intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 225 insertions, 0 deletions

diff --git a/contrib/python/ipython/py2/IPython/utils/_process_posix.py b/contrib/python/ipython/py2/IPython/utils/_process_posix.py
new file mode 100644
index 0000000000..ac3a9a0507
--- /dev/null
+++ b/contrib/python/ipython/py2/IPython/utils/_process_posix.py
@@ -0,0 +1,225 @@
+"""Posix-specific implementation of process utilities.
+
+This file is only meant to be imported by process.py, not by end-users.
+"""
+
+#-----------------------------------------------------------------------------
+#  Copyright (C) 2010-2011  The IPython Development Team
+#
+#  Distributed under the terms of the BSD License.  The full license is in
+#  the file COPYING, distributed as part of this software.
+#-----------------------------------------------------------------------------
+
+#-----------------------------------------------------------------------------
+# Imports
+#-----------------------------------------------------------------------------
+from __future__ import print_function
+
+# Stdlib
+import errno
+import os
+import subprocess as sp
+import sys
+
+import pexpect
+
+# Our own
+from ._process_common import getoutput, arg_split
+from IPython.utils import py3compat
+from IPython.utils.encoding import DEFAULT_ENCODING
+
+#-----------------------------------------------------------------------------
+# Function definitions
+#-----------------------------------------------------------------------------
+
+def _find_cmd(cmd):
+    """Find the full path to a command using which."""
+
+    path = sp.Popen(['/usr/bin/env', 'which', cmd],
+                    stdout=sp.PIPE, stderr=sp.PIPE).communicate()[0]
+    return py3compat.bytes_to_str(path)
+
+
+class ProcessHandler(object):
+    """Execute subprocesses under the control of pexpect.
+    """
+    # Timeout in seconds to wait on each reading of the subprocess' output.
+    # This should not be set too low to avoid cpu overusage from our side,
+    # since we read in a loop whose period is controlled by this timeout.
+    read_timeout = 0.05
+
+    # Timeout to give a process if we receive SIGINT, between sending the
+    # SIGINT to the process and forcefully terminating it.
+    terminate_timeout = 0.2
+
+    # File object where stdout and stderr of the subprocess will be written
+    logfile = None
+
+    # Shell to call for subprocesses to execute
+    _sh = None
+
+    @property
+    def sh(self):
+        if self._sh is None:        
+            self._sh = pexpect.which('sh')
+            if self._sh is None:
+                raise OSError('"sh" shell not found')
+        
+        return self._sh
+
+    def __init__(self, logfile=None, read_timeout=None, terminate_timeout=None):
+        """Arguments are used for pexpect calls."""
+        self.read_timeout = (ProcessHandler.read_timeout if read_timeout is
+                             None else read_timeout)
+        self.terminate_timeout = (ProcessHandler.terminate_timeout if
+                                  terminate_timeout is None else
+                                  terminate_timeout)
+        self.logfile = sys.stdout if logfile is None else logfile
+
+    def getoutput(self, cmd):
+        """Run a command and return its stdout/stderr as a string.
+
+        Parameters
+        ----------
+        cmd : str
+          A command to be executed in the system shell.
+
+        Returns
+        -------
+        output : str
+          A string containing the combination of stdout and stderr from the
+        subprocess, in whatever order the subprocess originally wrote to its
+        file descriptors (so the order of the information in this string is the
+        correct order as would be seen if running the command in a terminal).
+        """
+        try:
+            return pexpect.run(self.sh, args=['-c', cmd]).replace('\r\n', '\n')
+        except KeyboardInterrupt:
+            print('^C', file=sys.stderr, end='')
+
+    def getoutput_pexpect(self, cmd):
+        """Run a command and return its stdout/stderr as a string.
+
+        Parameters
+        ----------
+        cmd : str
+          A command to be executed in the system shell.
+
+        Returns
+        -------
+        output : str
+          A string containing the combination of stdout and stderr from the
+        subprocess, in whatever order the subprocess originally wrote to its
+        file descriptors (so the order of the information in this string is the
+        correct order as would be seen if running the command in a terminal).
