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_READONLY_DATABASE,
90 NOTMUCH_STATUS_XAPIAN_EXCEPTION,
91 NOTMUCH_STATUS_FILE_ERROR,
92 NOTMUCH_STATUS_FILE_NOT_EMAIL,
93 NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID,
94 NOTMUCH_STATUS_NULL_POINTER,
95 NOTMUCH_STATUS_TAG_TOO_LONG,
96 NOTMUCH_STATUS_UNBALANCED_FREEZE_THAW,
98 NOTMUCH_STATUS_LAST_STATUS
101 /* Get a string representation of a notmuch_status_t value.
103 * The result is readonly.
106 notmuch_status_to_string (notmuch_status_t status);
108 /* Various opaque data types. For each notmuch_<foo>_t see the various
109 * notmuch_<foo> functions below. */
110 typedef struct _notmuch_database notmuch_database_t;
111 typedef struct _notmuch_query notmuch_query_t;
112 typedef struct _notmuch_threads notmuch_threads_t;
113 typedef struct _notmuch_thread notmuch_thread_t;
114 typedef struct _notmuch_messages notmuch_messages_t;
115 typedef struct _notmuch_message notmuch_message_t;
116 typedef struct _notmuch_tags notmuch_tags_t;
118 /* Create a new, empty notmuch database located at 'path'.
120 * The path should be a top-level directory to a collection of
121 * plain-text email messages (one message per file). This call will
122 * create a new ".notmuch" directory within 'path' where notmuch will
125 * After a successful call to notmuch_database_create, the returned
126 * database will be open so the caller should call
127 * notmuch_database_close when finished with it.
129 * The database will not yet have any data in it
130 * (notmuch_database_create itself is a very cheap function). Messages
131 * contained within 'path' can be added to the database by calling
132 * notmuch_database_add_message.
134 * In case of any failure, this function returns NULL, (after printing
135 * an error message on stderr).
138 notmuch_database_create (const char *path);
141 NOTMUCH_DATABASE_MODE_READ_ONLY = 0,
142 NOTMUCH_DATABASE_MODE_READ_WRITE
143 } notmuch_database_mode_t;
145 /* XXX: I think I'd like this to take an extra argument of
146 * notmuch_status_t* for returning a status value on failure. */
148 /* Open an existing notmuch database located at 'path'.
150 * The database should have been created at some time in the past,
151 * (not necessarily by this process), by calling
152 * notmuch_database_create with 'path'. By default the database should be
153 * opened for reading only. In order to write to the database you need to
154 * pass the NOTMUCH_DATABASE_MODE_WRITABLE mode.
156 * An existing notmuch database can be identified by the presence of a
157 * directory named ".notmuch" below 'path'.
159 * The caller should call notmuch_database_close when finished with
162 * In case of any failure, this function returns NULL, (after printing
163 * an error message on stderr).
166 notmuch_database_open (const char *path,
167 notmuch_database_mode_t mode);
169 /* Close the given notmuch database, freeing all associated
170 * resources. See notmuch_database_open. */
172 notmuch_database_close (notmuch_database_t *database);
174 /* Return the database path of the given database.
176 * The return value is a string owned by notmuch so should not be
177 * modified nor freed by the caller. */
179 notmuch_database_get_path (notmuch_database_t *database);
181 /* Store an mtime within the database for 'path'.
183 * Here,'path' should be the path of a directory relative to the path
184 * of 'database' (see notmuch_database_get_path), or else should be an
185 * absolute path with initial components that match the path of
188 * The intention is for the caller to use the mtime to allow efficient
189 * identification of new messages to be added to the database. The
190 * recommended usage is as follows:
192 * o Read the mtime of a directory from the filesystem
194 * o Call add_message for all mail files in the directory
196 * o Call notmuch_database_set_directory_mtime
198 * Then, when wanting to check for updates to the directory in the
199 * future, the client can call notmuch_database_get_directory_mtime
200 * and know that it only needs to add files if the mtime of the
201 * directory and files are newer than the stored timestamp.
