X-Git-Url: https://git.rapsys.eu/youtubedl/blobdiff_plain/ee121ffd5cd3fe6fd1daa5699cae3becf3483dd3..11021a3e7a38072a0072edc613930e0a1193196c:/youtube_dl/utils.py

diff --git a/youtube_dl/utils.py b/youtube_dl/utils.py
index 2853ba5..057cd20 100644
--- a/youtube_dl/utils.py
+++ b/youtube_dl/utils.py
@@ -1,354 +1,1241 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
+import ctypes
+import datetime
+import email.utils
+import errno
 import gzip
-import htmlentitydefs
-import HTMLParser
+import itertools
+import io
+import json
 import locale
+import math
 import os
+import pipes
+import platform
 import re
+import ssl
+import socket
+import struct
+import subprocess
 import sys
+import traceback
 import zlib
-import urllib2
-import email.utils
-import json
 
 try:
-	import cStringIO as StringIO
+    import urllib.request as compat_urllib_request
+except ImportError: # Python 2
+    import urllib2 as compat_urllib_request
+
+try:
+    import urllib.error as compat_urllib_error
+except ImportError: # Python 2
+    import urllib2 as compat_urllib_error
+
+try:
+    import urllib.parse as compat_urllib_parse
+except ImportError: # Python 2
+    import urllib as compat_urllib_parse
+
+try:
+    from urllib.parse import urlparse as compat_urllib_parse_urlparse
+except ImportError: # Python 2
+    from urlparse import urlparse as compat_urllib_parse_urlparse
+
+try:
+    import urllib.parse as compat_urlparse
+except ImportError: # Python 2
+    import urlparse as compat_urlparse
+
+try:
+    import http.cookiejar as compat_cookiejar
+except ImportError: # Python 2
+    import cookielib as compat_cookiejar
+
+try:
+    import html.entities as compat_html_entities
+except ImportError: # Python 2
+    import htmlentitydefs as compat_html_entities
+
+try:
+    import html.parser as compat_html_parser
+except ImportError: # Python 2
+    import HTMLParser as compat_html_parser
+
+try:
+    import http.client as compat_http_client
+except ImportError: # Python 2
+    import httplib as compat_http_client
+
+try:
+    from urllib.error import HTTPError as compat_HTTPError
+except ImportError:  # Python 2
+    from urllib2 import HTTPError as compat_HTTPError
+
+try:
+    from urllib.request import urlretrieve as compat_urlretrieve
+except ImportError:  # Python 2
+    from urllib import urlretrieve as compat_urlretrieve
+
+
+try:
+    from subprocess import DEVNULL
+    compat_subprocess_get_DEVNULL = lambda: DEVNULL
 except ImportError:
-	import StringIO
+    compat_subprocess_get_DEVNULL = lambda: open(os.path.devnull, 'w')
+
+try:
+    from urllib.parse import parse_qs as compat_parse_qs
+except ImportError: # Python 2
+    # HACK: The following is the correct parse_qs implementation from cpython 3's stdlib.
+    # Python 2's version is apparently totally broken
+    def _unquote(string, encoding='utf-8', errors='replace'):
+        if string == '':
+            return string
+        res = string.split('%')
+        if len(res) == 1:
+            return string
+        if encoding is None:
+            encoding = 'utf-8'
+        if errors is None:
+            errors = 'replace'
+        # pct_sequence: contiguous sequence of percent-encoded bytes, decoded
+        pct_sequence = b''
+        string = res[0]
+        for item in res[1:]:
+            try:
+                if not item:
+                    raise ValueError
+                pct_sequence += item[:2].decode('hex')
+                rest = item[2:]
+                if not rest:
+                    # This segment was just a single percent-encoded character.
+                    # May be part of a sequence of code units, so delay decoding.
+                    # (Stored in pct_sequence).
+                    continue
+            except ValueError:
+                rest = '%' + item
+            # Encountered non-percent-encoded characters. Flush the current
+            # pct_sequence.
+            string += pct_sequence.decode(encoding, errors) + rest
+            pct_sequence = b''
+        if pct_sequence:
+            # Flush the final pct_sequence
+            string += pct_sequence.decode(encoding, errors)
+        return string
+
+    def _parse_qsl(qs, keep_blank_values=False, strict_parsing=False,
+                encoding='utf-8', errors='replace'):
+        qs, _coerce_result = qs, unicode
+        pairs = [s2 for s1 in qs.split('&') for s2 in s1.split(';')]
+        r = []
+        for name_value in pairs:
+            if not name_value and not strict_parsing:
+                continue
+            nv = name_value.split('=', 1)
+            if len(nv) != 2:
+                if strict_parsing:
+                    raise ValueError("bad query field: %r" % (name_value,))
+                # Handle case of a control-name with no equal sign
+                if keep_blank_values:
+                    nv.append('')
+                else:
+                    continue
+            if len(nv[1]) or keep_blank_values:
+                name = nv[0].replace('+', ' ')
+                name = _unquote(name, encoding=encoding, errors=errors)
+                name = _coerce_result(name)
+                value = nv[1].replace('+', ' ')
+                value = _unquote(value, encoding=encoding, errors=errors)
+                value = _coerce_result(value)
+                r.append((name, value))
+        return r
+
+    def compat_parse_qs(qs, keep_blank_values=False, strict_parsing=False,
+                encoding='utf-8', errors='replace'):
+        parsed_result = {}
+        pairs = _parse_qsl(qs, keep_blank_values, strict_parsing,
+                        encoding=encoding, errors=errors)
+        for name, value in pairs:
+            if name in parsed_result:
+                parsed_result[name].append(value)
+            else:
+                parsed_result[name] = [value]
+        return parsed_result
+
+try:
+    compat_str = unicode # Python 2
+except NameError:
+    compat_str = str
+
+try:
+    compat_chr = unichr # Python 2
+except NameError:
+    compat_chr = chr
+
+def compat_ord(c):
+    if type(c) is int: return c
+    else: return ord(c)
+
+# This is not clearly defined otherwise
+compiled_regex_type = type(re.compile(''))
 
 std_headers = {
-	'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64; rv:5.0.1) Gecko/20100101 Firefox/5.0.1',
-	'Accept-Charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
-	'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
-	'Accept-Encoding': 'gzip, deflate',
-	'Accept-Language': 'en-us,en;q=0.5',
+    'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64; rv:10.0) Gecko/20100101 Firefox/10.0 (Chrome)',
+    'Accept-Charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
+    'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
+    'Accept-Encoding': 'gzip, deflate',
+    'Accept-Language': 'en-us,en;q=0.5',
 }
 
