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 10 import os 11 import subprocess 12 import sys 13 14 _DEFAULT_PADDING = 4 15 16 17 class HelperError(Exception): 18 """Exception raised for errors in the helper.""" 19 pass 20 21 22 def zero_pad(number, padding=_DEFAULT_PADDING): 23 """Converts an int into a zero padded string. 24 25 Args: 26 number(int): The number to convert. 27 padding(int): The number of chars in the output. Note that if you pass for 28 example number=23456 and padding=4, the output will still be '23456', 29 i.e. it will not be cropped. If you pass number=2 and padding=4, the 30 return value will be '0002'. 31 Return: 32 (string): The zero padded number converted to string. 33 """ 34 return str(number).zfill(padding) 35 36 37 def run_shell_command(cmd_list, fail_msg=None): 38 """Executes a command. 39 40 Args: 41 cmd_list(list): Command list to execute. 42 fail_msg(string): Message describing the error in case the command fails. 43 44 Return: 45 (string): The standard output from running the command. 46 47 Raise: 48 HelperError: If command fails. 49 """ 50 process = subprocess.Popen(cmd_list, stdout=subprocess.PIPE, 51 stderr=subprocess.PIPE) 52 output, error = process.communicate() 53 if process.returncode != 0: 54 if fail_msg: 55 print >> sys.stderr, fail_msg 56 raise HelperError('Failed to run %s: command returned %d and printed ' 57 '%s and %s' % (' '.join(cmd_list), process.returncode, 58 output, error)) 59 return output.strip() 60 61 62 def perform_action_on_all_files(directory, file_pattern, file_extension, 63 start_number, action, **kwargs): 64 """Function that performs a given action on all files matching a pattern. 65 66 It is assumed that the files are named file_patternxxxx.file_extension, where 67 xxxx are digits. The file names start from 68 file_patern0..start_number>.file_extension. 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. 77 78 Return: 79 (bool): Whether performing the action over all files was successful or not. 80 """ 81 file_prefix = os.path.join(directory, file_pattern) 82 file_exists = True 83 file_number = start_number 84 errors = False 85 86 while file_exists: 87 zero_padded_file_number = zero_pad(file_number) 88 file_name = file_prefix + zero_padded_file_number + '.' + file_extension 89 if os.path.isfile(file_name): 90 if not action(file_name=file_name, **kwargs): 91 errors = True 92 break 93 file_number += 1 94 else: 95 file_exists = False 96 return not errors 97
