Xcode忽略指定的异常断点

前言

日常的Xcode开发中，我们时常用【All Exceptions Breakpoint】来定位一些异常情况的断点 但该功能同时也会在@try@catch或者在使用诸如CoreData或Accessibility之类的异常大量框架时，很难追踪到您实际遇到的异常

解决方法

建立脚本

1. 采用以下脚本生成ignore_specified_objc_exceptions.py文件

代码语言：javascript复制

import lldb
import re
import shlex

# This script allows Xcode to selectively ignore Obj-C exceptions
# based on any selector on the NSException instance

def getRegister(target):
    if target.triple.startswith('x86_64'):
        return "rdi"
    elif target.triple.startswith('i386'):
        return "eax"
    elif target.triple.startswith('arm64'):
        return "x0"
    else:
        return "r0"

def callMethodOnException(frame, register, method):
    return frame.EvaluateExpression("(NSString *)[(NSException *)${0} {1}]".format(register, method)).GetObjectDescription()

def filterException(debugger, user_input, result, unused):
    target = debugger.GetSelectedTarget()
    frame = target.GetProcess().GetSelectedThread().GetFrameAtIndex(0)

    if frame.symbol.name != 'objc_exception_throw':
        # We can't handle anything except objc_exception_throw
        return None

    filters = shlex.split(user_input)

    register = getRegister(target)


    for filter in filters:
        method, regexp_str = filter.split(":", 1)
        value = callMethodOnException(frame, register, method)

        if value is None:
            output = "Unable to grab exception from register {0} with method {1}; skipping...".format(register, method)
            result.PutCString(output)
            result.flush()
            continue

        regexp = re.compile(regexp_str)

        if regexp.match(value):
            output = "Skipping exception because exception's {0} ({1}) matches {2}".format(method, value, regexp_str)
            result.PutCString(output)
            result.flush()

            # If we tell the debugger to continue before this script finishes,
            # Xcode gets into a weird state where it won't refuse to quit LLDB,
            # so we set async so the script terminates and hands control back to Xcode
            debugger.SetAsync(True)
            debugger.HandleCommand("continue")
            return None

    return None

def __lldb_init_module(debugger, unused):
    debugger.HandleCommand('command script add --function ignore_specified_objc_exceptions.filterException ignore_specified_objc_exceptions')

1. 将此脚本放在某处（例如~/Library/lldb/ignore_specified_objc_exceptions.py）
2. 在~/.lldbinit中添加以下内容：

代码语言：javascript复制

command script import ~/Library/lldb/ignore_specified_objc_exceptions.py

~/Library/lldb/ignore_specified_objc_exceptions.py如果您将其保存在其他位置，请替换为正确的路径。

使用方法

1. All Exceptions Breakpoint选择Objective-C
2. Debugger Command中添加以下语句： ignore_specified_objc_exceptions className:DTRpcException name: NSAccessibilityException 这样就忽略类名为DTRpcException或者name为NSAccessibilityException的异常

快捷部署方法

一键部署脚本：

代码语言：javascript复制

mkdir -p ~/Library/lldb
curl -L https://gist.github.com/chendo/6759305/raw/ignore_specified_objc_exceptions.py > ~/Library/lldb/ignore_specified_objc_exceptions.py
echo "command script import ~/Library/lldb/ignore_specified_objc_exceptions.py" >> ~/.lldbinit

参考：这里

access python

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