-#------------------------------------------------------------------------------
-class Messages(object):
- """Represents a list of notmuch messages
-
- This object provides an iterator over a list of notmuch messages
- (Technically, it provides a wrapper for the underlying
- *notmuch_messages_t* structure). Do note that the underlying library
- only provides a one-time iterator (it cannot reset the iterator to
- the start). Thus iterating over the function will "exhaust" the list
- of messages, and a subsequent iteration attempt will raise a
- :exc:`NotmuchError` STATUS.NOT_INITIALIZED. If you need to
- re-iterate over a list of messages you will need to retrieve a new
- :class:`Messages` object or cache your :class:`Message`\s in a list
- via::
-
- msglist = list(msgs)
-
- You can store and reuse the single :class:`Message` objects as often
- as you want as long as you keep the parent :class:`Messages` object
- around. (Due to hierarchical memory allocation, all derived
- :class:`Message` objects will be invalid when we delete the parent
- :class:`Messages` object, even if it was already exhausted.) So
- this works::
-
- db = Database()
- msgs = Query(db,'').search_messages() #get a Messages() object
- msglist = list(msgs)
-
- # msgs is "exhausted" now and msgs.next() will raise an exception.
- # However it will be kept alive until all retrieved Message()
- # objects are also deleted. If you do e.g. an explicit del(msgs)
- # here, the following lines would fail.
-
- # You can reiterate over *msglist* however as often as you want.
- # It is simply a list with :class:`Message`s.
-
- print (msglist[0].get_filename())
- print (msglist[1].get_filename())
- print (msglist[0].get_message_id())
-
-
- As :class:`Message` implements both __hash__() and __cmp__(), it is
- possible to make sets out of :class:`Messages` and use set
- arithmetic (this happens in python and will of course be *much*
- slower than redoing a proper query with the appropriate filters::
-
- s1, s2 = set(msgs1), set(msgs2)
- s.union(s2)
- s1 -= s2
- ...
-
- Be careful when using set arithmetic between message sets derived
- from different Databases (ie the same database reopened after
- messages have changed). If messages have added or removed associated
- files in the meantime, it is possible that the same message would be
- considered as a different object (as it points to a different file).
- """
-
- #notmuch_messages_get
- _get = nmlib.notmuch_messages_get
- _get.restype = c_void_p
-
- _collect_tags = nmlib.notmuch_messages_collect_tags
- _collect_tags.restype = c_void_p
-
- def __init__(self, msgs_p, parent=None):
- """
- :param msgs_p: A pointer to an underlying *notmuch_messages_t*
- structure. These are not publically exposed, so a user
- will almost never instantiate a :class:`Messages` object
- herself. They are usually handed back as a result,
- e.g. in :meth:`Query.search_messages`. *msgs_p* must be
- valid, we will raise an :exc:`NotmuchError`
- (STATUS.NULL_POINTER) if it is `None`.
- :type msgs_p: :class:`ctypes.c_void_p`
- :param parent: The parent object
- (ie :class:`Query`) these tags are derived from. It saves
- a reference to it, so we can automatically delete the db
- object once all derived objects are dead.
- :TODO: Make the iterator work more than once and cache the tags in
- the Python object.(?)
- """
- if msgs_p is None:
- NotmuchError(STATUS.NULL_POINTER)
-
- self._msgs = msgs_p
- #store parent, so we keep them alive as long as self is alive
- self._parent = parent
-
- def collect_tags(self):
- """Return the unique :class:`Tags` in the contained messages
-
- :returns: :class:`Tags`
- :exceptions: :exc:`NotmuchError` STATUS.NOT_INITIALIZED if not inited
-
- .. note:: :meth:`collect_tags` will iterate over the messages and
- therefore will not allow further iterations.
- """
- if self._msgs is None:
- raise NotmuchError(STATUS.NOT_INITIALIZED)
-
- # collect all tags (returns NULL on error)
- tags_p = Messages._collect_tags (self._msgs)
- #reset _msgs as we iterated over it and can do so only once
- self._msgs = None
-
- if tags_p == None:
- raise NotmuchError(STATUS.NULL_POINTER)
- return Tags(tags_p, self)
-
- def __iter__(self):
- """ Make Messages an iterator """
- return self
-
- def next(self):
- if self._msgs is None:
- raise NotmuchError(STATUS.NOT_INITIALIZED)
projects / notmuch / blobdiff