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"""
This file is part of notmuch.
Notmuch is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
Notmuch is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with notmuch. If not, see <http://www.gnu.org/licenses/>.
Copyright 2010 Sebastian Spaeth <Sebastian@SSpaeth.de>
"""
from .globals import (
nmlib,
Python3StringMixIn,
NotmuchThreadP,
NotmuchThreadsP,
)
from .errors import (
NullPointerError,
NotInitializedError,
)
from .thread import Thread
class Threads(Python3StringMixIn):
"""Represents a list of notmuch threads
This object provides an iterator over a list of notmuch threads
(Technically, it provides a wrapper for the underlying
*notmuch_threads_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 threads, and a subsequent iteration attempt
will raise a :exc:`NotInitializedError`. Also
note, that any function that uses iteration will also
exhaust the messages. So both::
for thread in threads: print thread
as well as::
number_of_msgs = len(threads)
will "exhaust" the threads. If you need to re-iterate over a list of
messages you will need to retrieve a new :class:`Threads` object.
Things are not as bad as it seems though, you can store and reuse
the single Thread objects as often as you want as long as you
keep the parent Threads object around. (Recall that due to
hierarchical memory allocation, all derived Threads objects will
be invalid when we delete the parent Threads() object, even if it
was already "exhausted".) So this works::
db = Database()
threads = Query(db,'').search_threads() #get a Threads() object
threadlist = []
for thread in threads:
threadlist.append(thread)
# threads is "exhausted" now and even len(threads) will raise an
# exception.
# However it will be kept around until all retrieved Thread() objects are
# also deleted. If you did e.g. an explicit del(threads) here, the
# following lines would fail.
# You can reiterate over *threadlist* however as often as you want.
# It is simply a list with Thread objects.
print (threadlist[0].get_thread_id())
print (threadlist[1].get_thread_id())
print (threadlist[0].get_total_messages())
"""
#notmuch_threads_get
_get = nmlib.notmuch_threads_get
_get.argtypes = [NotmuchThreadsP]
_get.restype = NotmuchThreadP
def __init__(self, threads_p, parent=None):
"""
:param threads_p: A pointer to an underlying *notmuch_threads_t*
structure. These are not publically exposed, so a user
will almost never instantiate a :class:`Threads` object
herself. They are usually handed back as a result,
e.g. in :meth:`Query.search_threads`. *threads_p* must be
valid, we will raise an :exc:`NullPointerError` if it is
`None`.
:type threads_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 not threads_p:
raise NullPointerError()
self._threads = threads_p
#store parent, so we keep them alive as long as self is alive
self._parent = parent
def __iter__(self):
""" Make Threads an iterator """
return self
_valid = nmlib.notmuch_threads_valid
_valid.argtypes = [NotmuchThreadsP]
_valid.restype = bool
_move_to_next = nmlib.notmuch_threads_move_to_next
_move_to_next.argtypes = [NotmuchThreadsP]
_move_to_next.restype = None
def __next__(self):
if not self._threads:
raise NotInitializedError()
if not self._valid(self._threads):
self._threads = None
raise StopIteration
thread = Thread(Threads._get(self._threads), self)
self._move_to_next(self._threads)
return thread
next = __next__ # python2.x iterator protocol compatibility
def __len__(self):
"""len(:class:`Threads`) returns the number of contained Threads
.. note:: As this iterates over the threads, we will not be able to
iterate over them again! So this will fail::
#THIS FAILS
threads = Database().create_query('').search_threads()
if len(threads) > 0: #this 'exhausts' threads
# next line raises :exc:`NotInitializedError`!!!
for thread in threads: print thread
"""
if not self._threads:
raise NotInitializedError()
i = 0
# returns 'bool'. On out-of-memory it returns None
while self._valid(self._threads):
self._move_to_next(self._threads)
i += 1
# reset self._threads to mark as "exhausted"
self._threads = None
return i
def __nonzero__(self):
'''
Implement truth value testing. If __nonzero__ is not
implemented, the python runtime would fall back to `len(..) >
0` thus exhausting the iterator.
:returns: True if the wrapped iterator has at least one more object
left.
'''
return self._threads and self._valid(self._threads)
_destroy = nmlib.notmuch_threads_destroy
_destroy.argtypes = [NotmuchThreadsP]
_destroy.restype = None
def __del__(self):
"""Close and free the notmuch Threads"""
if self._threads:
self._destroy(self._threads)
|
