1 /* notmuch - Not much of an email library, (just index and search)
3 * Copyright © 2009 Carl Worth
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 3 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see http://www.gnu.org/licenses/ .
18 * Author: Carl Worth <cworth@cworth.org>
25 # define NOTMUCH_BEGIN_DECLS extern "C" {
26 # define NOTMUCH_END_DECLS }
28 # define NOTMUCH_BEGIN_DECLS
29 # define NOTMUCH_END_DECLS
44 typedef int notmuch_bool_t;
46 /* Status codes used for the return values of most functions.
48 * A zero value (NOTMUCH_STATUS_SUCCESS) indicates that the function
49 * completed without error. Any other value indicates an error as
52 * NOTMUCH_STATUS_SUCCESS: No error occurred.
54 * NOTMUCH_STATUS_OUT_OF_MEMORY: Out of memory
56 * XXX: We don't really want to expose this lame XAPIAN_EXCEPTION
57 * value. Instead we should map to things like DATABASE_LOCKED or
60 * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred
62 * NOTMUCH_STATUS_FILE_ERROR: An error occurred trying to read or
63 * write to a file (this could be file not found, permission
66 * NOTMUCH_STATUS_FILE_NOT_EMAIL: A file was presented that doesn't
67 * appear to be an email message.
69 * NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID: A file contains a message ID
70 * that is identical to a message already in the database.
72 * NOTMUCH_STATUS_NULL_POINTER: The user erroneously passed a NULL
73 * pointer to a notmuch function.
75 * NOTMUCH_STATUS_TAG_TOO_LONG: A tag value is too long (exceeds
78 * NOTMUCH_STATUS_UNBALANCED_FREEZE_THAW: The notmuch_message_thaw
79 * function has been called more times than notmuch_message_freeze.
83 * NOTMUCH_STATUS_LAST_STATUS: Not an actual status value. Just a way
84 * to find out how many valid status values there are.
86 typedef enum _notmuch_status {
87 NOTMUCH_STATUS_SUCCESS = 0,
88 NOTMUCH_STATUS_OUT_OF_MEMORY,
89 NOTMUCH_STATUS_XAPIAN_EXCEPTION,
90 NOTMUCH_STATUS_FILE_ERROR,
91 NOTMUCH_STATUS_FILE_NOT_EMAIL,
92 NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID,
93 NOTMUCH_STATUS_NULL_POINTER,
94 NOTMUCH_STATUS_TAG_TOO_LONG,
95 NOTMUCH_STATUS_UNBALANCED_FREEZE_THAW,
97 NOTMUCH_STATUS_LAST_STATUS
100 /* Get a string representation of a notmuch_status_t value.
102 * The result is readonly.
105 notmuch_status_to_string (notmuch_status_t status);
107 /* Various opaque data types. For each notmuch_<foo>_t see the various
108 * notmuch_<foo> functions below. */
109 typedef struct _notmuch_database notmuch_database_t;
110 typedef struct _notmuch_query notmuch_query_t;
111 typedef struct _notmuch_threads notmuch_threads_t;
112 typedef struct _notmuch_thread notmuch_thread_t;
113 typedef struct _notmuch_messages notmuch_messages_t;
114 typedef struct _notmuch_message notmuch_message_t;
115 typedef struct _notmuch_tags notmuch_tags_t;
117 /* Create a new, empty notmuch database located at 'path'.
119 * The path should be a top-level directory to a collection of
120 * plain-text email messages (one message per file). This call will
121 * create a new ".notmuch" directory within 'path' where notmuch will
124 * After a successful call to notmuch_database_create, the returned
125 * database will be open so the caller should call
126 * notmuch_database_close when finished with it.
128 * The database will not yet have any data in it
129 * (notmuch_database_create itself is a very cheap function). Messages
130 * contained within 'path' can be added to the database by calling
131 * notmuch_database_add_message.
133 * In case of any failure, this function returns NULL, (after printing
134 * an error message on stderr).
137 notmuch_database_create (const char *path);
139 /* XXX: I think I'd like this to take an extra argument of
140 * notmuch_status_t* for returning a status value on failure. */
142 /* Open an existing notmuch database located at 'path'.
