file_utils.py

import os
import sys

class FileUtils:
	log = args = None
	FOUR_GIGS = (4*1024*1024*1024)

	def __init__(self, log, args):
		self.log = log
		self.args = args
		
	# Check if all dependent applications are installed on the system and present in PATH
	# TODO: Allow custom path to be specified for each of these if it is in a config file
	def check_dependencies(self):
		dependencies = ('mkvinfo', 'mediainfo', 'mkvextract', 'mplayer', 'faac', 'MP4Box')
		ospath = os.defpath.split(os.pathsep)
		for app in dependencies:
			app_present = False
			for path in ospath:
				if os.path.isfile(os.path.join(path, app)):
					self.log.debug("Found dependent application %s in %s" % (app, path))
					app_present = True
					break
					
			if not app_present:
				self.log.critical("Dependent application '%s' was not found in PATH. Please make sure it is installed." % app)
				sys.exit(1)
		
		return True
		
	def check_dest_dir(self, destination):
		if not os.path.isdir(destination):
			log.critical("Destination directory %s does not exist" % destination)
			sys.exit(1)
			
	def check_source_file(self, source_file):
		if not os.path.isfile(source_file):
			log.critical("Source file %s does not exist" % source_file)
			sys.exit(1)
			
		filesize = os.path.getsize(source_file)
		if (filesize >= self.FOUR_GIGS):
			log.warning("File size of %s is %i, which is over 4GiB. This file may not play on certain devices and cannot be copied to a FAT32-formatted storage medium." % (source_file, filesize))
			if self.args.error_filesize:
				log.critical("Cancelling processing as file size limit of 4GiB is exceeded")
				sys.exit(1)

	def hex_edit_video_file(self, path):
		with open(path, 'r+b') as f:
			f.seek(7)
			f.write("\x29")
		# File is automatically closed		

	def delete_temp_files(self, scratch_dir, extensions):
		for extension in extensions:
			temp_video = scratch_dir + "temp_video" + extension
			temp_audio = scratch_dir + "temp_audio" + extension
			if os.path.isfile(temp_video):
				self.log.debug("Cleaning up: deleting %s" % temp_video)
				os.unlink(temp_video)
			if os.path.isfile(temp_audio):
				self.log.debug("Cleaning up: deleting %s" % temp_audio)
				os.unlink(temp_audio)

		# Check for audiodump.aac and audiodump.wav
		other_files = ('audiodump.aac', 'audiodump.wav')
		for name in other_files:
			if os.path.isfile(scratch_dir + name):
				self.log.debug("Cleaning up: deleting %s" % scratch_dir + name)
				os.unlink(scratch_dir + name)