 def preferredencoding():
-	"""Get preferred encoding.
-
-	Returns the best encoding scheme for the system, based on
-	locale.getpreferredencoding() and some further tweaks.
-	"""
-	def yield_preferredencoding():
-		try:
-			pref = locale.getpreferredencoding()
-			u'TEST'.encode(pref)
-		except:
-			pref = 'UTF-8'
-		while True:
-			yield pref
-	return yield_preferredencoding().next()
+    """Get preferred encoding.
+
+    Returns the best encoding scheme for the system, based on
+    locale.getpreferredencoding() and some further tweaks.
+    """
+    try:
+        pref = locale.getpreferredencoding()
+        u'TEST'.encode(pref)
+    except:
+        pref = 'UTF-8'
+
+    return pref
+
+if sys.version_info < (3,0):
+    def compat_print(s):
+        print(s.encode(preferredencoding(), 'xmlcharrefreplace'))
+else:
+    def compat_print(s):
+        assert type(s) == type(u'')
+        print(s)
+
+# In Python 2.x, json.dump expects a bytestream.
+# In Python 3.x, it writes to a character stream
+if sys.version_info < (3,0):
+    def write_json_file(obj, fn):
+        with open(fn, 'wb') as f:
+            json.dump(obj, f)
+else:
+    def write_json_file(obj, fn):
+        with open(fn, 'w', encoding='utf-8') as f:
+            json.dump(obj, f)
 
+if sys.version_info >= (2,7):
+    def find_xpath_attr(node, xpath, key, val):
+        """ Find the xpath xpath[@key=val] """
+        assert re.match(r'^[a-zA-Z]+$', key)
+        assert re.match(r'^[a-zA-Z0-9@\s:._]*$', val)
+        expr = xpath + u"[@%s='%s']" % (key, val)
+        return node.find(expr)
+else:
+    def find_xpath_attr(node, xpath, key, val):
+        for f in node.findall(xpath):
+            if f.attrib.get(key) == val:
+                return f
+        return None
+
+# On python2.6 the xml.etree.ElementTree.Element methods don't support
+# the namespace parameter
+def xpath_with_ns(path, ns_map):
+    components = [c.split(':') for c in path.split('/')]
+    replaced = []
+    for c in components:
+        if len(c) == 1:
+            replaced.append(c[0])
+        else:
+            ns, tag = c
+            replaced.append('{%s}%s' % (ns_map[ns], tag))
+    return '/'.join(replaced)
 
 def htmlentity_transform(matchobj):
-	"""Transforms an HTML entity to a Unicode character.
-
-	This function receives a match object and is intended to be used with
-	the re.sub() function.
-	"""
-	entity = matchobj.group(1)
-
-	# Known non-numeric HTML entity
-	if entity in htmlentitydefs.name2codepoint:
-		return unichr(htmlentitydefs.name2codepoint[entity])
-
-	# Unicode character
-	mobj = re.match(ur'(?u)#(x?\d+)', entity)
-	if mobj is not None:
-		numstr = mobj.group(1)
-		if numstr.startswith(u'x'):
-			base = 16
-			numstr = u'0%s' % numstr
-		else:
-			base = 10
-		return unichr(long(numstr, base))
-
-	# Unknown entity in name, return its literal representation
-	return (u'&%s;' % entity)
-
-HTMLParser.locatestarttagend = re.compile(r"""<[a-zA-Z][-.a-zA-Z0-9:_]*(?:\s+(?:(?<=['"\s])[^\s/>][^\s/=>]*(?:\s*=+\s*(?:'[^']*'|"[^"]*"|(?!['"])[^>\s]*))?\s*)*)?\s*""", re.VERBOSE) # backport bugfix
-class IDParser(HTMLParser.HTMLParser):
-	"""Modified HTMLParser that isolates a tag with the specified id"""
-	def __init__(self, id):
-		self.id = id
-		self.result = None
-		self.started = False
-		self.depth = {}
-		self.html = None
-		self.watch_startpos = False
-		self.error_count = 0
-		HTMLParser.HTMLParser.__init__(self)
-
-	def error(self, message):
-		print >> sys.stderr, self.getpos()
-		if self.error_count > 10 or self.started:
-			raise HTMLParser.HTMLParseError(message, self.getpos())
-		self.rawdata = '\n'.join(self.html.split('\n')[self.getpos()[0]:]) # skip one line
-		self.error_count += 1
-		self.goahead(1)
-
-	def loads(self, html):
-		self.html = html
-		self.feed(html)
-		self.close()
-
-	def handle_starttag(self, tag, attrs):
-		attrs = dict(attrs)
-		if self.started:
-			self.find_startpos(None)
-		if 'id' in attrs and attrs['id'] == self.id:
-			self.result = [tag]
-			self.started = True
-			self.watch_startpos = True
-		if self.started:
-			if not tag in self.depth: self.depth[tag] = 0
-			self.depth[tag] += 1
-
-	def handle_endtag(self, tag):
-		if self.started:
-			if tag in self.depth: self.depth[tag] -= 1
-			if self.depth[self.result[0]] == 0:
-				self.started = False
-				self.result.append(self.getpos())
-
-	def find_startpos(self, x):
-		"""Needed to put the start position of the result (self.result[1])
-		after the opening tag with the requested id"""
-		if self.watch_startpos:
-			self.watch_startpos = False
-			self.result.append(self.getpos())
-	handle_entityref = handle_charref = handle_data = handle_comment = \
-	handle_decl = handle_pi = unknown_decl = find_startpos
-
-	def get_result(self):
-		if self.result == None: return None
-		if len(self.result) != 3: return None
-		lines = self.html.split('\n')
-		lines = lines[self.result[1][0]-1:self.result[2][0]]
-		lines[0] = lines[0][self.result[1][1]:]
-		if len(lines) == 1:
-			lines[-1] = lines[-1][:self.result[2][1]-self.result[1][1]]
-		lines[-1] = lines[-1][:self.result[2][1]]
-		return '\n'.join(lines).strip()
+    """Transforms an HTML entity to a character.
+
+    This function receives a match object and is intended to be used with
+    the re.sub() function.
+    """
+    entity = matchobj.group(1)
+
+    # Known non-numeric HTML entity
+    if entity in compat_html_entities.name2codepoint:
+        return compat_chr(compat_html_entities.name2codepoint[entity])
+
+    mobj = re.match(u'(?u)#(x?\\d+)', entity)
+    if mobj is not None:
+        numstr = mobj.group(1)
+        if numstr.startswith(u'x'):
+            base = 16
+            numstr = u'0%s' % numstr
+        else:
+            base = 10
+        return compat_chr(int(numstr, base))
+
+    # Unknown entity in name, return its literal representation
+    return (u'&%s;' % entity)
+
+compat_html_parser.locatestarttagend = re.compile(r"""<[a-zA-Z][-.a-zA-Z0-9:_]*(?:\s+(?:(?<=['"\s])[^\s/>][^\s/=>]*(?:\s*=+\s*(?:'[^']*'|"[^"]*"|(?!['"])[^>\s]*))?\s*)*)?\s*""", re.VERBOSE) # backport bugfix
+class BaseHTMLParser(compat_html_parser.HTMLParser):
+    def __init(self):
+        compat_html_parser.HTMLParser.__init__(self)
+        self.html = None
+
+    def loads(self, html):
+        self.html = html
+        self.feed(html)
+        self.close()
+
+class AttrParser(BaseHTMLParser):
+    """Modified HTMLParser that isolates a tag with the specified attribute"""
+    def __init__(self, attribute, value):
+        self.attribute = attribute
+        self.value = value
+        self.result = None
+        self.started = False
+        self.depth = {}
+        self.watch_startpos = False
+        self.error_count = 0
+        BaseHTMLParser.__init__(self)
+
+    def error(self, message):
+        if self.error_count > 10 or self.started:
+            raise compat_html_parser.HTMLParseError(message, self.getpos())
+        self.rawdata = '\n'.join(self.html.split('\n')[self.getpos()[0]:]) # skip one line
+        self.error_count += 1
+        self.goahead(1)
+
+    def handle_starttag(self, tag, attrs):
+        attrs = dict(attrs)
+        if self.started:
+            self.find_startpos(None)
+        if self.attribute in attrs and attrs[self.attribute] == self.value:
+            self.result = [tag]
+            self.started = True
+            self.watch_startpos = True
+        if self.started:
+            if not tag in self.depth: self.depth[tag] = 0
+            self.depth[tag] += 1
+
+    def handle_endtag(self, tag):
+        if self.started:
+            if tag in self.depth: self.depth[tag] -= 1
+            if self.depth[self.result[0]] == 0:
+                self.started = False
+                self.result.append(self.getpos())
+
+    def find_startpos(self, x):
+        """Needed to put the start position of the result (self.result[1])
+        after the opening tag with the requested id"""
+        if self.watch_startpos:
+            self.watch_startpos = False
+            self.result.append(self.getpos())
+    handle_entityref = handle_charref = handle_data = handle_comment = \
+    handle_decl = handle_pi = unknown_decl = find_startpos
+
+    def get_result(self):
+        if self.result is None:
+            return None
+        if len(self.result) != 3:
+            return None
+        lines = self.html.split('\n')
+        lines = lines[self.result[1][0]-1:self.result[2][0]]
+        lines[0] = lines[0][self.result[1][1]:]
+        if len(lines) == 1:
+            lines[-1] = lines[-1][:self.result[2][1]-self.result[1][1]]
+        lines[-1] = lines[-1][:self.result[2][1]]
+        return '\n'.join(lines).strip()
+# Hack for https://github.com/rg3/youtube-dl/issues/662
+if sys.version_info < (2, 7, 3):
+    AttrParser.parse_endtag = (lambda self, i:
+        i + len("</scr'+'ipt>")
+        if self.rawdata[i:].startswith("</scr'+'ipt>")
+        else compat_html_parser.HTMLParser.parse_endtag(self, i))
 
