bpo-25720: Fix the method for checking pad state of curses WINDOW (GH-4164) (#4212)

Modify the code to use ncurses is_pad() instead of checking WINDOW
_flags field.  If your platform does not provide the is_pad(), the
existing way that checks the field will be enabled.

Note: This change does not drop support for platforms where do not
have both WINDOW _flags field and is_pad().
(cherry picked from commit 8bc7d63560024681dce9f40445f2877b2987e92c)

1 files changed, 16 insertions, 8 deletions

diff --git a/Modules/_cursesmodule.c b/Modules/_cursesmodule.c
index ec6316b..94c67c1 100644
--- a/Modules/_cursesmodule.c
+++ b/Modules/_cursesmodule.c
@@ -936,6 +936,12 @@ int py_mvwdelch(WINDOW *w, int y, int x)
 }
 #endif
 
+#if defined(HAVE_CURSES_IS_PAD)
+#define py_is_pad(win)      is_pad(win)
+#elif defined(WINDOW_HAS_FLAGS)
+#define py_is_pad(win)      ((win) ? ((win)->_flags & _ISPAD) != 0 : FALSE)
+#endif
+
 /* chgat, added by Fabian Kreutz <fabian.kreutz at gmx.net> */
 
 static PyObject *
@@ -1075,10 +1081,11 @@ PyCursesWindow_EchoChar(PyCursesWindowObject *self, PyObject *args)
     if (!PyCurses_ConvertToChtype(self, temp, &ch))
         return NULL;
 
-#ifdef WINDOW_HAS_FLAGS
-    if (self->win->_flags & _ISPAD)
+#ifdef py_is_pad
+    if (py_is_pad(self->win)) {
         return PyCursesCheckERR(pechochar(self->win, ch | attr),
                                 "echochar");
+    }
     else
 #endif
         return PyCursesCheckERR(wechochar(self->win, ch | attr),
@@ -1607,10 +1614,10 @@ PyCursesWindow_NoOutRefresh(PyCursesWindowObject *self, PyObject *args)
     int pminrow,pmincol,sminrow,smincol,smaxrow,smaxcol;
     int rtn;
 
-#ifndef WINDOW_HAS_FLAGS
+#ifndef py_is_pad
     if (0)
 #else
-        if (self->win->_flags & _ISPAD)
+        if (py_is_pad(self->win))
 #endif
         {
             switch(PyTuple_Size(args)) {
@@ -1782,10 +1789,10 @@ PyCursesWindow_Refresh(PyCursesWindowObject *self, PyObject *args)
     int pminrow,pmincol,sminrow,smincol,smaxrow,smaxcol;
     int rtn;
 
-#ifndef WINDOW_HAS_FLAGS
+#ifndef py_is_pad
     if (0)
 #else
-        if (self->win->_flags & _ISPAD)
+        if (py_is_pad(self->win))
 #endif
         {
             switch(PyTuple_Size(args)) {
@@ -1851,9 +1858,10 @@ PyCursesWindow_SubWin(PyCursesWindowObject *self, PyObject *args)
     }
 
     /* printf("Subwin: %i %i %i %i   \n", nlines, ncols, begin_y, begin_x); */
-#ifdef WINDOW_HAS_FLAGS
-    if (self->win->_flags & _ISPAD)
+#ifdef py_is_pad
+    if (py_is_pad(self->win)) {
         win = subpad(self->win, nlines, ncols, begin_y, begin_x);
+    }
     else
 #endif
         win = subwin(self->win, nlines, ncols, begin_y, begin_x);