micropython/py/objexcept.c

559 lines
22 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <string.h>
#include <stdarg.h>
#include <assert.h>
#include <stdio.h>
#include "py/objlist.h"
#include "py/objstr.h"
#include "py/objtuple.h"
#include "py/objtype.h"
#include "py/runtime.h"
#include "py/gc.h"
#include "py/mperrno.h"
// Number of items per traceback entry (file, line, block)
#define TRACEBACK_ENTRY_LEN (3)
// Optionally allocated buffer for storing some traceback, the tuple argument,
// and possible string object and data, for when the heap is locked.
#if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
// When used the layout of the emergency exception buffer is:
// - traceback entry (file, line, block)
// - traceback entry (file, line, block)
// - mp_obj_tuple_t object
// - n_args * mp_obj_t for tuple
// - mp_obj_str_t object
// - string data
#define EMG_BUF_TRACEBACK_OFFSET (0)
#define EMG_BUF_TRACEBACK_SIZE (2 * TRACEBACK_ENTRY_LEN * sizeof(size_t))
#define EMG_BUF_TUPLE_OFFSET (EMG_BUF_TRACEBACK_OFFSET + EMG_BUF_TRACEBACK_SIZE)
#define EMG_BUF_TUPLE_SIZE(n_args) (sizeof(mp_obj_tuple_t) + n_args * sizeof(mp_obj_t))
#define EMG_BUF_STR_OFFSET (EMG_BUF_TUPLE_OFFSET + EMG_BUF_TUPLE_SIZE(1))
# if MICROPY_EMERGENCY_EXCEPTION_BUF_SIZE > 0
#define mp_emergency_exception_buf_size MICROPY_EMERGENCY_EXCEPTION_BUF_SIZE
void mp_init_emergency_exception_buf(void) {
// Nothing to do since the buffer was declared statically. We put this
// definition here so that the calling code can call this function
// regardless of how its configured (makes the calling code a bit cleaner).
}
#else
#define mp_emergency_exception_buf_size MP_STATE_VM(mp_emergency_exception_buf_size)
void mp_init_emergency_exception_buf(void) {
mp_emergency_exception_buf_size = 0;
MP_STATE_VM(mp_emergency_exception_buf) = NULL;
}
mp_obj_t mp_alloc_emergency_exception_buf(mp_obj_t size_in) {
mp_int_t size = mp_obj_get_int(size_in);
void *buf = NULL;
if (size > 0) {
buf = m_new(byte, size);
}
int old_size = mp_emergency_exception_buf_size;
void *old_buf = MP_STATE_VM(mp_emergency_exception_buf);
// Update the 2 variables atomically so that an interrupt can't occur
// between the assignments.
mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
mp_emergency_exception_buf_size = size;
MP_STATE_VM(mp_emergency_exception_buf) = buf;
MICROPY_END_ATOMIC_SECTION(atomic_state);
if (old_buf != NULL) {
m_del(byte, old_buf, old_size);
}
return mp_const_none;
}
#endif
#endif // MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
// Instance of GeneratorExit exception - needed by generator.close()
// This would belong to objgenerator.c, but to keep mp_obj_exception_t
// definition module-private so far, have it here.
