PyLint fixes for tools-webrtc and webrtc/tools

webrtc/tools/barcode_tools/barcode_encoder.py

 #!/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 optparse
 import os
 import sys
 
 import helper_functions
 
 _DEFAULT_BARCODE_WIDTH = 352
 _DEFAULT_BARCODES_FILE = 'barcodes.yuv'
 
 
-def generate_upca_barcodes(number_of_barcodes, barcode_width, barcode_height,
-                           output_directory='.',
-                           path_to_zxing='zxing-read-only'):
+def GenerateUpcaBarcodes(number_of_barcodes, barcode_width, barcode_height,
+                         output_directory='.',
+                         path_to_zxing='zxing-read-only'):
   """Generates UPC-A barcodes.
 
   This function generates a number_of_barcodes UPC-A barcodes. The function
   calls an example Java encoder from the Zxing library. The barcodes are
   generated as PNG images. The width of the barcodes shouldn't be less than 102
   pixels because otherwise Zxing can't properly generate the barcodes.
 
   Args:
     number_of_barcodes(int): The number of barcodes to generate.
     barcode_width(int): Width of barcode in pixels.
     barcode_height(int): Height of barcode in pixels.
     output_directory(string): Output directory where to store generated
       barcodes.
     path_to_zxing(string): The path to Zxing.
 
   Return:
     (bool): True if the conversion is successful.
   """
   base_file_name = os.path.join(output_directory, "barcode_")
-  jars = _form_jars_string(path_to_zxing)
+  jars = _FormJarsString(path_to_zxing)
   command_line_encoder = 'com.google.zxing.client.j2se.CommandLineEncoder'
   barcode_width = str(barcode_width)
   barcode_height = str(barcode_height)
 
   errors = False
   for i in range(number_of_barcodes):
     suffix = helper_functions.zero_pad(i)
     # Barcodes starting from 0
     content = helper_functions.zero_pad(i, 11)
     output_file_name = base_file_name + suffix + ".png"
 
     command = ["java", "-cp", jars, command_line_encoder,
                "--barcode_format=UPC_A", "--height=%s" % barcode_height,
                "--width=%s" % barcode_width,
                "--output=%s" % (output_file_name), "%s" % (content)]
     try:
       helper_functions.run_shell_command(
           command, fail_msg=('Error during barcode %s generation' % content))
     except helper_functions.HelperError as err:
       print >> sys.stderr, err
       errors = True
   return not errors
 
 
-def convert_png_to_yuv_barcodes(input_directory='.', output_directory='.'):
+def ConvertPngToYuvBarcodes(input_directory='.', output_directory='.'):
   """Converts PNG barcodes to YUV barcode images.
 
   This function reads all the PNG files from the input directory which are in
   the format frame_xxxx.png, where xxxx is the number of the frame, starting
   from 0000. The frames should be consecutive numbers. The output YUV file is
   named frame_xxxx.yuv. The function uses ffmpeg to do the conversion.
 
   Args:
     input_directory(string): The input direcotry to read the PNG barcodes from.
     output_directory(string): The putput directory to write the YUV files to.
   Return:
     (bool): True if the conversion was without errors.
   """
   return helper_functions.perform_action_on_all_files(
-      input_directory, 'barcode_', 'png', 0, _convert_to_yuv_and_delete,
+      input_directory, 'barcode_', 'png', 0, _ConvertToYuvAndDelete,
       output_directory=output_directory, pattern='barcode_')
 
 
-def _convert_to_yuv_and_delete(output_directory, file_name, pattern):
+def _ConvertToYuvAndDelete(output_directory, file_name, pattern):
   """Converts a PNG file to a YUV file and deletes the PNG file.
 
   Args:
     output_directory(string): The output directory for the YUV file.
     file_name(string): The PNG file name.
     pattern(string): The file pattern of the PNG/YUV file. The PNG/YUV files are
       named patternxx..x.png/yuv, where xx..x are digits starting from 00..0.
   Return:
     (bool): True upon successful conversion, false otherwise.
   """
@@ skipping 12 matching lines @@
     helper_functions.run_shell_command(
         command, fail_msg=('Error during PNG to YUV conversion of %s' %
                            file_name))
     os.remove(file_name)
   except helper_functions.HelperError as err:
     print >> sys.stderr, err
     return False
   return True
 
 
-def combine_yuv_frames_into_one_file(output_file_name, input_directory='.'):
+def CombineYuvFramesIntoOneFile(output_file_name, input_directory='.'):
   """Combines several YUV frames into one YUV video file.
 
   The function combines the YUV frames from input_directory into one YUV video
   file. The frames should be named in the format frame_xxxx.yuv where xxxx
   stands for the frame number. The numbers have to be consecutive and start from
   0000. The YUV frames are removed after they have been added to the video.
 
