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

4 files changed, 24 insertions, 67 deletions

diff --git a/Objects/call.c b/Objects/call.c
index be8e90d03d..3250f8a10d 100644
--- a/Objects/call.c
+++ b/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);
 }
 
 
diff --git a/Objects/listobject.c b/Objects/listobject.c
index cbd6e81ea4..b6524e8bd7 100644
--- a/Objects/listobject.c
+++ b/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]
diff --git a/Objects/structseq.c b/Objects/structseq.c
index cf94155f18..56b06c707f 100644
--- a/Objects/structseq.c
+++ b/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;
diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index 9cf3f3dd66..75d2bf95e6 100644
--- a/Objects/tupleobject.c
+++ b/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 *