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>'
22 from ctypes import c_char_p, c_void_p, c_uint, c_long, byref, POINTER
23 from notmuch.globals import (
38 from notmuch.message import Message
39 from notmuch.tag import Tags
40 from .query import Query
42 class Database(object):
43 """The :class:`Database` is the highest-level object that notmuch
44 provides. It references a notmuch database, and can be opened in
45 read-only or read-write mode. A :class:`Query` can be derived from
46 or be applied to a specific database to find messages. Also adding
47 and removing messages to the database happens via this
48 object. Modifications to the database are not atmic by default (see
49 :meth:`begin_atomic`) and once a database has been modified, all
50 other database objects pointing to the same data-base will throw an
51 :exc:`XapianError` as the underlying database has been
52 modified. Close and reopen the database to continue working with it.
54 :class:`Database` objects implement the context manager protocol
55 so you can use the :keyword:`with` statement to ensure that the
56 database is properly closed.
60 Any function in this class can and will throw an
61 :exc:`NotInitializedError` if the database was not intitialized
66 Do remember that as soon as we tear down (e.g. via `del db`) this
67 object, all underlying derived objects such as queries, threads,
68 messages, tags etc will be freed by the underlying library as well.
69 Accessing these objects will lead to segfaults and other unexpected
70 behavior. See above for more details.
73 """Class attribute to cache user's default database"""
75 MODE = Enum(['READ_ONLY', 'READ_WRITE'])
76 """Constants: Mode in which to open the database"""
78 """notmuch_database_get_directory"""
79 _get_directory = nmlib.notmuch_database_get_directory
80 _get_directory.argtypes = [NotmuchDatabaseP, c_char_p]
81 _get_directory.restype = NotmuchDirectoryP
83 """notmuch_database_get_path"""
84 _get_path = nmlib.notmuch_database_get_path
85 _get_path.argtypes = [NotmuchDatabaseP]
86 _get_path.restype = c_char_p
88 """notmuch_database_get_version"""
89 _get_version = nmlib.notmuch_database_get_version
90 _get_version.argtypes = [NotmuchDatabaseP]
91 _get_version.restype = c_uint
93 """notmuch_database_open"""
94 _open = nmlib.notmuch_database_open
95 _open.argtypes = [c_char_p, c_uint]
96 _open.restype = NotmuchDatabaseP
98 """notmuch_database_upgrade"""
99 _upgrade = nmlib.notmuch_database_upgrade
100 _upgrade.argtypes = [NotmuchDatabaseP, c_void_p, c_void_p]
101 _upgrade.restype = c_uint
103 """ notmuch_database_find_message"""
104 _find_message = nmlib.notmuch_database_find_message
105 _find_message.argtypes = [NotmuchDatabaseP, c_char_p,
106 POINTER(NotmuchMessageP)]
107 _find_message.restype = c_uint
109 """notmuch_database_find_message_by_filename"""
110 _find_message_by_filename = nmlib.notmuch_database_find_message_by_filename
111 _find_message_by_filename.argtypes = [NotmuchDatabaseP, c_char_p,
112 POINTER(NotmuchMessageP)]
113 _find_message_by_filename.restype = c_uint
115 """notmuch_database_get_all_tags"""
116 _get_all_tags = nmlib.notmuch_database_get_all_tags
117 _get_all_tags.argtypes = [NotmuchDatabaseP]
118 _get_all_tags.restype = NotmuchTagsP
120 """notmuch_database_create"""
121 _create = nmlib.notmuch_database_create
122 _create.argtypes = [c_char_p]
123 _create.restype = NotmuchDatabaseP
125 def __init__(self, path=None, create=False, mode=0):
126 """If *path* is `None`, we will try to read a users notmuch
127 configuration and use his configured database. The location of the
128 configuration file can be specified through the environment variable
129 *NOTMUCH_CONFIG*, falling back to the default `~/.notmuch-config`.
131 If *create* is `True`, the database will always be created in
132 :attr:`MODE`.READ_WRITE mode. Default mode for opening is READ_ONLY.
134 :param path: Directory to open/create the database in (see
135 above for behavior if `None`)
136 :type path: `str` or `None`
137 :param create: Pass `False` to open an existing, `True` to create a new
140 :param mode: Mode to open a database in. Is always
141 :attr:`MODE`.READ_WRITE when creating a new one.