+        """
+        try:
+            return pexpect.run(self.sh, args=['-c', cmd]).replace('\r\n', '\n')
+        except KeyboardInterrupt:
+            print('^C', file=sys.stderr, end='')
+
+    def system(self, cmd):
+        """Execute a command in a subshell.
+
+        Parameters
+        ----------
+        cmd : str
+          A command to be executed in the system shell.
+
+        Returns
+        -------
+        int : child's exitstatus
+        """
+        # Get likely encoding for the output.
+        enc = DEFAULT_ENCODING
+        
+        # Patterns to match on the output, for pexpect.  We read input and
+        # allow either a short timeout or EOF
+        patterns = [pexpect.TIMEOUT, pexpect.EOF]
+        # the index of the EOF pattern in the list.
+        # even though we know it's 1, this call means we don't have to worry if
+        # we change the above list, and forget to change this value:
+        EOF_index = patterns.index(pexpect.EOF)
+        # The size of the output stored so far in the process output buffer.
+        # Since pexpect only appends to this buffer, each time we print we
+        # record how far we've printed, so that next time we only print *new*
+        # content from the buffer.
+        out_size = 0
+        try:
+            # Since we're not really searching the buffer for text patterns, we
+            # can set pexpect's search window to be tiny and it won't matter.
+            # We only search for the 'patterns' timeout or EOF, which aren't in
+            # the text itself.
+            #child = pexpect.spawn(pcmd, searchwindowsize=1)
+            if hasattr(pexpect, 'spawnb'):
+                child = pexpect.spawnb(self.sh, args=['-c', cmd]) # Pexpect-U
+            else:
+                child = pexpect.spawn(self.sh, args=['-c', cmd])  # Vanilla Pexpect
+            flush = sys.stdout.flush
+            while True:
+                # res is the index of the pattern that caused the match, so we
+                # know whether we've finished (if we matched EOF) or not
+                res_idx = child.expect_list(patterns, self.read_timeout)
+                print(child.before[out_size:].decode(enc, 'replace'), end='')
+                flush()
+                if res_idx==EOF_index:
+                    break
+                # Update the pointer to what we've already printed
+                out_size = len(child.before)
+        except KeyboardInterrupt:
+            # We need to send ^C to the process.  The ascii code for '^C' is 3
+            # (the character is known as ETX for 'End of Text', see
+            # curses.ascii.ETX).
+            child.sendline(chr(3))
+            # Read and print any more output the program might produce on its
+            # way out.
+            try:
+                out_size = len(child.before)
+                child.expect_list(patterns, self.terminate_timeout)
+                print(child.before[out_size:].decode(enc, 'replace'), end='')
+                sys.stdout.flush()
+            except KeyboardInterrupt:
+                # Impatient users tend to type it multiple times
+                pass
+            finally:
+                # Ensure the subprocess really is terminated
+                child.terminate(force=True)
+        # add isalive check, to ensure exitstatus is set:
+        child.isalive()
+
+        # We follow the subprocess pattern, returning either the exit status
+        # as a positive number, or the terminating signal as a negative
+        # number.
+        # on Linux, sh returns 128+n for signals terminating child processes on Linux
+        # on BSD (OS X), the signal code is set instead
+        if child.exitstatus is None:
+            # on WIFSIGNALED, pexpect sets signalstatus, leaving exitstatus=None
+            if child.signalstatus is None:
+                # this condition may never occur,
+                # but let's be certain we always return an integer.
+                return 0
+            return -child.signalstatus
+        if child.exitstatus > 128:
+            return -(child.exitstatus - 128)
+        return child.exitstatus
+
+
+# Make system() with a functional interface for outside use.  Note that we use
+# getoutput() from the _common utils, which is built on top of popen(). Using
+# pexpect to get subprocess output produces difficult to parse output, since
+# programs think they are talking to a tty and produce highly formatted output
+# (ls is a good example) that makes them hard.
+system = ProcessHandler().system
+
+def check_pid(pid):
+    try:
+        os.kill(pid, 0)
+    except OSError as err:
+        if err.errno == errno.ESRCH:
+            return False
+        elif err.errno == errno.EPERM:
+            # Don't have permission to signal the process - probably means it exists
+            return True
+        raise
+    else:
+        return True