有用的lldb命令，而且Chisel还支持添加本地以及自定义命令。本文从工具介绍开始，带大家认识并使用这一强大工具。

Chisel 简介

github地址

安装

直接按照官方文档进行：

1. 安装Homebrew

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

2. 安装Chisel

brew update
brew install chisel

3. 更新.lldbinit
   .lldbinit文件是lldb启动之前加载的文件，用于lldb的初始化，每次lldb启动都会加载。安装chisel成功之后，终端会打印如下提示，按照提示，将启动chisel的命令复制到.lldbinit文件中。

   
   chisel安装.png
   

   我是通过如下命令直接将上面的命令写入文件中(>>表示追加到文件尾，如果你已经添加过则无需再次添加)

echo command script import /usr/local/opt/chisel/libexec/fblldb.py >> ~/.lldbinit

4. 重启xcode并check
   check方法有两种，第一种是打开终端依次输入：llbd<enter>,help<enter>；第二种方法是打开xcode，打断点并执行到断点处，输入help命令。滚动help的结果，当找到Current user-defined commands:一行，即表示安装成功。

   
   chisel安装check.png

Chisel常用命令简介

• pmethods
  print the class and instance methods of a class.

• pclass
  Print the inheritance starting from an instance of any class.

• poobjc
  Print the expression result, with the expression run in an ObjC++ context. (Shortcut for "expression -O -l ObjC++ -- " ).

• pviews
  Print the recursion description of <aView>.

• pcells
  Print the visible cells of the highest table view in the hierarchy.

• pblock
  Print the block`s implementation address and signature.

• mask
  Add a transparent rectangle to the window to reveal a possibly obscured or hidden view or layer's bounds

• border
  Draws a border around <viewOrLayer>. Color and width can be optionally provided. Additionally depth can be provided in order to recursively border subviews.

• show
  Show a view or layer.

添加本地及自定义命令

参考官方文档，这里整理出基本步骤如下：

1. 开发命令脚本
   官方文档提供了一个example（源码贴在下面方便大家阅读）
2. 更新.lldbinit
   同Chisel安装完成后的步骤一样，需要将初始化的命令同步到.lldbinit文件中。
3. check命令
   同check Chisel是否安装成功的方法一样。

#!/usr/bin/python
# Example file with custom commands, located at /magical/commands/example.py

import lldb
import fblldbbase as fb

def lldbcommands():
  return [ PrintKeyWindowLevel() ]
  
class PrintKeyWindowLevel(fb.FBCommand):
  def name(self):
    return 'pkeywinlevel'
    
  def description(self):
    return 'An incredibly contrived command that prints the window level of the key window.'
    
  def run(self, arguments, options):
    # It's a good habit to explicitly cast the type of all return
    # values and arguments. LLDB can't always find them on its own.
    lldb.debugger.HandleCommand('p (CGFloat)[(id)[(id)[UIApplication sharedApplication] keyWindow] windowLevel]')

最后，Enjoy yourself！