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;
117 typedef struct _notmuch_directory notmuch_directory_t;
118 typedef struct _notmuch_files notmuch_files_t;
120 /* Create a new, empty notmuch database located at 'path'.
122 * The path should be a top-level directory to a collection of
123 * plain-text email messages (one message per file). This call will
124 * create a new ".notmuch" directory within 'path' where notmuch will
127 * After a successful call to notmuch_database_create, the returned
128 * database will be open so the caller should call
129 * notmuch_database_close when finished with it.
131 * The database will not yet have any data in it
132 * (notmuch_database_create itself is a very cheap function). Messages
133 * contained within 'path' can be added to the database by calling
134 * notmuch_database_add_message.
136 * In case of any failure, this function returns NULL, (after printing
137 * an error message on stderr).
140 notmuch_database_create (const char *path);
143 NOTMUCH_DATABASE_MODE_READ_ONLY = 0,
144 NOTMUCH_DATABASE_MODE_READ_WRITE
145 } notmuch_database_mode_t;
147 /* XXX: I think I'd like this to take an extra argument of
148 * notmuch_status_t* for returning a status value on failure. */
150 /* Open an existing notmuch database located at 'path'.
152 * The database should have been created at some time in the past,
153 * (not necessarily by this process), by calling
154 * notmuch_database_create with 'path'. By default the database should be
155 * opened for reading only. In order to write to the database you need to
156 * pass the NOTMUCH_DATABASE_MODE_WRITABLE mode.
158 * An existing notmuch database can be identified by the presence of a
159 * directory named ".notmuch" below 'path'.
161 * The caller should call notmuch_database_close when finished with
164 * In case of any failure, this function returns NULL, (after printing
165 * an error message on stderr).
168 notmuch_database_open (const char *path,
169 notmuch_database_mode_t mode);
171 /* Close the given notmuch database, freeing all associated
172 * resources. See notmuch_database_open. */
174 notmuch_database_close (notmuch_database_t *database);
176 /* Return the database path of the given database.
178 * The return value is a string owned by notmuch so should not be
179 * modified nor freed by the caller. */
181 notmuch_database_get_path (notmuch_database_t *database);
183 /* Read the stored contents of a directory from the database.
185 * Here, 'dirname' should be a path relative to the path of
186 * 'database' (see notmuch_database_get_path), or else should be an
187 * absolute filename with initial components that match the path of
190 * The stored mtime of the directory along with a list of messages
191 * and directories in the database contained in 'dirname' are
192 * returned in 'directory'. The entries are sorted by filename.
195 notmuch_database_read_directory (notmuch_database_t *database,
196 const char *filename,
197 notmuch_directory_t **directory);
199 /* Return the recorded 'mtime' for the given directory
202 notmuch_directory_get_mtime (notmuch_directory_t *directory);
204 /* Return a notmuch_files_t iterator for all regular files in 'directory'.
207 notmuch_directory_get_files (notmuch_directory_t *directory);
209 /* Return a notmuch_files_t iterator for all sub-directories of
213 notmuch_directory_get_subdirs (notmuch_directory_t *directory);
215 /* Does the given notmuch_files_t object contain any more results.
218 notmuch_files_has_more (notmuch_files_t *files);
220 /* Get the current filename from 'files' as a string.
223 notmuch_files_get_filename (notmuch_files_t *files);
225 /* Add a new message to the given notmuch database.
227 * Here,'filename' should be a path relative to the path of
228 * 'database' (see notmuch_database_get_path), or else should be an
229 * absolute filename with initial components that match the path of
232 * The file should be a single mail message (not a multi-message mbox)
233 * that is expected to remain at its current location, (since the
234 * notmuch database will reference the filename, and will not copy the
235 * entire contents of the file.
237 * If 'message' is not NULL, then, on successful return '*message'
238 * will be initialized to a message object that can be used for things
239 * such as adding tags to the just-added message. The user should call
240 * notmuch_message_destroy when done with the message. On any failure
241 * '*message' will be set to NULL.
245 * NOTMUCH_STATUS_SUCCESS: Message successfully added to database.
247 * NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID: Message has the same message
248 * ID as another message already in the database. Nothing added
251 * NOTMUCH_STATUS_FILE_ERROR: an error occurred trying to open the
252 * file, (such as permission denied, or file not found,
253 * etc.). Nothing added to the database.
255 * NOTMUCH_STATUS_FILE_NOT_EMAIL: the contents of filename don't look
256 * like an email message. Nothing added to the database.
259 notmuch_database_add_message (notmuch_database_t *database,
260 const char *filename,
261 notmuch_message_t **message);
263 /* Remove a message from the given notmuch database.
265 * Note that the only this particular filename association is removed
266 * from the database. If the same message (as determined by the
267 * message ID) is still available via other filenames, then the
268 * message will persist in the database for those filenames. When the
269 * last filename is removed for a particular message, the database
270 * content for that message will be entirely removed.
273 notmuch_database_remove_message (notmuch_database_t *database,
274 const char *filename);
276 /* Find a message with the given message_id.
278 * If the database contains a message with the given message_id, then
279 * a new notmuch_message_t object is returned. The caller should call
280 * notmuch_message_destroy when done with the message.
282 * If no message is found with the given message_id or if an
283 * out-of-memory situation occurs, this function returns NULL.
286 notmuch_database_find_message (notmuch_database_t *database,
287 const char *message_id);
289 /* Return a list of all tags found in the database.
