cpython/Python/modsupport.c
Victor Stinner 8021875bbc
bpo-1635741: Add PyModule_AddObjectRef() function (GH-23122)
Added PyModule_AddObjectRef() function: similar to
PyModule_AddObjectRef() but don't steal a reference to the value on
success.
2020-11-04 13:59:15 +01:00

715 lines
18 KiB
C

/* Module support implementation */
#include "Python.h"
#include "pycore_abstract.h" // _PyIndex_Check()
#define FLAG_SIZE_T 1
typedef double va_double;
static PyObject *va_build_value(const char *, va_list, int);
static PyObject **va_build_stack(PyObject **small_stack, Py_ssize_t small_stack_len, const char *, va_list, int, Py_ssize_t*);
/* Package context -- the full module name for package imports */
const char *_Py_PackageContext = NULL;
int
_Py_convert_optional_to_ssize_t(PyObject *obj, void *result)
{
Py_ssize_t limit;
if (obj == Py_None) {
return 1;
}
else if (_PyIndex_Check(obj)) {
limit = PyNumber_AsSsize_t(obj, PyExc_OverflowError);
if (limit == -1 && PyErr_Occurred()) {
return 0;
}
}
else {
PyErr_Format(PyExc_TypeError,
"argument should be integer or None, not '%.200s'",
Py_TYPE(obj)->tp_name);
return 0;
}
*((Py_ssize_t *)result) = limit;
return 1;
}
/* Helper for mkvalue() to scan the length of a format */
static Py_ssize_t
countformat(const char *format, char endchar)
{
Py_ssize_t count = 0;
int level = 0;
while (level > 0 || *format != endchar) {
switch (*format) {
case '\0':
/* Premature end */
PyErr_SetString(PyExc_SystemError,
"unmatched paren in format");
return -1;
case '(':
case '[':
case '{':
if (level == 0) {
count++;
}
level++;
break;
case ')':
case ']':
case '}':
level--;
break;
case '#':
case '&':
case ',':
case ':':
case ' ':
case '\t':
break;
default:
if (level == 0) {
count++;
}
}
format++;
}
return count;
}
/* Generic function to create a value -- the inverse of getargs() */
/* After an original idea and first implementation by Steven Miale */
static PyObject *do_mktuple(const char**, va_list *, char, Py_ssize_t, int);
static int do_mkstack(PyObject **, const char**, va_list *, char, Py_ssize_t, int);
static PyObject *do_mklist(const char**, va_list *, char, Py_ssize_t, int);
static PyObject *do_mkdict(const char**, va_list *, char, Py_ssize_t, int);
static PyObject *do_mkvalue(const char**, va_list *, int);
static void
do_ignore(const char **p_format, va_list *p_va, char endchar, Py_ssize_t n, int flags)
{
PyObject *v;
Py_ssize_t i;
assert(PyErr_Occurred());
v = PyTuple_New(n);
for (i = 0; i < n; i++) {
PyObject *exception, *value, *tb, *w;
PyErr_Fetch(&exception, &value, &tb);
w = do_mkvalue(p_format, p_va, flags);
PyErr_Restore(exception, value, tb);
if (w != NULL) {
if (v != NULL) {
PyTuple_SET_ITEM(v, i, w);
}
else {
Py_DECREF(w);
}
}
}
Py_XDECREF(v);
if (**p_format != endchar) {
PyErr_SetString(PyExc_SystemError,
"Unmatched paren in format");
return;
}
if (endchar) {
++*p_format;
}
}
static PyObject *
do_mkdict(const char **p_format, va_list *p_va, char endchar, Py_ssize_t n, int flags)
{
PyObject *d;
Py_ssize_t i;
if (n < 0)
return NULL;
if (n % 2) {
PyErr_SetString(PyExc_SystemError,
"Bad dict format");
do_ignore(p_format, p_va, endchar, n, flags);
return NULL;
}
/* Note that we can't bail immediately on error as this will leak
refcounts on any 'N' arguments. */
if ((d = PyDict_New()) == NULL) {
do_ignore(p_format, p_va, endchar, n, flags);
return NULL;
}
