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[3.14] gh-134209: use heap-allocated memory in _curses.window.{instr,getstr} (GH-134283) #134391

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Merged
merged 1 commit into from
May 20, 2025
Merged

[3.14] gh-134209: use heap-allocated memory in _curses.window.{instr,getstr} (GH-134283) #134391

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8 changes: 8 additions & 0 deletions Doc/library/curses.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -988,6 +988,10 @@ the following methods and attributes:
window.getstr(y, x, n)

Read a bytes object from the user, with primitive line editing capacity.
The maximum value for *n* is 2047.

.. versionchanged:: 3.14
The maximum value for *n* was increased from 1023 to 2047.


.. method:: window.getyx()
Expand Down Expand Up @@ -1079,6 +1083,10 @@ the following methods and attributes:
current cursor position, or at *y*, *x* if specified. Attributes are stripped
from the characters. If *n* is specified, :meth:`instr` returns a string
at most *n* characters long (exclusive of the trailing NUL).
The maximum value for *n* is 2047.

.. versionchanged:: 3.14
The maximum value for *n* was increased from 1023 to 2047.


.. method:: window.is_linetouched(line)
Expand Down
3 changes: 3 additions & 0 deletions Misc/NEWS.d/next/Library/2025-05-19-20-59-06.gh-issue-134209.anhTcF.rst
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@@ -0,0 +1,3 @@
:mod:`curses`: The :meth:`curses.window.instr` and :meth:`curses.window.getstr`
methods now allocate their internal buffer on the heap instead of the stack;
in addition, the max buffer size is increased from 1023 to 2047.
102 changes: 69 additions & 33 deletions Modules/_cursesmodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1687,7 +1687,7 @@ _curses.window.getstr
x: int
X-coordinate.
]
n: int = 1023
n: int = 2047
Maximal number of characters.
/

Expand All @@ -1700,62 +1700,80 @@ PyCursesWindow_GetStr(PyObject *op, PyObject *args)
PyCursesWindowObject *self = _PyCursesWindowObject_CAST(op);

int x, y, n;
char rtn[1024]; /* This should be big enough.. I hope */
int rtn2;
int rtn;

/* could make the buffer size larger/dynamic */
Py_ssize_t max_buf_size = 2048;
PyObject *result = PyBytes_FromStringAndSize(NULL, max_buf_size);
if (result == NULL)
return NULL;
char *buf = PyBytes_AS_STRING(result);

switch (PyTuple_Size(args)) {
case 0:
Py_BEGIN_ALLOW_THREADS
rtn2 = wgetnstr(self->win,rtn, 1023);
rtn = wgetnstr(self->win, buf, max_buf_size - 1);
Py_END_ALLOW_THREADS
break;
case 1:
if (!PyArg_ParseTuple(args,"i;n", &n))
return NULL;
goto error;
if (n < 0) {
PyErr_SetString(PyExc_ValueError, "'n' must be nonnegative");
return NULL;
goto error;
}
Py_BEGIN_ALLOW_THREADS
rtn2 = wgetnstr(self->win, rtn, Py_MIN(n, 1023));
rtn = wgetnstr(self->win, buf, Py_MIN(n, max_buf_size - 1));
Py_END_ALLOW_THREADS
break;
case 2:
if (!PyArg_ParseTuple(args,"ii;y,x",&y,&x))
return NULL;
goto error;
Py_BEGIN_ALLOW_THREADS
#ifdef STRICT_SYSV_CURSES
rtn2 = wmove(self->win,y,x)==ERR ? ERR : wgetnstr(self->win, rtn, 1023);
rtn = wmove(self->win,y,x)==ERR ? ERR : wgetnstr(self->win, rtn, max_buf_size - 1);
#else
rtn2 = mvwgetnstr(self->win,y,x,rtn, 1023);
rtn = mvwgetnstr(self->win,y,x,buf, max_buf_size - 1);
#endif
Py_END_ALLOW_THREADS
break;
case 3:
if (!PyArg_ParseTuple(args,"iii;y,x,n", &y, &x, &n))
return NULL;
goto error;
if (n < 0) {
PyErr_SetString(PyExc_ValueError, "'n' must be nonnegative");
return NULL;
goto error;
}
#ifdef STRICT_SYSV_CURSES
Py_BEGIN_ALLOW_THREADS
rtn2 = wmove(self->win,y,x)==ERR ? ERR :
wgetnstr(self->win, rtn, Py_MIN(n, 1023));
rtn = wmove(self->win,y,x)==ERR ? ERR :
wgetnstr(self->win, rtn, Py_MIN(n, max_buf_size - 1));
Py_END_ALLOW_THREADS
#else
Py_BEGIN_ALLOW_THREADS
rtn2 = mvwgetnstr(self->win, y, x, rtn, Py_MIN(n, 1023));
rtn = mvwgetnstr(self->win, y, x, buf, Py_MIN(n, max_buf_size - 1));
Py_END_ALLOW_THREADS
#endif
break;
default:
PyErr_SetString(PyExc_TypeError, "getstr requires 0 to 3 arguments");
goto error;
}