203 * Note: The notmuch_database_get_directory_mtime function does not
204 * allow the caller to distinguish a timestamp of 0 from a
205 * non-existent timestamp. So don't store a timestamp of 0 unless you
206 * are comfortable with that.
210 * NOTMUCH_STATUS_SUCCESS: mtime successfully stored in database.
212 * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception
213 * occurred, mtime not stored.
216 notmuch_database_set_directory_mtime (notmuch_database_t *database,
220 /* Retrieve the mtime from the database for 'path'.
222 * Returns the mtime value previously stored by calling
223 * notmuch_database_set_directory_mtime with the same 'path'.
225 * Returns 0 if no mtime is stored for 'path' or if any error occurred
226 * querying the database.
229 notmuch_database_get_directory_mtime (notmuch_database_t *database,
232 /* Add a new message to the given notmuch database.
234 * Here,'filename' should be a path relative to the path of
235 * 'database' (see notmuch_database_get_path), or else should be an
236 * absolute filename with initial components that match the path of
239 * The file should be a single mail message (not a multi-message mbox)
240 * that is expected to remain at its current location, (since the
241 * notmuch database will reference the filename, and will not copy the
242 * entire contents of the file.
244 * If 'message' is not NULL, then, on successful return '*message'
245 * will be initialized to a message object that can be used for things
246 * such as adding tags to the just-added message. The user should call
247 * notmuch_message_destroy when done with the message. On any failure
248 * '*message' will be set to NULL.
252 * NOTMUCH_STATUS_SUCCESS: Message successfully added to database.
254 * NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID: Message has the same message
255 * ID as another message already in the database. Nothing added
258 * NOTMUCH_STATUS_FILE_ERROR: an error occurred trying to open the
259 * file, (such as permission denied, or file not found,
260 * etc.). Nothing added to the database.
262 * NOTMUCH_STATUS_FILE_NOT_EMAIL: the contents of filename don't look
263 * like an email message. Nothing added to the database.
266 notmuch_database_add_message (notmuch_database_t *database,
267 const char *filename,
268 notmuch_message_t **message);
270 /* Remove a message from the given notmuch database.
272 * Note that the only this particular filename association is removed
273 * from the database. If the same message (as determined by the
274 * message ID) is still available via other filenames, then the
275 * message will persist in the database for those filenames. When the
276 * last filename is removed for a particular message, the database
277 * content for that message will be entirely removed.
280 notmuch_database_remove_message (notmuch_database_t *database,
281 const char *filename);
283 /* Find a message with the given message_id.
285 * If the database contains a message with the given message_id, then
286 * a new notmuch_message_t object is returned. The caller should call
287 * notmuch_message_destroy when done with the message.
289 * If no message is found with the given message_id or if an
290 * out-of-memory situation occurs, this function returns NULL.
293 notmuch_database_find_message (notmuch_database_t *database,
294 const char *message_id);
296 /* Return a list of all tags found in the database.
298 * This function creates a list of all tags found in the database. The
299 * resulting list contains all tags from all messages found in the database.
301 * On error this function returns NULL.
304 notmuch_database_get_all_tags (notmuch_database_t *db);
306 /* Create a new query for 'database'.
308 * Here, 'database' should be an open database, (see
309 * notmuch_database_open and notmuch_database_create).
311 * For the query string, we'll document the syntax here more
312 * completely in the future, but it's likely to be a specialized
313 * version of the general Xapian query syntax:
315 * http://xapian.org/docs/queryparser.html
317 * As a special case, passing a length-zero string, (that is ""), will
318 * result in a query that returns all messages in the database.
320 * See notmuch_query_set_sort for controlling the order of results and
321 * notmuch_query_search to actually execute the query.
323 * User should call notmuch_query_destroy when finished with this
326 * Will return NULL if insufficient memory is available.
