/usr/lib/python3/dist-packages/curtsies/input.py is in python3-curtsies 0.2.11-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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import os
import signal
import select
import sys
import termios
import time
import tty
import logging
logger = logging.getLogger(__name__)
from .termhelpers import Nonblocking
from . import events
PY3 = sys.version_info[0] >= 3
READ_SIZE = 1024
assert READ_SIZE >= events.MAX_KEYPRESS_SIZE
# if a keypress could require more bytes than we read to be identified,
# the paste logic that reads more data as needed might not work.
class ReplacedSigIntHandler(object):
def __init__(self, handler):
self.handler = handler
def __enter__(self):
self.orig_sigint_handler = signal.getsignal(signal.SIGINT)
signal.signal(signal.SIGINT, self.handler)
def __exit__(self, type, value, traceback):
signal.signal(signal.SIGINT, self.orig_sigint_handler)
class Input(object):
"""Keypress and control event generator"""
def __init__(self, in_stream=None, keynames='curtsies',
paste_threshold=events.MAX_KEYPRESS_SIZE+1, sigint_event=False):
"""Returns an Input instance.
Args:
in_stream (file): Defaults to sys.__stdin__
keynames (string): How keypresses should be named - one of
'curtsies', 'curses', or 'plain'.
paste_threshold (int): How many bytes must be read in one
os.read on the in_stream to trigger the keypresses they
represent to be combined into a single paste event
sigint_event (bool): Whether SIGINT signals from the OS
should be intercepted and returned as SigIntEvent objects
"""
if in_stream is None:
in_stream = sys.__stdin__
self.in_stream = in_stream
self.unprocessed_bytes = [] # leftover from stdin, unprocessed yet
self.keynames = keynames
self.paste_threshold = paste_threshold
self.sigint_event = sigint_event
self.sigints = []
self.readers = []
self.queued_interrupting_events = []
self.queued_events = []
self.queued_scheduled_events = []
# prospective: this could be useful for an external select loop
def fileno(self):
return self.in_stream.fileno()
def __enter__(self):
self.original_stty = termios.tcgetattr(self.in_stream)
tty.setcbreak(self.in_stream, termios.TCSANOW)
if sys.platform == 'darwin':
attrs = termios.tcgetattr(self.in_stream)
VDSUSP = termios.VSUSP + 1
attrs[-1][VDSUSP] = 0
termios.tcsetattr(self.in_stream, termios.TCSANOW, attrs)
if self.sigint_event:
self.orig_sigint_handler = signal.getsignal(signal.SIGINT)
signal.signal(signal.SIGINT, self.sigint_handler)
return self
def __exit__(self, type, value, traceback):
if self.sigint_event:
signal.signal(signal.SIGINT, self.orig_sigint_handler)
termios.tcsetattr(self.in_stream, termios.TCSANOW, self.original_stty)
def sigint_handler(self, signum, frame):
self.sigints.append(events.SigIntEvent())
def __iter__(self):
return self
def next(self):
return self.send(None)
__next__ = next
def unget_bytes(self, string):
"""Adds bytes to be internal buffer to be read
This method is for reporting bytes from an in_stream read
not initiated by this Input object"""
self.unprocessed_bytes.extend(string[i:i + 1]
for i in range(len(string)))
def _wait_for_read_ready_or_timeout(self, timeout):
"""Returns tuple of whether stdin is ready to read and an event.
If an event is returned, that event is more pressing than reading
bytes on stdin to create a keyboard input event.
If stdin is ready, either there are bytes to read or a SIGTSTP
triggered by dsusp has been received"""
remaining_timeout = timeout
t0 = time.time()
while True:
try:
(rs, _, _) = select.select(
[self.in_stream.fileno()] + self.readers,
[], [], remaining_timeout)
if not rs:
return False, None
r = rs[0] # if there's more than one, get it in the next loop
if r == self.in_stream.fileno():
return True, None
else:
os.read(r, 1024)
if self.queued_interrupting_events:
return False, self.queued_interrupting_events.pop(0)
elif remaining_timeout is not None:
remaining_timeout = max(0, t0 + timeout - time.time())
continue
else:
continue
except select.error:
if self.sigints:
return False, self.sigints.pop()
if remaining_timeout is not None:
remaining_timeout = max(timeout - (time.time() - t0), 0)
def send(self, timeout=None):
"""Returns an event or None if no events occur before timeout."""
