diff options
Diffstat (limited to 'epan/exceptions.h')
| -rw-r--r-- | epan/exceptions.h | 84 |
1 files changed, 67 insertions, 17 deletions
diff --git a/epan/exceptions.h b/epan/exceptions.h index 66bbcce485..355224e930 100644 --- a/epan/exceptions.h +++ b/epan/exceptions.h @@ -81,23 +81,31 @@ * This is really something like: * * { - * x = setjmp() + * caught = FALSE: + * x = setjmp(); * if (x == 0) { * <TRY code> * } - * else if (x == 1) { + * if (!caught && x == 1) { + * caught = TRUE; * <CATCH(1) code> * } - * else if (x == 2) { + * if (!caught && x == 2) { + * caught = TRUE; * <CATCH(2) code> * } - * else if (x == 3 || x == 4) { + * if (!caught && (x == 3 || x == 4)) { + * caught = TRUE; * <CATCH2(3,4) code> * } - * else { - * <CATCH_ALL code> { + * if (!caught && x != 0) { + * caught = TRUE; + * <CATCH_ALL code> * } * <FINALLY code> + * if(!caught) { + * RETHROW(x) + * } * }<ENDTRY tag> * * All CATCH's must precede a CATCH_ALL. @@ -125,40 +133,65 @@ * CLEANUP_CB_CALL_AND_POP */ +/* we do up to three passes through the bit of code after except_try_push(), + * and except_state is used to keep track of where we are. + */ +#define EXCEPT_CAUGHT 1 /* exception has been caught, no need to rethrow at + * END_TRY */ + +#define EXCEPT_RETHROWN 2 /* the exception was rethrown from a CATCH + * block. Don't reenter the CATCH blocks, but do + * execute FINALLY and rethrow at END_TRY */ +#define EXCEPT_FINALLY 4 /* we've entered the FINALLY block - don't allow + * RETHROW, and don't reenter FINALLY if a + * different exception is thrown */ #define TRY \ {\ except_t *exc; \ + volatile int except_state = 0; \ static const except_id_t catch_spec[] = { \ { XCEPT_GROUP_ETHEREAL, XCEPT_CODE_ANY } }; \ except_try_push(catch_spec, 1, &exc); \ - if (exc == 0) { \ + \ + if(except_state & EXCEPT_CAUGHT) \ + except_state |= EXCEPT_RETHROWN; \ + except_state &= ~EXCEPT_CAUGHT; \ + \ + if (except_state == 0 && exc == 0) \ /* user's code goes here */ #define ENDTRY \ - } \ + /* rethrow the exception if necessary */ \ + if(!(except_state&EXCEPT_CAUGHT) && exc != 0) \ + except_rethrow(exc); \ except_try_pop();\ } +/* the (except_state |= EXCEPT_CAUGHT) in the below is a way of setting + * except_state before the user's code, without disrupting the user's code if + * it's a one-liner. + */ #define CATCH(x) \ - } \ - else if (exc->except_id.except_code == (x)) { \ + if (except_state == 0 && exc != 0 && exc->except_id.except_code == (x) && \ + (except_state |= EXCEPT_CAUGHT)) \ /* user's code goes here */ #define CATCH2(x,y) \ - } \ - else if (exc->except_id.except_code == (x) || exc->except_id.except_code == (y)) { \ + if (except_state == 0 && exc != 0 && \ + (exc->except_id.except_code == (x) || exc->except_id.except_code == (y)) && \ + (except_state|=EXCEPT_CAUGHT)) \ /* user's code goes here */ #define CATCH_ALL \ - } \ - else { \ + if (except_state == 0 && exc != 0 && \ + (except_state|=EXCEPT_CAUGHT)) \ /* user's code goes here */ + #define FINALLY \ - } \ - { \ + if( !(except_state & EXCEPT_FINALLY) && (except_state|=EXCEPT_FINALLY)) \ /* user's code goes here */ #define THROW(x) \ @@ -169,7 +202,24 @@ #define GET_MESSAGE except_message(exc) -#define RETHROW except_rethrow(exc) +#define RETHROW \ + { \ + /* check we're in a catch block */ \ + g_assert(except_state == EXCEPT_CAUGHT); \ + /* we can't use except_rethrow here, as that pops a catch block \ + * off the stack, and we don't want to do that, because we want to \ + * excecute the FINALLY {} block first. \ + * except_throw doesn't provide an interface to rethrow an existing \ + * exception; however, longjmping back to except_try_push() has the \ + * desired effect. \ + * \ + * Note also that THROW and RETHROW should provide much the same \ + * functionality in terms of which blocks to enter, so any messing \ + * about with except_state in here would indicate that THROW is \ + * doing the wrong thing. \ + */ \ + longjmp(except_ch.except_jmp,1); \ + } #define EXCEPT_CODE except_code(exc) |