const mp_obj_exception_t mp_const_GeneratorExit_obj = {{&mp_type_GeneratorExit}, 0, 0, NULL, (mp_obj_tuple_t*)&mp_const_empty_tuple_obj};
void mp_obj_exception_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
mp_obj_exception_t *o = MP_OBJ_TO_PTR(o_in);
mp_print_kind_t k = kind & ~PRINT_EXC_SUBCLASS;
bool is_subclass = kind & PRINT_EXC_SUBCLASS;
if (!is_subclass && (k == PRINT_REPR || k == PRINT_EXC)) {
mp_print_str(print, qstr_str(o->base.type->name));
}
if (k == PRINT_EXC) {
mp_print_str(print, ": ");
}
if (k == PRINT_STR || k == PRINT_EXC) {
if (o->args == NULL || o->args->len == 0) {
mp_print_str(print, "");
return;
} else if (o->args->len == 1) {
#if MICROPY_PY_UERRNO
// try to provide a nice OSError error message
if (o->base.type == &mp_type_OSError && mp_obj_is_small_int(o->args->items[0])) {
qstr qst = mp_errno_to_str(o->args->items[0]);
if (qst != MP_QSTR_NULL) {
mp_printf(print, "[Errno " INT_FMT "] %q", MP_OBJ_SMALL_INT_VALUE(o->args->items[0]), qst);
return;
}
}
#endif
mp_obj_print_helper(print, o->args->items[0], PRINT_STR);
return;
}
}
mp_obj_tuple_print(print, MP_OBJ_FROM_PTR(o->args), kind);
}
mp_obj_t mp_obj_exception_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
mp_arg_check_num(n_args, n_kw, 0, MP_OBJ_FUN_ARGS_MAX, false);
// Try to allocate memory for the exception, with fallback to emergency exception object
mp_obj_exception_t *o_exc = m_new_obj_maybe(mp_obj_exception_t);
if (o_exc == NULL) {
o_exc = &MP_STATE_VM(mp_emergency_exception_obj);
}
// Populate the exception object
o_exc->base.type = type;
o_exc->traceback_data = NULL;
mp_obj_tuple_t *o_tuple;
if (n_args == 0) {
// No args, can use the empty tuple straightaway
o_tuple = (mp_obj_tuple_t*)&mp_const_empty_tuple_obj;
} else {
// Try to allocate memory for the tuple containing the args
o_tuple = m_new_obj_var_maybe(mp_obj_tuple_t, mp_obj_t, n_args);
#if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
// If we are called by mp_obj_new_exception_msg_varg then it will have
// reserved room (after the traceback data) for a tuple with 1 element.
// Otherwise we are free to use the whole buffer after the traceback data.
if (o_tuple == NULL && mp_emergency_exception_buf_size >=
EMG_BUF_TUPLE_OFFSET + EMG_BUF_TUPLE_SIZE(n_args)) {
o_tuple = (mp_obj_tuple_t*)
((uint8_t*)MP_STATE_VM(mp_emergency_exception_buf) + EMG_BUF_TUPLE_OFFSET);
}
#endif
if (o_tuple == NULL) {
// No memory for a tuple, fallback to an empty tuple
o_tuple = (mp_obj_tuple_t*)&mp_const_empty_tuple_obj;
} else {
// Have memory for a tuple so populate it
o_tuple->base.type = &mp_type_tuple;
o_tuple->len = n_args;
memcpy(o_tuple->items, args, n_args * sizeof(mp_obj_t));
}
}
// Store the tuple of args in the exception object
o_exc->args = o_tuple;
return MP_OBJ_FROM_PTR(o_exc);
}
// Get exception "value" - that is, first argument, or None
mp_obj_t mp_obj_exception_get_value(mp_obj_t self_in) {
mp_obj_exception_t *self = MP_OBJ_TO_PTR(self_in);
if (self->args->len == 0) {
return mp_const_none;
} else {
return self->args->items[0];
}
}
void mp_obj_exception_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
mp_obj_exception_t *self = MP_OBJ_TO_PTR(self_in);
if (dest[0] != MP_OBJ_NULL) {
// store/delete attribute
if (attr == MP_QSTR___traceback__ && dest[1] == mp_const_none) {
// We allow 'exc.__traceback__ = None' assignment as low-level
// optimization of pre-allocating exception instance and raising
// it repeatedly - this avoids memory allocation during raise.