 def get_element_by_id(id, html):
-	"""Return the content of the tag with the specified id in the passed HTML document"""
-	parser = IDParser(id)
-	try:
-		parser.loads(html)
-	except HTMLParser.HTMLParseError:
-		pass
-	return parser.get_result()
+    """Return the content of the tag with the specified ID in the passed HTML document"""
+    return get_element_by_attribute("id", id, html)
+
+def get_element_by_attribute(attribute, value, html):
+    """Return the content of the tag with the specified attribute in the passed HTML document"""
+    parser = AttrParser(attribute, value)
+    try:
+        parser.loads(html)
+    except compat_html_parser.HTMLParseError:
+        pass
+    return parser.get_result()
+
+class MetaParser(BaseHTMLParser):
+    """
+    Modified HTMLParser that isolates a meta tag with the specified name 
+    attribute.
+    """
+    def __init__(self, name):
+        BaseHTMLParser.__init__(self)
+        self.name = name
+        self.content = None
+        self.result = None
+
+    def handle_starttag(self, tag, attrs):
+        if tag != 'meta':
+            return
+        attrs = dict(attrs)
+        if attrs.get('name') == self.name:
+            self.result = attrs.get('content')
+
+    def get_result(self):
+        return self.result
+
+def get_meta_content(name, html):
+    """
+    Return the content attribute from the meta tag with the given name attribute.
+    """
+    parser = MetaParser(name)
+    try:
+        parser.loads(html)
+    except compat_html_parser.HTMLParseError:
+        pass
+    return parser.get_result()
 
 
 def clean_html(html):
-	"""Clean an HTML snippet into a readable string"""
-	# Newline vs <br />
-	html = html.replace('\n', ' ')
-	html = re.sub('\s*<\s*br\s*/?\s*>\s*', '\n', html)
-	# Strip html tags
-	html = re.sub('<.*?>', '', html)
-	# Replace html entities
-	html = unescapeHTML(html)
-	return html
+    """Clean an HTML snippet into a readable string"""
+    # Newline vs <br />
+    html = html.replace('\n', ' ')
+    html = re.sub(r'\s*<\s*br\s*/?\s*>\s*', '\n', html)
+    html = re.sub(r'<\s*/\s*p\s*>\s*<\s*p[^>]*>', '\n', html)
+    # Strip html tags
+    html = re.sub('<.*?>', '', html)
+    # Replace html entities
+    html = unescapeHTML(html)
+    return html.strip()
 