329 notmuch_query_create (notmuch_database_t *database,
330 const char *query_string);
332 /* Sort values for notmuch_query_set_sort */
334 NOTMUCH_SORT_OLDEST_FIRST,
335 NOTMUCH_SORT_NEWEST_FIRST,
336 NOTMUCH_SORT_MESSAGE_ID
339 /* Specify the sorting desired for this query. */
341 notmuch_query_set_sort (notmuch_query_t *query, notmuch_sort_t sort);
343 /* Execute a query for threads, returning a notmuch_threads_t object
344 * which can be used to iterate over the results. The returned threads
345 * object is owned by the query and as such, will only be valid until
346 * notmuch_query_destroy.
348 * Typical usage might be:
350 * notmuch_query_t *query;
351 * notmuch_threads_t *threads;
352 * notmuch_thread_t *thread;
354 * query = notmuch_query_create (database, query_string);
356 * for (threads = notmuch_query_search_threads (query);
357 * notmuch_threads_has_more (threads);
358 * notmuch_threads_advance (threads))
360 * thread = notmuch_threads_get (threads);
362 * notmuch_thread_destroy (thread);
365 * notmuch_query_destroy (query);
367 * Note: If you are finished with a thread before its containing
368 * query, you can call notmuch_thread_destroy to clean up some memory
369 * sooner (as in the above example). Otherwise, if your thread objects
370 * are long-lived, then you don't need to call notmuch_thread_destroy
371 * and all the memory will still be reclaimed when the query is
374 * Note that there's no explicit destructor needed for the
375 * notmuch_threads_t object. (For consistency, we do provide a
376 * notmuch_threads_destroy function, but there's no good reason
377 * to call it if the query is about to be destroyed).
380 notmuch_query_search_threads (notmuch_query_t *query);
382 /* Execute a query for messages, returning a notmuch_messages_t object
383 * which can be used to iterate over the results. The returned
384 * messages object is owned by the query and as such, will only be
385 * valid until notmuch_query_destroy.
387 * Typical usage might be:
389 * notmuch_query_t *query;
390 * notmuch_messages_t *messages;
391 * notmuch_message_t *message;
393 * query = notmuch_query_create (database, query_string);
395 * for (messages = notmuch_query_search_messages (query);
396 * notmuch_messages_has_more (messages);
397 * notmuch_messages_advance (messages))
399 * message = notmuch_messages_get (messages);
401 * notmuch_message_destroy (message);
404 * notmuch_query_destroy (query);
406 * Note: If you are finished with a message before its containing
407 * query, you can call notmuch_message_destroy to clean up some memory
408 * sooner (as in the above example). Otherwise, if your message
409 * objects are long-lived, then you don't need to call
410 * notmuch_message_destroy and all the memory will still be reclaimed
411 * when the query is destroyed.
413 * Note that there's no explicit destructor needed for the
414 * notmuch_messages_t object. (For consistency, we do provide a
415 * notmuch_messages_destroy function, but there's no good
416 * reason to call it if the query is about to be destroyed).
419 notmuch_query_search_messages (notmuch_query_t *query);
421 /* Destroy a notmuch_query_t along with any associated resources.
423 * This will in turn destroy any notmuch_threads_t and
424 * notmuch_messages_t objects generated by this query, (and in
425 * turn any notmuch_thrad_t and notmuch_message_t objects generated
426 * from those results, etc.), if such objects haven't already been
430 notmuch_query_destroy (notmuch_query_t *query);
432 /* Does the given notmuch_threads_t object contain any more
435 * When this function returns TRUE, notmuch_threads_get will
436 * return a valid object. Whereas when this function returns FALSE,
437 * notmuch_threads_get will return NULL.
439 * See the documentation of notmuch_query_search_threads for example
440 * code showing how to iterate over a notmuch_threads_t object.
443 notmuch_threads_has_more (notmuch_threads_t *threads);
445 /* Get the current thread from 'threads' as a notmuch_thread_t.
447 * Note: The returned thread belongs to 'threads' and has a lifetime
448 * identical to it (and the query to which it belongs).
