+
+
+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):
+ return v if v is None else int(v)
+
+
+def parse_duration(s):
+ if s is None:
+ return None
+
+ m = re.match(
+ r'(?:(?:(?P<hours>[0-9]+):)?(?P<mins>[0-9]+):)?(?P<secs>[0-9]+)$', 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