Remove support for Python <3.8 from C code

Similarly to the previous commit, the bulk of the work is removing code
for PY_VERSION_HEX < 0x03080000, removing #if guards around
PY_VERSION_HEX >= 0x03080000, and removing unnecessary macro
definitions.

Signed-off-by: Rodrigo Tobar <rtobar@icrar.org>

Author: rtobar

src/c/_cffi_backend.c

@@ -141,20 +141,10 @@
 #include "malloc_closure.h"
 
 
-#if PY_VERSION_HEX >= 0x03030000
-# define PyText_GetSize PyUnicode_GetLength
-#else
-# define PyText_GetSize PyUnicode_GetSize
-#endif
-
 #if PY_VERSION_HEX < 0x030900a4
 # define Py_SET_REFCNT(obj, val) (Py_REFCNT(obj) = (val))
 #endif
 
-#if PY_VERSION_HEX >= 0x03080000
-# define USE_WRITEUNRAISABLEMSG
-#endif
-
 /************************************************************/
 
 /* base type flag: exactly one of the following: */
@@ -4431,7 +4421,7 @@ static void *b_do_dlopen(PyObject *args, const char **p_printable_filename,
             if (*p_printable_filename == NULL)
                 return NULL;
 
-            sz1 = PyText_GetSize(filename_unicode) + 1;
+            sz1 = PyUnicode_GetLength(filename_unicode) + 1;
             sz1 *= 2;   /* should not be needed, but you never know */
             w1 = alloca(sizeof(wchar_t) * sz1);
             sz1 = PyUnicode_AsWideChar(filename_unicode,
@@ -5137,7 +5127,7 @@ static PyObject *b_complete_struct_or_union(PyObject *self, PyObject *args)
         if (!(sflags & SF_GCC_ARM_BITFIELDS) && fbitsize >= 0) {
             if (!(sflags & SF_MSVC_BITFIELDS)) {
                 /* GCC: anonymous bitfields (of any size) don't cause alignment */
-                do_align = PyText_GetSize(fname) > 0;
+                do_align = PyUnicode_GetLength(fname) > 0;
             }
             else {
                 /* MSVC: zero-sized bitfields don't cause alignment */
@@ -5181,7 +5171,7 @@ static PyObject *b_complete_struct_or_union(PyObject *self, PyObject *args)
                 byteoffset = foffset;
             }
 
-            if (PyText_GetSize(fname) == 0 &&
+            if (PyUnicode_GetLength(fname) == 0 &&
                     ftype->ct_flags & (CT_STRUCT|CT_UNION)) {
                 /* a nested anonymous struct or union */
                 CFieldObject *cfsrc = (CFieldObject *)ftype->ct_extra;
@@ -5252,7 +5242,7 @@ static PyObject *b_complete_struct_or_union(PyObject *self, PyObject *args)
             field_offset_bytes &= ~(falign - 1);
 
             if (fbitsize == 0) {
-                if (PyText_GetSize(fname) > 0) {
+                if (PyUnicode_GetLength(fname) > 0) {
                     PyErr_Format(PyExc_TypeError,
                                  "field '%s.%s' is declared with :0",
                                  ct->ct_name, PyUnicode_AsUTF8(fname));
@@ -5341,7 +5331,7 @@ static PyObject *b_complete_struct_or_union(PyObject *self, PyObject *args)
                 if (sflags & SF_GCC_BIG_ENDIAN)
                     bitshift = 8 * ftype->ct_size - fbitsize - bitshift;
 
-                if (PyText_GetSize(fname) > 0) {
+                if (PyUnicode_GetLength(fname) > 0) {
 
                     *previous = _add_field(interned_fields, fname, ftype,
                                        field_offset_bytes, bitshift, fbitsize,
@@ -5996,7 +5986,6 @@ static void _my_PyErr_WriteUnraisable(PyObject *t, PyObject *v, PyObject *tb,
                                       char *extra_error_line)
 {
     /* like PyErr_WriteUnraisable(), but write a full traceback */
-#ifdef USE_WRITEUNRAISABLEMSG
 
