bpo-36030: Add _PyTuple_FromArray() function (GH-11954)

Include/internal/pycore_tupleobject.h

@@ -11,6 +11,7 @@ extern "C" {
 #include "tupleobject.h"
 
 #define _PyTuple_ITEMS(op) (_PyTuple_CAST(op)->ob_item)
+PyAPI_FUNC(PyObject *) _PyTuple_FromArray(PyObject *const *, Py_ssize_t);
 
 #ifdef __cplusplus
 }

Modules/itertoolsmodule.c

@@ -1,6 +1,7 @@
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
+#include "pycore_tupleobject.h"
 #include "structmember.h"
 
 /* Itertools module written and maintained
@@ -2239,15 +2240,10 @@ product_next(productobject *lz)
         /* Copy the previous result tuple or re-use it if available */
         if (Py_REFCNT(result) > 1) {
             PyObject *old_result = result;
-            result = PyTuple_New(npools);
+            result = _PyTuple_FromArray(_PyTuple_ITEMS(old_result), npools);
             if (result == NULL)
                 goto empty;
             lz->result = result;
-            for (i=0; i < npools; i++) {
-                elem = PyTuple_GET_ITEM(old_result, i);
-                Py_INCREF(elem);
-                PyTuple_SET_ITEM(result, i, elem);
-            }
             Py_DECREF(old_result);
         }
         /* Now, we've got the only copy so we can update it in-place */
@@ -2569,15 +2565,10 @@ combinations_next(combinationsobject *co)
         /* Copy the previous result tuple or re-use it if available */
         if (Py_REFCNT(result) > 1) {
             PyObject *old_result = result;
-            result = PyTuple_New(r);
+            result = _PyTuple_FromArray(_PyTuple_ITEMS(old_result), r);
             if (result == NULL)
                 goto empty;
             co->result = result;
-            for (i=0; i<r ; i++) {
-                elem = PyTuple_GET_ITEM(old_result, i);
-                Py_INCREF(elem);
-                PyTuple_SET_ITEM(result, i, elem);
-            }
             Py_DECREF(old_result);
         }
         /* Now, we've got the only copy so we can update it in-place
@@ -2910,15 +2901,10 @@ cwr_next(cwrobject *co)
         /* Copy the previous result tuple or re-use it if available */
         if (Py_REFCNT(result) > 1) {
             PyObject *old_result = result;
-            result = PyTuple_New(r);
+            result = _PyTuple_FromArray(_PyTuple_ITEMS(old_result), r);
             if (result == NULL)
                 goto empty;
             co->result = result;
-            for (i=0; i<r ; i++) {
-                elem = PyTuple_GET_ITEM(old_result, i);
-                Py_INCREF(elem);
-                PyTuple_SET_ITEM(result, i, elem);
-            }
             Py_DECREF(old_result);
         }
         /* Now, we've got the only copy so we can update it in-place CPython's
@@ -3258,15 +3244,10 @@ permutations_next(permutationsobject *po)
         /* Copy the previous result tuple or re-use it if available */
         if (Py_REFCNT(result) > 1) {
             PyObject *old_result = result;
-            result = PyTuple_New(r);
+            result = _PyTuple_FromArray(_PyTuple_ITEMS(old_result), r);
             if (result == NULL)
                 goto empty;
             po->result = result;
-            for (i=0; i<r ; i++) {
-                elem = PyTuple_GET_ITEM(old_result, i);
-                Py_INCREF(elem);
-                PyTuple_SET_ITEM(result, i, elem);
-            }
             Py_DECREF(old_result);
         }
         /* Now, we've got the only copy so we can update it in-place */

Objects/call.c

@@ -1276,20 +1276,7 @@ PyObject_CallFunctionObjArgs(PyObject *callable, ...)
 _Py_NO_INLINE PyObject *
 _PyStack_AsTuple(PyObject *const *stack, Py_ssize_t nargs)
 {
-    PyObject *args;
-    Py_ssize_t i;
-
-    args = PyTuple_New(nargs);
-    if (args == NULL) {
-        return NULL;
-    }
-
-    for (i=0; i < nargs; i++) {
-        PyObject *item = stack[i];
-        Py_INCREF(item);
-        PyTuple_SET_ITEM(args, i, item);
-    }
-    return args;
+    return _PyTuple_FromArray(stack, nargs);
 }
 
 
@@ -1297,24 +1284,11 @@ PyObject*
 _PyStack_AsTupleSlice(PyObject *const *stack, Py_ssize_t nargs,
                       Py_ssize_t start, Py_ssize_t end)
 {
-    PyObject *args;
-    Py_ssize_t i;
-
     assert(0 <= start);
     assert(end <= nargs);
     assert(start <= end);
 
-    args = PyTuple_New(end - start);
-    if (args == NULL) {
-        return NULL;
-    }
-
-    for (i=start; i < end; i++) {
-        PyObject *item = stack[i];
-        Py_INCREF(item);
-        PyTuple_SET_ITEM(args, i - start, item);
-    }
-    return args;
+    return _PyTuple_FromArray(stack + start, end - start);
 }
 
 

