Revert "Remove deprecated barcode scanning functionality"

This reverts commit ff292f30d9a4b7a56aea872fe488d342f47202a3.

Reason for revert: issues with downstream projects

Original change's description:
> Remove deprecated barcode scanning functionality
> 
> This code is not used anymore, but it's not possible to land this CL
> until issue webrtc:9665 is fixed.
> 
> Bug: webrtc:9642,webrtc:9665
> Change-Id: Idb68e9bdf51b4239788cd6869dcb44dae87d7c56
> Reviewed-on: https://webrtc-review.googlesource.com/c/95951
> Reviewed-by: Paulina Hensman <phensman@webrtc.org>
> Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
> Commit-Queue: Magnus Jedvert <magjed@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#25289}

TBR=phoglund@webrtc.org,mbonadei@webrtc.org,magjed@webrtc.org,phensman@webrtc.org

Change-Id: I440025777a17d8580526289d4198da1fc3f7d62e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:9642, webrtc:9665
Reviewed-on: https://webrtc-review.googlesource.com/c/107348
Reviewed-by: Alessio Bazzica <alessiob@webrtc.org>
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25291}

rtc_tools/barcode_tools/helper_functions.py

@@ -0,0 +1,105 @@
+#!/usr/bin/env python
+# Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+import multiprocessing
+import os
+import subprocess
+import sys
+
+_DEFAULT_PADDING = 4
+
+
+class HelperError(Exception):
+  """Exception raised for errors in the helper."""
+  pass
+
+
+def ZeroPad(number, padding=_DEFAULT_PADDING):
+  """Converts an int into a zero padded string.
+
+  Args:
+    number(int): The number to convert.
+    padding(int): The number of chars in the output. Note that if you pass for
+      example number=23456 and padding=4, the output will still be '23456',
+      i.e. it will not be cropped. If you pass number=2 and padding=4, the
+      return value will be '0002'.
+  Return:
+    (string): The zero padded number converted to string.
+  """
+  return str(number).zfill(padding)
+
+
+def RunShellCommand(cmd_list, fail_msg=None):
+  """Executes a command.
+
+  Args:
+    cmd_list(list): Command list to execute.
+    fail_msg(string): Message describing the error in case the command fails.
+
+  Return:
+    (string): The standard output from running the command.
+
+  Raise:
+    HelperError: If command fails.
+  """
+  process = subprocess.Popen(cmd_list, stdout=subprocess.PIPE,
+                             stderr=subprocess.PIPE)
+  output, error = process.communicate()
+  if process.returncode != 0:
+    if fail_msg:
+      print >> sys.stderr, fail_msg
+    raise HelperError('Failed to run %s: command returned %d and printed '
+                      '%s and %s' % (' '.join(cmd_list), process.returncode,
+                                     output, error))
+  return output.strip()
+
+
+def PerformActionOnAllFiles(directory, file_pattern, file_extension,
+                            start_number, action, **kwargs):
+  """Function that performs a given action on all files matching a pattern.
+
+  It is assumed that the files are named file_patternxxxx.file_extension, where
+  xxxx are digits starting from start_number.
+
+  Args:
+    directory(string): The directory where the files live.
+    file_pattern(string): The name pattern of the files.
+    file_extension(string): The files' extension.
+    start_number(int): From where to start to count frames.
+    action(function): The action to be performed over the files. Must return
+        False if the action failed, True otherwise. It should take a file name
+        as the first argument and **kwargs as arguments. The function must be
+        possible to pickle, so it cannot be a bound function (for instance).
+
+  Return:
+    (bool): Whether performing the action over all files was successful or not.
+  """
+  file_prefix = os.path.join(directory, file_pattern)
+  file_number = start_number
+
+  process_pool = multiprocessing.Pool(processes=multiprocessing.cpu_count())
+  results = []
+  while True:
+    zero_padded_file_number = ZeroPad(file_number)
+    file_name = file_prefix + zero_padded_file_number + '.' + file_extension
+    if not os.path.isfile(file_name):
+      break
+    future = process_pool.apply_async(action, args=(file_name,), kwds=kwargs)
+    results.append(future)
+    file_number += 1
+
+  successful = True
+  for result in results:
+    if not result.get():
+      print "At least one action %s failed for files %sxxxx.%s." % (
+          action, file_pattern, file_extension)
+      successful = False
+
+  process_pool.close()
+  return successful