InfoMagic Source Code 1993 July/THE_SOURCE_CODE_CD_ROM.iso/gnu/nihcl-3.0/lib/Exception.c

C/C++ Source or Header | 1990-05-19 | 5.3 KB | 215 lines

/* Exception.c -- NIHCL exception handling

    THIS SOFTWARE FITS THE DESCRIPTION IN THE U.S. COPYRIGHT ACT OF A
    "UNITED STATES GOVERNMENT WORK".  IT WAS WRITTEN AS A PART OF THE
    AUTHOR'S OFFICIAL DUTIES AS A GOVERNMENT EMPLOYEE.  THIS MEANS IT
    CANNOT BE COPYRIGHTED.  THIS SOFTWARE IS FREELY AVAILABLE TO THE
    PUBLIC FOR USE WITHOUT A COPYRIGHT NOTICE, AND THERE ARE NO
    RESTRICTIONS ON ITS USE, NOW OR SUBSEQUENTLY.

Author:
    K. E. Gorlen
    Bg. 12A, Rm. 2033
    Computer Systems Laboratory
    Division of Computer Research and Technology
    National Institutes of Health
    Bethesda, Maryland 20892
    Phone: [phone]
    uucp: uunet!nih-csl!kgorlen
    Internet: [e-mail]
    February, 1986

Function:

NIHCL exception handling.

$Log:    Exception.c,v $
 * Revision 3.0  90/05/20  00:19:30  kgorlen
 * Release for 1st edition.
 *
*/

#include "ExceptAct.h"
#include <osfcn.h>
#include <libc.h>
#include <errlib.h>
#include <stdarg.h>

#include "nihclconfig.h"
#include "nihclerrs.h"
#include "nihclerrsx.h"

static char rcsid[] = "$Header: /afs/alw.nih.gov/unix/sun4_40c/usr/local/src/nihcl-3.0/share/lib/RCS/Exception.c,v 3.0 90/05/20 00:19:30 kgorlen Rel $";

static ExceptionEnv topExceptionEnv;

static Catch topCatch;
Catch* Catch::stackTop = &topCatch;
ExceptionEnv* ExceptionEnv::stackTop = 0;
ExceptionEnv* ExceptionEnv::lastResort = 0;

void ExceptionEnv::raise(int exception)
{
    if (exception == 0) {
        cerr << "Tried to RAISE exception code 0\n";
        abort();
    }
    if (prev == 0) {    // i.e.,  this == lastResort
        cerr << "NIHCL: fatal: Unhandled exception code " << exception << '\n';
        exit(1);
    }
    pop();
#if STACK_GROWS_DOWN
    for (register Catch* p = Catch::stackTop->next; p < (Catch*)this && p != Catch::stackTop; p = p->next)
#else
    for (register Catch* p = Catch::stackTop->next; p > (Catch*)this && p != Catch::stackTop; p = p->next)
#endif
        p->obj->destroyer();
    Catch::stackTop->next = p;
    p->prev = Catch::stackTop;
    longjmp(env,exception);
}

Catch::Catch()
{
    next = prev = this;
    obj = Object::nil;
}

Catch::Catch(Object* ob)
{
    obj = ob;
    void* top[2];
#if STACK_GROWS_DOWN
    if ((void*)this < (void*)ExceptionEnv::stackTop && (void*)this > (void*)top) {    // this on stack
#else
    if ((void*)this > (void*)ExceptionEnv::stackTop && (void*)this < (void*)top) {    // this on stack
#endif
        next = stackTop->next;
        prev = stackTop;
        stackTop->next = this;
        next->prev = this;
    }
    else next = 0;        // Catch object was allocated by new
}

Catch::~Catch()
{
    if (next != 0) {
        next->prev = prev;
        prev->next = next;
    }
    obj->destroyer();
}

static ExceptionActionTbl mainExceptionActionTbl;
ExceptionActionTbl* ExceptionActionTbl::active = &mainExceptionActionTbl;

#ifdef sparc
// Use magic name to make stdarg work
#define sev_ __builtin_va_alist
#endif

void NIHCL::setError(int err, int sev_, ...)
{
    ExceptionActionTbl::active->act((unsigned)err,sev_);
#ifdef TRACE
printf("seterror> Error No: %d  Severity: %d\n",err,sev_);
#endif
    errno = err;
        char buf[132],buf0[132];

    errfac_errorText(err,buf/*OUT*/);

    char* p = errfac_argumentCodes(err);
#ifdef TRACE
printf("seterror> argument codes %s\n",p);
#endif
    va_list ap;
    va_start(ap,sev_);
    while ( *p != '\0' ) { // set up next arg
      errfac_prepNextArg(buf/*IN*/,buf0/*OUT*/);
      switch ( *(p++) ) {
         case 'I':
        int i = va_arg(ap,int);
             sprintf(buf,buf0,i);
                  break;
         case 'S':
        char* s = va_arg(ap,char*);
             sprintf(buf,buf0,s);
            break;
         case 'D':
            double d = va_arg(ap,double);
             sprintf(buf,buf0,d);
            break;
         default : // ignored
            break;
         }// end switch
          }// end while
    va_end(ap);

    int severity = (sev_ < 0)? sev_:(errfac_severity(err));
    errfac_errorMessage(severity,buf);
    if ( errfac_isExitSeverity(severity) ) {
       cerr << "NIHCL: fatal: Tried to continue after error "
        << err <<'\n';
       abort();
       }
}

ExceptionActionTbl::ExceptionActionTbl()
{
    client_exception_trap = NULL;
    for (register int i=NIHCL__LAST_ERROR-NIHCL__FIRSTERROR; i>=0; i--)
        action[i] = ExceptionAction::ABORT;
}

void ExceptionActionTbl::act(unsigned error, int sev)
{
    if (client_exception_trap != NULL) {
        (*client_exception_trap)(error,sev);
    }
    if (error >= NIHCL__FIRSTERROR && error <= NIHCL__LAST_ERROR) {
        switch (action[error-NIHCL__FIRSTERROR]) {
            case ExceptionAction::RAISE: RAISE(error);
            case ExceptionAction::ABORT: return;
        }
    }
}

ExceptionAction::ExceptionAction(unsigned error)
{
    if ( (error < NIHCL__FIRSTERROR)||(error > NIHCL__LAST_ERROR) ) {
        setError(NIHCL_BADERRNUM,DEFAULT,"ExceptionAction",error);
        return;
    }
    error_code = error;
    old_action = ExceptionActionTbl::active->action[error-NIHCL__FIRSTERROR];
}

ExceptionAction::~ExceptionAction()
{
    ExceptionActionTbl::active->action[error_code-NIHCL__FIRSTERROR] = old_action;
}

AbortException::AbortException(unsigned error) : ExceptionAction(error)
{
    ExceptionActionTbl::active->action[error-NIHCL__FIRSTERROR] = ExceptionAction::ABORT;
}

RaiseException::RaiseException(unsigned error) : ExceptionAction(error)
{
    ExceptionActionTbl::active->action[error-NIHCL__FIRSTERROR] = ExceptionAction::RAISE;
}

ExceptionTrap::ExceptionTrap(exceptionTrapTy xtrap)
{
    old_trap = ExceptionActionTbl::active->client_exception_trap;
    ExceptionActionTbl::active->client_exception_trap = xtrap;
}

ExceptionTrap::~ExceptionTrap()
{
    ExceptionActionTbl::active->client_exception_trap = old_trap;
}