   Args:
     output_file_name(string): The name of the file to produce.
     input_directory(string): The directory from which the YUV frames are read.
   Return:
     (bool): True if the frame stitching went OK.
   """
   output_file = open(output_file_name, "wb")
   success = helper_functions.perform_action_on_all_files(
-      input_directory, 'barcode_', 'yuv', 0, _add_to_file_and_delete,
+      input_directory, 'barcode_', 'yuv', 0, _AddToFileAndDelete,
       output_file=output_file)
   output_file.close()
   return success
 
-def _add_to_file_and_delete(output_file, file_name):
+def _AddToFileAndDelete(output_file, file_name):
   """Adds the contents of a file to a previously opened file.
 
   Args:
     output_file(file): The ouput file, previously opened.
     file_name(string): The file name of the file to add to the output file.
 
   Return:
     (bool): True if successful, False otherwise.
   """
   input_file = open(file_name, "rb")
   input_file_contents = input_file.read()
   output_file.write(input_file_contents)
   input_file.close()
   try:
     os.remove(file_name)
   except OSError as e:
     print >> sys.stderr, 'Error deleting file %s.\nError: %s' % (file_name, e)
     return False
   return True
 
 
-def _overlay_barcode_and_base_frames(barcodes_file, base_file, output_file,
-                                     barcodes_component_sizes,
-                                     base_component_sizes):
+def _OverlayBarcodeAndBaseFrames(barcodes_file, base_file, output_file,
+                                 barcodes_component_sizes,
+                                 base_component_sizes):
   """Overlays the next YUV frame from a file with a barcode.
 
   Args:
     barcodes_file(FileObject): The YUV file containing the barcodes (opened).
     base_file(FileObject): The base YUV file (opened).
     output_file(FileObject): The output overlaid file (opened).
     barcodes_component_sizes(list of tuples): The width and height of each Y, U
       and V plane of the barcodes YUV file.
     base_component_sizes(list of tuples): The width and height of each Y, U and
       V plane of the base YUV file.
@@ skipping 19 matching lines @@
         return False
 
       if not barcode_plane_traversed:
         # Substitute part of the base component with the top component
         output_file.write(barcode_plane)
         base_plane = base_plane[barcode_comp_width:]
       output_file.write(base_plane)
   return True
 
 
-def overlay_yuv_files(barcode_width, barcode_height, base_width, base_height,
-                      barcodes_file_name, base_file_name, output_file_name):
+def OverlayYuvFiles(barcode_width, barcode_height, base_width, base_height,
+                    barcodes_file_name, base_file_name, output_file_name):
   """Overlays two YUV files starting from the upper left corner of both.
 
   Args:
     barcode_width(int): The width of the barcode (to be overlaid).
     barcode_height(int): The height of the barcode (to be overlaid).
     base_width(int): The width of a frame of the base file.
     base_height(int): The height of a frame of the base file.
     barcodes_file_name(string): The name of the YUV file containing the YUV
       barcodes.
     base_file_name(string): The name of the base YUV file.
     output_file_name(string): The name of the output file where the overlaid
       video will be written.
   """
   # Component sizes = [Y_sizes, U_sizes, V_sizes]
   barcodes_component_sizes = [(barcode_width, barcode_height),
                               (barcode_width/2, barcode_height/2),
                               (barcode_width/2, barcode_height/2)]
   base_component_sizes = [(base_width, base_height),
                           (base_width/2, base_height/2),
                           (base_width/2, base_height/2)]
 
   barcodes_file = open(barcodes_file_name, 'rb')
   base_file = open(base_file_name, 'rb')
   output_file = open(output_file_name, 'wb')
 
   data_left = True
   while data_left:
-    data_left = _overlay_barcode_and_base_frames(barcodes_file, base_file,
-                                                 output_file,
-                                                 barcodes_component_sizes,
-                                                 base_component_sizes)
+    data_left = _OverlayBarcodeAndBaseFrames(barcodes_file, base_file,
+                                             output_file,
+                                             barcodes_component_sizes,
+                                             base_component_sizes)
 
   barcodes_file.close()
   base_file.close()
   output_file.close()
 
 
-def calculate_frames_number_from_yuv(yuv_width, yuv_height, file_name):
+def CalculateFramesNumberFromYuv(yuv_width, yuv_height, file_name):
   """Calculates the number of frames of a YUV video.
 
   Args:
     yuv_width(int): Width of a frame of the yuv file.
     yuv_height(int): Height of a frame of the YUV file.
     file_name(string): The name of the YUV file.
   Return:
     (int): The number of frames in the YUV file.
   """
   file_size = os.path.getsize(file_name)
 
   y_plane_size = yuv_width * yuv_height
   u_plane_size = (yuv_width/2) * (yuv_height/2)  # Equals to V plane size too
   frame_size = y_plane_size + (2 * u_plane_size)
   return int(file_size/frame_size)  # Should be int anyway
 
 
-def _form_jars_string(path_to_zxing):
+def _FormJarsString(path_to_zxing):
   """Forms the the Zxing core and javase jars argument.
 