for (i = 0; i < n; i+= 2) {
PyObject *k, *v;
k = do_mkvalue(p_format, p_va, flags);
if (k == NULL) {
do_ignore(p_format, p_va, endchar, n - i - 1, flags);
Py_DECREF(d);
return NULL;
}
v = do_mkvalue(p_format, p_va, flags);
if (v == NULL || PyDict_SetItem(d, k, v) < 0) {
do_ignore(p_format, p_va, endchar, n - i - 2, flags);
Py_DECREF(k);
Py_XDECREF(v);
Py_DECREF(d);
return NULL;
}
Py_DECREF(k);
Py_DECREF(v);
}
if (**p_format != endchar) {
Py_DECREF(d);
PyErr_SetString(PyExc_SystemError,
"Unmatched paren in format");
return NULL;
}
if (endchar)
++*p_format;
return d;
}
static PyObject *
do_mklist(const char **p_format, va_list *p_va, char endchar, Py_ssize_t n, int flags)
{
PyObject *v;
Py_ssize_t i;
if (n < 0)
return NULL;
/* Note that we can't bail immediately on error as this will leak
refcounts on any 'N' arguments. */
v = PyList_New(n);
if (v == NULL) {
do_ignore(p_format, p_va, endchar, n, flags);
return NULL;
}
for (i = 0; i < n; i++) {
PyObject *w = do_mkvalue(p_format, p_va, flags);
if (w == NULL) {
do_ignore(p_format, p_va, endchar, n - i - 1, flags);
Py_DECREF(v);
return NULL;
}
PyList_SET_ITEM(v, i, w);
}
if (**p_format != endchar) {
Py_DECREF(v);
PyErr_SetString(PyExc_SystemError,
"Unmatched paren in format");
return NULL;
}
if (endchar)
++*p_format;
return v;
}
static int
do_mkstack(PyObject **stack, const char **p_format, va_list *p_va,
char endchar, Py_ssize_t n, int flags)
{
Py_ssize_t i;
if (n < 0) {
return -1;
}
/* Note that we can't bail immediately on error as this will leak
refcounts on any 'N' arguments. */
for (i = 0; i < n; i++) {
PyObject *w = do_mkvalue(p_format, p_va, flags);
if (w == NULL) {
do_ignore(p_format, p_va, endchar, n - i - 1, flags);
goto error;
}
stack[i] = w;
}
if (**p_format != endchar) {
PyErr_SetString(PyExc_SystemError,
"Unmatched paren in format");
goto error;
}
if (endchar) {
++*p_format;
}
return 0;
error:
n = i;
for (i=0; i < n; i++) {
Py_DECREF(stack[i]);
}
return -1;
}
static PyObject *
do_mktuple(const char **p_format, va_list *p_va, char endchar, Py_ssize_t n, int flags)
{
PyObject *v;
Py_ssize_t i;
if (n < 0)
return NULL;
/* Note that we can't bail immediately on error as this will leak
refcounts on any 'N' arguments. */
if ((v = PyTuple_New(n)) == NULL) {
do_ignore(p_format, p_va, endchar, n, flags);
return NULL;
}
for (i = 0; i < n; i++) {
PyObject *w = do_mkvalue(p_format, p_va, flags);
if (w == NULL) {
do_ignore(p_format, p_va, endchar, n - i - 1, flags);
Py_DECREF(v);
return NULL;
}
PyTuple_SET_ITEM(v, i, w);
}
if (**p_format != endchar) {
Py_DECREF(v);
PyErr_SetString(PyExc_SystemError,
"Unmatched paren in format");
return NULL;
}
if (endchar)
++*p_format;
return v;
}
static PyObject *
do_mkvalue(const char **p_format, va_list *p_va, int flags)
{
#define ERROR_NEED_PY_SSIZE_T_CLEAN \
{ \
PyErr_SetString(PyExc_SystemError, \
"PY_SSIZE_T_CLEAN macro must be defined for '#' formats"); \
return NULL; \
}
for (;;) {
switch (*(*p_format)++) {
case '(':
return do_mktuple(p_format, p_va, ')',
countformat(*p_format, ')'), flags);
case '[':
return do_mklist(p_format, p_va, ']',
countformat(*p_format, ']'), flags);
case '{':
return do_mkdict(p_format, p_va, '}',
countformat(*p_format, '}'), flags);
case 'b':
case 'B':
case 'h':
case 'i':
return PyLong_FromLong((long)va_arg(*p_va, int));
case 'H':
return PyLong_FromLong((long)va_arg(*p_va, unsigned int));
