Viewing file:  pty_helper.py (2.98 KB) -rw-r--r--
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"""
Helper to run a script in a pseudo-terminal.
"""
import os
import selectors
import subprocess
import sys
from contextlib import ExitStack
from errno import EIO
from test.support.import_helper import import_module
def run_pty(script, input=b"dummy input\r", env=None):
pty = import_module('pty')
output = bytearray()
[master, slave] = pty.openpty()
args = (sys.executable, '-c', script)
proc = subprocess.Popen(args, stdin=slave, stdout=slave, stderr=slave, env=env)
os.close(slave)
with ExitStack() as cleanup:
cleanup.enter_context(proc)
def terminate(proc):
try:
proc.terminate()
except ProcessLookupError:
# Workaround for Open/Net BSD bug (Issue 16762)
pass
cleanup.callback(terminate, proc)
cleanup.callback(os.close, master)
# Avoid using DefaultSelector and PollSelector. Kqueue() does not
# work with pseudo-terminals on OS X < 10.9 (Issue 20365) and Open
# BSD (Issue 20667). Poll() does not work with OS X 10.6 or 10.4
# either (Issue 20472). Hopefully the file descriptor is low enough
# to use with select().
sel = cleanup.enter_context(selectors.SelectSelector())
sel.register(master, selectors.EVENT_READ | selectors.EVENT_WRITE)
os.set_blocking(master, False)
while True:
for [_, events] in sel.select():
if events & selectors.EVENT_READ:
try:
chunk = os.read(master, 0x10000)
except OSError as err:
# Linux raises EIO when slave is closed (Issue 5380)
if err.errno != EIO:
raise
chunk = b""
if not chunk:
return output
output.extend(chunk)
if events & selectors.EVENT_WRITE:
try:
input = input[os.write(master, input):]
except OSError as err:
# Apparently EIO means the slave was closed
if err.errno != EIO:
raise
input = b"" # Stop writing
if not input:
sel.modify(master, selectors.EVENT_READ)
######################################################################
## Fake stdin (for testing interactive debugging)
######################################################################
class FakeInput:
"""
A fake input stream for pdb's interactive debugger. Whenever a
line is read, print it (to simulate the user typing it), and then
return it. The set of lines to return is specified in the
constructor; they should not have trailing newlines.
"""
def __init__(self, lines):
self.lines = lines
def readline(self):
line = self.lines.pop(0)
print(line)
return line + '\n'
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