lib-tty.py

"""Terminal utilities."""

# Author: Steen Lumholt.

from termios import *

__all__ = ["setraw", "setcbreak"]

# Indexes for termios list.
IFLAG = 0
OFLAG = 1
CFLAG = 2
LFLAG = 3
ISPEED = 4
OSPEED = 5
CC = 6

def setraw(fd, when=TCSAFLUSH):
    """Put terminal into a raw mode."""
    mode = tcgetattr(fd)
    mode[IFLAG] = mode[IFLAG] & ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON)
    mode[OFLAG] = mode[OFLAG] & ~(OPOST)
    mode[CFLAG] = mode[CFLAG] & ~(CSIZE | PARENB)
    mode[CFLAG] = mode[CFLAG] | CS8
    mode[LFLAG] = mode[LFLAG] & ~(ECHO | ICANON | IEXTEN | ISIG)
    mode[CC][VMIN] = 1
    mode[CC][VTIME] = 0
    tcsetattr(fd, when, mode)

def setcbreak(fd, when=TCSAFLUSH):
    """Put terminal into a cbreak mode."""
    mode = tcgetattr(fd)
    mode[LFLAG] = mode[LFLAG] & ~(ECHO | ICANON)
    mode[CC][VMIN] = 1
    mode[CC][VTIME] = 0
    tcsetattr(fd, when, mode)

ttyattrs-default.txt

IFLAG ICRNL
OFLAG OPOST
CFLAG CSIZE
CFLAG CS8
LFLAG ECHO
LFLAG ICANON
LFLAG IEXTEN
LFLAG ISIG

ttyattrs-raw.txt

CFLAG CSIZE
CFLAG CS8

ttyattrs.diff

diff --git a/ttyattrs-default.txt b/ttyattrs-raw.txt
index 63294d6..fcf2255 100644
--- a/ttyattrs-default.txt
+++ b/ttyattrs-raw.txt
@@ -1,8 +1,2 @@
-IFLAG ICRNL
-OFLAG OPOST
 CFLAG CSIZE
 CFLAG CS8
-LFLAG ECHO
-LFLAG ICANON
-LFLAG IEXTEN
-LFLAG ISIG

ttyattrs.py

import tty, sys, termios, io
import difflib

# Indexes for termios list.
IFLAG = 0
OFLAG = 1
CFLAG = 2
LFLAG = 3
ISPEED = 4
OSPEED = 5
CC = 6

checks = {
    IFLAG: ('BRKINT', 'ICRNL', 'INPCK', 'ISTRIP', 'IXON'),
    OFLAG: ('OPOST',),
    CFLAG: ('CSIZE', 'PARENB', 'CS8'),
    LFLAG: ('ECHO', 'ICANON', 'IEXTEN', 'ISIG')
}

attr_name = {
    IFLAG: 'IFLAG',
    OFLAG: 'OFLAG',
    CFLAG: 'CFLAG',
    LFLAG: 'LFLAG',
    ISPEED: 'ISPEED',
    OSPEED: 'OSPEED',
    CC: 'CC',
}



def print_flags(tcattrs, fd=sys.stdout):
    for attr_i, flag_names in checks.items():
        for flag_name in flag_names:
            result = tcattrs[attr_i] & getattr(termios, flag_name)
            is_set = result > 0

            # message = f'{attr_name[attr_i]} {flag_name} = {is_set} ({result})'
            message = None
            if is_set:
                message = f'{attr_name[attr_i]} {flag_name}'

            if message is not None:
                print(message, file=fd)


default = termios.tcgetattr(sys.stdout)
tty.setraw(sys.stdout)
raw = termios.tcgetattr(sys.stdout)

# termios.tcsetattr(sys.stdout, termios.TCSAFLUSH, default)

print_flags(default, open('ttyattrs-default.txt', 'w'))
print_flags(raw, open('ttyattrs-raw.txt', 'w'))

ttytest.py

import termios
import time
import tty
import sys
from termios import *


# Indexes for termios list.
IFLAG = 0
OFLAG = 1
CFLAG = 2
LFLAG = 3
ISPEED = 4
OSPEED = 5
CC = 6

def print_stuff():
    for i in range(5):
        print(f'stuff {i}')

def modify_attrs(i, func):
    attrs = termios.tcgetattr(sys.stdout)
    attrs[i] = func(attrs[i])
    termios.tcsetattr(sys.stdout, TCSAFLUSH, attrs)

print_stuff()
#modify_attrs(OFLAG, lambda x: x & ~OPOST)
tty.setraw(sys.stdout)
# print_stuff()
# modify_attrs(OFLAG, lambda x: x | OPOST)
# modify_attrs(LFLAG, lambda x: x | ICANON | ECHO)
# print_stuff()
import pdb; pdb.set_trace()

# Observed attr changes by tty.setraw
# diff --git a/ttyattrs-default.txt b/ttyattrs-raw.txt
# index 63294d6..fcf2255 100644
# --- a/ttyattrs-default.txt
# +++ b/ttyattrs-raw.txt
# @@ -1,8 +1,2 @@
# -IFLAG ICRNL
# -OFLAG OPOST
#  CFLAG CSIZE
#  CFLAG CS8
# -LFLAG ECHO
# -LFLAG ICANON
# -LFLAG IEXTEN
# -LFLAG ISIG

# Full
mode[IFLAG] = mode[IFLAG] | (BRKINT | ICRNL | INPCK | ISTRIP | IXON)
mode[OFLAG] = mode[OFLAG] | (OPOST)
mode[CFLAG] = mode[CFLAG] | (CSIZE | PARENB)
mode[LFLAG] = mode[LFLAG] | (ECHO | ICANON | IEXTEN | ISIG)

# Based on observed
mode[IFLAG] = mode[IFLAG] | ICRNL
mode[OFLAG] = mode[OFLAG] | (OPOST)
mode[LFLAG] = mode[LFLAG] | (ECHO | ICANON | IEXTEN | ISIG)