Quickly renamed. Also removed the long comment explaining why this is

better than the old error API.
This commit is contained in:
Guido van Rossum 1997-04-29 18:22:47 +00:00
parent 58d8e3dd9e
commit 373c869a6a
1 changed files with 56 additions and 90 deletions

View File

@ -29,43 +29,9 @@ PERFORMANCE OF THIS SOFTWARE.
******************************************************************/ ******************************************************************/
/* Error handling -- see also run.c */ /* Error handling */
/* New error handling interface. #include "Python.h"
The following problem exists (existed): methods of built-in modules
are called with 'self' and 'args' arguments, but without a context
argument, so they have no way to raise a specific exception.
The same is true for the object implementations: no context argument.
The old convention was to set 'errno' and to return NULL.
The caller (usually call_function() in eval.c) detects the NULL
return value and then calls puterrno(ctx) to turn the errno value
into a true exception. Problems with this approach are:
- it used standard errno values to indicate Python-specific errors,
but this means that when such an error code is reported by a system
call (e.g., in module posix), the user gets a confusing message
- errno is a global variable, which makes extensions to a multi-
threading environment difficult; e.g., in IRIX, multi-threaded
programs must use the function oserror() instead of looking in errno
- there is no portable way to add new error numbers for specic
situations -- the value space for errno is reserved to the OS, yet
the way to turn module-specific errors into a module-specific
exception requires module-specific values for errno
- there is no way to add a more situation-specific message to an
error.
The new interface solves all these problems. To return an error, a
built-in function calls err_set(exception), err_setval(exception,
value) or err_setstr(exception, string), and returns NULL. These
functions save the value for later use by puterrno(). To adapt this
scheme to a multi-threaded environment, only the implementation of
err_setval() has to be changed.
*/
#include "allobjects.h"
#include "traceback.h"
#include <errno.h>
#ifdef SYMANTEC__CFM68K__ #ifdef SYMANTEC__CFM68K__
#pragma lib_export on #pragma lib_export on
@ -77,7 +43,7 @@ PERFORMANCE OF THIS SOFTWARE.
XXX PROBLEM: some positive errors have a meaning for MacOS, XXX PROBLEM: some positive errors have a meaning for MacOS,
but some library routines set Unix error numbers... but some library routines set Unix error numbers...
*/ */
extern char *PyMac_StrError PROTO((int)); extern char *PyMac_StrError Py_PROTO((int));
#undef strerror #undef strerror
#define strerror PyMac_StrError #define strerror PyMac_StrError
#endif #endif
@ -85,127 +51,127 @@ extern char *PyMac_StrError PROTO((int));
#ifndef __STDC__ #ifndef __STDC__
#ifndef MS_WINDOWS #ifndef MS_WINDOWS
extern char *strerror PROTO((int)); extern char *strerror Py_PROTO((int));
#endif #endif
#endif #endif
/* Last exception stored by err_setval() */ /* Last exception stored */
static object *last_exception; static PyObject *last_exception;
static object *last_exc_val; static PyObject *last_exc_val;
void void
err_restore(exception, value, traceback) PyErr_Restore(exception, value, traceback)
object *exception; PyObject *exception;
object *value; PyObject *value;
object *traceback; PyObject *traceback;
{ {
err_clear(); PyErr_Clear();
last_exception = exception; last_exception = exception;
last_exc_val = value; last_exc_val = value;
(void) tb_store(traceback); (void) PyTraceBack_Store(traceback);
XDECREF(traceback); Py_XDECREF(traceback);
} }
void void
err_setval(exception, value) PyErr_SetObject(exception, value)
object *exception; PyObject *exception;
object *value; PyObject *value;
{ {
XINCREF(exception); Py_XINCREF(exception);
XINCREF(value); Py_XINCREF(value);
err_restore(exception, value, (object *)NULL); PyErr_Restore(exception, value, (PyObject *)NULL);
} }
void void
err_set(exception) PyErr_SetNone(exception)
object *exception; PyObject *exception;
{ {
err_setval(exception, (object *)NULL); PyErr_SetObject(exception, (PyObject *)NULL);
} }
void void
err_setstr(exception, string) PyErr_SetString(exception, string)
object *exception; PyObject *exception;
const char *string; const char *string;
{ {
object *value = newstringobject(string); PyObject *value = PyString_FromString(string);
err_setval(exception, value); PyErr_SetObject(exception, value);
XDECREF(value); Py_XDECREF(value);
} }
object * PyObject *
err_occurred() PyErr_Occurred()
{ {
return last_exception; return last_exception;
} }
void void
err_fetch(p_exc, p_val, p_tb) PyErr_Fetch(p_exc, p_val, p_tb)
object **p_exc; PyObject **p_exc;
object **p_val; PyObject **p_val;
object **p_tb; PyObject **p_tb;
{ {
*p_exc = last_exception; *p_exc = last_exception;
last_exception = NULL; last_exception = NULL;
*p_val = last_exc_val; *p_val = last_exc_val;
last_exc_val = NULL; last_exc_val = NULL;
*p_tb = tb_fetch(); *p_tb = PyTraceBack_Fetch();
} }
void void
err_clear() PyErr_Clear()
{ {
object *tb; PyObject *tb;
XDECREF(last_exception); Py_XDECREF(last_exception);
last_exception = NULL; last_exception = NULL;
XDECREF(last_exc_val); Py_XDECREF(last_exc_val);
last_exc_val = NULL; last_exc_val = NULL;
/* Also clear interpreter stack trace */ /* Also clear interpreter stack trace */
tb = tb_fetch(); tb = PyTraceBack_Fetch();
XDECREF(tb); Py_XDECREF(tb);
} }
/* Convenience functions to set a type error exception and return 0 */ /* Convenience functions to set a type error exception and return 0 */
int int
err_badarg() PyErr_BadArgument()
{ {
err_setstr(TypeError, "illegal argument type for built-in operation"); PyErr_SetString(PyExc_TypeError, "illegal argument type for built-in operation");
return 0; return 0;
} }
object * PyObject *
err_nomem() PyErr_NoMemory()
{ {
err_set(MemoryError); PyErr_SetNone(PyExc_MemoryError);
return NULL; return NULL;
} }
object * PyObject *
err_errno(exc) PyErr_SetFromErrno(exc)
object *exc; PyObject *exc;
{ {
object *v; PyObject *v;
int i = errno; int i = errno;
#ifdef EINTR #ifdef EINTR
if (i == EINTR && sigcheck()) if (i == EINTR && PyErr_CheckSignals())
return NULL; return NULL;
#endif #endif
v = mkvalue("(is)", i, strerror(i)); v = Py_BuildValue("(is)", i, strerror(i));
if (v != NULL) { if (v != NULL) {
err_setval(exc, v); PyErr_SetObject(exc, v);
DECREF(v); Py_DECREF(v);
} }
return NULL; return NULL;
} }
void void
err_badcall() PyErr_BadInternalCall()
{ {
err_setstr(SystemError, "bad argument to internal function"); PyErr_SetString(PyExc_SystemError, "bad argument to internal function");
} }