// However, uPy will keep adding traceback entries to such
// exception instance, so before throwing it, traceback should
// be cleared like above.
self->traceback_len = 0;
dest[0] = MP_OBJ_NULL; // indicate success
}
return;
}
if (attr == MP_QSTR_args) {
dest[0] = MP_OBJ_FROM_PTR(self->args);
} else if (self->base.type == &mp_type_StopIteration && attr == MP_QSTR_value) {
dest[0] = mp_obj_exception_get_value(self_in);
}
}
const mp_obj_type_t mp_type_BaseException = {
{ &mp_type_type },
.name = MP_QSTR_BaseException,
.print = mp_obj_exception_print,
.make_new = mp_obj_exception_make_new,
.attr = mp_obj_exception_attr,
};
// List of all exceptions, arranged as in the table at:
// http://docs.python.org/3/library/exceptions.html
MP_DEFINE_EXCEPTION(SystemExit, BaseException)
MP_DEFINE_EXCEPTION(KeyboardInterrupt, BaseException)
MP_DEFINE_EXCEPTION(GeneratorExit, BaseException)
MP_DEFINE_EXCEPTION(Exception, BaseException)
#if MICROPY_PY_ASYNC_AWAIT
MP_DEFINE_EXCEPTION(StopAsyncIteration, Exception)
#endif
MP_DEFINE_EXCEPTION(StopIteration, Exception)
MP_DEFINE_EXCEPTION(ArithmeticError, Exception)
//MP_DEFINE_EXCEPTION(FloatingPointError, ArithmeticError)
MP_DEFINE_EXCEPTION(OverflowError, ArithmeticError)
MP_DEFINE_EXCEPTION(ZeroDivisionError, ArithmeticError)
MP_DEFINE_EXCEPTION(AssertionError, Exception)
MP_DEFINE_EXCEPTION(AttributeError, Exception)
//MP_DEFINE_EXCEPTION(BufferError, Exception)
//MP_DEFINE_EXCEPTION(EnvironmentError, Exception) use OSError instead
MP_DEFINE_EXCEPTION(EOFError, Exception)
MP_DEFINE_EXCEPTION(ImportError, Exception)
//MP_DEFINE_EXCEPTION(IOError, Exception) use OSError instead
MP_DEFINE_EXCEPTION(LookupError, Exception)
MP_DEFINE_EXCEPTION(IndexError, LookupError)
MP_DEFINE_EXCEPTION(KeyError, LookupError)
MP_DEFINE_EXCEPTION(MemoryError, Exception)
MP_DEFINE_EXCEPTION(NameError, Exception)
/*
MP_DEFINE_EXCEPTION(UnboundLocalError, NameError)
*/
MP_DEFINE_EXCEPTION(OSError, Exception)
#if MICROPY_PY_BUILTINS_TIMEOUTERROR
MP_DEFINE_EXCEPTION(TimeoutError, OSError)
#endif
/*
MP_DEFINE_EXCEPTION(BlockingIOError, OSError)
MP_DEFINE_EXCEPTION(ChildProcessError, OSError)
MP_DEFINE_EXCEPTION(ConnectionError, OSError)
MP_DEFINE_EXCEPTION(BrokenPipeError, ConnectionError)
MP_DEFINE_EXCEPTION(ConnectionAbortedError, ConnectionError)
MP_DEFINE_EXCEPTION(ConnectionRefusedError, ConnectionError)
MP_DEFINE_EXCEPTION(ConnectionResetError, ConnectionError)
MP_DEFINE_EXCEPTION(InterruptedError, OSError)
MP_DEFINE_EXCEPTION(IsADirectoryError, OSError)
MP_DEFINE_EXCEPTION(NotADirectoryError, OSError)
MP_DEFINE_EXCEPTION(PermissionError, OSError)
MP_DEFINE_EXCEPTION(ProcessLookupError, OSError)
MP_DEFINE_EXCEPTION(FileExistsError, OSError)
MP_DEFINE_EXCEPTION(FileNotFoundError, OSError)
MP_DEFINE_EXCEPTION(ReferenceError, Exception)
*/
MP_DEFINE_EXCEPTION(RuntimeError, Exception)
MP_DEFINE_EXCEPTION(NotImplementedError, RuntimeError)
MP_DEFINE_EXCEPTION(SyntaxError, Exception)