     /* PyErr_WriteUnraisable actually writes the full traceback anyway
        from Python 3.4, but we can't really get the formatting of the
@@ -6033,34 +6022,6 @@ static void _my_PyErr_WriteUnraisable(PyObject *t, PyObject *v, PyObject *tb,
     else
         PyErr_WriteUnraisable(obj);   /* best effort */
     PyErr_Clear();
-
-#else
-
-    /* version for Python 2.7 and < 3.8 */
-    PyObject *f;
-    /* jump through hoops to ensure the tb is attached to v, on Python 3 */
-    PyErr_NormalizeException(&t, &v, &tb);
-    if (tb == NULL) {
-        tb = Py_None;
-        Py_INCREF(tb);
-    }
-    PyException_SetTraceback(v, tb);
-    f = PySys_GetObject("stderr");
-    if (f != NULL) {
-        if (obj != NULL) {
-            PyFile_WriteString(objdescr, f);
-            PyFile_WriteObject(obj, f, 0);
-            PyFile_WriteString(":\n", f);
-        }
-        if (extra_error_line != NULL)
-            PyFile_WriteString(extra_error_line, f);
-        PyErr_Display(t, v, tb);
-    }
-    Py_XDECREF(t);
-    Py_XDECREF(v);
-    Py_XDECREF(tb);
-
-#endif
 }
 
 static void general_invoke_callback(int decode_args_from_libffi,
@@ -6110,11 +6071,7 @@ static void general_invoke_callback(int decode_args_from_libffi,
         goto error;
     if (convert_from_object_fficallback(result, SIGNATURE(1), py_res,
                                         decode_args_from_libffi) < 0) {
-#ifdef USE_WRITEUNRAISABLEMSG
         extra_error_line = ", trying to convert the result back to C";
-#else
-        extra_error_line = "Trying to convert the result back to C:\n";
-#endif
         goto error;
     }
  done:
@@ -6166,16 +6123,9 @@ static void general_invoke_callback(int decode_args_from_libffi,
             _my_PyErr_WriteUnraisable(exc1, val1, tb1,
                                       "From cffi callback ", py_ob,
                                       extra_error_line);
-#ifdef USE_WRITEUNRAISABLEMSG
             _my_PyErr_WriteUnraisable(exc2, val2, tb2,
                  "during handling of the above exception by 'onerror'",
                  NULL, NULL);
-#else
-            extra_error_line = ("\nDuring the call to 'onerror', "
-                                "another exception occurred:\n\n");
-            _my_PyErr_WriteUnraisable(exc2, val2, tb2,
-                                      NULL, NULL, extra_error_line);
-#endif
             _cffi_stop_error_capture(ecap);
         }
     }
@@ -6243,14 +6193,6 @@ static PyObject *prepare_callback_info_tuple(CTypeDescrObject *ct,
     infotuple = Py_BuildValue("OOOO", ct, ob, py_rawerr, onerror_ob);
     Py_DECREF(py_rawerr);
 
-#if defined(WITH_THREAD) && PY_VERSION_HEX < 0x03070000
-    /* We must setup the GIL here, in case the callback is invoked in
-       some other non-Pythonic thread.  This is the same as ctypes.
-       But PyEval_InitThreads() is always a no-op from CPython 3.7
-       (the call from ctypes was removed some time later I think). */
-    PyEval_InitThreads();
-#endif
-
     return infotuple;
 }
 

src/c/call_python.c

@@ -1,16 +1,7 @@
-#if PY_VERSION_HEX >= 0x03080000
-# define HAVE_PYINTERPSTATE_GETDICT
-#endif
-
-
 static PyObject *_current_interp_key(void)
 {
     PyInterpreterState *interp = PyThreadState_GET()->interp;
-#ifdef HAVE_PYINTERPSTATE_GETDICT
     return PyInterpreterState_GetDict(interp);   /* shared reference */
-#else
-    return interp->modules;
-#endif
 }
 
 static PyObject *_get_interpstate_dict(void)
@@ -33,11 +24,7 @@ static PyObject *_get_interpstate_dict(void)
     }
 
     interp = tstate->interp;
-#ifdef HAVE_PYINTERPSTATE_GETDICT
     interpdict = PyInterpreterState_GetDict(interp);   /* shared reference */
-#else
-    interpdict = interp->builtins;
-#endif
     if (interpdict == NULL) {
         /* subinterpreter was cleared already, or is being cleared right now,
            to a point that is too much for us to continue */

src/c/minibuffer.h

@@ -208,13 +208,6 @@ mb_richcompare(PyObject *self, PyObject *other, int op)
 