142 :type mode: :attr:`MODE`
143 :raises: :exc:`NotmuchError` or derived exception in case of
148 # no path specified. use a user's default database
149 if Database._std_db_path is None:
150 #the following line throws a NotmuchError if it fails
151 Database._std_db_path = self._get_user_default_db()
152 path = Database._std_db_path
155 self.open(path, mode)
162 def _assert_db_is_initialized(self):
163 """Raises :exc:`NotInitializedError` if self._db is `None`"""
165 raise NotInitializedError()
167 def create(self, path):
168 """Creates a new notmuch database
170 This function is used by __init__() and usually does not need
171 to be called directly. It wraps the underlying
172 *notmuch_database_create* function and creates a new notmuch
173 database at *path*. It will always return a database in :attr:`MODE`
174 .READ_WRITE mode as creating an empty database for
175 reading only does not make a great deal of sense.
177 :param path: A directory in which we should create the database.
179 :raises: :exc:`NotmuchError` in case of any failure
180 (possibly after printing an error message on stderr).
182 if self._db is not None:
183 raise NotmuchError(message="Cannot create db, this Database() "
184 "already has an open one.")
186 res = Database._create(_str(path), Database.MODE.READ_WRITE)
190 message="Could not create the specified database")
193 def open(self, path, mode=0):
194 """Opens an existing database
196 This function is used by __init__() and usually does not need
197 to be called directly. It wraps the underlying
198 *notmuch_database_open* function.
200 :param status: Open the database in read-only or read-write mode
201 :type status: :attr:`MODE`
202 :raises: Raises :exc:`NotmuchError` in case of any failure
203 (possibly after printing an error message on stderr).
205 res = Database._open(_str(path), mode)
208 raise NotmuchError(message="Could not open the specified database")
211 _close = nmlib.notmuch_database_close
212 _close.argtypes = [NotmuchDatabaseP]
213 _close.restype = None
216 """Close and free the notmuch database if needed"""
217 if self._db is not None:
218 self._close(self._db)
223 Implements the context manager protocol.
227 def __exit__(self, exc_type, exc_value, traceback):
229 Implements the context manager protocol.
234 """Returns the file path of an open database"""
235 self._assert_db_is_initialized()
236 return Database._get_path(self._db).decode('utf-8')
238 def get_version(self):
239 """Returns the database format version
241 :returns: The database version as positive integer
243 self._assert_db_is_initialized()
244 return Database._get_version(self._db)
246 _needs_upgrade = nmlib.notmuch_database_needs_upgrade
247 _needs_upgrade.argtypes = [NotmuchDatabaseP]
248 _needs_upgrade.restype = bool
250 def needs_upgrade(self):
251 """Does this database need to be upgraded before writing to it?
253 If this function returns `True` then no functions that modify the
254 database (:meth:`add_message`,
255 :meth:`Message.add_tag`, :meth:`Directory.set_mtime`,
256 etc.) will work unless :meth:`upgrade` is called successfully first.
258 :returns: `True` or `False`
260 self._assert_db_is_initialized()
261 return self._needs_upgrade(self._db)
264 """Upgrades the current database
266 After opening a database in read-write mode, the client should
267 check if an upgrade is needed (notmuch_database_needs_upgrade) and
268 if so, upgrade with this function before making any modifications.
270 NOT IMPLEMENTED: The optional progress_notify callback can be
271 used by the caller to provide progress indication to the
272 user. If non-NULL it will be called periodically with
273 'progress' as a floating-point value in the range of [0.0..1.0]
274 indicating the progress made so far in the upgrade process.
276 :TODO: catch exceptions, document return values and etc...
278 self._assert_db_is_initialized()
279 status = Database._upgrade(self._db, None, None)
280 #TODO: catch exceptions, document return values and etc
283 _begin_atomic = nmlib.notmuch_database_begin_atomic
284 _begin_atomic.argtypes = [NotmuchDatabaseP]
285 _begin_atomic.restype = c_uint
287 def begin_atomic(self):
288 """Begin an atomic database operation
290 Any modifications performed between a successful
291 :meth:`begin_atomic` and a :meth:`end_atomic` will be applied to
292 the database atomically. Note that, unlike a typical database
293 transaction, this only ensures atomicity, not durability;
294 neither begin nor end necessarily flush modifications to disk.
