diff options
Diffstat (limited to 'Objects/exceptions.c')
| -rw-r--r-- | Objects/exceptions.c | 152 |
1 files changed, 138 insertions, 14 deletions
diff --git a/Objects/exceptions.c b/Objects/exceptions.c index 6b04700621..bff7f0819e 100644 --- a/Objects/exceptions.c +++ b/Objects/exceptions.c @@ -16,9 +16,6 @@ PyObject *PyExc_IOError = NULL; #ifdef MS_WINDOWS PyObject *PyExc_WindowsError = NULL; #endif -#ifdef __VMS -PyObject *PyExc_VMSError = NULL; -#endif /* The dict map from errno codes to OSError subclasses */ static PyObject *errnomap = NULL; @@ -121,11 +118,11 @@ BaseException_str(PyBaseExceptionObject *self) static PyObject * BaseException_repr(PyBaseExceptionObject *self) { - char *name; - char *dot; + const char *name; + const char *dot; - name = (char *)Py_TYPE(self)->tp_name; - dot = strrchr(name, '.'); + name = Py_TYPE(self)->tp_name; + dot = (const char *) strrchr(name, '.'); if (dot != NULL) name = dot+1; return PyUnicode_FromFormat("%s%R", name, self->args); @@ -845,7 +842,7 @@ oserror_init(PyOSErrorObject *self, PyObject **p_args, /* Steals the reference to args */ Py_CLEAR(self->args); self->args = args; - args = NULL; + *p_args = args = NULL; return 0; } @@ -885,11 +882,12 @@ OSError_new(PyTypeObject *type, PyObject *args, PyObject *kwds) PyObject *winerror = NULL; #endif + Py_INCREF(args); + if (!oserror_use_init(type)) { if (!_PyArg_NoKeywords(type->tp_name, kwds)) - return NULL; + goto error; - Py_INCREF(args); if (oserror_parse_args(&args, &myerrno, &strerror, &filename #ifdef MS_WINDOWS , &winerror @@ -932,6 +930,7 @@ OSError_new(PyTypeObject *type, PyObject *args, PyObject *kwds) goto error; } + Py_XDECREF(args); return (PyObject *) self; error: @@ -2327,7 +2326,7 @@ PyObject *PyExc_RecursionErrorInst = NULL; } #ifdef MS_WINDOWS -#include <Winsock2.h> +#include <winsock2.h> /* The following constants were added to errno.h in VS2010 but have preferred WSA equivalents. */ #undef EADDRINUSE @@ -2471,9 +2470,6 @@ _PyExc_Init(PyObject *bltinmod) #ifdef MS_WINDOWS INIT_ALIAS(WindowsError, OSError) #endif -#ifdef __VMS - INIT_ALIAS(VMSError, OSError) -#endif POST_INIT(EOFError) POST_INIT(RuntimeError) POST_INIT(NotImplementedError) @@ -2591,3 +2587,131 @@ _PyExc_Fini(void) free_preallocated_memerrors(); Py_CLEAR(errnomap); } + +/* Helper to do the equivalent of "raise X from Y" in C, but always using + * the current exception rather than passing one in. + * + * We currently limit this to *only* exceptions that use the BaseException + * tp_init and tp_new methods, since we can be reasonably sure we can wrap + * those correctly without losing data and without losing backwards + * compatibility. + * + * We also aim to rule out *all* exceptions that might be storing additional + * state, whether by having a size difference relative to BaseException, + * additional arguments passed in during construction or by having a + * non-empty instance dict. + * + * We need to be very careful with what we wrap, since changing types to + * a broader exception type would be backwards incompatible for + * existing codecs, and with different init or new method implementations + * may either not support instantiation with PyErr_Format or lose + * information when instantiated that way. + * + * XXX (ncoghlan): This could be made more comprehensive by exploiting the + * fact that exceptions are expected to support pickling. If more builtin + * exceptions (e.g. AttributeError) start to be converted to rich + * exceptions with additional attributes, that's probably a better approach + * to pursue over adding special cases for particular stateful subclasses. + * + * Returns a borrowed reference to the new exception (if any), NULL if the + * existing exception was left in place. + */ +PyObject * +_PyErr_TrySetFromCause(const char *format, ...) +{ + PyObject* msg_prefix; + PyObject *exc, *val, *tb; + PyTypeObject *caught_type; + PyObject **dictptr; + PyObject *instance_args; + Py_ssize_t num_args, caught_type_size, base_exc_size; + PyObject *new_exc, *new_val, *new_tb; + va_list vargs; + int same_basic_size; + + PyErr_Fetch(&exc, &val, &tb); + caught_type = (PyTypeObject *)exc; + /* Ensure type info indicates no extra state is stored at the C level + * and that the type can be reinstantiated using PyErr_Format + */ + caught_type_size = caught_type->tp_basicsize; + base_exc_size = _PyExc_BaseException.tp_basicsize; + same_basic_size = ( + caught_type_size == base_exc_size || + (PyType_SUPPORTS_WEAKREFS(caught_type) && + (caught_type_size == base_exc_size + sizeof(PyObject *)) + ) + ); + if (caught_type->tp_init != (initproc)BaseException_init || + caught_type->tp_new != BaseException_new || + !same_basic_size || + caught_type->tp_itemsize != _PyExc_BaseException.tp_itemsize) { + /* We can't be sure we can wrap this safely, since it may contain + * more state than just the exception type. Accordingly, we just + * leave it alone. + */ + PyErr_Restore(exc, val, tb); + return NULL; + } + + /* Check the args are empty or contain a single string */ + PyErr_NormalizeException(&exc, &val, &tb); + instance_args = ((PyBaseExceptionObject *)val)->args; + num_args = PyTuple_GET_SIZE(instance_args); + if (num_args > 1 || + (num_args == 1 && + !PyUnicode_CheckExact(PyTuple_GET_ITEM(instance_args, 0)))) { + /* More than 1 arg, or the one arg we do have isn't a string + */ + PyErr_Restore(exc, val, tb); + return NULL; + } + + /* Ensure the instance dict is also empty */ + dictptr = _PyObject_GetDictPtr(val); + if (dictptr != NULL && *dictptr != NULL && + PyObject_Length(*dictptr) > 0) { + /* While we could potentially copy a non-empty instance dictionary + * to the replacement exception, for now we take the more + * conservative path of leaving exceptions with attributes set + * alone. + */ + PyErr_Restore(exc, val, tb); + return NULL; + } + + /* For exceptions that we can wrap safely, we chain the original + * exception to a new one of the exact same type with an + * error message that mentions the additional details and the + * original exception. + * + * It would be nice to wrap OSError and various other exception + * types as well, but that's quite a bit trickier due to the extra + * state potentially stored on OSError instances. + */ + + Py_XDECREF(tb); + +#ifdef HAVE_STDARG_PROTOTYPES + va_start(vargs, format); +#else + va_start(vargs); +#endif + msg_prefix = PyUnicode_FromFormatV(format, vargs); + va_end(vargs); + if (msg_prefix == NULL) { + Py_DECREF(exc); + Py_DECREF(val); + return NULL; + } + + PyErr_Format(exc, "%U (%s: %S)", + msg_prefix, Py_TYPE(val)->tp_name, val); + Py_DECREF(exc); + Py_DECREF(msg_prefix); + PyErr_Fetch(&new_exc, &new_val, &new_tb); + PyErr_NormalizeException(&new_exc, &new_val, &new_tb); + PyException_SetCause(new_val, val); + PyErr_Restore(new_exc, new_val, new_tb); + return new_val; +} |