1#!/usr/bin/env python
2# Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
3#
4# Use of this source code is governed by a BSD-style license
5# that can be found in the LICENSE file in the root of the source
6# tree. An additional intellectual property rights grant can be found
7# in the file PATENTS.  All contributing project authors may
8# be found in the AUTHORS file in the root of the source tree.
9
10import multiprocessing
11import os
12import subprocess
13import sys
14
15_DEFAULT_PADDING = 4
16
17
18class HelperError(Exception):
19  """Exception raised for errors in the helper."""
20  pass
21
22
23def zero_pad(number, padding=_DEFAULT_PADDING):
24  """Converts an int into a zero padded string.
25
26  Args:
27    number(int): The number to convert.
28    padding(int): The number of chars in the output. Note that if you pass for
29      example number=23456 and padding=4, the output will still be '23456',
30      i.e. it will not be cropped. If you pass number=2 and padding=4, the
31      return value will be '0002'.
32  Return:
33    (string): The zero padded number converted to string.
34  """
35  return str(number).zfill(padding)
36
37
38def run_shell_command(cmd_list, fail_msg=None):
39  """Executes a command.
40
41  Args:
42    cmd_list(list): Command list to execute.
43    fail_msg(string): Message describing the error in case the command fails.
44
45  Return:
46    (string): The standard output from running the command.
47
48  Raise:
49    HelperError: If command fails.
50  """
51  process = subprocess.Popen(cmd_list, stdout=subprocess.PIPE,
52                             stderr=subprocess.PIPE)
53  output, error = process.communicate()
54  if process.returncode != 0:
55    if fail_msg:
56      print >> sys.stderr, fail_msg
57    raise HelperError('Failed to run %s: command returned %d and printed '
58                      '%s and %s' % (' '.join(cmd_list), process.returncode,
59                                     output, error))
60  return output.strip()
61
62
63def perform_action_on_all_files(directory, file_pattern, file_extension,
64                                start_number, action, **kwargs):
65  """Function that performs a given action on all files matching a pattern.
66
67  It is assumed that the files are named file_patternxxxx.file_extension, where
68  xxxx are digits starting from start_number.
69
70  Args:
71    directory(string): The directory where the files live.
72    file_pattern(string): The name pattern of the files.
73    file_extension(string): The files' extension.
74    start_number(int): From where to start to count frames.
75    action(function): The action to be performed over the files. Must return
76        False if the action failed, True otherwise. It should take a file name
77        as the first argument and **kwargs as arguments. The function must be
78        possible to pickle, so it cannot be a bound function (for instance).
79
80  Return:
81    (bool): Whether performing the action over all files was successful or not.
82  """
83  file_prefix = os.path.join(directory, file_pattern)
84  file_number = start_number
85
86  process_pool = multiprocessing.Pool(processes=multiprocessing.cpu_count())
87  results = []
88  while True:
89    zero_padded_file_number = zero_pad(file_number)
90    file_name = file_prefix + zero_padded_file_number + '.' + file_extension
91    if not os.path.isfile(file_name):
92      break
93    future = process_pool.apply_async(action, args=(file_name,), kwds=kwargs)
94    results.append(future)
95    file_number += 1
96
97  successful = True
98  for result in results:
99    if not result.get():
100      print "At least one action %s failed for files %sxxxx.%s." % (
101          action, file_pattern, file_extension)
102      successful = False
103
104  process_pool.close()
105  return successful
106