   Args:
     path_to_zxing(string): The path to the Zxing checkout folder.
   Return:
     (string): The newly formed jars argument.
   """
   javase_jar = os.path.join(path_to_zxing, "javase", "javase.jar")
   core_jar = os.path.join(path_to_zxing, "core", "core.jar")
   delimiter = ':'
   if os.name != 'posix':
     delimiter = ';'
   return javase_jar + delimiter + core_jar
 
-def _parse_args():
+def _ParseArgs():
   """Registers the command-line options."""
   usage = "usage: %prog [options]"
   parser = optparse.OptionParser(usage=usage)
 
   parser.add_option('--barcode_width', type='int',
                     default=_DEFAULT_BARCODE_WIDTH,
                     help=('Width of the barcodes to be overlaid on top of the'
                           ' base file. Default: %default'))
   parser.add_option('--barcode_height', type='int', default=32,
                     help=('Height of the barcodes to be overlaid on top of the'
@@ skipping 26 matching lines @@
   parser.add_option('--yuv_frames_input_dir', type='string', default='.',
                     help=('Input directory from where the YUV will be '
                           'read before combination. Default: %default'))
   parser.add_option('--zxing_dir', type='string', default='zxing',
                     help=('Path to the Zxing barcodes library. '
                           'Default: %default'))
   options = parser.parse_args()[0]
   return options
 
 
-def _main():
+def main():
   """The main function.
 
   A simple invocation will be:
   ./webrtc/tools/barcode_tools/barcode_encoder.py --barcode_height=32
   --base_frame_width=352 --base_frame_height=288
   --base_yuv=<path_and_name_of_base_file>
   --output_yuv=<path and name_of_output_file>
   """
-  options = _parse_args()
+  options = _ParseArgs()
   # The barcodes with will be different than the base frame width only if
   # explicitly specified at the command line.
   if options.barcode_width == _DEFAULT_BARCODE_WIDTH:
     options.barcode_width = options.base_frame_width
   # If the user provides a value for the barcodes YUV video file, we will keep
   # it. Otherwise we create a temp file which is removed after it has been used.
   keep_barcodes_yuv_file = False
   if options.barcodes_yuv != _DEFAULT_BARCODES_FILE:
     keep_barcodes_yuv_file = True
 
   # Calculate the number of barcodes - it is equal to the number of frames in
   # the base file.
-  number_of_barcodes = calculate_frames_number_from_yuv(
+  number_of_barcodes = CalculateFramesNumberFromYuv(
       options.base_frame_width, options.base_frame_height, options.base_yuv)
 
   script_dir = os.path.dirname(os.path.abspath(sys.argv[0]))
   zxing_dir = os.path.join(script_dir, 'third_party', 'zxing')
   # Generate barcodes - will generate them in PNG.
-  generate_upca_barcodes(number_of_barcodes, options.barcode_width,
-                         options.barcode_height,
-                         output_directory=options.png_barcodes_output_dir,
-                         path_to_zxing=zxing_dir)
+  GenerateUpcaBarcodes(number_of_barcodes, options.barcode_width,
+                       options.barcode_height,
+                       output_directory=options.png_barcodes_output_dir,
+                       path_to_zxing=zxing_dir)
   # Convert the PNG barcodes to to YUV format.
-  convert_png_to_yuv_barcodes(options.png_barcodes_input_dir,
-                              options.yuv_barcodes_output_dir)
+  ConvertPngToYuvBarcodes(options.png_barcodes_input_dir,
+                          options.yuv_barcodes_output_dir)
   # Combine the YUV barcodes into one YUV file.
-  combine_yuv_frames_into_one_file(options.barcodes_yuv,
-                                   input_directory=options.yuv_frames_input_dir)
+  CombineYuvFramesIntoOneFile(options.barcodes_yuv,
+                              input_directory=options.yuv_frames_input_dir)
   # Overlay the barcodes over the base file.
-  overlay_yuv_files(options.barcode_width, options.barcode_height,
-                    options.base_frame_width, options.base_frame_height,
-                    options.barcodes_yuv, options.base_yuv, options.output_yuv)
+  OverlayYuvFiles(options.barcode_width, options.barcode_height,
+                  options.base_frame_width, options.base_frame_height,
+                  options.barcodes_yuv, options.base_yuv, options.output_yuv)
 
   if not keep_barcodes_yuv_file:
     # Remove the temporary barcodes YUV file
     os.remove(options.barcodes_yuv)
 
 
 if __name__ == '__main__':
-  sys.exit(_main())
+  sys.exit(main())