No need to use select() for TTYIO

Instead make read() block with timeout via termios
This commit is contained in:
Kovid Goyal 2018-06-18 11:10:16 +05:30
parent f820f72768
commit c5583d380d
No known key found for this signature in database
GPG Key ID: 06BC317B515ACE7C
2 changed files with 19 additions and 15 deletions

View File

@ -105,21 +105,29 @@ stop_profiler(PyObject UNUSED *self) {
#endif
static inline bool
put_tty_in_raw_mode(int fd, const struct termios* termios_p) {
put_tty_in_raw_mode(int fd, const struct termios* termios_p, bool read_with_timeout) {
struct termios raw_termios = *termios_p;
cfmakeraw(&raw_termios);
raw_termios.c_cc[VMIN] = 1; raw_termios.c_cc[VTIME] = 0;
if (read_with_timeout) {
raw_termios.c_cc[VMIN] = 0; raw_termios.c_cc[VTIME] = 1;
} else {
raw_termios.c_cc[VMIN] = 1; raw_termios.c_cc[VTIME] = 0;
}
if (tcsetattr(fd, TCSAFLUSH, &raw_termios) != 0) { PyErr_SetFromErrno(PyExc_OSError); return false; }
return true;
}
static PyObject*
open_tty(PyObject *self UNUSED, PyObject *args UNUSED) {
int fd = open("/dev/tty", O_RDWR | O_NONBLOCK | O_CLOEXEC | O_NOCTTY);
open_tty(PyObject *self UNUSED, PyObject *args) {
int read_with_timeout = 0;
if (!PyArg_ParseTuple(args, "|p", &read_with_timeout)) return NULL;
int flags = O_RDWR | O_CLOEXEC | O_NOCTTY;
if (!read_with_timeout) flags |= O_NONBLOCK;
int fd = open("/dev/tty", flags);
struct termios *termios_p = calloc(1, sizeof(struct termios));
if (!termios_p) return PyErr_NoMemory();
if (tcgetattr(fd, termios_p) != 0) { free(termios_p); PyErr_SetFromErrno(PyExc_OSError); return NULL; }
if (!put_tty_in_raw_mode(fd, termios_p)) { free(termios_p); return NULL; }
if (!put_tty_in_raw_mode(fd, termios_p, read_with_timeout != 0)) { free(termios_p); return NULL; }
return Py_BuildValue("iN", fd, PyLong_FromVoidPtr(termios_p));
}
@ -138,7 +146,7 @@ normal_tty(PyObject *self UNUSED, PyObject *args) {
static PyObject*
raw_tty(PyObject *self UNUSED, PyObject *args) {
TTY_ARGS
if (!put_tty_in_raw_mode(fd, termios_p)) return NULL;
if (!put_tty_in_raw_mode(fd, termios_p, false)) return NULL;
Py_RETURN_NONE;
}
@ -155,7 +163,7 @@ close_tty(PyObject *self UNUSED, PyObject *args) {
#undef TTY_ARGS
static PyMethodDef module_methods[] = {
{"open_tty", open_tty, METH_NOARGS, ""},
{"open_tty", open_tty, METH_VARARGS, ""},
{"normal_tty", normal_tty, METH_VARARGS, ""},
{"raw_tty", raw_tty, METH_VARARGS, ""},
{"close_tty", close_tty, METH_VARARGS, ""},

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@ -369,7 +369,7 @@ def write_all(fd, data):
class TTYIO:
def __enter__(self):
self.tty_fd, self.original_termios = open_tty()
self.tty_fd, self.original_termios = open_tty(True)
return self
def __exit__(self, *a):
@ -383,17 +383,13 @@ class TTYIO:
write_all(self.tty_fd, chunk)
def recv(self, more_needed, timeout, sz=1):
import select
fd = self.tty_fd
start_time = monotonic()
while timeout > monotonic() - start_time:
rd = select.select([fd], [], [], max(0, timeout - (monotonic() - start_time)))[0]
if not rd:
break
# will block for 0.1 secs waiting for data because we have set
# VMIN=0 VTIME=1 in termios
data = os.read(fd, sz)
if not data:
break # eof
if not more_needed(data):
if data and not more_needed(data):
break