144 * The database should have been created at some time in the past,
145 * (not necessarily by this process), by calling
146 * notmuch_database_create with 'path'.
148 * An existing notmuch database can be identified by the presence of a
149 * directory named ".notmuch" below 'path'.
151 * The caller should call notmuch_database_close when finished with
154 * In case of any failure, this function returns NULL, (after printing
155 * an error message on stderr).
158 notmuch_database_open (const char *path);
160 /* Close the given notmuch database, freeing all associated
161 * resources. See notmuch_database_open. */
163 notmuch_database_close (notmuch_database_t *database);
165 /* Return the database path of the given database.
167 * The return value is a string owned by notmuch so should not be
168 * modified nor freed by the caller. */
170 notmuch_database_get_path (notmuch_database_t *database);
172 /* Store a timestamp within the database.
174 * The Notmuch database will not interpret this key nor the timestamp
175 * values at all. It will merely store them together and return the
176 * timestamp when notmuch_database_get_timestamp is called with the
177 * same value for 'key'.
179 * The intention is for the caller to use the timestamp to allow
180 * efficient identification of new messages to be added to the
181 * database. The recommended usage is as follows:
183 * o Read the mtime of a directory from the filesystem
185 * o Call add_message for all mail files in the directory
187 * o Call notmuch_database_set_timestamp with the path of the
188 * directory as 'key' and the originally read mtime as 'value'.
190 * Then, when wanting to check for updates to the directory in the
191 * future, the client can call notmuch_database_get_timestamp and know
192 * that it only needs to add files if the mtime of the directory and
193 * files are newer than the stored timestamp.
195 * Note: The notmuch_database_get_timestamp function does not allow
196 * the caller to distinguish a timestamp of 0 from a non-existent
197 * timestamp. So don't store a timestamp of 0 unless you are
198 * comfortable with that.
202 * NOTMUCH_STATUS_SUCCESS: Timestamp successfully stored in database.
204 * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception
205 * occurred. Timestamp not stored.
208 notmuch_database_set_timestamp (notmuch_database_t *database,
209 const char *key, time_t timestamp);
211 /* Retrieve a timestamp from the database.
213 * Returns the timestamp value previously stored by calling
214 * notmuch_database_set_timestamp with the same value for 'key'.
216 * Returns 0 if no timestamp is stored for 'key' or if any error
217 * occurred querying the database.
220 notmuch_database_get_timestamp (notmuch_database_t *database,
223 /* Add a new message to the given notmuch database.
225 * Here,'filename' should be a path relative to the the path of
226 * 'database' (see notmuch_database_get_path), or else should be an
227 * absolute filename with initial components that match the path of
230 * The file should be a single mail message (not a multi-message mbox)
231 * that is expected to remain at its current location, (since the
232 * notmuch database will reference the filename, and will not copy the
233 * entire contents of the file.
235 * If 'message' is not NULL, then, on successful return '*message'
236 * will be initialized to a message object that can be used for things
237 * such as adding tags to the just-added message. The user should call
238 * notmuch_message_destroy when done with the message. On any failure
239 * '*message' will be set to NULL.
243 * NOTMUCH_STATUS_SUCCESS: Message successfully added to database.
245 * NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID: Message has the same message
246 * ID as another message already in the database. Nothing added
249 * NOTMUCH_STATUS_FILE_ERROR: an error occurred trying to open the
250 * file, (such as permission denied, or file not found,
251 * etc.). Nothing added to the database.
253 * NOTMUCH_STATUS_FILE_NOT_EMAIL: the contents of filename don't look
254 * like an email message. Nothing added to the database.
257 notmuch_database_add_message (notmuch_database_t *database,
258 const char *filename,
259 notmuch_message_t **message);
261 /* Find a message with the given messsage_id.
263 * If the database contains a message with the given message_id, then
264 * a new notmuch_message_t object is returned. The caller should call
265 * notmuch_message_destroy when done with the message.
267 * If no message is found with the given message_id or if an
268 * out-of-memory situation occurs, this function returns NULL.
271 notmuch_database_find_message (notmuch_database_t *database,
272 const char *message_id);
274 /* Create a new query for 'database'.
276 * Here, 'database' should be an open database, (see
277 * notmuch_database_open and notmuch_database_create).