case 'I':
{
unsigned int n;
n = va_arg(*p_va, unsigned int);
return PyLong_FromUnsignedLong(n);
}
case 'n':
#if SIZEOF_SIZE_T!=SIZEOF_LONG
return PyLong_FromSsize_t(va_arg(*p_va, Py_ssize_t));
#endif
/* Fall through from 'n' to 'l' if Py_ssize_t is long */
case 'l':
return PyLong_FromLong(va_arg(*p_va, long));
case 'k':
{
unsigned long n;
n = va_arg(*p_va, unsigned long);
return PyLong_FromUnsignedLong(n);
}
case 'L':
return PyLong_FromLongLong((long long)va_arg(*p_va, long long));
case 'K':
return PyLong_FromUnsignedLongLong((long long)va_arg(*p_va, unsigned long long));
case 'u':
{
PyObject *v;
Py_UNICODE *u = va_arg(*p_va, Py_UNICODE *);
Py_ssize_t n;
if (**p_format == '#') {
++*p_format;
if (flags & FLAG_SIZE_T) {
n = va_arg(*p_va, Py_ssize_t);
}
else {
n = va_arg(*p_va, int);
ERROR_NEED_PY_SSIZE_T_CLEAN;
}
}
else
n = -1;
if (u == NULL) {
v = Py_None;
Py_INCREF(v);
}
else {
if (n < 0)
n = wcslen(u);
v = PyUnicode_FromWideChar(u, n);
}
return v;
}
case 'f':
case 'd':
return PyFloat_FromDouble(
(double)va_arg(*p_va, va_double));
case 'D':
return PyComplex_FromCComplex(
*((Py_complex *)va_arg(*p_va, Py_complex *)));
case 'c':
{
char p[1];
p[0] = (char)va_arg(*p_va, int);
return PyBytes_FromStringAndSize(p, 1);
}
case 'C':
{
int i = va_arg(*p_va, int);
return PyUnicode_FromOrdinal(i);
}
case 's':
case 'z':
case 'U': /* XXX deprecated alias */
{
PyObject *v;
const char *str = va_arg(*p_va, const char *);
Py_ssize_t n;
if (**p_format == '#') {
++*p_format;
if (flags & FLAG_SIZE_T) {
n = va_arg(*p_va, Py_ssize_t);
}
else {
n = va_arg(*p_va, int);
ERROR_NEED_PY_SSIZE_T_CLEAN;
}
}
else
n = -1;
if (str == NULL) {
v = Py_None;
Py_INCREF(v);
}
else {
if (n < 0) {
size_t m = strlen(str);
if (m > PY_SSIZE_T_MAX) {
PyErr_SetString(PyExc_OverflowError,
"string too long for Python string");
return NULL;
}
n = (Py_ssize_t)m;
}
v = PyUnicode_FromStringAndSize(str, n);
}
return v;
}
case 'y':
{
PyObject *v;
const char *str = va_arg(*p_va, const char *);
Py_ssize_t n;
if (**p_format == '#') {
++*p_format;
if (flags & FLAG_SIZE_T) {
n = va_arg(*p_va, Py_ssize_t);
}
else {
n = va_arg(*p_va, int);
ERROR_NEED_PY_SSIZE_T_CLEAN;
}
}
else
n = -1;
if (str == NULL) {
v = Py_None;
Py_INCREF(v);
}
else {
if (n < 0) {
size_t m = strlen(str);
if (m > PY_SSIZE_T_MAX) {
PyErr_SetString(PyExc_OverflowError,
"string too long for Python bytes");
return NULL;
}
n = (Py_ssize_t)m;
}
v = PyBytes_FromStringAndSize(str, n);
}
return v;
}
case 'N':
case 'S':
case 'O':
if (**p_format == '&') {
typedef PyObject *(*converter)(void *);
converter func = va_arg(*p_va, converter);
void *arg = va_arg(*p_va, void *);
++*p_format;
return (*func)(arg);
}
else {
PyObject *v;
v = va_arg(*p_va, PyObject *);
if (v != NULL) {
if (*(*p_format - 1) != 'N')
Py_INCREF(v);
}
else if (!PyErr_Occurred())
/* If a NULL was passed
* because a call that should
* have constructed a value
* failed, that's OK, and we
* pass the error on; but if
* no error occurred it's not
* clear that the caller knew
* what she was doing. */
PyErr_SetString(PyExc_SystemError,
"NULL object passed to Py_BuildValue");
return v;
}
case ':':
case ',':
case ' ':
case '\t':
break;
default:
PyErr_SetString(PyExc_SystemError,
"bad format char passed to Py_BuildValue");
return NULL;
}
}
#undef ERROR_NEED_PY_SSIZE_T_CLEAN
}
PyObject *
Py_BuildValue(const char *format, ...)