Objects/listobject.c

@@ -3,6 +3,7 @@
 #include "Python.h"
 #include "pycore_object.h"
 #include "pycore_pystate.h"
+#include "pycore_tupleobject.h"
 #include "pycore_accu.h"
 
 #ifdef STDC_HEADERS
@@ -2501,26 +2502,11 @@ PyList_Reverse(PyObject *v)
 PyObject *
 PyList_AsTuple(PyObject *v)
 {
-    PyObject *w;
-    PyObject **p, **q;
-    Py_ssize_t n;
     if (v == NULL || !PyList_Check(v)) {
         PyErr_BadInternalCall();
         return NULL;
     }
-    n = Py_SIZE(v);
-    w = PyTuple_New(n);
-    if (w == NULL)
-        return NULL;
-    p = ((PyTupleObject *)w)->ob_item;
-    q = ((PyListObject *)v)->ob_item;
-    while (--n >= 0) {
-        Py_INCREF(*q);
-        *p = *q;
-        p++;
-        q++;
-    }
-    return w;
+    return _PyTuple_FromArray(((PyListObject *)v)->ob_item, Py_SIZE(v));
 }
 
 /*[clinic input]

Objects/structseq.c

@@ -2,6 +2,7 @@
    and posixmodule for example uses. */
 
 #include "Python.h"
+#include "pycore_tupleobject.h"
 #include "structmember.h"
 
 static const char visible_length_key[] = "n_sequence_fields";
@@ -250,7 +251,7 @@ structseq_reduce(PyStructSequence* self, PyObject *Py_UNUSED(ignored))
     n_fields = REAL_SIZE(self);
     n_visible_fields = VISIBLE_SIZE(self);
     n_unnamed_fields = UNNAMED_FIELDS(self);
-    tup = PyTuple_New(n_visible_fields);
+    tup = _PyTuple_FromArray(self->ob_item, n_visible_fields);
     if (!tup)
         goto error;
 
@@ -258,12 +259,7 @@ structseq_reduce(PyStructSequence* self, PyObject *Py_UNUSED(ignored))
     if (!dict)
         goto error;
 
-    for (i = 0; i < n_visible_fields; i++) {
-        Py_INCREF(self->ob_item[i]);
-        PyTuple_SET_ITEM(tup, i, self->ob_item[i]);
-    }
-
-    for (; i < n_fields; i++) {
+    for (i = n_visible_fields; i < n_fields; i++) {
         const char *n = Py_TYPE(self)->tp_members[i-n_unnamed_fields].name;
         if (PyDict_SetItemString(dict, n, self->ob_item[i]) < 0)
             goto error;

Objects/tupleobject.c

@@ -419,14 +419,26 @@ tupleitem(PyTupleObject *a, Py_ssize_t i)
     return a->ob_item[i];
 }
 
+PyObject *
+_PyTuple_FromArray(PyObject *const *src, Py_ssize_t n)
+{
+    PyTupleObject *tuple = (PyTupleObject *)PyTuple_New(n);
+    if (tuple == NULL) {
+        return NULL;
+    }
+    PyObject **dst = tuple->ob_item;
+    for (Py_ssize_t i = 0; i < n; i++) {
+        PyObject *item = src[i];
+        Py_INCREF(item);
+        dst[i] = item;
+    }
+    return (PyObject *)tuple;
+}
+
 static PyObject *
 tupleslice(PyTupleObject *a, Py_ssize_t ilow,
            Py_ssize_t ihigh)
 {
-    PyTupleObject *np;
-    PyObject **src, **dest;
-    Py_ssize_t i;
-    Py_ssize_t len;
     if (ilow < 0)
         ilow = 0;
     if (ihigh > Py_SIZE(a))
@@ -437,18 +449,7 @@ tupleslice(PyTupleObject *a, Py_ssize_t ilow,
         Py_INCREF(a);
         return (PyObject *)a;
     }
-    len = ihigh - ilow;
-    np = (PyTupleObject *)PyTuple_New(len);
-    if (np == NULL)
-        return NULL;
-    src = a->ob_item + ilow;
-    dest = np->ob_item;
-    for (i = 0; i < len; i++) {
-        PyObject *v = src[i];
-        Py_INCREF(v);
-        dest[i] = v;
-    }
-    return (PyObject *)np;
+    return _PyTuple_FromArray(a->ob_item + ilow, ihigh - ilow);
 }
 
 PyObject *

Python/ceval.c

@@ -3831,16 +3831,11 @@ _PyEval_EvalCodeWithName(PyObject *_co, PyObject *globals, PyObject *locals,
 
     /* Pack other positional arguments into the *args argument */
     if (co->co_flags & CO_VARARGS) {
-        u = PyTuple_New(argcount - n);
+        u = _PyTuple_FromArray(args + n, argcount - n);
         if (u == NULL) {
             goto fail;
         }
         SETLOCAL(total_args, u);
-        for (i = n; i < argcount; i++) {
-            x = args[i];
-            Py_INCREF(x);
-            PyTuple_SET_ITEM(u, i-n, x);
-        }
     }
 
     /* Handle keyword arguments passed as two strided arrays */