MP_DEFINE_EXCEPTION(IndentationError, SyntaxError)
/*
MP_DEFINE_EXCEPTION(TabError, IndentationError)
*/
//MP_DEFINE_EXCEPTION(SystemError, Exception)
MP_DEFINE_EXCEPTION(TypeError, Exception)
#if MICROPY_EMIT_NATIVE
MP_DEFINE_EXCEPTION(ViperTypeError, TypeError)
#endif
MP_DEFINE_EXCEPTION(ValueError, Exception)
#if MICROPY_PY_BUILTINS_STR_UNICODE
MP_DEFINE_EXCEPTION(UnicodeError, ValueError)
//TODO: Implement more UnicodeError subclasses which take arguments
#endif
/*
MP_DEFINE_EXCEPTION(Warning, Exception)
MP_DEFINE_EXCEPTION(DeprecationWarning, Warning)
MP_DEFINE_EXCEPTION(PendingDeprecationWarning, Warning)
MP_DEFINE_EXCEPTION(RuntimeWarning, Warning)
MP_DEFINE_EXCEPTION(SyntaxWarning, Warning)
MP_DEFINE_EXCEPTION(UserWarning, Warning)
MP_DEFINE_EXCEPTION(FutureWarning, Warning)
MP_DEFINE_EXCEPTION(ImportWarning, Warning)
MP_DEFINE_EXCEPTION(UnicodeWarning, Warning)
MP_DEFINE_EXCEPTION(BytesWarning, Warning)
MP_DEFINE_EXCEPTION(ResourceWarning, Warning)
*/
mp_obj_t mp_obj_new_exception(const mp_obj_type_t *exc_type) {
return mp_obj_new_exception_args(exc_type, 0, NULL);
}
// "Optimized" version for common(?) case of having 1 exception arg
mp_obj_t mp_obj_new_exception_arg1(const mp_obj_type_t *exc_type, mp_obj_t arg) {
return mp_obj_new_exception_args(exc_type, 1, &arg);
}
mp_obj_t mp_obj_new_exception_args(const mp_obj_type_t *exc_type, size_t n_args, const mp_obj_t *args) {
assert(exc_type->make_new == mp_obj_exception_make_new);
return exc_type->make_new(exc_type, n_args, 0, args);
}
mp_obj_t mp_obj_new_exception_msg(const mp_obj_type_t *exc_type, const char *msg) {
// Check that the given type is an exception type
assert(exc_type->make_new == mp_obj_exception_make_new);
// Try to allocate memory for the message
mp_obj_str_t *o_str = m_new_obj_maybe(mp_obj_str_t);
#if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
// If memory allocation failed and there is an emergency buffer then try to use
// that buffer to store the string object, reserving room at the start for the
// traceback and 1-tuple.
if (o_str == NULL
&& mp_emergency_exception_buf_size >= EMG_BUF_STR_OFFSET + sizeof(mp_obj_str_t)) {
o_str = (mp_obj_str_t*)((uint8_t*)MP_STATE_VM(mp_emergency_exception_buf)
+ EMG_BUF_STR_OFFSET);
}
#endif
if (o_str == NULL) {
// No memory for the string object so create the exception with no args
return mp_obj_exception_make_new(exc_type, 0, 0, NULL);
}
// Create the string object and call mp_obj_exception_make_new to create the exception
o_str->base.type = &mp_type_str;
o_str->hash = qstr_compute_hash(o_str->data, o_str->len);
o_str->len = strlen(msg);
o_str->data = (const byte*)msg;
mp_obj_t arg = MP_OBJ_FROM_PTR(o_str);
return mp_obj_exception_make_new(exc_type, 1, 0, &arg);
}
// The following struct and function implement a simple printer that conservatively
// allocates memory and truncates the output data if no more memory can be obtained.
