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 nmlib, STATUS, NotmuchError, NotmuchTagsP
24 """Represents a list of notmuch tags
26 This object provides an iterator over a list of notmuch tags (which
27 are unicode instances).
29 Do note that the underlying library only provides a one-time
30 iterator (it cannot reset the iterator to the start). Thus iterating
31 over the function will "exhaust" the list of tags, and a subsequent
32 iteration attempt will raise a :exc:`NotmuchError`
33 STATUS.NOT_INITIALIZED. Also note, that any function that uses
34 iteration (nearly all) will also exhaust the tags. So both::
36 for tag in tags: print tag
40 number_of_tags = len(tags)
44 #str() iterates over all tags to construct a space separated list
47 will "exhaust" the Tags. If you need to re-iterate over a list of
48 tags you will need to retrieve a new :class:`Tags` object.
52 _get = nmlib.notmuch_tags_get
53 _get.argtypes = [NotmuchTagsP]
54 _get.restype = c_char_p
56 def __init__(self, tags_p, parent=None):
58 :param tags_p: A pointer to an underlying *notmuch_tags_t*
59 structure. These are not publically exposed, so a user
60 will almost never instantiate a :class:`Tags` object
61 herself. They are usually handed back as a result,
62 e.g. in :meth:`Database.get_all_tags`. *tags_p* must be
63 valid, we will raise an :exc:`NotmuchError`
64 (STATUS.NULL_POINTER) if it is `None`.
65 :type tags_p: :class:`ctypes.c_void_p`
66 :param parent: The parent object (ie :class:`Database` or
67 :class:`Message` these tags are derived from, and saves a
68 reference to it, so we can automatically delete the db object
69 once all derived objects are dead.
70 :TODO: Make the iterator optionally work more than once by
71 cache the tags in the Python object(?)
74 raise NotmuchError(STATUS.NULL_POINTER)
77 #save reference to parent object so we keep it alive
81 """ Make Tags an iterator """
84 _valid = nmlib.notmuch_tags_valid
85 _valid.argtypes = [NotmuchTagsP]
88 _move_to_next = nmlib.notmuch_tags_move_to_next
89 _move_to_next.argtypes = [NotmuchTagsP]
90 _move_to_next.restype = None
93 if self._tags is None:
94 raise NotmuchError(STATUS.NOT_INITIALIZED)
95 if not self._valid(self._tags):
98 tag = Tags._get(self._tags).decode('UTF-8')
99 self._move_to_next(self._tags)
102 def __nonzero__(self):
103 """Implement bool(Tags) check that can be repeatedly used
105 If __nonzero__ is not implemented, "if Tags()"
106 will implicitly call __len__, using up our iterator, so it is
107 important that this function is defined.
109 :returns: True if the Tags() iterator has at least one more Tag
111 return self._valid(self._tags) > 0
114 return unicode(self).encode('utf-8')
116 def __unicode__(self):
117 """string representation of :class:`Tags`: a space separated list of tags
121 As this iterates over the tags, we will not be able to iterate over
122 them again (as in retrieve them)! If the tags have been exhausted
123 already, this will raise a :exc:`NotmuchError`
124 STATUS.NOT_INITIALIZED on subsequent attempts.
126 return " ".join(self)
128 _destroy = nmlib.notmuch_tags_destroy
129 _destroy.argtypes = [NotmuchTagsP]
130 _destroy.restype = None
133 """Close and free the notmuch tags"""
134 if self._tags is not None:
135 self._destroy(self._tags)