Add PyFrozenDict_New(iterable)

Author: vstinner

Include/cpython/dictobject.h

@@ -113,3 +113,6 @@ PyAPI_FUNC(int) PyDict_ClearWatcher(int watcher_id);
 // Mark given dictionary as "watched" (callback will be called if it is modified)
 PyAPI_FUNC(int) PyDict_Watch(int watcher_id, PyObject* dict);
 PyAPI_FUNC(int) PyDict_Unwatch(int watcher_id, PyObject* dict);
+
+// Create a frozendict. Create an empty dictionary if iterable is NULL.
+PyAPI_FUNC(PyObject*) PyFrozenDict_New(PyObject *iterable);

Objects/dictobject.c

@@ -138,7 +138,6 @@ As a consequence of this, split keys have a maximum size of 16.
 // Forward declarations
 static PyObject* frozendict_new(PyTypeObject *type, PyObject *args,
                                 PyObject *kwds);
-static PyObject* _PyFrozenDict_New(void);
 
 
 /*[clinic input]
@@ -4135,7 +4134,7 @@ copy_lock_held(PyObject *o)
     if (mp->ma_used == 0) {
         /* The dict is empty; just return a new dict. */
         if (frozendict) {
-            return _PyFrozenDict_New();
+            return PyFrozenDict_New(NULL);
         }
         else {
             return PyDict_New();
@@ -4211,7 +4210,7 @@ copy_lock_held(PyObject *o)
     }
 
     if (frozendict) {
-        copy = _PyFrozenDict_New();
+        copy = PyFrozenDict_New(NULL);
     }
     else {
         copy = PyDict_New();
@@ -7911,15 +7910,37 @@ frozendict_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     }
     PyFrozenDictObject *self = _PyFrozenDictObject_CAST(d);
     self->ma_hash = -1;
+
+    if (args != NULL) {
+        if (dict_update_common(d, args, kwds, "frozendict") < 0) {
+            Py_DECREF(d);
+            return NULL;
+        }
+    }
+    else {
+        assert(kwds == NULL);
+    }
+
     return d;
 }
 
 
-static PyObject*
-_PyFrozenDict_New(void)
+PyObject*
+PyFrozenDict_New(PyObject *iterable)
 {
-    PyObject *args = Py_GetConstant(Py_CONSTANT_EMPTY_TUPLE);
-    return frozendict_new(&PyFrozenDict_Type, args, NULL);
+    if (iterable != NULL) {
+        PyObject *args = PyTuple_Pack(1, iterable);
+        if (args == NULL) {
+            return NULL;
+        }
+        PyObject *frozendict = frozendict_new(&PyFrozenDict_Type, args, NULL);
+        Py_DECREF(args);
+        return frozendict;
+    }
+    else {
+        PyObject *args = Py_GetConstantBorrowed(Py_CONSTANT_EMPTY_TUPLE);
+        return frozendict_new(&PyFrozenDict_Type, args, NULL);
+    }
 }