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vstinnervstinner
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Add _Py_VaBuildStack() function
Issue #28915: Similar to Py_VaBuildValue(), but work on a C array of PyObject*, instead of creating a tuple.
1 parent b551b6c commit e9abde4

2 files changed

Lines changed: 111 additions & 0 deletions

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‎Include/modsupport.h‎

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -21,9 +21,16 @@ extern "C" {
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#endif /* !Py_LIMITED_API */
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#define Py_BuildValue _Py_BuildValue_SizeT
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#define Py_VaBuildValue _Py_VaBuildValue_SizeT
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#define _Py_VaBuildStack _Py_VaBuildStack_SizeT
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#else
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#ifndef Py_LIMITED_API
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PyAPI_FUNC(PyObject *) _Py_VaBuildValue_SizeT(const char *, va_list);
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PyAPI_FUNC(PyObject **) _Py_VaBuildStack_SizeT(
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PyObject **small_stack,
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Py_ssize_t small_stack_len,
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const char *format,
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va_list va,
33+
Py_ssize_t *p_nargs);
2734
#endif /* !Py_LIMITED_API */
2835
#endif
2936

@@ -47,6 +54,12 @@ PyAPI_FUNC(int) PyArg_VaParseTupleAndKeywords(PyObject *, PyObject *,
4754
const char *, char **, va_list);
4855
#endif
4956
PyAPI_FUNC(PyObject *) Py_VaBuildValue(const char *, va_list);
57+
PyAPI_FUNC(PyObject **) _Py_VaBuildStack(
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PyObject **small_stack,
59+
Py_ssize_t small_stack_len,
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const char *format,
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va_list va,
62+
Py_ssize_t *p_nargs);
5063

5164
#ifndef Py_LIMITED_API
5265
typedef struct _PyArg_Parser {

‎Python/modsupport.c‎

Lines changed: 98 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -7,6 +7,7 @@
77
typedef double va_double;
88

99
static PyObject *va_build_value(const char *, va_list, int);
10+
static PyObject **va_build_stack(PyObject **small_stack, Py_ssize_t small_stack_len, const char *, va_list, int, Py_ssize_t*);
1011

1112
/* Package context -- the full module name for package imports */
1213
const char *_Py_PackageContext = NULL;
@@ -60,6 +61,7 @@ countformat(const char *format, char endchar)
6061
/* After an original idea and first implementation by Steven Miale */
6162

6263
static PyObject *do_mktuple(const char**, va_list *, char, Py_ssize_t, int);
64+
static int do_mkstack(PyObject **, const char**, va_list *, char, Py_ssize_t, int);
6365
static PyObject *do_mklist(const char**, va_list *, char, Py_ssize_t, int);
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static PyObject *do_mkdict(const char**, va_list *, char, Py_ssize_t, int);
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static PyObject *do_mkvalue(const char**, va_list *, int);
@@ -182,6 +184,43 @@ do_mklist(const char **p_format, va_list *p_va, char endchar, Py_ssize_t n, int
182184
return v;
183185
}
184186

187+
static int
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do_mkstack(PyObject **stack, const char **p_format, va_list *p_va,
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char endchar, Py_ssize_t n, int flags)
190+
{
191+
Py_ssize_t i;
192+
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if (n < 0) {
194+
return -1;
195+
}
196+
/* Note that we can't bail immediately on error as this will leak
197+
refcounts on any 'N' arguments. */
198+
for (i = 0; i < n; i++) {
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PyObject *w = do_mkvalue(p_format, p_va, flags);
200+
if (w == NULL) {
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do_ignore(p_format, p_va, endchar, n - i - 1, flags);
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goto error;
203+
}
204+
stack[i] = w;
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}
206+
if (**p_format != endchar) {
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PyErr_SetString(PyExc_SystemError,
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"Unmatched paren in format");
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goto error;
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}
211+
if (endchar) {
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++*p_format;
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}
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return 0;
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error:
217+
n = i;
218+
for (i=0; i < n; i++) {
219+
Py_DECREF(stack[i]);
220+
}
221+
return -1;
222+
}
223+
185224
static PyObject *
186225
do_mktuple(const char **p_format, va_list *p_va, char endchar, Py_ssize_t n, int flags)
187226
{
@@ -488,6 +527,65 @@ va_build_value(const char *format, va_list va, int flags)
488527
return retval;
489528
}
490529

530+
PyObject **
531+
_Py_VaBuildStack(PyObject **small_stack, Py_ssize_t small_stack_len,
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const char *format, va_list va, Py_ssize_t *p_nargs)
533+
{
534+
return va_build_stack(small_stack, small_stack_len, format, va, 0, p_nargs);
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}
536+
537+
PyObject **
538+
_Py_VaBuildStack_SizeT(PyObject **small_stack, Py_ssize_t small_stack_len,
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const char *format, va_list va, Py_ssize_t *p_nargs)
540+
{
541+
return va_build_stack(small_stack, small_stack_len, format, va, FLAG_SIZE_T, p_nargs);
542+
}
543+
544+
static PyObject **
545+
va_build_stack(PyObject **small_stack, Py_ssize_t small_stack_len,
546+
const char *format, va_list va, int flags, Py_ssize_t *p_nargs)
547+
{
548+
const char *f;
549+
Py_ssize_t n;
550+
va_list lva;
551+
PyObject **stack;
552+
int res;
553+
554+
n = countformat(format, '\0');
555+
if (n < 0) {
556+
*p_nargs = 0;
557+
return NULL;
558+
}
559+
560+
if (n == 0) {
561+
*p_nargs = 0;
562+
return small_stack;
563+
}
564+
565+
if (n <= small_stack_len) {
566+
stack = small_stack;
567+
}
568+
else {
569+
stack = PyMem_Malloc(n * sizeof(stack[0]));
570+
if (stack == NULL) {
571+
PyErr_NoMemory();
572+
return NULL;
573+
}
574+
}
575+
576+
va_copy(lva, va);
577+
f = format;
578+
res = do_mkstack(stack, &f, &lva, '\0', n, flags);
579+
va_end(lva);
580+
581+
if (res < 0) {
582+
return NULL;
583+
}
584+
585+
*p_nargs = n;
586+
return stack;
587+
}
588+
491589

492590
PyObject *
493591
PyEval_CallFunction(PyObject *callable, const char *format, ...)

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