 
 def sanitize_open(filename, open_mode):
-	"""Try to open the given filename, and slightly tweak it if this fails.
-
-	Attempts to open the given filename. If this fails, it tries to change
-	the filename slightly, step by step, until it's either able to open it
-	or it fails and raises a final exception, like the standard open()
-	function.
-
-	It returns the tuple (stream, definitive_file_name).
-	"""
-	try:
-		if filename == u'-':
-			if sys.platform == 'win32':
-				import msvcrt
-				msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
-			return (sys.stdout, filename)
-		stream = open(encodeFilename(filename), open_mode)
-		return (stream, filename)
-	except (IOError, OSError), err:
-		# In case of error, try to remove win32 forbidden chars
-		filename = re.sub(ur'[/<>:"\|\?\*]', u'#', filename)
-
-		# An exception here should be caught in the caller
-		stream = open(encodeFilename(filename), open_mode)
-		return (stream, filename)
+    """Try to open the given filename, and slightly tweak it if this fails.
+
+    Attempts to open the given filename. If this fails, it tries to change
+    the filename slightly, step by step, until it's either able to open it
+    or it fails and raises a final exception, like the standard open()
+    function.
+
+    It returns the tuple (stream, definitive_file_name).
+    """
+    try:
+        if filename == u'-':
+            if sys.platform == 'win32':
+                import msvcrt
+                msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
+            return (sys.stdout.buffer if hasattr(sys.stdout, 'buffer') else sys.stdout, filename)
+        stream = open(encodeFilename(filename), open_mode)
+        return (stream, filename)
+    except (IOError, OSError) as err:
+        if err.errno in (errno.EACCES,):
+            raise
+
+        # In case of error, try to remove win32 forbidden chars
+        alt_filename = os.path.join(
+                        re.sub(u'[/<>:"\\|\\\\?\\*]', u'#', path_part)
+                        for path_part in os.path.split(filename)
+                       )
+        if alt_filename == filename:
+            raise
+        else:
+            # An exception here should be caught in the caller
+            stream = open(encodeFilename(filename), open_mode)
+            return (stream, alt_filename)
 
 
 def timeconvert(timestr):
-	"""Convert RFC 2822 defined time string into system timestamp"""
-	timestamp = None
-	timetuple = email.utils.parsedate_tz(timestr)
-	if timetuple is not None:
-		timestamp = email.utils.mktime_tz(timetuple)
-	return timestamp
-	
-def sanitize_filename(s):
-	"""Sanitizes a string so it could be used as part of a filename."""
-	def replace_insane(char):
-		if char in u' .\\/|?*<>:"' or ord(char) < 32:
-			return '_'
-		return char
-	return u''.join(map(replace_insane, s)).strip('_')
+    """Convert RFC 2822 defined time string into system timestamp"""
+    timestamp = None
+    timetuple = email.utils.parsedate_tz(timestr)
+    if timetuple is not None:
+        timestamp = email.utils.mktime_tz(timetuple)
+    return timestamp
+
+def sanitize_filename(s, restricted=False, is_id=False):
+    """Sanitizes a string so it could be used as part of a filename.
+    If restricted is set, use a stricter subset of allowed characters.
+    Set is_id if this is not an arbitrary string, but an ID that should be kept if possible
+    """
+    def replace_insane(char):
+        if char == '?' or ord(char) < 32 or ord(char) == 127:
+            return ''
+        elif char == '"':
+            return '' if restricted else '\''
+        elif char == ':':
+            return '_-' if restricted else ' -'
+        elif char in '\\/|*<>':
+            return '_'
+        if restricted and (char in '!&\'()[]{}$;`^,#' or char.isspace()):
+            return '_'
+        if restricted and ord(char) > 127:
+            return '_'
+        return char
+
+    result = u''.join(map(replace_insane, s))
+    if not is_id:
+        while '__' in result:
+            result = result.replace('__', '_')
+        result = result.strip('_')
+        # Common case of "Foreign band name - English song title"
+        if restricted and result.startswith('-_'):
+            result = result[2:]
+        if not result:
+            result = '_'
+    return result
 
 def orderedSet(iterable):
-	""" Remove all duplicates from the input iterable """
-	res = []
-	for el in iterable:
-		if el not in res:
-			res.append(el)
-	return res
+    """ Remove all duplicates from the input iterable """
+    res = []
+    for el in iterable:
+        if el not in res:
+            res.append(el)
+    return res
 
 def unescapeHTML(s):
-	"""
-	@param s a string (of type unicode)
-	"""
-	assert type(s) == type(u'')
+    """
+    @param s a string
+    """
+    assert type(s) == type(u'')
+
+    result = re.sub(u'(?u)&(.+?);', htmlentity_transform, s)
+    return result
+
+
+def encodeFilename(s, for_subprocess=False):
+    """
+    @param s The name of the file
+    """
+
+    assert type(s) == compat_str
+
+    # Python 3 has a Unicode API
+    if sys.version_info >= (3, 0):
+        return s
 
-	result = re.sub(ur'(?u)&(.+?);', htmlentity_transform, s)
-	return result
+    if sys.platform == 'win32' and sys.getwindowsversion()[0] >= 5:
+        # Pass u'' directly to use Unicode APIs on Windows 2000 and up
+        # (Detecting Windows NT 4 is tricky because 'major >= 4' would
+        # match Windows 9x series as well. Besides, NT 4 is obsolete.)
+        if not for_subprocess:
+            return s
+        else:
+            # For subprocess calls, encode with locale encoding
+            # Refer to http://stackoverflow.com/a/9951851/35070
+            encoding = preferredencoding()
+    else:
+        encoding = sys.getfilesystemencoding()
+    if encoding is None:
+        encoding = 'utf-8'
+    return s.encode(encoding, 'ignore')
 
-def encodeFilename(s):
-	"""
-	@param s The name of the file (of type unicode)
-	"""
 
-	assert type(s) == type(u'')
+def decodeOption(optval):
+    if optval is None:
+        return optval
+    if isinstance(optval, bytes):
+        optval = optval.decode(preferredencoding())
+
+    assert isinstance(optval, compat_str)
+    return optval
+
+def formatSeconds(secs):
+    if secs > 3600:
+        return '%d:%02d:%02d' % (secs // 3600, (secs % 3600) // 60, secs % 60)
+    elif secs > 60:
+        return '%d:%02d' % (secs // 60, secs % 60)
+    else:
+        return '%d' % secs
+
+
+def make_HTTPS_handler(opts_no_check_certificate, **kwargs):
+    if sys.version_info < (3, 2):
+        import httplib
+
+        class HTTPSConnectionV3(httplib.HTTPSConnection):
+            def __init__(self, *args, **kwargs):
+                httplib.HTTPSConnection.__init__(self, *args, **kwargs)
+
+            def connect(self):
+                sock = socket.create_connection((self.host, self.port), self.timeout)
+                if getattr(self, '_tunnel_host', False):
+                    self.sock = sock
+                    self._tunnel()
+                try:
+                    self.sock = ssl.wrap_socket(sock, self.key_file, self.cert_file, ssl_version=ssl.PROTOCOL_SSLv3)
+                except ssl.SSLError:
+                    self.sock = ssl.wrap_socket(sock, self.key_file, self.cert_file, ssl_version=ssl.PROTOCOL_SSLv23)
+
+        class HTTPSHandlerV3(compat_urllib_request.HTTPSHandler):
+            def https_open(self, req):
+                return self.do_open(HTTPSConnectionV3, req)
+        return HTTPSHandlerV3(**kwargs)
+    else:
+        context = ssl.SSLContext(ssl.PROTOCOL_SSLv3)
+        context.verify_mode = (ssl.CERT_NONE
+                               if opts_no_check_certificate
+                               else ssl.CERT_REQUIRED)
+        context.set_default_verify_paths()
+        try:
+            context.load_default_certs()
+        except AttributeError:
+            pass  # Python < 3.4
+        return compat_urllib_request.HTTPSHandler(context=context, **kwargs)
+
+class ExtractorError(Exception):
+    """Error during info extraction."""
+    def __init__(self, msg, tb=None, expected=False, cause=None):
+        """ tb, if given, is the original traceback (so that it can be printed out).
+        If expected is set, this is a normal error message and most likely not a bug in youtube-dl.
+        """
+
+        if sys.exc_info()[0] in (compat_urllib_error.URLError, socket.timeout, UnavailableVideoError):
+            expected = True
+        if not expected:
+            msg = msg + u'; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.'
+        super(ExtractorError, self).__init__(msg)
+
+        self.traceback = tb
+        self.exc_info = sys.exc_info()  # preserve original exception
+        self.cause = cause
+
+    def format_traceback(self):
+        if self.traceback is None:
+            return None
+        return u''.join(traceback.format_tb(self.traceback))
+
+
+class RegexNotFoundError(ExtractorError):
+    """Error when a regex didn't match"""
+    pass
 