296 :returns: :attr:`STATUS`.SUCCESS or raises
297 :raises: :exc:`NotmuchError`: :attr:`STATUS`.XAPIAN_EXCEPTION
298 Xapian exception occurred; atomic section not entered.
300 *Added in notmuch 0.9*"""
301 self._assert_db_is_initialized()
302 status = self._begin_atomic(self._db)
303 if status != STATUS.SUCCESS:
304 raise NotmuchError(status)
307 _end_atomic = nmlib.notmuch_database_end_atomic
308 _end_atomic.argtypes = [NotmuchDatabaseP]
309 _end_atomic.restype = c_uint
311 def end_atomic(self):
312 """Indicate the end of an atomic database operation
314 See :meth:`begin_atomic` for details.
316 :returns: :attr:`STATUS`.SUCCESS or raises
320 :attr:`STATUS`.XAPIAN_EXCEPTION
321 A Xapian exception occurred; atomic section not
323 :attr:`STATUS`.UNBALANCED_ATOMIC:
324 end_atomic has been called more times than begin_atomic.
326 *Added in notmuch 0.9*"""
327 self._assert_db_is_initialized()
328 status = self._end_atomic(self._db)
329 if status != STATUS.SUCCESS:
330 raise NotmuchError(status)
333 def get_directory(self, path):
334 """Returns a :class:`Directory` of path,
335 (creating it if it does not exist(?))
339 This call needs a writeable database in
340 :attr:`Database.MODE`.READ_WRITE mode. The underlying library will
341 exit the program if this method is used on a read-only database!
343 :param path: An unicode string containing the path relative to the path
344 of database (see :meth:`get_path`), or else should be an absolute
345 path with initial components that match the path of 'database'.
346 :returns: :class:`Directory` or raises an exception.
348 :exc:`NotmuchError` with :attr:`STATUS`.FILE_ERROR
349 If path is not relative database or absolute with initial
350 components same as database.
352 self._assert_db_is_initialized()
353 # sanity checking if path is valid, and make path absolute
354 if path[0] == os.sep:
355 # we got an absolute path
356 if not path.startswith(self.get_path()):
357 # but its initial components are not equal to the db path
358 raise FileError('Database().get_directory() called '
359 'with a wrong absolute path')
362 #we got a relative path, make it absolute
363 abs_dirpath = os.path.abspath(os.path.join(self.get_path(), path))
365 dir_p = Database._get_directory(self._db, _str(path))
367 # return the Directory, init it with the absolute path
368 return Directory(_str(abs_dirpath), dir_p, self)
370 _add_message = nmlib.notmuch_database_add_message
371 _add_message.argtypes = [NotmuchDatabaseP, c_char_p,
372 POINTER(NotmuchMessageP)]
373 _add_message.restype = c_uint
375 def add_message(self, filename, sync_maildir_flags=False):
376 """Adds a new message to the database
378 :param filename: should be a path relative to the path of the
379 open database (see :meth:`get_path`), or else should be an
380 absolute filename with initial components that match the
381 path of the database.
383 The file should be a single mail message (not a
384 multi-message mbox) that is expected to remain at its
385 current location, since the notmuch database will reference
386 the filename, and will not copy the entire contents of the
389 :param sync_maildir_flags: If the message contains Maildir
390 flags, we will -depending on the notmuch configuration- sync
391 those tags to initial notmuch tags, if set to `True`. It is
392 `False` by default to remain consistent with the libnotmuch
393 API. You might want to look into the underlying method
394 :meth:`Message.maildir_flags_to_tags`.
396 :returns: On success, we return
398 1) a :class:`Message` object that can be used for things
399 such as adding tags to the just-added message.
400 2) one of the following :attr:`STATUS` values:
402 :attr:`STATUS`.SUCCESS
403 Message successfully added to database.
404 :attr:`STATUS`.DUPLICATE_MESSAGE_ID
405 Message has the same message ID as another message already
406 in the database. The new filename was successfully added
407 to the list of the filenames for the existing message.
409 :rtype: 2-tuple(:class:`Message`, :attr:`STATUS`)
411 :raises: Raises a :exc:`NotmuchError` with the following meaning.
412 If such an exception occurs, nothing was added to the database.
414 :attr:`STATUS`.FILE_ERROR
415 An error occurred trying to open the file, (such as
416 permission denied, or file not found, etc.).