450 * See the documentation of notmuch_query_search_threads for example
451 * code showing how to iterate over a notmuch_threads_t object.
453 * If an out-of-memory situation occurs, this function will return
457 notmuch_threads_get (notmuch_threads_t *threads);
459 /* Advance the 'threads' iterator to the next thread.
461 * See the documentation of notmuch_query_search_threads for example
462 * code showing how to iterate over a notmuch_threads_t object.
465 notmuch_threads_advance (notmuch_threads_t *threads);
467 /* Destroy a notmuch_threads_t object.
469 * It's not strictly necessary to call this function. All memory from
470 * the notmuch_threads_t object will be reclaimed when the
471 * containg query object is destroyed.
474 notmuch_threads_destroy (notmuch_threads_t *threads);
476 /* Return an estimate of the number of messages matching a search
478 * This function performs a search and returns Xapian's best
479 * guess as to number of matching messages.
482 notmuch_query_count_messages (notmuch_query_t *query);
484 /* Get the thread ID of 'thread'.
486 * The returned string belongs to 'thread' and as such, should not be
487 * modified by the caller and will only be valid for as long as the
488 * thread is valid, (which is until notmuch_thread_destroy or until
489 * the query from which it derived is destroyed).
492 notmuch_thread_get_thread_id (notmuch_thread_t *thread);
494 /* Get the total number of messages in 'thread'.
496 * This count consists of all messages in the database belonging to
497 * this thread. Contrast with notmuch_thread_get_matched_messages() .
500 notmuch_thread_get_total_messages (notmuch_thread_t *thread);
502 /* Get a notmuch_messages_t iterator for the top-level messages in
505 * This iterator will not necessarily iterate over all of the messages
506 * in the thread. It will only iterate over the messages in the thread
507 * which are not replies to other messages in the thread.
509 * To iterate over all messages in the thread, the caller will need to
510 * iterate over the result of notmuch_message_get_replies for each
511 * top-level message (and do that recursively for the resulting
515 notmuch_thread_get_toplevel_messages (notmuch_thread_t *thread);
517 /* Get the number of messages in 'thread' that matched the search.
519 * This count includes only the messages in this thread that were
520 * matched by the search from which the thread was created. Contrast
521 * with notmuch_thread_get_total_messages() .
524 notmuch_thread_get_matched_messages (notmuch_thread_t *thread);
526 /* Get the authors of 'thread'
528 * The returned string is a comma-separated list of the names of the
529 * authors of mail messages in the query results that belong to this
532 * The returned string belongs to 'thread' and as such, should not be
533 * modified by the caller and will only be valid for as long as the
534 * thread is valid, (which is until notmuch_thread_destroy or until
535 * the query from which it derived is destroyed).
538 notmuch_thread_get_authors (notmuch_thread_t *thread);
540 /* Get the subject of 'thread'
542 * The subject is taken from the first message (according to the query
543 * order---see notmuch_query_set_sort) in the query results that
544 * belongs to this thread.
546 * The returned string belongs to 'thread' and as such, should not be
547 * modified by the caller and will only be valid for as long as the
548 * thread is valid, (which is until notmuch_thread_destroy or until
549 * the query from which it derived is destroyed).
552 notmuch_thread_get_subject (notmuch_thread_t *thread);
554 /* Get the date of the oldest message in 'thread' as a time_t value.
557 notmuch_thread_get_oldest_date (notmuch_thread_t *thread);
559 /* Get the date of the oldest message in 'thread' as a time_t value.
562 notmuch_thread_get_newest_date (notmuch_thread_t *thread);
564 /* Get the tags for 'thread', returning a notmuch_tags_t object which
565 * can be used to iterate over all tags.
