Add Popen.start property.

subprocess2.py

 # coding=utf8
 # Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 """Collection of subprocess wrapper functions.
 
 In theory you shouldn't need anything else in subprocess, or this module failed.
 """
 
 from __future__ import with_statement
@@ skipping 121 matching lines @@
 
 
 class Popen(subprocess.Popen):
   """Wraps subprocess.Popen() with various workarounds.
 
   - Forces English output since it's easier to parse the stdout if it is always
     in English.
   - Sets shell=True on windows by default. You can override this by forcing
     shell parameter to a value.
   - Adds support for VOID to not buffer when not needed.
+  - Adds self.start property.
 
   Note: Popen() can throw OSError when cwd or args[0] doesn't exist. Translate
   exceptions generated by cygwin when it fails trying to emulate fork().
   """
   def __init__(self, args, **kwargs):
     # Make sure we hack subprocess if necessary.
     hack_subprocess()
     add_kill()
 
     env = get_english_env(kwargs.get('env'))
@@ skipping 21 matching lines @@
         # Replaces VOID with handle to /dev/null.
         # Create a temporary file to workaround python's deadlock.
         # http://docs.python.org/library/subprocess.html#subprocess.Popen.wait
         # When the pipe fills up, it will deadlock this process. Using a real
         # file works around that issue.
         kwargs[stream] = open(os.devnull, 'w')
 
     fix('stdout')
     fix('stderr')
 
+    self.start = time.time()
+
     try:
       super(Popen, self).__init__(args, **kwargs)
     except OSError, e:
       if e.errno == errno.EAGAIN and sys.platform == 'cygwin':
         # Convert fork() emulation failure into a CygwinRebaseError().
         raise CygwinRebaseError(
             e.errno,
             args,
             kwargs.get('cwd'),
             None,
             'Visit '
             'http://code.google.com/p/chromium/wiki/CygwinDllRemappingFailure '
             'to learn how to fix this error; you need to rebase your cygwin '
             'dlls')
       # Popen() can throw OSError when cwd or args[0] doesn't exist. Let it go
       # through
       raise
 
 
 def communicate(args, timeout=None, **kwargs):
-  """Wraps subprocess.Popen().communicate().
+  """Wraps subprocess.Popen().communicate() and add timeout support.
 
   Returns ((stdout, stderr), returncode).
 
   - The process will be killed after |timeout| seconds and returncode set to
     TIMED_OUT.
   - Automatically passes stdin content as input so do not specify stdin=PIPE.
   """
   stdin = kwargs.pop('stdin', None)
   if stdin is not None:
     if stdin is VOID:
@@ skipping 11 matching lines @@
     if stdin is not None:
       return proc.communicate(stdin), proc.returncode
     else:
       return proc.communicate(), proc.returncode
 
   # Create a temporary file to workaround python's deadlock.
   # http://docs.python.org/library/subprocess.html#subprocess.Popen.wait
   # When the pipe fills up, it will deadlock this process. Using a real file
   # works around that issue.
   with tempfile.TemporaryFile() as buff:
-    start = time.time()
     kwargs['stdout'] = buff
     proc = Popen(args, **kwargs)
     if stdin is not None:
       proc.stdin.write(stdin)
     while proc.returncode is None:
       proc.poll()
-      if timeout and (time.time() - start) > timeout:
+      if timeout and (time.time() - proc.start) > timeout:
         proc.kill()
         proc.wait()
         # It's -9 on linux and 1 on Windows. Standardize to TIMED_OUT.
         proc.returncode = TIMED_OUT
       time.sleep(0.001)
     # Now that the process died, reset the cursor and read the file.
     buff.seek(0)
     out = (buff.read(), None)
   return out, proc.returncode
 
@@ skipping 49 matching lines @@
 
   Captures stdout of a process call and returns stdout only.
 
   - Throws if return code is not 0.
   - Works even prior to python 2.7.
   - Blocks stdin by default if not specified since no output will be visible.
   - As per doc, "The stdout argument is not allowed as it is used internally."
   """
   kwargs.setdefault('stdin', VOID)
   return check_call_out(args, stdout=PIPE, **kwargs)[0]