417 :attr:`STATUS`.FILE_NOT_EMAIL
418 The contents of filename don't look like an email
420 :attr:`STATUS`.READ_ONLY_DATABASE
421 Database was opened in read-only mode so no message can
424 self._assert_db_is_initialized()
425 msg_p = NotmuchMessageP()
426 status = self._add_message(self._db, _str(filename), byref(msg_p))
428 if not status in [STATUS.SUCCESS, STATUS.DUPLICATE_MESSAGE_ID]:
429 raise NotmuchError(status)
431 #construct Message() and return
432 msg = Message(msg_p, self)
433 #automatic sync initial tags from Maildir flags
434 if sync_maildir_flags:
435 msg.maildir_flags_to_tags()
438 _remove_message = nmlib.notmuch_database_remove_message
439 _remove_message.argtypes = [NotmuchDatabaseP, c_char_p]
440 _remove_message.restype = c_uint
442 def remove_message(self, filename):
443 """Removes a message (filename) from the given notmuch database
445 Note that only this particular filename association is removed from
446 the database. If the same message (as determined by the message ID)
447 is still available via other filenames, then the message will
448 persist in the database for those filenames. When the last filename
449 is removed for a particular message, the database content for that
450 message will be entirely removed.
452 :returns: A :attr:`STATUS` value with the following meaning:
454 :attr:`STATUS`.SUCCESS
455 The last filename was removed and the message was removed
457 :attr:`STATUS`.DUPLICATE_MESSAGE_ID
458 This filename was removed but the message persists in the
459 database with at least one other filename.
461 :raises: Raises a :exc:`NotmuchError` with the following meaning.
462 If such an exception occurs, nothing was removed from the
465 :attr:`STATUS`.READ_ONLY_DATABASE
466 Database was opened in read-only mode so no message can be
469 self._assert_db_is_initialized()
470 return self._remove_message(self._db, _str(filename))
472 def find_message(self, msgid):
473 """Returns a :class:`Message` as identified by its message ID
475 Wraps the underlying *notmuch_database_find_message* function.
477 :param msgid: The message ID
478 :type msgid: unicode or str
479 :returns: :class:`Message` or `None` if no message is found.
481 :exc:`OutOfMemoryError`
482 If an Out-of-memory occured while constructing the message.
484 In case of a Xapian Exception. These exceptions
485 include "Database modified" situations, e.g. when the
486 notmuch database has been modified by another program
487 in the meantime. In this case, you should close and
488 reopen the database and retry.
489 :exc:`NotInitializedError` if
490 the database was not intitialized.
492 self._assert_db_is_initialized()
493 msg_p = NotmuchMessageP()
494 status = Database._find_message(self._db, _str(msgid), byref(msg_p))
495 if status != STATUS.SUCCESS:
496 raise NotmuchError(status)
497 return msg_p and Message(msg_p, self) or None
499 def find_message_by_filename(self, filename):
500 """Find a message with the given filename
504 This call needs a writeable database in
505 :attr:`Database.MODE`.READ_WRITE mode. The underlying library will
506 exit the program if this method is used on a read-only database!
508 :returns: If the database contains a message with the given
509 filename, then a class:`Message:` is returned. This
510 function returns None if no message is found with the given
514 :exc:`OutOfMemoryError`
515 If an Out-of-memory occured while constructing the message.
517 In case of a Xapian Exception. These exceptions
518 include "Database modified" situations, e.g. when the
519 notmuch database has been modified by another program
520 in the meantime. In this case, you should close and
521 reopen the database and retry.
522 :exc:`NotInitializedError` if
523 the database was not intitialized.
525 *Added in notmuch 0.9*"""
526 self._assert_db_is_initialized()
527 msg_p = NotmuchMessageP()
528 status = Database._find_message_by_filename(self._db, _str(filename),
530 if status != STATUS.SUCCESS:
531 raise NotmuchError(status)
532 return msg_p and Message(msg_p, self) or None
534 def get_all_tags(self):
535 """Returns :class:`Tags` with a list of all tags found in the database
537 :returns: :class:`Tags`
538 :execption: :exc:`NotmuchError` with :attr:`STATUS`.NULL_POINTER
541 self._assert_db_is_initialized()
542 tags_p = Database._get_all_tags(self._db)
544 raise NullPointerError()
545 return Tags(tags_p, self)
547 def create_query(self, querystring):
548 """Returns a :class:`Query` derived from this database
550 This is a shorthand method for doing::
553 # Automatically frees the Database() when 'q' is deleted
555 q = Database(dbpath).create_query('from:"Biene Maja"')
557 # long version, which is functionally equivalent but will keep the
558 # Database in the 'db' variable around after we delete 'q':
560 db = Database(dbpath)
561 q = Query(db,'from:"Biene Maja"')
