避免“如果清除失败”的模式重复 [英] Pattern to avoid "if failed cleanup" repetition

问题描述

我有一些看起来像这样的代码：

I have some code that looks like this:

int myfunc()
{
     blah a;
     blah2 b;
     blah3 c;
     blah4 d;
     blah5 e;

     int iRes = DoSomething1(a, b, c);
     if (iRes > 0)
     {
         clean1(a, b, c);
         clean2(d, e);
         log_error();
         return 1;
     }

     iRes = DoSomething2(a, c, e);
     if (iRes > 0)
     {
         clean1(a, b, c);
         clean2(d, e);
         log_error();
         return 1;
     }

     ...

     iRes = DoSomething10(c, d, e);
     if (iRes > 0)
     {
         clean1(a, b, c);
         clean2(d, e);
         log_error();
         return 1;
     }

     clean1(a, b, c);
     clean2(d, e);
     return 0;
}

如何在C或C ++中避免重复 if（iRes> 0）{clean1（a，b，c）; clean2（d，e）; log_error（）;返回1; } 在每个函数调用之后？

How, in C or C++, avoid the repetition of if (iRes > 0) { clean1(a, b, c); clean2(d, e); log_error(); return 1; } after each function calls?

注意：

• 在实际代码中，这些函数 DoSomethingx（）和 cleanx（）是API函数，不是我自己写的


• 我想避免使用第二个函数 clean （）在 myfunct（）之外定义，它将处理清理和错误


• 我考虑过使用预处理程序宏，但我怀疑在这种情况下这是否是一个好习惯

• In the real code, these functions DoSomethingx() and cleanx() are API functions, not written by myself
• I'd like to avoid having a second function clean() defined outside of myfunct() that would handle the cleanup + error
• I thought about using preprocessor macro, but I doubt it's a good practice for such situations

示例：

此代码是这种情况的一个示例：实际上，每10行代码= 仅2行仅用于实际执行某操作 + 8行错误测试和清除...更好吗？

This code is an example of such a situation: every 10 lines of code is in fact = 2 lines only for actually doing something + 8 lines of error testing and cleanup... Can we do nicer?

推荐答案

正如贾斯汀（Justin）所言，答案会有所不同

As Justin mentioned, the answers will be quite different depending on the language.

如果您在C语言中，这是 goto 拥有据点的最终位置之一语言。例如，如果您有：

If you are in C, this is one of the final places where goto has a stronghold in the language. For example, if you have:

int myfunc()
{
     blah a;
     blah2 b;
     blah3 c;
     blah4 d;
     blah5 e;

     int iRes = DoSomething1(a, b, c);
     if (iRes > 0)
     {
         goto error_cleanup;
     }

     iRes = DoSomething2(a, c, e);
     if (iRes > 0)
     {
         goto error_cleanup;
     }

     /*...*/

     iRes = DoSomething10(c, d, e);
     if (iRes > 0)
     {
         goto error_cleanup;
     }

     /* SUCCESS */
     clean1(a, b, c);
     clean2(d, e);
     return 0;

 /* ERROR EXIT POINT */
 error_cleanup:

     clean1(a, b, c);
     clean2(d, e);
     log_error();
     return 1;
 }

但是，在C ++中，即使出现异常，我们也需要处理此清理代码抛出，这又使事情变得更加棘手。但是，在c ++中，我们也有RAII，这意味着应该使用析构函数。

However, in C++ we need to deal with this cleanup code even when exceptions are thrown, which puts another wrench into the scheme of things. However, in c++ we also have RAII, which means destructors is the way to go.

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