if (rtn == ERR) {
Py_DECREF(result);
return Py_GetConstant(Py_CONSTANT_EMPTY_BYTES);
}

if (_PyBytes_Resize(&result, strlen(buf)) < 0) {
return NULL;
}
if (rtn2 == ERR)
rtn[0] = 0;
return PyBytes_FromString(rtn);

return result;

error:
Py_DECREF(result);
return NULL;
}

/*[clinic input]
Expand Down Expand Up @@ -1889,7 +1907,7 @@ _curses.window.instr
x: int
X-coordinate.
]
n: int = 1023
n: int = 2047
Maximal number of characters.
/

Expand All @@ -1906,43 +1924,61 @@ PyCursesWindow_InStr(PyObject *op, PyObject *args)
PyCursesWindowObject *self = _PyCursesWindowObject_CAST(op);

int x, y, n;
char rtn[1024]; /* This should be big enough.. I hope */
int rtn2;
int rtn;

/* could make the buffer size larger/dynamic */
Py_ssize_t max_buf_size = 2048;
PyObject *result = PyBytes_FromStringAndSize(NULL, max_buf_size);
if (result == NULL)
return NULL;
char *buf = PyBytes_AS_STRING(result);

switch (PyTuple_Size(args)) {
case 0:
rtn2 = winnstr(self->win,rtn, 1023);
rtn = winnstr(self->win, buf, max_buf_size - 1);
break;
case 1:
if (!PyArg_ParseTuple(args,"i;n", &n))
return NULL;
goto error;
if (n < 0) {
PyErr_SetString(PyExc_ValueError, "'n' must be nonnegative");
return NULL;
goto error;
}
rtn2 = winnstr(self->win, rtn, Py_MIN(n, 1023));
rtn = winnstr(self->win, buf, Py_MIN(n, max_buf_size - 1));
break;
case 2:
if (!PyArg_ParseTuple(args,"ii;y,x",&y,&x))
return NULL;
rtn2 = mvwinnstr(self->win,y,x,rtn,1023);
goto error;
rtn = mvwinnstr(self->win, y, x, buf, max_buf_size - 1);
break;
case 3:
if (!PyArg_ParseTuple(args, "iii;y,x,n", &y, &x, &n))
return NULL;
goto error;
if (n < 0) {
PyErr_SetString(PyExc_ValueError, "'n' must be nonnegative");
return NULL;
goto error;
}
rtn2 = mvwinnstr(self->win, y, x, rtn, Py_MIN(n,1023));
rtn = mvwinnstr(self->win, y, x, buf, Py_MIN(n, max_buf_size - 1));
break;
default:
PyErr_SetString(PyExc_TypeError, "instr requires 0 or 3 arguments");
goto error;
}

if (rtn == ERR) {
Py_DECREF(result);
return Py_GetConstant(Py_CONSTANT_EMPTY_BYTES);
}

if (_PyBytes_Resize(&result, strlen(buf)) < 0) {
return NULL;
}
if (rtn2 == ERR)
rtn[0] = 0;
return PyBytes_FromString(rtn);

return result;

error:
Py_DECREF(result);
return NULL;
}

/*[clinic input]
Expand Down
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