279 * For the query string, we'll document the syntax here more
280 * completely in the future, but it's likely to be a specialized
281 * version of the general Xapian query syntax:
283 * http://xapian.org/docs/queryparser.html
285 * As a special case, passing a length-zero string, (that is ""), will
286 * result in a query that returns all messages in the database.
288 * See notmuch_query_set_sort for controlling the order of results and
289 * notmuch_query_search to actually execute the query.
291 * User should call notmuch_query_destroy when finished with this
294 * Will return NULL if insufficient memory is available.
297 notmuch_query_create (notmuch_database_t *database,
298 const char *query_string);
300 /* Sort values for notmuch_query_set_sort */
302 NOTMUCH_SORT_DATE_OLDEST_FIRST,
303 NOTMUCH_SORT_DATE_NEWEST_FIRST,
304 NOTMUCH_SORT_MESSAGE_ID
307 /* Specify the sorting desired for this query. */
309 notmuch_query_set_sort (notmuch_query_t *query, notmuch_sort_t sort);
311 /* Execute a query for threads, returning a notmuch_threads_t object
312 * which can be used to iterate over the results. The returned threads
313 * object is owned by the query and as such, will only be valid until
314 * notmuch_query_destroy.
316 * Typical usage might be:
318 * notmuch_query_t *query;
319 * notmuch_threads_t *threads;
320 * notmuch_thread_t *thread;
322 * query = notmuch_query_create (database, query_string);
324 * for (threads = notmuch_query_search_threads (query);
325 * notmuch_threads_has_more (threads);
326 * notmuch_threads_advance (threads))
328 * thread = notmuch_threads_get (threads);
330 * notmuch_thread_destroy (thread);
333 * notmuch_query_destroy (query);
335 * Note: If you are finished with a thread before its containing
336 * query, you can call notmuch_thread_destroy to clean up some memory
337 * sooner (as in the above example). Otherwise, if your thread objects
338 * are long-lived, then you don't need to call notmuch_thread_destroy
339 * and all the memory will still be reclaimed when the query is
342 * Note that there's no explicit destructor needed for the
343 * notmuch_threads_t object. (For consistency, we do provide a
344 * notmuch_threads_destroy function, but there's no good reason
345 * to call it if the query is about to be destroyed).
348 notmuch_query_search_threads (notmuch_query_t *query);
350 /* Execute a query for messages, returning a notmuch_messages_t object
351 * which can be used to iterate over the results. The returned
352 * messages object is owned by the query and as such, will only be
353 * valid until notmuch_query_destroy.
355 * Typical usage might be:
357 * notmuch_query_t *query;
358 * notmuch_messages_t *messages;
359 * notmuch_message_t *message;
361 * query = notmuch_query_create (database, query_string);
363 * for (messages = notmuch_query_search_messages (query);
364 * notmuch_messages_has_more (messages);
365 * notmuch_messages_advance (messages))
367 * message = notmuch_messages_get (messages);
369 * notmuch_message_destroy (message);
372 * notmuch_query_destroy (query);
374 * Note: If you are finished with a message before its containing
375 * query, you can call notmuch_message_destroy to clean up some memory
376 * sooner (as in the above example). Otherwise, if your message
377 * objects are long-lived, then you don't need to call
378 * notmuch_message_destroy and all the memory will still be reclaimed
379 * when the query is destroyed.
381 * Note that there's no explicit destructor needed for the
382 * notmuch_messages_t object. (For consistency, we do provide a
383 * notmuch_messages_destroy function, but there's no good
384 * reason to call it if the query is about to be destroyed).
387 notmuch_query_search_messages (notmuch_query_t *query);
389 /* Destroy a notmuch_query_t along with any associated resources.
391 * This will in turn destroy any notmuch_threads_t and
392 * notmuch_messages_t objects generated by this query, (and in
393 * turn any notmuch_thrad_t and notmuch_message_t objects generated
394 * from those results, etc.), if such objects haven't already been
398 notmuch_query_destroy (notmuch_query_t *query);
400 /* Does the given notmuch_threads_t object contain any more
403 * When this function returns TRUE, notmuch_threads_get will
404 * return a valid object. Whereas when this function returns FALSE,
405 * notmuch_threads_get will return NULL.