{
va_list va;
PyObject* retval;
va_start(va, format);
retval = va_build_value(format, va, 0);
va_end(va);
return retval;
}
PyObject *
_Py_BuildValue_SizeT(const char *format, ...)
{
va_list va;
PyObject* retval;
va_start(va, format);
retval = va_build_value(format, va, FLAG_SIZE_T);
va_end(va);
return retval;
}
PyObject *
Py_VaBuildValue(const char *format, va_list va)
{
return va_build_value(format, va, 0);
}
PyObject *
_Py_VaBuildValue_SizeT(const char *format, va_list va)
{
return va_build_value(format, va, FLAG_SIZE_T);
}
static PyObject *
va_build_value(const char *format, va_list va, int flags)
{
const char *f = format;
Py_ssize_t n = countformat(f, '\0');
va_list lva;
PyObject *retval;
if (n < 0)
return NULL;
if (n == 0) {
Py_RETURN_NONE;
}
va_copy(lva, va);
if (n == 1) {
retval = do_mkvalue(&f, &lva, flags);
} else {
retval = do_mktuple(&f, &lva, '\0', n, flags);
}
va_end(lva);
return retval;
}
PyObject **
_Py_VaBuildStack(PyObject **small_stack, Py_ssize_t small_stack_len,
const char *format, va_list va, Py_ssize_t *p_nargs)
{
return va_build_stack(small_stack, small_stack_len, format, va, 0, p_nargs);
}
PyObject **
_Py_VaBuildStack_SizeT(PyObject **small_stack, Py_ssize_t small_stack_len,
const char *format, va_list va, Py_ssize_t *p_nargs)
{
return va_build_stack(small_stack, small_stack_len, format, va, FLAG_SIZE_T, p_nargs);
}
static PyObject **
va_build_stack(PyObject **small_stack, Py_ssize_t small_stack_len,
const char *format, va_list va, int flags, Py_ssize_t *p_nargs)
{
const char *f;
Py_ssize_t n;
va_list lva;
PyObject **stack;
int res;
n = countformat(format, '\0');
if (n < 0) {
*p_nargs = 0;
return NULL;
}
if (n == 0) {
*p_nargs = 0;
return small_stack;
}
if (n <= small_stack_len) {
stack = small_stack;
}
else {
stack = PyMem_Malloc(n * sizeof(stack[0]));
if (stack == NULL) {
PyErr_NoMemory();
return NULL;
}
}
va_copy(lva, va);
f = format;
res = do_mkstack(stack, &f, &lva, '\0', n, flags);
va_end(lva);
if (res < 0) {
if (stack != small_stack) {
PyMem_Free(stack);
}
return NULL;
}
*p_nargs = n;
return stack;
}
int
PyModule_AddObjectRef(PyObject *mod, const char *name, PyObject *value)
{
if (!PyModule_Check(mod)) {
PyErr_SetString(PyExc_TypeError,
"PyModule_AddObjectRef() first argument "
"must be a module");
return -1;
}
if (!value) {
if (!PyErr_Occurred()) {
PyErr_SetString(PyExc_SystemError,
"PyModule_AddObjectRef() must be called "
"with an exception raised if value is NULL");
}
return -1;
}
PyObject *dict = PyModule_GetDict(mod);
if (dict == NULL) {
/* Internal error -- modules must have a dict! */
PyErr_Format(PyExc_SystemError, "module '%s' has no __dict__",
PyModule_GetName(mod));
return -1;
}
if (PyDict_SetItemString(dict, name, value)) {
return -1;
}
return 0;
}
int
PyModule_AddObject(PyObject *mod, const char *name, PyObject *value)
{
int res = PyModule_AddObjectRef(mod, name, value);
if (res == 0) {
Py_DECREF(value);
}
return res;
}
int
PyModule_AddIntConstant(PyObject *m, const char *name, long value)
{
PyObject *obj = PyLong_FromLong(value);
if (!obj) {
return -1;
}
int res = PyModule_AddObjectRef(m, name, obj);
Py_DECREF(obj);
return res;
}
int
PyModule_AddStringConstant(PyObject *m, const char *name, const char *value)
{
PyObject *obj = PyUnicode_FromString(value);
if (!obj) {
return -1;
}
int res = PyModule_AddObjectRef(m, name, obj);
Py_DECREF(obj);
return res;
}
int
PyModule_AddType(PyObject *module, PyTypeObject *type)
{
if (PyType_Ready(type) < 0) {
return -1;
}
const char *name = _PyType_Name(type);
assert(name != NULL);
return PyModule_AddObjectRef(module, name, (PyObject *)type);
}