563 This function is a python extension and not in the underlying C API.
565 return Query(self, querystring)
568 return "'Notmuch DB " + self.get_path() + "'"
570 def _get_user_default_db(self):
571 """ Reads a user's notmuch config and returns his db location
573 Throws a NotmuchError if it cannot find it"""
576 from configparser import SafeConfigParser
579 from ConfigParser import SafeConfigParser
581 config = SafeConfigParser()
582 conf_f = os.getenv('NOTMUCH_CONFIG',
583 os.path.expanduser('~/.notmuch-config'))
584 config.readfp(codecs.open(conf_f, 'r', 'utf-8'))
585 if not config.has_option('database', 'path'):
586 raise NotmuchError(message="No DB path specified"
587 " and no user default found")
588 return config.get('database', 'path')
592 """Property returning a pointer to `notmuch_database_t` or `None`
594 This should normally not be needed by a user (and is not yet
595 guaranteed to remain stable in future versions).
600 class Directory(object):
601 """Represents a directory entry in the notmuch directory
603 Modifying attributes of this object will modify the
604 database, not the real directory attributes.
606 The Directory object is usually derived from another object
607 e.g. via :meth:`Database.get_directory`, and will automatically be
608 become invalid whenever that parent is deleted. You should
609 therefore initialized this object handing it a reference to the
610 parent, preventing the parent from automatically being garbage
614 """notmuch_directory_get_mtime"""
615 _get_mtime = nmlib.notmuch_directory_get_mtime
616 _get_mtime.argtypes = [NotmuchDirectoryP]
617 _get_mtime.restype = c_long
619 """notmuch_directory_set_mtime"""
620 _set_mtime = nmlib.notmuch_directory_set_mtime
621 _set_mtime.argtypes = [NotmuchDirectoryP, c_long]
622 _set_mtime.restype = c_uint
624 """notmuch_directory_get_child_files"""
625 _get_child_files = nmlib.notmuch_directory_get_child_files
626 _get_child_files.argtypes = [NotmuchDirectoryP]
627 _get_child_files.restype = NotmuchFilenamesP
629 """notmuch_directory_get_child_directories"""
630 _get_child_directories = nmlib.notmuch_directory_get_child_directories
631 _get_child_directories.argtypes = [NotmuchDirectoryP]
632 _get_child_directories.restype = NotmuchFilenamesP
634 def _assert_dir_is_initialized(self):
635 """Raises a NotmuchError(:attr:`STATUS`.NOT_INITIALIZED)
638 raise NotInitializedError()
640 def __init__(self, path, dir_p, parent):
642 :param path: The absolute path of the directory object as unicode.
643 :param dir_p: The pointer to an internal notmuch_directory_t object.
644 :param parent: The object this Directory is derived from
645 (usually a :class:`Database`). We do not directly use
646 this, but store a reference to it as long as
647 this Directory object lives. This keeps the
650 assert isinstance(path, unicode), "Path needs to be an UNICODE object"
653 self._parent = parent
655 def set_mtime(self, mtime):
656 """Sets the mtime value of this directory in the database
658 The intention is for the caller to use the mtime to allow efficient
659 identification of new messages to be added to the database. The
660 recommended usage is as follows:
662 * Read the mtime of a directory from the filesystem
664 * Call :meth:`Database.add_message` for all mail files in
667 * Call notmuch_directory_set_mtime with the mtime read from the
668 filesystem. Then, when wanting to check for updates to the
669 directory in the future, the client can call :meth:`get_mtime`
670 and know that it only needs to add files if the mtime of the
671 directory and files are newer than the stored timestamp.