567 * Note: In the Notmuch database, tags are stored on individual
568 * messages, not on threads. So the tags returned here will be all
569 * tags of the messages which matched the search and which belong to
572 * The tags object is owned by the thread and as such, will only be
573 * valid for as long as the thread is valid, (for example, until
574 * notmuch_thread_destroy or until the query from which it derived is
577 * Typical usage might be:
579 * notmuch_thread_t *thread;
580 * notmuch_tags_t *tags;
583 * thread = notmuch_threads_get (threads);
585 * for (tags = notmuch_thread_get_tags (thread);
586 * notmuch_tags_has_more (tags);
587 * notmuch_result_advance (tags))
589 * tag = notmuch_tags_get (tags);
593 * notmuch_thread_destroy (thread);
595 * Note that there's no explicit destructor needed for the
596 * notmuch_tags_t object. (For consistency, we do provide a
597 * notmuch_tags_destroy function, but there's no good reason to call
598 * it if the message is about to be destroyed).
601 notmuch_thread_get_tags (notmuch_thread_t *thread);
603 /* Destroy a notmuch_thread_t object. */
605 notmuch_thread_destroy (notmuch_thread_t *thread);
607 /* Does the given notmuch_messages_t object contain any more
610 * When this function returns TRUE, notmuch_messages_get will return a
611 * valid object. Whereas when this function returns FALSE,
612 * notmuch_messages_get will return NULL.
614 * See the documentation of notmuch_query_search_messages for example
615 * code showing how to iterate over a notmuch_messages_t object.
618 notmuch_messages_has_more (notmuch_messages_t *messages);
620 /* Get the current message from 'messages' as a notmuch_message_t.
622 * Note: The returned message belongs to 'messages' and has a lifetime
623 * identical to it (and the query to which it belongs).
625 * See the documentation of notmuch_query_search_messages for example
626 * code showing how to iterate over a notmuch_messages_t object.
628 * If an out-of-memory situation occurs, this function will return
632 notmuch_messages_get (notmuch_messages_t *messages);
634 /* Advance the 'messages' iterator to the next result.
636 * See the documentation of notmuch_query_search_messages for example
637 * code showing how to iterate over a notmuch_messages_t object.
640 notmuch_messages_advance (notmuch_messages_t *messages);
642 /* Destroy a notmuch_messages_t object.
644 * It's not strictly necessary to call this function. All memory from
645 * the notmuch_messages_t object will be reclaimed when the containing
646 * query object is destroyed.
649 notmuch_messages_destroy (notmuch_messages_t *messages);
651 /* Return a list of tags from all messages.
653 * The resulting list is guaranteed not to contain duplicated tags.
655 * WARNING: You can no longer iterate over messages after calling this
656 * function, because the iterator will point at the end of the list.
657 * We do not have a function to reset the iterator yet and the only
658 * way how you can iterate over the list again is to recreate the
661 * The function returns NULL on error.
664 notmuch_messages_collect_tags (notmuch_messages_t *messages);
666 /* Get the message ID of 'message'.
668 * The returned string belongs to 'message' and as such, should not be
669 * modified by the caller and will only be valid for as long as the
670 * message is valid, (which is until the query from which it derived
673 * This function will not return NULL since Notmuch ensures that every
674 * message has a unique message ID, (Notmuch will generate an ID for a
675 * message if the original file does not contain one).
678 notmuch_message_get_message_id (notmuch_message_t *message);
680 /* Get the thread ID of 'message'.
682 * The returned string belongs to 'message' and as such, should not be
683 * modified by the caller and will only be valid for as long as the
684 * message is valid, (for example, until the user calls
685 * notmuch_message_destroy on 'message' or until a query from which it
686 * derived is destroyed).
688 * This function will not return NULL since Notmuch ensures that every
689 * message belongs to a single thread.
692 notmuch_message_get_thread_id (notmuch_message_t *message);
694 /* Get a notmuch_messages_t iterator for all of the replies to
697 * Note: This call only makes sense if 'message' was ultimately
698 * obtained from a notmuch_thread_t object, (such as by coming
699 * directly from the result of calling notmuch_thread_get_
700 * toplevel_messages or by any number of subsequent
701 * calls to notmuch_message_get_replies).
