C 工具库2：异常处理

使用setjmp,longjmp实现的C与言异常处理框架。

提供 抛出异常，捕获异常等功能。

exception.h

#ifndef _EXCEPTION_H
#define _EXCEPTION_H

#define except_alloc_failed 1   //内存分配失败
#define except_list_empty   2   //list_pop操作,当list为空触发
//............

#endif

except.h

#ifndef _EXCEPT_H
#define _EXCEPT_H
#include <setjmp.h>
#include <stdio.h>
#include <assert.h>

struct exception_frame
{
    struct exception_frame *pre;
    jmp_buf jumpbuffer;
    int exception;
    int line;
    const char *file;
};

extern struct exception_frame *exception_stack;

extern void exception_throw(int code,const char *file,int line);

/*一个函数第一次使用TRY前必须定义,如果重复定义会出现不确定的行为
* 主要是为了正确处理在TRY代码内的RETURN
*/
#define FUNCTION_TRY int function_except_stack_count = 0; 
#define TRY do{\
    ++function_except_stack_count;\
    struct exception_frame  frame;\
    frame.pre = exception_stack;\
    exception_stack = &frame;\
    if((frame.exception = setjmp(frame.jumpbuffer)) == 0)
    
#define THROW(EXP) exception_throw(EXP,__FILE__,__LINE__)

#define RETHROW exception_throw(frame.exception,frame.file,frame.line)

#define CATCH(EXP) else if(EXP == frame.exception ? frame.exception = 0,1:0)

#define CATCH_ALL else if(frame.exception ? frame.exception = 0,1:0)

#define ENDTRY --function_except_stack_count;\
               if(frame.exception){\
                    exception_throw(frame.exception,frame.file,frame.line);}\
               else if(exception_stack){\
                    exception_stack = exception_stack->pre;\
                    }\
            }while(0);                    

#define FINALLY
/*根据当前函数中try的处理情况丢弃数量正确的异常栈,再返回*/
#define RETURN(R) do{if(exception_stack){\
                        while(exception_stack && function_except_stack_count>0){\
                            function_except_stack_count--;\
                            exception_stack = exception_stack->pre;\
                        }\
                     }\
                     return R;\
                  }while(0)

#endif

except.c

#include "except.h"
#include <stdlib.h>

struct exception_frame *exception_stack = 0;

void exception_throw(int code,const char *file,int line)
{
    if(exception_stack)
    {
        
        exception_stack->exception = code;
        exception_stack->file = file;
        exception_stack->line = line;
        struct exception_frame *frame = exception_stack;
        exception_stack = frame->pre;
        longjmp(frame->jumpbuffer,code);
    }
    else
    {
        printf("unsolved exception %d,file:%s line:%d\n",code,file,line);
    }
}

test.c

#include "except.h"

int func1()
{
    FUNCTION_TRY
    TRY{
        TRY{
            RETURN(0);
            func2();
        }
        printf("func1 %d\n",function_except_stack_count);
        ENDTRY
    }
    CATCH(1)
    {
        printf("catch a exception\n");
    }
    FINALLY
    {
        printf("func1 %d\n",function_except_stack_count);
        RETURN(0);
        printf("func1 finally\n");
    }
    ENDTRY
}

int func2()
{
    printf("beginjump\n");
    THROW(2);
    printf("end of func2\n");
}

int main()
{

    FUNCTION_TRY
    TRY{
        func1();
        printf("return\n");
        TRY{
            func1();
        }
        CATCH(2)
        {
            printf("catch a exception 2\n");
            TRY{
                THROW(2);
            }
            ENDTRY
            
        }
        FINALLY
        {
            printf("finally\n");
        }
        ENDTRY
    }
    CATCH_ALL
    {
        printf("catch all\n");
    }    
    ENDTRY
    return 0;
}