 /* pfffffffffffff pages of copy-paste from listobject.c */
 
-/* pfffffffffffff#2: the PySlice_GetIndicesEx() *macro* should not
-   be called, because C extension modules compiled with it differ
-   on ABI between 3.6.0, 3.6.1 and 3.6.2. */
-#if PY_VERSION_HEX < 0x03070000 && defined(PySlice_GetIndicesEx) && !defined(PYPY_VERSION)
-#undef PySlice_GetIndicesEx
-#endif
-
 static PyObject *mb_subscript(MiniBufferObj *self, PyObject *item)
 {
     if (PyIndex_Check(item)) {

src/c/misc_thread_common.h

@@ -325,20 +325,12 @@ static void restore_errno_only(void)
      It was added in 3.5.2 but should never be used in 3.5.x
      because it is not available in 3.5.0 or 3.5.1.
 */
-#if PY_VERSION_HEX >= 0x03050100 && PY_VERSION_HEX < 0x03060000
-PyAPI_DATA(void *volatile) _PyThreadState_Current;
-#endif
-
 static PyThreadState *get_current_ts(void)
 {
 #if PY_VERSION_HEX >= 0x030D0000
     return PyThreadState_GetUnchecked();
-#elif PY_VERSION_HEX >= 0x03060000
-    return _PyThreadState_UncheckedGet();
-#elif defined(_Py_atomic_load_relaxed)
-    return (PyThreadState*)_Py_atomic_load_relaxed(&_PyThreadState_Current);
 #else
-    return (PyThreadState*)_PyThreadState_Current;  /* assume atomic read */
+    return _PyThreadState_UncheckedGet();
 #endif
 }
 

src/cffi/_embedding.h

@@ -244,10 +244,6 @@ static int _cffi_initialize_python(void)
     goto done;
 }
 
-#if PY_VERSION_HEX < 0x03080000
-PyAPI_DATA(char *) _PyParser_TokenNames[];  /* from CPython */
-#endif
-
 static int _cffi_carefully_make_gil(void)
 {
     /* This does the basic initialization of Python.  It can be called
@@ -292,27 +288,6 @@ static int _cffi_carefully_make_gil(void)
     */
 
 #ifdef WITH_THREAD
-# if PY_VERSION_HEX < 0x03080000
-    char *volatile *lock = (char *volatile *)_PyParser_TokenNames;
-    char *old_value, *locked_value;
-
-    while (1) {    /* spin loop */
-        old_value = *lock;
-        locked_value = old_value + 1;
-        if (old_value[0] == 'E') {
-            assert(old_value[1] == 'N');
-            if (cffi_compare_and_swap(lock, old_value, locked_value))
-                break;
-        }
-        else {
-            assert(old_value[0] == 'N');
-            /* should ideally do a spin loop instruction here, but
-               hard to do it portably and doesn't really matter I
-               think: PyEval_InitThreads() should be very fast, and
-               this is only run at start-up anyway. */
-        }
-    }
-# else
 #  if PY_VERSION_HEX < 0x030C0000
     int volatile *lock = (int volatile *)&PyCapsule_Type.tp_version_tag;
     int old_value, locked_value = -42;
@@ -345,26 +320,16 @@ static int _cffi_carefully_make_gil(void)
                this is only run at start-up anyway. */
         }
     }
-# endif
 #endif
 
     /* call Py_InitializeEx() */
     if (!Py_IsInitialized()) {
         _cffi_py_initialize();
-#if PY_VERSION_HEX < 0x03070000
-        PyEval_InitThreads();
-#endif
         PyEval_SaveThread();  /* release the GIL */
         /* the returned tstate must be the one that has been stored into the
            autoTLSkey by _PyGILState_Init() called from Py_Initialize(). */
     }
     else {
-#if PY_VERSION_HEX < 0x03070000
-        /* PyEval_InitThreads() is always a no-op from CPython 3.7 */
-        PyGILState_STATE state = PyGILState_Ensure();
-        PyEval_InitThreads();
-        PyGILState_Release(state);
-#endif
     }
 
 #ifdef WITH_THREAD