407 * See the documentation of notmuch_query_search_threads for example
408 * code showing how to iterate over a notmuch_threads_t object.
411 notmuch_threads_has_more (notmuch_threads_t *threads);
413 /* Get the current thread from 'threads' as a notmuch_thread_t.
415 * Note: The returned thread belongs to 'threads' and has a lifetime
416 * identical to it (and the query to which it belongs).
418 * See the documentation of notmuch_query_search_threads for example
419 * code showing how to iterate over a notmuch_threads_t object.
421 * If an out-of-memory situation occurs, this function will return
425 notmuch_threads_get (notmuch_threads_t *threads);
427 /* Advance the 'threads' iterator to the next thread.
429 * See the documentation of notmuch_query_search_threads for example
430 * code showing how to iterate over a notmuch_threads_t object.
433 notmuch_threads_advance (notmuch_threads_t *threads);
435 /* Destroy a notmuch_threads_t object.
437 * It's not strictly necessary to call this function. All memory from
438 * the notmuch_threads_t object will be reclaimed when the
439 * containg query object is destroyed.
442 notmuch_threads_destroy (notmuch_threads_t *threads);
444 /* Get the thread ID of 'thread'.
446 * The returned string belongs to 'thread' and as such, should not be
447 * modified by the caller and will only be valid for as long as the
448 * thread is valid, (which is until notmuch_thread_destroy or until
449 * the query from which it derived is destroyed).
452 notmuch_thread_get_thread_id (notmuch_thread_t *thread);
454 /* Get the subject of 'thread'
456 * The subject is taken from the first message (according to the query
457 * order---see notmuch_query_set_sort) in the query results that
458 * belongs to this thread.
460 * The returned string belongs to 'thread' and as such, should not be
461 * modified by the caller and will only be valid for as long as the
462 * thread is valid, (which is until notmuch_thread_destroy or until
463 * the query from which it derived is destroyed).
466 notmuch_thread_get_subject (notmuch_thread_t *thread);
468 /* Get the date of the oldest message in 'thread' as a time_t value.
471 notmuch_thread_get_oldest_date (notmuch_thread_t *thread);
473 /* Get the date of the oldest message in 'thread' as a time_t value.
476 notmuch_thread_get_newest_date (notmuch_thread_t *thread);
478 /* Get the tags for 'thread', returning a notmuch_tags_t object which
479 * can be used to iterate over all tags.
481 * Note: In the Notmuch database, tags are stored on individual
482 * messages, not on threads. So the tags returned here will be all
483 * tags of the messages which matched the search and which belong to
486 * The tags object is owned by the thread and as such, will only be
487 * valid for as long as the thread is valid, (for example, until
488 * notmuch_thread_destroy or until the query from which it derived is
491 * Typical usage might be:
493 * notmuch_thread_t *thread;
494 * notmuch_tags_t *tags;
497 * thread = notmuch_threads_get (threads);
499 * for (tags = notmuch_thread_get_tags (thread);
500 * notmuch_tags_has_more (tags);
501 * notmuch_result_advance (tags))
503 * tag = notmuch_tags_get (tags);
507 * notmuch_thread_destroy (thread);
509 * Note that there's no explicit destructor needed for the
510 * notmuch_tags_t object. (For consistency, we do provide a
511 * notmuch_tags_destroy function, but there's no good reason to call
512 * it if the message is about to be destroyed).
515 notmuch_thread_get_tags (notmuch_thread_t *thread);
517 /* Destroy a notmuch_thread_t object. */
519 notmuch_thread_destroy (notmuch_thread_t *thread);
521 /* Does the given notmuch_messages_t object contain any more
524 * When this function returns TRUE, notmuch_messages_get will return a
525 * valid object. Whereas when this function returns FALSE,
526 * notmuch_messages_get will return NULL.
528 * See the documentation of notmuch_query_search_messages for example
529 * code showing how to iterate over a notmuch_messages_t object.
532 notmuch_messages_has_more (notmuch_messages_t *messages);
534 /* Get the current message from 'messages' as a notmuch_message_t.
536 * Note: The returned message belongs to 'messages' and has a lifetime
537 * identical to it (and the query to which it belongs).