-	if sys.platform == 'win32' and sys.getwindowsversion().major >= 5:
-		# Pass u'' directly to use Unicode APIs on Windows 2000 and up
-		# (Detecting Windows NT 4 is tricky because 'major >= 4' would
-		# match Windows 9x series as well. Besides, NT 4 is obsolete.)
-		return s
-	else:
-		return s.encode(sys.getfilesystemencoding(), 'ignore')
 
 class DownloadError(Exception):
-	"""Download Error exception.
+    """Download Error exception.
 
-	This exception may be thrown by FileDownloader objects if they are not
-	configured to continue on errors. They will contain the appropriate
-	error message.
-	"""
-	pass
+    This exception may be thrown by FileDownloader objects if they are not
+    configured to continue on errors. They will contain the appropriate
+    error message.
+    """
+    def __init__(self, msg, exc_info=None):
+        """ exc_info, if given, is the original exception that caused the trouble (as returned by sys.exc_info()). """
+        super(DownloadError, self).__init__(msg)
+        self.exc_info = exc_info
 
 
 class SameFileError(Exception):
-	"""Same File exception.
+    """Same File exception.
 
-	This exception will be thrown by FileDownloader objects if they detect
-	multiple files would have to be downloaded to the same file on disk.
-	"""
-	pass
+    This exception will be thrown by FileDownloader objects if they detect
+    multiple files would have to be downloaded to the same file on disk.
+    """
+    pass
 
 
 class PostProcessingError(Exception):
-	"""Post Processing exception.
+    """Post Processing exception.
 
-	This exception may be raised by PostProcessor's .run() method to
-	indicate an error in the postprocessing task.
-	"""
-	pass
+    This exception may be raised by PostProcessor's .run() method to
+    indicate an error in the postprocessing task.
+    """
+    def __init__(self, msg):
+        self.msg = msg
 
 class MaxDownloadsReached(Exception):
-	""" --max-downloads limit has been reached. """
-	pass
+    """ --max-downloads limit has been reached. """
+    pass
 
 
 class UnavailableVideoError(Exception):
-	"""Unavailable Format exception.
+    """Unavailable Format exception.
 
-	This exception will be thrown when a video is requested
-	in a format that is not available for that video.
-	"""
-	pass
+    This exception will be thrown when a video is requested
+    in a format that is not available for that video.
+    """
+    pass
 
