mirror of
https://github.com/python/cpython.git
synced 2025-11-04 11:49:12 +00:00
54f22ed30b
who writes: Here is batch 2, as a big collection of CVS context diffs. Along with moving comments into docstrings, i've added a couple of missing docstrings and attempted to make sure more module docstrings begin with a one-line summary. I did not add docstrings to the methods in profile.py for fear of upsetting any careful optimizations there, though i did move class documentation into class docstrings. The convention i'm using is to leave credits/version/copyright type of stuff in # comments, and move the rest of the descriptive stuff about module usage into module docstrings. Hope this is okay.
127 lines
4.1 KiB
Python
127 lines
4.1 KiB
Python
"""Spawn a command with pipes to its stdin, stdout, and optionally stderr.
|
|
|
|
The normal os.popen(cmd, mode) call spawns a shell command and provides a
|
|
file interface to just the input or output of the process depending on
|
|
whether mode is 'r' or 'w'. This module provides the functions popen2(cmd)
|
|
and popen3(cmd) which return two or three pipes to the spawned command.
|
|
"""
|
|
|
|
import os
|
|
import sys
|
|
import string
|
|
|
|
MAXFD = 256 # Max number of file descriptors (os.getdtablesize()???)
|
|
|
|
_active = []
|
|
|
|
def _cleanup():
|
|
for inst in _active[:]:
|
|
inst.poll()
|
|
|
|
class Popen3:
|
|
"""Class representing a child process. Normally instances are created
|
|
by the factory functions popen2() and popen3()."""
|
|
|
|
def __init__(self, cmd, capturestderr=0, bufsize=-1):
|
|
"""The parameter 'cmd' is the shell command to execute in a
|
|
sub-process. The 'capturestderr' flag, if true, specifies that
|
|
the object should capture standard error output of the child process.
|
|
The default is false. If the 'bufsize' parameter is specified, it
|
|
specifies the size of the I/O buffers to/from the child process."""
|
|
if type(cmd) == type(''):
|
|
cmd = ['/bin/sh', '-c', cmd]
|
|
p2cread, p2cwrite = os.pipe()
|
|
c2pread, c2pwrite = os.pipe()
|
|
if capturestderr:
|
|
errout, errin = os.pipe()
|
|
self.pid = os.fork()
|
|
if self.pid == 0:
|
|
# Child
|
|
os.close(0)
|
|
os.close(1)
|
|
if os.dup(p2cread) <> 0:
|
|
sys.stderr.write('popen2: bad read dup\n')
|
|
if os.dup(c2pwrite) <> 1:
|
|
sys.stderr.write('popen2: bad write dup\n')
|
|
if capturestderr:
|
|
os.close(2)
|
|
if os.dup(errin) <> 2: pass
|
|
for i in range(3, MAXFD):
|
|
try:
|
|
os.close(i)
|
|
except: pass
|
|
try:
|
|
os.execvp(cmd[0], cmd)
|
|
finally:
|
|
os._exit(1)
|
|
# Shouldn't come here, I guess
|
|
os._exit(1)
|
|
os.close(p2cread)
|
|
self.tochild = os.fdopen(p2cwrite, 'w', bufsize)
|
|
os.close(c2pwrite)
|
|
self.fromchild = os.fdopen(c2pread, 'r', bufsize)
|
|
if capturestderr:
|
|
os.close(errin)
|
|
self.childerr = os.fdopen(errout, 'r', bufsize)
|
|
else:
|
|
self.childerr = None
|
|
self.sts = -1 # Child not completed yet
|
|
_active.append(self)
|
|
|
|
def poll(self):
|
|
"""Return the exit status of the child process if it has finished,
|
|
or -1 if it hasn't finished yet."""
|
|
if self.sts < 0:
|
|
try:
|
|
pid, sts = os.waitpid(self.pid, os.WNOHANG)
|
|
if pid == self.pid:
|
|
self.sts = sts
|
|
_active.remove(self)
|
|
except os.error:
|
|
pass
|
|
return self.sts
|
|
|
|
def wait(self):
|
|
"""Wait for and return the exit status of the child process."""
|
|
pid, sts = os.waitpid(self.pid, 0)
|
|
if pid == self.pid:
|
|
self.sts = sts
|
|
_active.remove(self)
|
|
return self.sts
|
|
|
|
def popen2(cmd, bufsize=-1):
|
|
"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
|
|
specified, it sets the buffer size for the I/O pipes. The file objects
|
|
(child_stdout, child_stdin) are returned."""
|
|
_cleanup()
|
|
inst = Popen3(cmd, 0, bufsize)
|
|
return inst.fromchild, inst.tochild
|
|
|
|
def popen3(cmd, bufsize=-1):
|
|
"""Execute the shell command 'cmd' in a sub-process. If 'bufsize' is
|
|
specified, it sets the buffer size for the I/O pipes. The file objects
|
|
(child_stdout, child_stdin, child_stderr) are returned."""
|
|
_cleanup()
|
|
inst = Popen3(cmd, 1, bufsize)
|
|
return inst.fromchild, inst.tochild, inst.childerr
|
|
|
|
def _test():
|
|
teststr = "abc\n"
|
|
print "testing popen2..."
|
|
r, w = popen2('cat')
|
|
w.write(teststr)
|
|
w.close()
|
|
assert r.read() == teststr
|
|
print "testing popen3..."
|
|
r, w, e = popen3(['cat'])
|
|
w.write(teststr)
|
|
w.close()
|
|
assert r.read() == teststr
|
|
assert e.read() == ""
|
|
for inst in _active[:]:
|
|
inst.wait()
|
|
assert not _active
|
|
print "All OK"
|
|
|
|
if __name__ == '__main__':
|
|
_test()
|