OSSP CVS Repository

Check-in Number:	1896
Date:	2002-Feb-25 11:30:15 (local) 2002-Feb-25 10:30:15 (UTC)
User:	rse
Branch:
Comment:	Allow ex_shield clauses to be dynamically nested. Without this the whole functionality would be useless in practice.
Tickets:
Inspections:
Files:	ossp-pkg/ex/ex.h      1.14 -> 1.15     13 inserted, 9 deleted ossp-pkg/ex/ex.pod      1.19 -> 1.20     9 inserted, 0 deleted

---

ossp-pkg/ex/ex.h 1.14 -> 1.15

--- ex.h 2002/01/31 19:54:05 1.14 +++ ex.h 2002/02/25 10:30:15 1.15 @@ -94,7 +94,8 @@ /* declare the context type (private) */ typedef struct { __ex_mctx_t *ctx_mctx; /* permanent machine context of enclosing try/catch */ - int ctx_disabled; /* permanent flag whether exception handling is disabled */ + int ctx_shielding;/* permanent counter of exception shielding level */ + int ctx_shield; /* temporary flag for exception shielding macro */ int ctx_caught; /* temporary flag whether exception was caught */ int ctx_cleanup; /* temporary flag whether cleanup block was present */ volatile ex_t ctx_ex; /* temporary exception storage */ @@ -102,11 +103,12 @@ /* the static and dynamic initializers for a context structure */ #define EX_CTX_INITIALIZER \ - { NULL, 0, 0, 0, { NULL, NULL, NULL, NULL, 0, NULL } } + { NULL, 0, 0, 0, 0, { NULL, NULL, NULL, NULL, 0, NULL } } #define EX_CTX_INITIALIZE(ctx) \ do { \ (ctx)->ctx_mctx = NULL; \ - (ctx)->ctx_disabled = 0; \ + (ctx)->ctx_shielding = 0; \ + (ctx)->ctx_shield = 0; \ (ctx)->ctx_caught = 0; \ (ctx)->ctx_cleanup = 0; \ (ctx)->ctx_ex.ex_class = NULL; \ @@ -176,7 +178,7 @@ /* the throwing of a new exception */ #define ex_throw(c,o,v) \ - (__ex_ctx()->ctx_disabled ? 0 : \ + (__ex_ctx()->ctx_shielding > 0 ? 0 : \ (__ex_ctx()->ctx_ex.ex_class = (void *)(c), \ __ex_ctx()->ctx_ex.ex_object = (void *)(o), \ __ex_ctx()->ctx_ex.ex_value = (void *)(v), \ @@ -189,22 +191,24 @@ /* the re-throwing of an already caught exception */ #define ex_rethrow \ - (__ex_ctx()->ctx_disabled ? 0 : \ + (__ex_ctx()->ctx_shielding > 0 ? 0 : \ ( __ex_ctx()->ctx_mctx == NULL \ ? (__ex_terminate((ex_t *)&(__ex_ctx()->ctx_ex)), -1) \ : (__ex_mctx_restore(__ex_ctx()->ctx_mctx), 1) )) /* shield an operation from exception handling */ #define ex_shield \ - for (__ex_ctx()->ctx_disabled = 1; \ - __ex_ctx()->ctx_disabled == 1; \ - __ex_ctx()->ctx_disabled = 0) + for (__ex_ctx()->ctx_shielding++, \ + __ex_ctx()->ctx_shield = 1; \ + __ex_ctx()->ctx_shield == 1; \ + __ex_ctx()->ctx_shield = 0, \ + __ex_ctx()->ctx_shielding--) /* exception handling tests */ #define ex_catching \ (__ex_ctx()->ctx_mctx != NULL) #define ex_shielding \ - (__ex_ctx()->ctx_disabled) + (__ex_ctx()->ctx_shielding > 0) /* optional namespace mapping */ #if defined(__EX_NS_UCCXX__)

---

ossp-pkg/ex/ex.pod 1.19 -> 1.20

--- ex.pod 2002/01/31 20:48:05 1.19 +++ ex.pod 2002/02/25 10:30:15 1.20 @@ -220,6 +220,15 @@ of exceptions, i.e., inside the dynamic scope of B<ex_shield> all B<ex_throw> operations are silently ignored. +The B<ex_shield> block is a regular B<ISO-C> language statement block, +but it is not allowed to jump into it via C<goto> or C<longjmp>(3) or +out of it via C<break>, C<return>, C<goto> or C<longjmp>(3) because this +would cause the shielding level to become out of sync. Jumping into +an B<ex_shield> clause would avoid increasing the exception shielding +level, and jumping out of it would avoid decreasing it. In both cases +the result is an incorrect exception shielding level. Nevertheless you +are allowed to nest B<ex_shield> clauses. + =item B<ex_catching> This is a boolean flag which can be checked inside the dynamic scope