539 * See the documentation of notmuch_query_search_messages for example
540 * code showing how to iterate over a notmuch_messages_t object.
542 * If an out-of-memory situation occurs, this function will return
546 notmuch_messages_get (notmuch_messages_t *messages);
548 /* Advance the 'messages' iterator to the next result.
550 * See the documentation of notmuch_query_search_messages for example
551 * code showing how to iterate over a notmuch_messages_t object.
554 notmuch_messages_advance (notmuch_messages_t *messages);
556 /* Destroy a notmuch_messages_t object.
558 * It's not strictly necessary to call this function. All memory from
559 * the notmuch_messages_t object will be reclaimed when the containg
560 * query object is destroyed.
563 notmuch_messages_destroy (notmuch_messages_t *messages);
565 /* Get the message ID of 'message'.
567 * The returned string belongs to 'message' and as such, should not be
568 * modified by the caller and will only be valid for as long as the
569 * message is valid, (which is until the query from which it derived
572 * This function will not return NULL since Notmuch ensures that every
573 * message has a unique message ID, (Notmuch will generate an ID for a
574 * message if the original file does not contain one).
577 notmuch_message_get_message_id (notmuch_message_t *message);
579 /* Get the thread ID of 'message'.
581 * The returned string belongs to 'message' and as such, should not be
582 * modified by the caller and will only be valid for as long as the
583 * message is valid, (for example, until the user calls
584 * notmuch_message_destroy on 'message' or until a query from which it
585 * derived is destroyed).
587 * This function will not return NULL since Notmuch ensures that every
588 * message belongs to a single thread.
591 notmuch_message_get_thread_id (notmuch_message_t *message);
593 /* Get the filename for the email corresponding to 'message'.
595 * The returned filename is an absolute filename, (the initial
596 * component will match notmuch_database_get_path() ).
598 * The returned string belongs to the message so should not be
599 * modified or freed by the caller (nor should it be referenced after
600 * the message is destroyed). */
602 notmuch_message_get_filename (notmuch_message_t *message);
604 /* Get the date of 'message' as a time_t value.
606 * For the original textual representation of the Date header from the
607 * message call notmuch_message_get_header() with a header value of
610 notmuch_message_get_date (notmuch_message_t *message);
612 /* Get the value of the specified header from 'message'.
614 * The value will be read from the actual message file, not from the
615 * notmuch database. The header name is case insensitive.
617 * The returned string belongs to the message so should not be
618 * modified or freed by the caller (nor should it be referenced after
619 * the message is destroyed).
621 * Returns NULL if the message does not contain a header line matching
622 * 'header' of if any error occurs.
625 notmuch_message_get_header (notmuch_message_t *message, const char *header);
627 /* Get the tags for 'message', returning a notmuch_tags_t object which
628 * can be used to iterate over all tags.
630 * The tags object is owned by the message and as such, will only be
631 * valid for as long as the message is valid, (which is until the
632 * query from which it derived is destroyed).
634 * Typical usage might be:
636 * notmuch_message_t *message;
637 * notmuch_tags_t *tags;
640 * message = notmuch_database_find_message (database, message_id);
642 * for (tags = notmuch_message_get_tags (message);
643 * notmuch_tags_has_more (tags);
644 * notmuch_result_advance (tags))
646 * tag = notmuch_tags_get (tags);
650 * notmuch_message_destroy (message);
652 * Note that there's no explicit destructor needed for the
653 * notmuch_tags_t object. (For consistency, we do provide a
654 * notmuch_tags_destroy function, but there's no good reason to call
655 * it if the message is about to be destroyed).
658 notmuch_message_get_tags (notmuch_message_t *message);
660 /* The longest possible tag value. */
661 #define NOTMUCH_TAG_MAX 200
663 /* Add a tag to the given message.
667 * NOTMUCH_STATUS_SUCCESS: Tag successfully added to message
669 * NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
671 * NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is too long
672 * (exceeds NOTMUCH_TAG_MAX)
675 notmuch_message_add_tag (notmuch_message_t *message, const char *tag);
677 /* Remove a tag from the given message.
681 * NOTMUCH_STATUS_SUCCESS: Tag successfully removed from message
683 * NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
685 * NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is too long
686 * (exceeds NOTMUCH_TAG_MAX)
689 notmuch_message_remove_tag (notmuch_message_t *message, const char *tag);
691 /* Remove all tags from the given message.