 
 class ContentTooShortError(Exception):
-	"""Content Too Short exception.
-
-	This exception may be raised by FileDownloader objects when a file they
-	download is too small for what the server announced first, indicating
-	the connection was probably interrupted.
-	"""
-	# Both in bytes
-	downloaded = None
-	expected = None
-
-	def __init__(self, downloaded, expected):
-		self.downloaded = downloaded
-		self.expected = expected
-
-
-class Trouble(Exception):
-	"""Trouble helper exception
-	
-	This is an exception to be handled with
-	FileDownloader.trouble
-	"""
-
-class YoutubeDLHandler(urllib2.HTTPHandler):
-	"""Handler for HTTP requests and responses.
-
-	This class, when installed with an OpenerDirector, automatically adds
-	the standard headers to every HTTP request and handles gzipped and
-	deflated responses from web servers. If compression is to be avoided in
-	a particular request, the original request in the program code only has
-	to include the HTTP header "Youtubedl-No-Compression", which will be
-	removed before making the real request.
-
-	Part of this code was copied from:
-
-	http://techknack.net/python-urllib2-handlers/
-
-	Andrew Rowls, the author of that code, agreed to release it to the
-	public domain.
-	"""
-
-	@staticmethod
-	def deflate(data):
-		try:
-			return zlib.decompress(data, -zlib.MAX_WBITS)
-		except zlib.error:
-			return zlib.decompress(data)
-
-	@staticmethod
-	def addinfourl_wrapper(stream, headers, url, code):
-		if hasattr(urllib2.addinfourl, 'getcode'):
-			return urllib2.addinfourl(stream, headers, url, code)
-		ret = urllib2.addinfourl(stream, headers, url)
-		ret.code = code
-		return ret
-
-	def http_request(self, req):
-		for h in std_headers:
-			if h in req.headers:
-				del req.headers[h]
-			req.add_header(h, std_headers[h])
-		if 'Youtubedl-no-compression' in req.headers:
-			if 'Accept-encoding' in req.headers:
-				del req.headers['Accept-encoding']
-			del req.headers['Youtubedl-no-compression']
-		return req
-
-	def http_response(self, req, resp):
-		old_resp = resp
-		# gzip
-		if resp.headers.get('Content-encoding', '') == 'gzip':
-			gz = gzip.GzipFile(fileobj=StringIO.StringIO(resp.read()), mode='r')
-			resp = self.addinfourl_wrapper(gz, old_resp.headers, old_resp.url, old_resp.code)
-			resp.msg = old_resp.msg
-		# deflate
-		if resp.headers.get('Content-encoding', '') == 'deflate':
-			gz = StringIO.StringIO(self.deflate(resp.read()))
-			resp = self.addinfourl_wrapper(gz, old_resp.headers, old_resp.url, old_resp.code)
-			resp.msg = old_resp.msg
-		return resp
+    """Content Too Short exception.
+
+    This exception may be raised by FileDownloader objects when a file they
+    download is too small for what the server announced first, indicating
+    the connection was probably interrupted.
+    """
+    # Both in bytes
+    downloaded = None
+    expected = None
+
+    def __init__(self, downloaded, expected):
+        self.downloaded = downloaded
+        self.expected = expected
+
+class YoutubeDLHandler(compat_urllib_request.HTTPHandler):
+    """Handler for HTTP requests and responses.
+
+    This class, when installed with an OpenerDirector, automatically adds
+    the standard headers to every HTTP request and handles gzipped and
+    deflated responses from web servers. If compression is to be avoided in
+    a particular request, the original request in the program code only has
+    to include the HTTP header "Youtubedl-No-Compression", which will be
+    removed before making the real request.
+
+    Part of this code was copied from:
+
+    http://techknack.net/python-urllib2-handlers/
+
+    Andrew Rowls, the author of that code, agreed to release it to the
+    public domain.
+    """
+
+    @staticmethod
+    def deflate(data):
+        try:
+            return zlib.decompress(data, -zlib.MAX_WBITS)
+        except zlib.error:
+            return zlib.decompress(data)
+
+    @staticmethod
+    def addinfourl_wrapper(stream, headers, url, code):
+        if hasattr(compat_urllib_request.addinfourl, 'getcode'):
+            return compat_urllib_request.addinfourl(stream, headers, url, code)
+        ret = compat_urllib_request.addinfourl(stream, headers, url)
+        ret.code = code
+        return ret
+
+    def http_request(self, req):
+        for h,v in std_headers.items():
+            if h in req.headers:
+                del req.headers[h]
+            req.add_header(h, v)
+        if 'Youtubedl-no-compression' in req.headers:
+            if 'Accept-encoding' in req.headers:
+                del req.headers['Accept-encoding']
+            del req.headers['Youtubedl-no-compression']
+        if 'Youtubedl-user-agent' in req.headers:
+            if 'User-agent' in req.headers:
+                del req.headers['User-agent']
+            req.headers['User-agent'] = req.headers['Youtubedl-user-agent']
+            del req.headers['Youtubedl-user-agent']
+        return req
+
+    def http_response(self, req, resp):
+        old_resp = resp
+        # gzip
+        if resp.headers.get('Content-encoding', '') == 'gzip':
+            content = resp.read()
+            gz = gzip.GzipFile(fileobj=io.BytesIO(content), mode='rb')
+            try:
+                uncompressed = io.BytesIO(gz.read())
+            except IOError as original_ioerror:
+                # There may be junk add the end of the file
+                # See http://stackoverflow.com/q/4928560/35070 for details
+                for i in range(1, 1024):
+                    try:
+                        gz = gzip.GzipFile(fileobj=io.BytesIO(content[:-i]), mode='rb')
+                        uncompressed = io.BytesIO(gz.read())
+                    except IOError:
+                        continue
+                    break
+                else:
+                    raise original_ioerror
+            resp = self.addinfourl_wrapper(uncompressed, old_resp.headers, old_resp.url, old_resp.code)
+            resp.msg = old_resp.msg
+        # deflate
+        if resp.headers.get('Content-encoding', '') == 'deflate':
+            gz = io.BytesIO(self.deflate(resp.read()))
+            resp = self.addinfourl_wrapper(gz, old_resp.headers, old_resp.url, old_resp.code)
+            resp.msg = old_resp.msg
+        return resp
+
+    https_request = http_request
+    https_response = http_response
+
+
+def unified_strdate(date_str):
+    """Return a string with the date in the format YYYYMMDD"""
+    upload_date = None
+    #Replace commas
+    date_str = date_str.replace(',', ' ')
+    # %z (UTC offset) is only supported in python>=3.2
+    date_str = re.sub(r' ?(\+|-)[0-9]{2}:?[0-9]{2}$', '', date_str)
+    format_expressions = [
+        '%d %B %Y',
+        '%d %b %Y',
+        '%B %d %Y',
+        '%b %d %Y',
+        '%Y-%m-%d',
+        '%d/%m/%Y',
+        '%Y/%m/%d %H:%M:%S',
+        '%Y-%m-%d %H:%M:%S',
+        '%d.%m.%Y %H:%M',
+        '%Y-%m-%dT%H:%M:%SZ',
+        '%Y-%m-%dT%H:%M:%S.%fZ',
+        '%Y-%m-%dT%H:%M:%S.%f0Z',
+        '%Y-%m-%dT%H:%M:%S',
+        '%Y-%m-%dT%H:%M',
+    ]
+    for expression in format_expressions:
+        try:
+            upload_date = datetime.datetime.strptime(date_str, expression).strftime('%Y%m%d')