675 :meth:`get_mtime` function does not allow the caller to
676 distinguish a timestamp of 0 from a non-existent timestamp. So
677 don't store a timestamp of 0 unless you are comfortable with
680 :param mtime: A (time_t) timestamp
681 :raises: :exc:`XapianError` a Xapian exception occurred, mtime
683 :raises: :exc:`ReadOnlyDatabaseError` the database was opened
684 in read-only mode so directory mtime cannot be modified
685 :raises: :exc:`NotInitializedError` the directory object has not
688 self._assert_dir_is_initialized()
689 status = Directory._set_mtime(self._dir_p, mtime)
691 if status != STATUS.SUCCESS:
692 raise NotmuchError(status)
695 """Gets the mtime value of this directory in the database
697 Retrieves a previously stored mtime for this directory.
699 :param mtime: A (time_t) timestamp
700 :raises: :exc:`NotmuchError`:
702 :attr:`STATUS`.NOT_INITIALIZED
703 The directory has not been initialized
705 self._assert_dir_is_initialized()
706 return Directory._get_mtime(self._dir_p)
708 # Make mtime attribute a property of Directory()
709 mtime = property(get_mtime, set_mtime, doc="""Property that allows getting
710 and setting of the Directory *mtime* (read-write)
712 See :meth:`get_mtime` and :meth:`set_mtime` for usage and
713 possible exceptions.""")
715 def get_child_files(self):
716 """Gets a Filenames iterator listing all the filenames of
717 messages in the database within the given directory.
719 The returned filenames will be the basename-entries only (not
722 self._assert_dir_is_initialized()
723 files_p = Directory._get_child_files(self._dir_p)
724 return Filenames(files_p, self)
726 def get_child_directories(self):
727 """Gets a :class:`Filenames` iterator listing all the filenames of
728 sub-directories in the database within the given directory
730 The returned filenames will be the basename-entries only (not
733 self._assert_dir_is_initialized()
734 files_p = Directory._get_child_directories(self._dir_p)
735 return Filenames(files_p, self)
739 """Returns the absolute path of this Directory (read-only)"""
743 """Object representation"""
744 return "<notmuch Directory object '%s'>" % self._path
746 _destroy = nmlib.notmuch_directory_destroy
747 _destroy.argtypes = [NotmuchDirectoryP]
748 _destroy.argtypes = None
751 """Close and free the Directory"""
752 if self._dir_p is not None:
753 self._destroy(self._dir_p)
756 class Filenames(object):
757 """An iterator over File- or Directory names stored in the database"""
759 #notmuch_filenames_get
760 _get = nmlib.notmuch_filenames_get
761 _get.argtypes = [NotmuchFilenamesP]
762 _get.restype = c_char_p
764 def __init__(self, files_p, parent):
766 :param files_p: The pointer to an internal notmuch_filenames_t object.
767 :param parent: The object this Directory is derived from
768 (usually a Directory()). We do not directly use
769 this, but store a reference to it as long as
770 this Directory object lives. This keeps the
773 self._files_p = files_p
774 self._parent = parent
777 """ Make Filenames an iterator """
780 _valid = nmlib.notmuch_filenames_valid
781 _valid.argtypes = [NotmuchFilenamesP]
782 _valid.restype = bool
784 _move_to_next = nmlib.notmuch_filenames_move_to_next
785 _move_to_next.argtypes = [NotmuchFilenamesP]
786 _move_to_next.restype = None
789 if not self._files_p:
790 raise NotInitializedError()
792 if not self._valid(self._files_p):
796 file_ = Filenames._get(self._files_p)
797 self._move_to_next(self._files_p)
798 return file_.decode('utf-8', 'ignore')
799 next = __next__ # python2.x iterator protocol compatibility
802 """len(:class:`Filenames`) returns the number of contained files
806 As this iterates over the files, we will not be able to
807 iterate over them again! So this will fail::
810 files = Database().get_directory('').get_child_files()
811 if len(files) > 0: # this 'exhausts' msgs
813 # NotmuchError(:attr:`STATUS`.NOT_INITIALIZED)
814 for file in files: print file
816 if not self._files_p:
817 raise NotInitializedError()
820 while self._valid(self._files_p):
821 self._move_to_next(self._files_p)
826 _destroy = nmlib.notmuch_filenames_destroy
827 _destroy.argtypes = [NotmuchFilenamesP]
828 _destroy.restype = None
831 """Close and free Filenames"""
832 if self._files_p is not None:
833 self._destroy(self._files_p)