// It leaves room for a null byte at the end of the buffer.
struct _exc_printer_t {
bool allow_realloc;
size_t alloc;
size_t len;
byte *buf;
};
STATIC void exc_add_strn(void *data, const char *str, size_t len) {
struct _exc_printer_t *pr = data;
if (pr->len + len >= pr->alloc) {
// Not enough room for data plus a null byte so try to grow the buffer
if (pr->allow_realloc) {
size_t new_alloc = pr->alloc + len + 16;
byte *new_buf = m_renew_maybe(byte, pr->buf, pr->alloc, new_alloc, true);
if (new_buf == NULL) {
pr->allow_realloc = false;
len = pr->alloc - pr->len - 1;
} else {
pr->alloc = new_alloc;
pr->buf = new_buf;
}
} else {
len = pr->alloc - pr->len - 1;
}
}
memcpy(pr->buf + pr->len, str, len);
pr->len += len;
}
mp_obj_t mp_obj_new_exception_msg_varg(const mp_obj_type_t *exc_type, const char *fmt, ...) {
assert(fmt != NULL);
// Check that the given type is an exception type
assert(exc_type->make_new == mp_obj_exception_make_new);
// Try to allocate memory for the message
mp_obj_str_t *o_str = m_new_obj_maybe(mp_obj_str_t);
size_t o_str_alloc = strlen(fmt) + 1;
byte *o_str_buf = m_new_maybe(byte, o_str_alloc);
bool used_emg_buf = false;
#if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
// If memory allocation failed and there is an emergency buffer then try to use
// that buffer to store the string object and its data (at least 16 bytes for
// the string data), reserving room at the start for the traceback and 1-tuple.
if ((o_str == NULL || o_str_buf == NULL)
&& mp_emergency_exception_buf_size >= EMG_BUF_STR_OFFSET + sizeof(mp_obj_str_t) + 16) {
used_emg_buf = true;
o_str = (mp_obj_str_t*)((uint8_t*)MP_STATE_VM(mp_emergency_exception_buf)
+ EMG_BUF_STR_OFFSET);
o_str_buf = (byte*)&o_str[1];
o_str_alloc = (uint8_t*)MP_STATE_VM(mp_emergency_exception_buf)
+ mp_emergency_exception_buf_size - o_str_buf;
}
#endif
if (o_str == NULL) {
// No memory for the string object so create the exception with no args
return mp_obj_exception_make_new(exc_type, 0, 0, NULL);
}
if (o_str_buf == NULL) {
// No memory for the string buffer: assume that the fmt string is in ROM
// and use that data as the data of the string
o_str->len = o_str_alloc - 1; // will be equal to strlen(fmt)
o_str->data = (const byte*)fmt;
} else {
// We have some memory to format the string
struct _exc_printer_t exc_pr = {!used_emg_buf, o_str_alloc, 0, o_str_buf};
mp_print_t print = {&exc_pr, exc_add_strn};
va_list ap;
va_start(ap, fmt);
mp_vprintf(&print, fmt, ap);
va_end(ap);
exc_pr.buf[exc_pr.len] = '\0';
o_str->len = exc_pr.len;
o_str->data = exc_pr.buf;
}
// Create the string object and call mp_obj_exception_make_new to create the exception
o_str->base.type = &mp_type_str;
o_str->hash = qstr_compute_hash(o_str->data, o_str->len);
mp_obj_t arg = MP_OBJ_FROM_PTR(o_str);
return mp_obj_exception_make_new(exc_type, 1, 0, &arg);
}
// return true if the given object is an exception type
bool mp_obj_is_exception_type(mp_obj_t self_in) {
if (mp_obj_is_type(self_in, &mp_type_type)) {
// optimisation when self_in is a builtin exception
mp_obj_type_t *self = MP_OBJ_TO_PTR(self_in);
if (self->make_new == mp_obj_exception_make_new) {
return true;
}
}
return mp_obj_is_subclass_fast(self_in, MP_OBJ_FROM_PTR(&mp_type_BaseException));
}
// return true if the given object is an instance of an exception type
bool mp_obj_is_exception_instance(mp_obj_t self_in) {
return mp_obj_is_exception_type(MP_OBJ_FROM_PTR(mp_obj_get_type(self_in)));
}
// Return true if exception (type or instance) is a subclass of given
// exception type. Assumes exc_type is a subclass of BaseException, as
// defined by mp_obj_is_exception_type(exc_type).
