Bug 26458

Currently there are already two functions for creating the $XDG_CONFIG_HOME and $XDG_DATA_HOME directories: xdg.BaseDirectory.save_config_path(*resource) and xdg.BaseDirectory.save_data_path(*resource).
However, despite that fact that people often purge their cache and the fact that the cache should be easy to use as well there is no xdg.BaseDirectory.save_cache_path() function.

I would suggest to add one to make the life of the developers easier.

The function would like this:

def save_cache_path(*resource):
    """Ensure $XDG_CACHE_HOME/<resource>/ exists, and return its path.
    'resource' is the name of some shared resource. Use this when updating
    a shared (between programs) database. Use the xdg_cache_home variable
    for loading."""
    resource = os.path.join(*resource)
    assert not resource.startswith('/')
    path = os.path.join(xdg_cache_home, resource)
    if not os.path.isdir(path):
        os.makedirs(path)
    return path