+        except ValueError:
+            pass
+    if upload_date is None:
+        timetuple = email.utils.parsedate_tz(date_str)
+        if timetuple:
+            upload_date = datetime.datetime(*timetuple[:6]).strftime('%Y%m%d')
+    return upload_date
+
+def determine_ext(url, default_ext=u'unknown_video'):
+    guess = url.partition(u'?')[0].rpartition(u'.')[2]
+    if re.match(r'^[A-Za-z0-9]+$', guess):
+        return guess
+    else:
+        return default_ext
+
+def subtitles_filename(filename, sub_lang, sub_format):
+    return filename.rsplit('.', 1)[0] + u'.' + sub_lang + u'.' + sub_format
+
+def date_from_str(date_str):
+    """
+    Return a datetime object from a string in the format YYYYMMDD or
+    (now|today)[+-][0-9](day|week|month|year)(s)?"""
+    today = datetime.date.today()
+    if date_str == 'now'or date_str == 'today':
+        return today
+    match = re.match('(now|today)(?P<sign>[+-])(?P<time>\d+)(?P<unit>day|week|month|year)(s)?', date_str)
+    if match is not None:
+        sign = match.group('sign')
+        time = int(match.group('time'))
+        if sign == '-':
+            time = -time
+        unit = match.group('unit')
+        #A bad aproximation?
+        if unit == 'month':
+            unit = 'day'
+            time *= 30
+        elif unit == 'year':
+            unit = 'day'
+            time *= 365
+        unit += 's'
+        delta = datetime.timedelta(**{unit: time})
+        return today + delta
+    return datetime.datetime.strptime(date_str, "%Y%m%d").date()
+    
+def hyphenate_date(date_str):
+    """
+    Convert a date in 'YYYYMMDD' format to 'YYYY-MM-DD' format"""
+    match = re.match(r'^(\d\d\d\d)(\d\d)(\d\d)$', date_str)
+    if match is not None:
+        return '-'.join(match.groups())
+    else:
+        return date_str
+
+class DateRange(object):
+    """Represents a time interval between two dates"""
+    def __init__(self, start=None, end=None):
+        """start and end must be strings in the format accepted by date"""
+        if start is not None:
+            self.start = date_from_str(start)
+        else:
+            self.start = datetime.datetime.min.date()
+        if end is not None:
+            self.end = date_from_str(end)
+        else:
+            self.end = datetime.datetime.max.date()
+        if self.start > self.end:
+            raise ValueError('Date range: "%s" , the start date must be before the end date' % self)
+    @classmethod
+    def day(cls, day):
+        """Returns a range that only contains the given day"""
+        return cls(day,day)
+    def __contains__(self, date):
+        """Check if the date is in the range"""
+        if not isinstance(date, datetime.date):
+            date = date_from_str(date)
+        return self.start <= date <= self.end
+    def __str__(self):
+        return '%s - %s' % ( self.start.isoformat(), self.end.isoformat())
+
+
+def platform_name():
+    """ Returns the platform name as a compat_str """
+    res = platform.platform()
+    if isinstance(res, bytes):
+        res = res.decode(preferredencoding())
+
+    assert isinstance(res, compat_str)
+    return res
+
+
+def write_string(s, out=None):
+    if out is None:
+        out = sys.stderr
+    assert type(s) == compat_str
+
+    if ('b' in getattr(out, 'mode', '') or
+            sys.version_info[0] < 3):  # Python 2 lies about mode of sys.stderr
+        s = s.encode(preferredencoding(), 'ignore')
+    try:
+        out.write(s)
+    except UnicodeEncodeError:
+        # In Windows shells, this can fail even when the codec is just charmap!?
+        # See https://wiki.python.org/moin/PrintFails#Issue
+        if sys.platform == 'win32' and hasattr(out, 'encoding'):
+            s = s.encode(out.encoding, 'ignore').decode(out.encoding)
+            out.write(s)
+        else:
+            raise
+
+    out.flush()
+
+
+def bytes_to_intlist(bs):
+    if not bs:
+        return []
+    if isinstance(bs[0], int):  # Python 3
+        return list(bs)
+    else:
+        return [ord(c) for c in bs]
+
+
+def intlist_to_bytes(xs):
+    if not xs:
+        return b''
+    if isinstance(chr(0), bytes):  # Python 2
+        return ''.join([chr(x) for x in xs])
+    else:
+        return bytes(xs)
+
+
+def get_cachedir(params={}):
+    cache_root = os.environ.get('XDG_CACHE_HOME',
+                                os.path.expanduser('~/.cache'))
+    return params.get('cachedir', os.path.join(cache_root, 'youtube-dl'))
+
+
+# Cross-platform file locking
+if sys.platform == 'win32':
+    import ctypes.wintypes
+    import msvcrt
+
+    class OVERLAPPED(ctypes.Structure):
+        _fields_ = [
+            ('Internal', ctypes.wintypes.LPVOID),
+            ('InternalHigh', ctypes.wintypes.LPVOID),
+            ('Offset', ctypes.wintypes.DWORD),
+            ('OffsetHigh', ctypes.wintypes.DWORD),
+            ('hEvent', ctypes.wintypes.HANDLE),
+        ]
+
+    kernel32 = ctypes.windll.kernel32
+    LockFileEx = kernel32.LockFileEx
+    LockFileEx.argtypes = [
+        ctypes.wintypes.HANDLE,     # hFile
+        ctypes.wintypes.DWORD,      # dwFlags
+        ctypes.wintypes.DWORD,      # dwReserved
+        ctypes.wintypes.DWORD,      # nNumberOfBytesToLockLow
+        ctypes.wintypes.DWORD,      # nNumberOfBytesToLockHigh
+        ctypes.POINTER(OVERLAPPED)  # Overlapped
+    ]
+    LockFileEx.restype = ctypes.wintypes.BOOL
+    UnlockFileEx = kernel32.UnlockFileEx
+    UnlockFileEx.argtypes = [
+        ctypes.wintypes.HANDLE,     # hFile
+        ctypes.wintypes.DWORD,      # dwReserved
+        ctypes.wintypes.DWORD,      # nNumberOfBytesToLockLow
+        ctypes.wintypes.DWORD,      # nNumberOfBytesToLockHigh
+        ctypes.POINTER(OVERLAPPED)  # Overlapped
+    ]
+    UnlockFileEx.restype = ctypes.wintypes.BOOL
+    whole_low = 0xffffffff
+    whole_high = 0x7fffffff
+
+    def _lock_file(f, exclusive):
+        overlapped = OVERLAPPED()
+        overlapped.Offset = 0
+        overlapped.OffsetHigh = 0
+        overlapped.hEvent = 0
+        f._lock_file_overlapped_p = ctypes.pointer(overlapped)
+        handle = msvcrt.get_osfhandle(f.fileno())
+        if not LockFileEx(handle, 0x2 if exclusive else 0x0, 0,
+                          whole_low, whole_high, f._lock_file_overlapped_p):
+            raise OSError('Locking file failed: %r' % ctypes.FormatError())
+
+    def _unlock_file(f):
+        assert f._lock_file_overlapped_p
+        handle = msvcrt.get_osfhandle(f.fileno())
+        if not UnlockFileEx(handle, 0,
+                            whole_low, whole_high, f._lock_file_overlapped_p):
+            raise OSError('Unlocking file failed: %r' % ctypes.FormatError())
+
+else:
+    import fcntl
+
+    def _lock_file(f, exclusive):
+        fcntl.lockf(f, fcntl.LOCK_EX if exclusive else fcntl.LOCK_SH)
+
+    def _unlock_file(f):
+        fcntl.lockf(f, fcntl.LOCK_UN)
+
+
+class locked_file(object):
+    def __init__(self, filename, mode, encoding=None):
+        assert mode in ['r', 'a', 'w']
+        self.f = io.open(filename, mode, encoding=encoding)
+        self.mode = mode
+
+    def __enter__(self):
+        exclusive = self.mode != 'r'
+        try:
