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/**
* Exception Handling Framework
*
* Exception Handling looks something like this;
*
* ### NOTE ###
* You must use a FINALLY block if you use "default:" block. Otherwise the
* default: block will get called in place of the FINALLY block.
*
*
* <pre>
* FRT_TRY
* FRT_RAISE(FRT_EXCEPTION, msg1);
* break;
* case FRT_EXCEPTION:
* // This should be called
* exception_handled = true;
* FRT_HANDLED();
* break;
* default:
* // shouldn't enter here
* break;
* FRT_XFINALLY
* // this code will always be run
* if (close_widget_one(arg) == 0) {
* FRT_RAISE(EXCEPTION_CODE, msg);
* }
* // this code will also always run, even if the above exception is
* // raised
* if (close_widget_two(arg) == 0) {
* FRT_RAISE(EXCEPTION_CODE, msg);
* }
* FRT_XENDTRY
* </pre>
*
* Basically exception handling uses the following macros;
*
* FRT_TRY
* Sets up the exception handler and need be placed before any expected
* exceptions would be raised.
*
* case <EXCEPTION_CODE>:
* Internally the exception handling uses a switch statement so use the case
* statement with the appropriate error code to catch Exceptions. Hence, if
* you want to catch all exceptions, use the default keyword.
*
* FRT_HANDLED
* If you catch and handle an exception you need to explicitely call
* FRT_HANDLED(); or the exeption will be re-raised once the current exception
* handling context is left.
*
* case FRT_FINALLY:
* Code in this block is always called. Use this block to close any
* resources opened in the Exception handling body.
*
* FRT_ENDTRY
* Must be placed at the end of all exception handling code.
*
* FRT_XFINALLY
* Similar to case FRT_FINALLY: except that it uses a fall through (ie, you must
* not use a break before it) instead of a jump to get to it. This saves a
* jump. It must be used in combination with FRT_XENDTRY and must not have any
* other catches. This is an optimization so should probably be not be used
* in most cases.
*
* FRT_XCATCHALL
* Like FRT_XFINALLY but the block is only called when an exception is raised.
* Must use in combination with FRT_XENDTRY and do not have any other FRT_FINALLY or
* catch block.
*
* FRT_XENDTRY
* Must use in combination with FRT_XFINALLY or FRT_XCATCHALL. Simply, it doesn't
* jump to FRT_FINALLY, making it more efficient.
*/
#ifndef FRT_EXCEPT_H
#define FRT_EXCEPT_H
#ifdef __cplusplus
extern "C" {
#endif
#include <setjmp.h>
#include "config.h"
/* TODO make this an enum */
#define FRT_BODY 0
#define FRT_FINALLY 1
#define FRT_EXCEPTION 2
#define FRT_FERRET_ERROR 2
#define FRT_IO_ERROR 3
#define FRT_FILE_NOT_FOUND_ERROR 4
#define FRT_ARG_ERROR 5
#define FRT_EOF_ERROR 6
#define FRT_UNSUPPORTED_ERROR 7
#define FRT_STATE_ERROR 8
#define FRT_PARSE_ERROR 9
#define FRT_MEM_ERROR 10
#define FRT_INDEX_ERROR 11
#define FRT_LOCK_ERROR 12
extern char *const FRT_UNSUPPORTED_ERROR_MSG;
extern char *const FRT_EOF_ERROR_MSG;
typedef struct frt_xcontext_t
{
jmp_buf jbuf;
struct frt_xcontext_t *next;
const char *msg;
volatile int excode;
unsigned int handled : 1;
unsigned int in_finally : 1;
} frt_xcontext_t;
#define FRT_TRY\
do {\
frt_xcontext_t xcontext;\
frt_xpush_context(&xcontext);\
switch (setjmp(xcontext.jbuf)) {\
case FRT_BODY:
#define FRT_XENDTRY\
}\
frt_xpop_context();\
} while (0);
#define FRT_ENDTRY\
}\
if (!xcontext.in_finally) {\
frt_xpop_context();\
xcontext.in_finally = 1;\
longjmp(xcontext.jbuf, FRT_FINALLY);\
}\
} while (0);
#define FRT_RETURN_EARLY() frt_xpop_context()
#define FRT_XFINALLY default: xcontext.in_finally = 1;
#define FRT_XCATCHALL break; default: xcontext.in_finally = 1;
#define FRT_HANDLED() xcontext.handled = 1; /* true */
#define FRT_XMSG_BUFFER_SIZE 2048
#ifdef FRT_HAS_ISO_VARARGS
# define FRT_RAISE(excode, ...) do {\
snprintf(frt_xmsg_buffer, FRT_XMSG_BUFFER_SIZE, __VA_ARGS__);\
snprintf(frt_xmsg_buffer_final, FRT_XMSG_BUFFER_SIZE,\
"Error occured in %s:%d - %s\n\t%s",\
__FILE__, __LINE__, __func__, frt_xmsg_buffer);\
frt_xraise(excode, frt_xmsg_buffer_final);\
} while (0)
#elif defined(FRT_HAS_GNUC_VARARGS)
# define FRT_RAISE(excode, args...) do {\
snprintf(frt_xmsg_buffer, FRT_XMSG_BUFFER_SIZE, ##args);\
snprintf(frt_xmsg_buffer_final, FRT_XMSG_BUFFER_SIZE,\
"Error occured in %s:%d - %s\n\t%s\n",\
__FILE__, __LINE__, __func__, frt_xmsg_buffer);\
frt_xraise(excode, frt_xmsg_buffer_final);\
} while (0)
#else
extern void FRT_RAISE(int excode, const char *fmt, ...);
#endif
#define RAISE_HELL() FRT_RAISE(FRT_FERRET_ERROR, "Hell")
extern void frt_xraise(int excode, const char *const msg);
extern void frt_xpush_context(frt_xcontext_t *context);
extern void frt_xpop_context();
extern char frt_xmsg_buffer[FRT_XMSG_BUFFER_SIZE];
extern char frt_xmsg_buffer_final[FRT_XMSG_BUFFER_SIZE];
#ifdef __cplusplus
} // extern "C"
#endif
#endif
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