2 This file is part of notmuch.
4 Notmuch is free software: you can redistribute it and/or modify it
5 under the terms of the GNU General Public License as published by the
6 Free Software Foundation, either version 3 of the License, or (at your
7 option) any later version.
9 Notmuch is distributed in the hope that it will be useful, but WITHOUT
10 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 You should have received a copy of the GNU General Public License
15 along with notmuch. If not, see <http://www.gnu.org/licenses/>.
17 Copyright 2010 Sebastian Spaeth <Sebastian@SSpaeth.de>'
19 from ctypes import c_char_p
20 from notmuch.globals import (
29 class Tags(Python3StringMixIn):
30 """Represents a list of notmuch tags
32 This object provides an iterator over a list of notmuch tags (which
33 are unicode instances).
35 Do note that the underlying library only provides a one-time
36 iterator (it cannot reset the iterator to the start). Thus iterating
37 over the function will "exhaust" the list of tags, and a subsequent
38 iteration attempt will raise a :exc:`NotInitializedError`.
39 Also note, that any function that uses iteration (nearly all) will
40 also exhaust the tags. So both::
42 for tag in tags: print tag
46 number_of_tags = len(tags)
50 #str() iterates over all tags to construct a space separated list
53 will "exhaust" the Tags. If you need to re-iterate over a list of
54 tags you will need to retrieve a new :class:`Tags` object.
58 _get = nmlib.notmuch_tags_get
59 _get.argtypes = [NotmuchTagsP]
60 _get.restype = c_char_p
62 def __init__(self, tags_p, parent=None):
64 :param tags_p: A pointer to an underlying *notmuch_tags_t*
65 structure. These are not publically exposed, so a user
66 will almost never instantiate a :class:`Tags` object
67 herself. They are usually handed back as a result,
68 e.g. in :meth:`Database.get_all_tags`. *tags_p* must be
69 valid, we will raise an :exc:`NullPointerError` if it is
71 :type tags_p: :class:`ctypes.c_void_p`
72 :param parent: The parent object (ie :class:`Database` or
73 :class:`Message` these tags are derived from, and saves a
74 reference to it, so we can automatically delete the db object
75 once all derived objects are dead.
76 :TODO: Make the iterator optionally work more than once by
77 cache the tags in the Python object(?)
80 raise NullPointerError()
83 #save reference to parent object so we keep it alive
87 """ Make Tags an iterator """
90 _valid = nmlib.notmuch_tags_valid
91 _valid.argtypes = [NotmuchTagsP]
94 _move_to_next = nmlib.notmuch_tags_move_to_next
95 _move_to_next.argtypes = [NotmuchTagsP]
96 _move_to_next.restype = None
100 raise NotInitializedError()
101 if not self._valid(self._tags):
104 tag = Tags._get(self._tags).decode('UTF-8')
105 self._move_to_next(self._tags)
107 next = __next__ # python2.x iterator protocol compatibility
109 def __nonzero__(self):
110 """Implement bool(Tags) check that can be repeatedly used
112 If __nonzero__ is not implemented, "if Tags()"
113 will implicitly call __len__, using up our iterator, so it is
114 important that this function is defined.
116 :returns: True if the Tags() iterator has at least one more Tag
118 return self._valid(self._tags) > 0
120 def __unicode__(self):
121 """string representation of :class:`Tags`: a space separated list of tags
125 As this iterates over the tags, we will not be able to iterate over
126 them again (as in retrieve them)! If the tags have been exhausted
127 already, this will raise a :exc:`NotInitializedError`on subsequent
130 return " ".join(self)
132 _destroy = nmlib.notmuch_tags_destroy
133 _destroy.argtypes = [NotmuchTagsP]
134 _destroy.restype = None
137 """Close and free the notmuch tags"""
138 if self._tags is not None:
139 self._destroy(self._tags)