703 * If 'message' was obtained through some non-thread means, (such as
704 * by a call to notmuch_query_search_messages), then this function
707 * If there are no replies to 'message', this function will return
708 * NULL. (Note that notmuch_messages_has_more will accept that NULL
709 * value as legitimate, and simply return FALSE for it.)
712 notmuch_message_get_replies (notmuch_message_t *message);
714 /* Get a filename for the email corresponding to 'message'.
716 * The returned filename is an absolute filename, (the initial
717 * component will match notmuch_database_get_path() ).
719 * The returned string belongs to the message so should not be
720 * modified or freed by the caller (nor should it be referenced after
721 * the message is destroyed).
723 * Note: If this message corresponds to multiple files in the mail
724 * store, (that is, multiple files contain identical message IDs),
725 * this function will arbitrarily return a single one of those
729 notmuch_message_get_filename (notmuch_message_t *message);
732 typedef enum _notmuch_message_flag {
733 NOTMUCH_MESSAGE_FLAG_MATCH,
734 } notmuch_message_flag_t;
736 /* Get a value of a flag for the email corresponding to 'message'. */
738 notmuch_message_get_flag (notmuch_message_t *message,
739 notmuch_message_flag_t flag);
741 /* Set a value of a flag for the email corresponding to 'message'. */
743 notmuch_message_set_flag (notmuch_message_t *message,
744 notmuch_message_flag_t flag, notmuch_bool_t value);
746 /* Get the date of 'message' as a time_t value.
748 * For the original textual representation of the Date header from the
749 * message call notmuch_message_get_header() with a header value of
752 notmuch_message_get_date (notmuch_message_t *message);
754 /* Get the value of the specified header from 'message'.
756 * The value will be read from the actual message file, not from the
757 * notmuch database. The header name is case insensitive.
759 * The returned string belongs to the message so should not be
760 * modified or freed by the caller (nor should it be referenced after
761 * the message is destroyed).
763 * Returns an empty string ("") if the message does not contain a
764 * header line matching 'header'. Returns NULL if any error occurs.
767 notmuch_message_get_header (notmuch_message_t *message, const char *header);
769 /* Get the tags for 'message', returning a notmuch_tags_t object which
770 * can be used to iterate over all tags.
772 * The tags object is owned by the message and as such, will only be
773 * valid for as long as the message is valid, (which is until the
774 * query from which it derived is destroyed).
776 * Typical usage might be:
778 * notmuch_message_t *message;
779 * notmuch_tags_t *tags;
782 * message = notmuch_database_find_message (database, message_id);
784 * for (tags = notmuch_message_get_tags (message);
785 * notmuch_tags_has_more (tags);
786 * notmuch_result_advance (tags))
788 * tag = notmuch_tags_get (tags);
792 * notmuch_message_destroy (message);
794 * Note that there's no explicit destructor needed for the
795 * notmuch_tags_t object. (For consistency, we do provide a
796 * notmuch_tags_destroy function, but there's no good reason to call
797 * it if the message is about to be destroyed).
800 notmuch_message_get_tags (notmuch_message_t *message);
802 /* The longest possible tag value. */
803 #define NOTMUCH_TAG_MAX 200
805 /* Add a tag to the given message.
809 * NOTMUCH_STATUS_SUCCESS: Tag successfully added to message
811 * NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
813 * NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is too long
814 * (exceeds NOTMUCH_TAG_MAX)
817 notmuch_message_add_tag (notmuch_message_t *message, const char *tag);
819 /* Remove a tag from the given message.
823 * NOTMUCH_STATUS_SUCCESS: Tag successfully removed from message
825 * NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
827 * NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is too long
828 * (exceeds NOTMUCH_TAG_MAX)
831 notmuch_message_remove_tag (notmuch_message_t *message, const char *tag);
833 /* Remove all tags from the given message.
835 * See notmuch_message_freeze for an example showing how to safely
836 * replace tag values.
