Add API for static strings, primarily good for identifiers.

Thanks to Konrad Schöbel and Jasper Schulz for helping with the mass-editing.

Include/abstract.h

@@ -7,6 +7,7 @@ extern "C" {
 #ifdef PY_SSIZE_T_CLEAN
 #define PyObject_CallFunction _PyObject_CallFunction_SizeT
 #define PyObject_CallMethod _PyObject_CallMethod_SizeT
+#define _PyObject_CallMethodId _PyObject_CallMethodId_SizeT
 #endif
 
 /* Abstract Object Interface (many thanks to Jim Fulton) */
@@ -307,11 +308,22 @@ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
      Python expression: o.method(args).
        */
 
+     PyAPI_FUNC(PyObject *) _PyObject_CallMethodId(PyObject *o, _Py_Identifier *method,
+                                                  char *format, ...);
+
+       /*
+         Like PyObject_CallMethod, but expect a _Py_Identifier* as the
+         method name.
+       */
+
      PyAPI_FUNC(PyObject *) _PyObject_CallFunction_SizeT(PyObject *callable,
                                                          char *format, ...);
      PyAPI_FUNC(PyObject *) _PyObject_CallMethod_SizeT(PyObject *o,
                                                        char *name,
                                                        char *format, ...);
+     PyAPI_FUNC(PyObject *) _PyObject_CallMethodId_SizeT(PyObject *o,
+                                                       _Py_Identifier *name,
+                                                       char *format, ...);
 
      PyAPI_FUNC(PyObject *) PyObject_CallFunctionObjArgs(PyObject *callable,
                                                          ...);

Include/object.h

@@ -454,6 +454,7 @@ PyAPI_FUNC(unsigned int) PyType_ClearCache(void);
 PyAPI_FUNC(void) PyType_Modified(PyTypeObject *);
 
 /* Generic operations on objects */
+struct _Py_Identifier;
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(int) PyObject_Print(PyObject *, FILE *, int);
 PyAPI_FUNC(void) _Py_BreakPoint(void);
@@ -471,6 +472,9 @@ PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *);
 PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *);
 PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *);
 PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *);
+PyAPI_FUNC(PyObject *) _PyObject_GetAttrId(PyObject *, struct _Py_Identifier *);
+PyAPI_FUNC(int) _PyObject_SetAttrId(PyObject *, struct _Py_Identifier *, PyObject *);
+PyAPI_FUNC(int) _PyObject_HasAttrId(PyObject *, struct _Py_Identifier *);
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(PyObject **) _PyObject_GetDictPtr(PyObject *);
 #endif

Include/unicodeobject.h

@@ -2024,6 +2024,40 @@ PyAPI_FUNC(int) _PyUnicode_CheckConsistency(
     int check_content);
 #endif
 
+/********************* String Literals ****************************************/
+/* This structure helps managing static strings. The basic usage goes like this:
+   Instead of doing
+
+       r = PyObject_CallMethod(o, "foo", "args", ...);
+
+   do
+
+       _Py_identifier(foo);
+       ...
+       r = _PyObject_CallMethodId(o, &PyId_foo, "args", ...);
+
+   PyId_foo is a static variable, either on block level or file level. On first
+   usage, the string "foo" is interned, and the structures are linked. On interpreter
+   shutdown, all strings are released (through _PyUnicode_ClearStaticStrings).
+
+   Alternatively, _Py_static_string allows to choose the variable name.
+   _PyUnicode_FromId returns a new reference to the interned string.
+   _PyObject_{Get,Set,Has}AttrId are __getattr__ versions using _Py_Identifier*.
+*/
+typedef struct _Py_Identifier {
+    struct _Py_Identifier *next;
+    const char* string;
+    PyObject *object;
+} _Py_Identifier;
+
+#define _Py_static_string(varname, value)  static _Py_Identifier varname = { 0, value, 0 };
+#define _Py_identifier(varname) _Py_static_string(PyId_##varname, #varname)
+
+/* Return an interned Unicode object for an Identifier; may fail if there is no memory.*/
+PyAPI_FUNC(PyObject*) _PyUnicode_FromId(_Py_Identifier*);
+/* Clear all static strings. */
+PyAPI_FUNC(void) _PyUnicode_ClearStaticStrings(void);
+
 #ifdef __cplusplus
 }
 #endif

Misc/NEWS

@@ -10,6 +10,8 @@ What's New in Python 3.3 Alpha 1?
 Core and Builtins
 -----------------
 
+- Add internal API for static strings (_Py_identifier et.al.).
+
 - Issue #13063: the Windows error ERROR_NO_DATA (numbered 232 and described
   as "The pipe is being closed") is now mapped to POSIX errno EPIPE
   (previously EINVAL).