if self.sigint_event:
with ReplacedSigIntHandler(self.sigint_handler):
return self._send(timeout)
else:
return self._send(timeout)
def _send(self, timeout):
def find_key():
"""Returns keypress identified by adding unprocessed bytes or None"""
current_bytes = []
while self.unprocessed_bytes:
current_bytes.append(self.unprocessed_bytes.pop(0))
e = events.get_key(current_bytes,
getpreferredencoding(),
keynames=self.keynames,
full=len(self.unprocessed_bytes)==0)
if e is not None:
self.current_bytes = []
return e
if current_bytes: # incomplete keys shouldn't happen
raise ValueError("Couldn't identify key sequence: %r" % self.current_bytes)
if self.sigints:
return self.sigints.pop()
if self.queued_events:
return self.queued_events.pop(0)
if self.queued_interrupting_events:
return self.queued_interrupting_events.pop(0)
if self.queued_scheduled_events:
self.queued_scheduled_events.sort() #TODO use a data structure that inserts sorted
when, _ = self.queued_scheduled_events[0]
if when < time.time():
logger.warning('popping an event! %r %r',
self.queued_scheduled_events[0],
self.queued_scheduled_events[1:])
return self.queued_scheduled_events.pop(0)[1]
else:
time_until_check = min(max(0, when - time.time()), timeout if timeout is not None else sys.maxsize)
else:
time_until_check = timeout
# try to find an already pressed key from prev input
e = find_key()
if e is not None:
return e
stdin_ready_for_read, event = self._wait_for_read_ready_or_timeout(time_until_check)
if event:
return event
if self.queued_scheduled_events and when < time.time(): # when should always be defined
# because queued_scheduled_events should not be modified during this time
logger.warning('popping an event! %r %r', self.queued_scheduled_events[0],
self.queued_scheduled_events[1:])
return self.queued_scheduled_events.pop(0)[1]
if not stdin_ready_for_read:
return None
num_bytes = self._nonblocking_read()
if num_bytes == 0:
# thought stdin was ready, but not bytes to read is triggered
# when SIGTSTP was send by dsusp
return None
if self.paste_threshold is not None and num_bytes > self.paste_threshold:
paste = events.PasteEvent()
while True:
if len(self.unprocessed_bytes) < events.MAX_KEYPRESS_SIZE:
self._nonblocking_read() # may need to read to get the rest of a keypress
e = find_key()
if e is None:
return paste
else:
paste.events.append(e)
else:
e = find_key()
assert e is not None
return e
def _nonblocking_read(self):
"""Returns the number of characters read and adds them to self.unprocessed_bytes"""
with Nonblocking(self.in_stream):
if PY3:
try:
data = os.read(self.in_stream.fileno(), READ_SIZE)
except BlockingIOError:
return 0
if data:
self.unprocessed_bytes.extend(data[i:i+1] for i in range(len(data)))
return len(data)
else:
return 0
else:
try:
data = os.read(self.in_stream.fileno(), READ_SIZE)
except OSError:
return 0
else:
self.unprocessed_bytes.extend(data)
return len(data)
def event_trigger(self, event_type):
"""Returns a callback that creates events.
Returned callback function will add an event of type event_type
to a queue which will be checked the next time an event is requested."""
def callback(**kwargs):
self.queued_events.append(event_type(**kwargs))
return callback
def scheduled_event_trigger(self, event_type):
"""Returns a callback that schedules events for the future.
Returned callback function will add an event of type event_type
to a queue which will be checked the next time an event is requested."""
def callback(when, **kwargs):
self.queued_scheduled_events.append((when, event_type(when=when, **kwargs)))
return callback
def threadsafe_event_trigger(self, event_type):
"""Returns a callback to creates events, interrupting current event requests.
Returned callback function will create an event of type event_type
which will interrupt an event request if one
is concurrently occuring, otherwise adding the event to a queue
that will be checked on the next event request."""
readfd, writefd = os.pipe()
self.readers.append(readfd)
def callback(**kwargs):
self.queued_interrupting_events.append(event_type(**kwargs)) #TODO use a threadsafe queue for this
logger.warning('added event to events list %r', self.queued_interrupting_events)
os.write(writefd, b'interrupting event!')
return callback
def getpreferredencoding():
return locale.getpreferredencoding() or sys.getdefaultencoding()
def main():
with Input() as input_generator:
print(repr(input_generator.send(2)))
print(repr(input_generator.send(1)))
print(repr(input_generator.send(.5)))
print(repr(input_generator.send(.2)))
for e in input_generator:
print(repr(e))
if __name__ == '__main__':
main()
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