def add_file(self, filename, patch_name=None, ignore=False):
""" Add file to the patch with patch_name.
If patch_name is None or empty the topmost patch will be used.
Adding an already added patch will raise an QuiltError if ignore is
False.
"""
file = File(filename)
if patch_name:
patch = Patch(patch_name)
else:
patch = self.db.top_patch()
if not patch:
raise NoAppliedPatch(self.db)
exists = self._file_in_patch(filename, patch, ignore)
if exists:
return
self._file_in_next_patches(filename, patch)
if file.is_link():
raise QuiltError("Cannot add symbolic link %s" % filename)
self._backup_file(file, patch)
if file.exists():
# be sure user can write original file
os.chmod(filename, file.get_mode() | stat.S_IWUSR | stat.S_IRUSR)
self.file_added(file, patch)