Modules/_bisectmodule.c

@@ -86,7 +86,9 @@ insort_right(PyObject *self, PyObject *args, PyObject *kw)
         if (PyList_Insert(list, index, item) < 0)
             return NULL;
     } else {
-        result = PyObject_CallMethod(list, "insert", "nO", index, item);
+        _Py_identifier(insert);
+
+        result = _PyObject_CallMethodId(list, &PyId_insert, "nO", index, item);
         if (result == NULL)
             return NULL;
         Py_DECREF(result);
@@ -186,7 +188,9 @@ insort_left(PyObject *self, PyObject *args, PyObject *kw)
         if (PyList_Insert(list, index, item) < 0)
             return NULL;
     } else {
-        result = PyObject_CallMethod(list, "insert", "iO", index, item);
+        _Py_identifier(insert);
+
+        result = _PyObject_CallMethodId(list, &PyId_insert, "iO", index, item);
         if (result == NULL)
             return NULL;
         Py_DECREF(result);

Modules/_collectionsmodule.c

@@ -1334,13 +1334,15 @@ defdict_reduce(defdictobject *dd)
     PyObject *items;
     PyObject *iter;
     PyObject *result;
+    _Py_identifier(items);
+
     if (dd->default_factory == NULL || dd->default_factory == Py_None)
         args = PyTuple_New(0);
     else
         args = PyTuple_Pack(1, dd->default_factory);
     if (args == NULL)
         return NULL;
-    items = PyObject_CallMethod((PyObject *)dd, "items", "()");
+    items = _PyObject_CallMethodId((PyObject *)dd, &PyId_items, "()");
     if (items == NULL) {
         Py_DECREF(args);
         return NULL;

Modules/_ctypes/_ctypes.c

@@ -3679,8 +3679,10 @@ _build_result(PyObject *result, PyObject *callargs,
             PyTuple_SET_ITEM(tup, index, v);
             index++;
         } else if (bit & outmask) {
+            _Py_identifier(__ctypes_from_outparam__);
+
             v = PyTuple_GET_ITEM(callargs, i);
-            v = PyObject_CallMethod(v, "__ctypes_from_outparam__", NULL);
+            v = _PyObject_CallMethodId(v, &PyId___ctypes_from_outparam__, NULL);
             if (v == NULL || numretvals == 1) {
                 Py_DECREF(callargs);
                 return v;

Modules/_ctypes/callproc.c

@@ -1687,13 +1687,15 @@ unpickle(PyObject *self, PyObject *args)
     PyObject *state;
     PyObject *result;
     PyObject *tmp;
+    _Py_identifier(__new__);
+    _Py_identifier(__setstate__);
 
     if (!PyArg_ParseTuple(args, "OO", &typ, &state))
         return NULL;
-    result = PyObject_CallMethod(typ, "__new__", "O", typ);
+    result = _PyObject_CallMethodId(typ, &PyId___new__, "O", typ);
     if (result == NULL)
         return NULL;
-    tmp = PyObject_CallMethod(result, "__setstate__", "O", state);
+    tmp = _PyObject_CallMethodId(result, &PyId___setstate__, "O", state);
     if (tmp == NULL) {
         Py_DECREF(result);
         return NULL;

Modules/_cursesmodule.c

@@ -1418,10 +1418,12 @@ PyCursesWindow_PutWin(PyCursesWindowObject *self, PyObject *stream)
     while (1) {
         char buf[BUFSIZ];
         Py_ssize_t n = fread(buf, 1, BUFSIZ, fp);
+        _Py_identifier(write);
+
         if (n <= 0)
             break;
         Py_DECREF(res);
-        res = PyObject_CallMethod(stream, "write", "y#", buf, n);
+        res = _PyObject_CallMethodId(stream, &PyId_write, "y#", buf, n);
         if (res == NULL)
             break;
     }
@@ -1911,6 +1913,7 @@ PyCurses_GetWin(PyCursesWindowObject *self, PyObject *stream)
     WINDOW *win;
 
     PyCursesInitialised;
+    _Py_identifier(read);
 
     strcpy(fn, "/tmp/py.curses.getwin.XXXXXX");
     fd = mkstemp(fn);
@@ -1922,7 +1925,7 @@ PyCurses_GetWin(PyCursesWindowObject *self, PyObject *stream)
         remove(fn);
         return PyErr_SetFromErrnoWithFilename(PyExc_IOError, fn);
     }
-    data = PyObject_CallMethod(stream, "read", "");
+    data = _PyObject_CallMethodId(stream, &PyId_read, "");
     if (data == NULL) {
         fclose(fp);
         remove(fn);