+            _lock_file(self.f, exclusive)
+        except IOError:
+            self.f.close()
+            raise
+        return self
+
+    def __exit__(self, etype, value, traceback):
+        try:
+            _unlock_file(self.f)
+        finally:
+            self.f.close()
+
+    def __iter__(self):
+        return iter(self.f)
+
+    def write(self, *args):
+        return self.f.write(*args)
+
+    def read(self, *args):
+        return self.f.read(*args)
+
+
+def shell_quote(args):
+    quoted_args = []
+    encoding = sys.getfilesystemencoding()
+    if encoding is None:
+        encoding = 'utf-8'
+    for a in args:
+        if isinstance(a, bytes):
+            # We may get a filename encoded with 'encodeFilename'
+            a = a.decode(encoding)
+        quoted_args.append(pipes.quote(a))
+    return u' '.join(quoted_args)
+
+
+def takewhile_inclusive(pred, seq):
+    """ Like itertools.takewhile, but include the latest evaluated element
+        (the first element so that Not pred(e)) """
+    for e in seq:
+        yield e
+        if not pred(e):
+            return
+
+
+def smuggle_url(url, data):
+    """ Pass additional data in a URL for internal use. """
+
+    sdata = compat_urllib_parse.urlencode(
+        {u'__youtubedl_smuggle': json.dumps(data)})
+    return url + u'#' + sdata
+
+
+def unsmuggle_url(smug_url, default=None):
+    if not '#__youtubedl_smuggle' in smug_url:
+        return smug_url, default
+    url, _, sdata = smug_url.rpartition(u'#')
+    jsond = compat_parse_qs(sdata)[u'__youtubedl_smuggle'][0]
+    data = json.loads(jsond)
+    return url, data
+
+
+def format_bytes(bytes):
+    if bytes is None:
+        return u'N/A'
+    if type(bytes) is str:
+        bytes = float(bytes)
+    if bytes == 0.0:
+        exponent = 0
+    else:
+        exponent = int(math.log(bytes, 1024.0))
+    suffix = [u'B', u'KiB', u'MiB', u'GiB', u'TiB', u'PiB', u'EiB', u'ZiB', u'YiB'][exponent]
+    converted = float(bytes) / float(1024 ** exponent)
+    return u'%.2f%s' % (converted, suffix)
+
+
+def str_to_int(int_str):
+    int_str = re.sub(r'[,\.]', u'', int_str)
+    return int(int_str)
+
+
+def get_term_width():
+    columns = os.environ.get('COLUMNS', None)
+    if columns:
+        return int(columns)
+
+    try:
+        sp = subprocess.Popen(
+            ['stty', 'size'],
+            stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        out, err = sp.communicate()
+        return int(out.split()[1])
+    except:
+        pass
+    return None
+
+
+def month_by_name(name):
+    """ Return the number of a month by (locale-independently) English name """
+
+    ENGLISH_NAMES = [
+        u'January', u'February', u'March', u'April', u'May', u'June',
+        u'July', u'August', u'September', u'October', u'November', u'December']
+    try:
+        return ENGLISH_NAMES.index(name) + 1
+    except ValueError:
+        return None
+
+
+def fix_xml_ampersands(xml_str):
+    """Replace all the '&' by '&amp;' in XML"""
+    return re.sub(
+        r'&(?!amp;|lt;|gt;|apos;|quot;|#x[0-9a-fA-F]{,4};|#[0-9]{,4};)',
+        u'&amp;',
+        xml_str)
+
+
+def setproctitle(title):
+    assert isinstance(title, compat_str)
+    try:
+        libc = ctypes.cdll.LoadLibrary("libc.so.6")
+    except OSError:
+        return
+    title = title
+    buf = ctypes.create_string_buffer(len(title) + 1)
+    buf.value = title.encode('utf-8')
+    try:
+        libc.prctl(15, ctypes.byref(buf), 0, 0, 0)
+    except AttributeError:
+        return  # Strange libc, just skip this
+
+
+def remove_start(s, start):
+    if s.startswith(start):
+        return s[len(start):]
+    return s
+
+
+def url_basename(url):
+    path = compat_urlparse.urlparse(url).path
+    return path.strip(u'/').split(u'/')[-1]
+
+
+class HEADRequest(compat_urllib_request.Request):
+    def get_method(self):
+        return "HEAD"
+
+
+def int_or_none(v, scale=1):
+    return v if v is None else (int(v) // scale)
+
+
+def parse_duration(s):
+    if s is None:
+        return None
+
+    m = re.match(
+        r'(?:(?:(?P<hours>[0-9]+)[:h])?(?P<mins>[0-9]+)[:m])?(?P<secs>[0-9]+)s?$', s)
+    if not m:
+        return None
+    res = int(m.group('secs'))
+    if m.group('mins'):
+        res += int(m.group('mins')) * 60
+        if m.group('hours'):
+            res += int(m.group('hours')) * 60 * 60
+    return res
+
+
+def prepend_extension(filename, ext):
+    name, real_ext = os.path.splitext(filename) 
+    return u'{0}.{1}{2}'.format(name, ext, real_ext)
+
+
+def check_executable(exe, args=[]):
+    """ Checks if the given binary is installed somewhere in PATH, and returns its name.
+    args can be a list of arguments for a short output (like -version) """
+    try:
+        subprocess.Popen([exe] + args, stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()
+    except OSError:
+        return False
+    return exe
+
+
+class PagedList(object):
+    def __init__(self, pagefunc, pagesize):
+        self._pagefunc = pagefunc
+        self._pagesize = pagesize
+
+    def __len__(self):
+        # This is only useful for tests
+        return len(self.getslice())
+
+    def getslice(self, start=0, end=None):
+        res = []
+        for pagenum in itertools.count(start // self._pagesize):
+            firstid = pagenum * self._pagesize
+            nextfirstid = pagenum * self._pagesize + self._pagesize
+            if start >= nextfirstid:
+                continue
+
+            page_results = list(self._pagefunc(pagenum))
+
+            startv = (
+                start % self._pagesize
+                if firstid <= start < nextfirstid
+                else 0)
+
+            endv = (
+                ((end - 1) % self._pagesize) + 1
+                if (end is not None and firstid <= end <= nextfirstid)
+                else None)
+
+            if startv != 0 or endv is not None:
+                page_results = page_results[startv:endv]
+            res.extend(page_results)
+
+            # A little optimization - if current page is not "full", ie. does
+            # not contain page_size videos then we can assume that this page
+            # is the last one - there are no more ids on further pages -
+            # i.e. no need to query again.
+            if len(page_results) + startv < self._pagesize:
+                break
+
+            # If we got the whole page, but the next page is not interesting,
+            # break out early as well
+            if end == nextfirstid:
+                break
+        return res
+
+
+def uppercase_escape(s):
+    return re.sub(
+        r'\\U([0-9a-fA-F]{8})',
+        lambda m: compat_chr(int(m.group(1), base=16)), s)
+
+try:
+    struct.pack(u'!I', 0)
+except TypeError:
+    # In Python 2.6 (and some 2.7 versions), struct requires a bytes argument
+    def struct_pack(spec, *args):
+        if isinstance(spec, compat_str):
+            spec = spec.encode('ascii')
+        return struct.pack(spec, *args)
+
+    def struct_unpack(spec, *args):
+        if isinstance(spec, compat_str):
+            spec = spec.encode('ascii')
+        return struct.unpack(spec, *args)
+else:
+    struct_pack = struct.pack
+    struct_unpack = struct.unpack