bool mp_obj_exception_match(mp_obj_t exc, mp_const_obj_t exc_type) {
// if exc is an instance of an exception, then extract and use its type
if (mp_obj_is_exception_instance(exc)) {
exc = MP_OBJ_FROM_PTR(mp_obj_get_type(exc));
}
return mp_obj_is_subclass_fast(exc, exc_type);
}
// traceback handling functions
#define GET_NATIVE_EXCEPTION(self, self_in) \
/* make sure self_in is an exception instance */ \
assert(mp_obj_is_exception_instance(self_in)); \
mp_obj_exception_t *self; \
if (mp_obj_is_native_exception_instance(self_in)) { \
self = MP_OBJ_TO_PTR(self_in); \
} else { \
self = MP_OBJ_TO_PTR(((mp_obj_instance_t*)MP_OBJ_TO_PTR(self_in))->subobj[0]); \
}
void mp_obj_exception_clear_traceback(mp_obj_t self_in) {
GET_NATIVE_EXCEPTION(self, self_in);
// just set the traceback to the null object
// we don't want to call any memory management functions here
self->traceback_data = NULL;
}
void mp_obj_exception_add_traceback(mp_obj_t self_in, qstr file, size_t line, qstr block) {
GET_NATIVE_EXCEPTION(self, self_in);
// append this traceback info to traceback data
// if memory allocation fails (eg because gc is locked), just return
if (self->traceback_data == NULL) {
self->traceback_data = m_new_maybe(size_t, TRACEBACK_ENTRY_LEN);
if (self->traceback_data == NULL) {
#if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
if (mp_emergency_exception_buf_size >= EMG_BUF_TRACEBACK_OFFSET + EMG_BUF_TRACEBACK_SIZE) {
// There is room in the emergency buffer for traceback data
size_t *tb = (size_t*)((uint8_t*)MP_STATE_VM(mp_emergency_exception_buf)
+ EMG_BUF_TRACEBACK_OFFSET);
self->traceback_data = tb;
self->traceback_alloc = EMG_BUF_TRACEBACK_SIZE / sizeof(size_t);
} else {
// Can't allocate and no room in emergency buffer
return;
}
#else
// Can't allocate
return;
#endif
} else {
// Allocated the traceback data on the heap
self->traceback_alloc = TRACEBACK_ENTRY_LEN;
}
self->traceback_len = 0;
} else if (self->traceback_len + TRACEBACK_ENTRY_LEN > self->traceback_alloc) {
#if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
if (self->traceback_data == (size_t*)MP_STATE_VM(mp_emergency_exception_buf)) {
// Can't resize the emergency buffer
return;
}
#endif
// be conservative with growing traceback data
size_t *tb_data = m_renew_maybe(size_t, self->traceback_data, self->traceback_alloc,
self->traceback_alloc + TRACEBACK_ENTRY_LEN, true);
if (tb_data == NULL) {
return;
}
self->traceback_data = tb_data;
self->traceback_alloc += TRACEBACK_ENTRY_LEN;
}
size_t *tb_data = &self->traceback_data[self->traceback_len];
self->traceback_len += TRACEBACK_ENTRY_LEN;
tb_data[0] = file;
tb_data[1] = line;
tb_data[2] = block;
}
void mp_obj_exception_get_traceback(mp_obj_t self_in, size_t *n, size_t **values) {
GET_NATIVE_EXCEPTION(self, self_in);
if (self->traceback_data == NULL) {
*n = 0;
*values = NULL;
} else {
*n = self->traceback_len;
*values = self->traceback_data;
}
}