693 * See notmuch_message_freeze for an example showing how to safely
694 * replace tag values.
697 notmuch_message_remove_all_tags (notmuch_message_t *message);
699 /* Freeze the current state of 'message' within the database.
701 * This means that changes to the message state, (via
702 * notmuch_message_add_tag, notmuch_message_remove_tag, and
703 * notmuch_message_remove_all_tags), will not be committed to the
704 * database until the message is thawed with notmuch_message_thaw.
706 * Multiple calls to freeze/thaw are valid and these calls with
707 * "stack". That is there must be as many calls to thaw as to freeze
708 * before a message is actually thawed.
710 * The ability to do freeze/thaw allows for safe transactions to
711 * change tag values. For example, explicitly setting a message to
712 * have a given set of tags might look like this:
714 * notmuch_message_freeze (message);
716 * notmuch_message_remove_all_tags (message);
718 * for (i = 0; i < NUM_TAGS; i++)
719 * notmuch_message_add_tag (message, tags[i]);
721 * notmuch_message_thaw (message);
723 * With freeze/thaw used like this, the message in the database is
724 * guaranteed to have either the full set of original tag value, or
725 * the full set of new tag values, but nothing in between.
727 * Imagine the example above without freeze/thaw and the operation
728 * somehow getting interrupted. This could result in the message being
729 * left with no tags if the interruption happened after
730 * notmuch_message_remove_all_tags but before notmuch_message_add_tag.
733 notmuch_message_freeze (notmuch_message_t *message);
735 /* Thaw the current 'message', synchronizing any changes that may have
736 * occurred while 'message' was frozen into the notmuch database.
738 * See notmuch_message_freeze for an example of how to use this
739 * function to safely provide tag changes.
741 * Multiple calls to freeze/thaw are valid and these calls with
742 * "stack". That is there must be as many calls to thaw as to freeze
743 * before a message is actually thawed.
747 * NOTMUCH_STATUS_SUCCESS: Message successfully thawed, (or at least
748 * its frozen count has successfully been reduced by 1).
750 * NOTMUCH_STATUS_UNBALANCE_FREEZE_THAW: An attempt was made to thaw
751 * an unfrozen message. That is, there have been an unbalanced
752 * number of calls to notmuch_message_freeze and
753 * notmuch_message_thaw.
756 notmuch_message_thaw (notmuch_message_t *message);
758 /* Destroy a notmuch_message_t object.
760 * It can be useful to call this function in the case of a single
761 * query object with many messages in the result, (such as iterating
762 * over the entire database). Otherwise, it's fine to never call this
763 * function and there will still be no memory leaks. (The memory from
764 * the messages get reclaimed when the containing query is destroyed.)
767 notmuch_message_destroy (notmuch_message_t *message);
769 /* Does the given notmuch_tags_t object contain any more tags.
771 * When this function returns TRUE, notmuch_tags_get will return a
772 * valid string. Whereas when this function returns FALSE,
773 * notmuch_tags_get will return NULL.
775 * See the documentation of notmuch_message_get_tags for example code
776 * showing how to iterate over a notmuch_tags_t object.
779 notmuch_tags_has_more (notmuch_tags_t *tags);
781 /* Get the current tag from 'tags' as a string.
783 * Note: The returned string belongs to 'tags' and has a lifetime
784 * identical to it (and the query to which it utlimately belongs).
786 * See the documentation of notmuch_message_get_tags for example code
787 * showing how to iterate over a notmuch_tags_t object.
790 notmuch_tags_get (notmuch_tags_t *tags);
792 /* Advance the 'tags' iterator to the next tag.
794 * See the documentation of notmuch_message_get_tags for example code
795 * showing how to iterate over a notmuch_tags_t object.
798 notmuch_tags_advance (notmuch_tags_t *tags);
800 /* Destroy a notmuch_tags_t object.
802 * It's not strictly necessary to call this function. All memory from
803 * the notmuch_tags_t object will be reclaimed when the containg
804 * message or query objects are destroyed.
807 notmuch_tags_destroy (notmuch_tags_t *tags);