839 notmuch_message_remove_all_tags (notmuch_message_t *message);
841 /* Freeze the current state of 'message' within the database.
843 * This means that changes to the message state, (via
844 * notmuch_message_add_tag, notmuch_message_remove_tag, and
845 * notmuch_message_remove_all_tags), will not be committed to the
846 * database until the message is thawed with notmuch_message_thaw.
848 * Multiple calls to freeze/thaw are valid and these calls with
849 * "stack". That is there must be as many calls to thaw as to freeze
850 * before a message is actually thawed.
852 * The ability to do freeze/thaw allows for safe transactions to
853 * change tag values. For example, explicitly setting a message to
854 * have a given set of tags might look like this:
856 * notmuch_message_freeze (message);
858 * notmuch_message_remove_all_tags (message);
860 * for (i = 0; i < NUM_TAGS; i++)
861 * notmuch_message_add_tag (message, tags[i]);
863 * notmuch_message_thaw (message);
865 * With freeze/thaw used like this, the message in the database is
866 * guaranteed to have either the full set of original tag value, or
867 * the full set of new tag values, but nothing in between.
869 * Imagine the example above without freeze/thaw and the operation
870 * somehow getting interrupted. This could result in the message being
871 * left with no tags if the interruption happened after
872 * notmuch_message_remove_all_tags but before notmuch_message_add_tag.
875 notmuch_message_freeze (notmuch_message_t *message);
877 /* Thaw the current 'message', synchronizing any changes that may have
878 * occurred while 'message' was frozen into the notmuch database.
880 * See notmuch_message_freeze for an example of how to use this
881 * function to safely provide tag changes.
883 * Multiple calls to freeze/thaw are valid and these calls with
884 * "stack". That is there must be as many calls to thaw as to freeze
885 * before a message is actually thawed.
889 * NOTMUCH_STATUS_SUCCESS: Message successfully thawed, (or at least
890 * its frozen count has successfully been reduced by 1).
892 * NOTMUCH_STATUS_UNBALANCE_FREEZE_THAW: An attempt was made to thaw
893 * an unfrozen message. That is, there have been an unbalanced
894 * number of calls to notmuch_message_freeze and
895 * notmuch_message_thaw.
898 notmuch_message_thaw (notmuch_message_t *message);
900 /* Destroy a notmuch_message_t object.
902 * It can be useful to call this function in the case of a single
903 * query object with many messages in the result, (such as iterating
904 * over the entire database). Otherwise, it's fine to never call this
905 * function and there will still be no memory leaks. (The memory from
906 * the messages get reclaimed when the containing query is destroyed.)
909 notmuch_message_destroy (notmuch_message_t *message);
911 /* Does the given notmuch_tags_t object contain any more tags.
913 * When this function returns TRUE, notmuch_tags_get will return a
914 * valid string. Whereas when this function returns FALSE,
915 * notmuch_tags_get will return NULL.
917 * See the documentation of notmuch_message_get_tags for example code
918 * showing how to iterate over a notmuch_tags_t object.
921 notmuch_tags_has_more (notmuch_tags_t *tags);
923 /* Get the current tag from 'tags' as a string.
925 * Note: The returned string belongs to 'tags' and has a lifetime
926 * identical to it (and the query to which it ultimately belongs).
928 * See the documentation of notmuch_message_get_tags for example code
929 * showing how to iterate over a notmuch_tags_t object.
932 notmuch_tags_get (notmuch_tags_t *tags);
934 /* Advance the 'tags' iterator to the next tag.
936 * See the documentation of notmuch_message_get_tags for example code
937 * showing how to iterate over a notmuch_tags_t object.
940 notmuch_tags_advance (notmuch_tags_t *tags);
942 /* Destroy a notmuch_tags_t object.
944 * It's not strictly necessary to call this function. All memory from
945 * the notmuch_tags_t object will be reclaimed when the containing
946 * message or query objects are destroyed.
949 notmuch_tags_destroy (notmuch_tags_t *tags);