291 * This function creates a list of all tags found in the database. The
292 * resulting list contains all tags from all messages found in the database.
294 * On error this function returns NULL.
297 notmuch_database_get_all_tags (notmuch_database_t *db);
299 /* Create a new query for 'database'.
301 * Here, 'database' should be an open database, (see
302 * notmuch_database_open and notmuch_database_create).
304 * For the query string, we'll document the syntax here more
305 * completely in the future, but it's likely to be a specialized
306 * version of the general Xapian query syntax:
308 * http://xapian.org/docs/queryparser.html
310 * As a special case, passing a length-zero string, (that is ""), will
311 * result in a query that returns all messages in the database.
313 * See notmuch_query_set_sort for controlling the order of results and
314 * notmuch_query_search to actually execute the query.
316 * User should call notmuch_query_destroy when finished with this
319 * Will return NULL if insufficient memory is available.
322 notmuch_query_create (notmuch_database_t *database,
323 const char *query_string);
325 /* Sort values for notmuch_query_set_sort */
327 NOTMUCH_SORT_OLDEST_FIRST,
328 NOTMUCH_SORT_NEWEST_FIRST,
329 NOTMUCH_SORT_MESSAGE_ID
332 /* Specify the sorting desired for this query. */
334 notmuch_query_set_sort (notmuch_query_t *query, notmuch_sort_t sort);
336 /* Execute a query for threads, returning a notmuch_threads_t object
337 * which can be used to iterate over the results. The returned threads
338 * object is owned by the query and as such, will only be valid until
339 * notmuch_query_destroy.
341 * Typical usage might be:
343 * notmuch_query_t *query;
344 * notmuch_threads_t *threads;
345 * notmuch_thread_t *thread;
347 * query = notmuch_query_create (database, query_string);
349 * for (threads = notmuch_query_search_threads (query);
350 * notmuch_threads_has_more (threads);
351 * notmuch_threads_advance (threads))
353 * thread = notmuch_threads_get (threads);
355 * notmuch_thread_destroy (thread);
358 * notmuch_query_destroy (query);
360 * Note: If you are finished with a thread before its containing
361 * query, you can call notmuch_thread_destroy to clean up some memory
362 * sooner (as in the above example). Otherwise, if your thread objects
363 * are long-lived, then you don't need to call notmuch_thread_destroy
364 * and all the memory will still be reclaimed when the query is
367 * Note that there's no explicit destructor needed for the
368 * notmuch_threads_t object. (For consistency, we do provide a
369 * notmuch_threads_destroy function, but there's no good reason
370 * to call it if the query is about to be destroyed).
373 notmuch_query_search_threads (notmuch_query_t *query);
375 /* Execute a query for messages, returning a notmuch_messages_t object
376 * which can be used to iterate over the results. The returned
377 * messages object is owned by the query and as such, will only be
378 * valid until notmuch_query_destroy.
380 * Typical usage might be:
382 * notmuch_query_t *query;
383 * notmuch_messages_t *messages;
384 * notmuch_message_t *message;
386 * query = notmuch_query_create (database, query_string);
388 * for (messages = notmuch_query_search_messages (query);
389 * notmuch_messages_has_more (messages);
390 * notmuch_messages_advance (messages))
392 * message = notmuch_messages_get (messages);
394 * notmuch_message_destroy (message);
397 * notmuch_query_destroy (query);
399 * Note: If you are finished with a message before its containing
400 * query, you can call notmuch_message_destroy to clean up some memory
401 * sooner (as in the above example). Otherwise, if your message
402 * objects are long-lived, then you don't need to call
403 * notmuch_message_destroy and all the memory will still be reclaimed
404 * when the query is destroyed.
406 * Note that there's no explicit destructor needed for the
407 * notmuch_messages_t object. (For consistency, we do provide a
408 * notmuch_messages_destroy function, but there's no good
409 * reason to call it if the query is about to be destroyed).
412 notmuch_query_search_messages (notmuch_query_t *query);
414 /* Destroy a notmuch_query_t along with any associated resources.
416 * This will in turn destroy any notmuch_threads_t and
417 * notmuch_messages_t objects generated by this query, (and in
418 * turn any notmuch_thrad_t and notmuch_message_t objects generated
419 * from those results, etc.), if such objects haven't already been
423 notmuch_query_destroy (notmuch_query_t *query);
425 /* Does the given notmuch_threads_t object contain any more
428 * When this function returns TRUE, notmuch_threads_get will
429 * return a valid object. Whereas when this function returns FALSE,
430 * notmuch_threads_get will return NULL.
432 * See the documentation of notmuch_query_search_threads for example
433 * code showing how to iterate over a notmuch_threads_t object.
436 notmuch_threads_has_more (notmuch_threads_t *threads);
438 /* Get the current thread from 'threads' as a notmuch_thread_t.
440 * Note: The returned thread belongs to 'threads' and has a lifetime
441 * identical to it (and the query to which it belongs).
443 * See the documentation of notmuch_query_search_threads for example
444 * code showing how to iterate over a notmuch_threads_t object.
446 * If an out-of-memory situation occurs, this function will return
450 notmuch_threads_get (notmuch_threads_t *threads);
452 /* Advance the 'threads' iterator to the next thread.
454 * See the documentation of notmuch_query_search_threads for example
455 * code showing how to iterate over a notmuch_threads_t object.
458 notmuch_threads_advance (notmuch_threads_t *threads);
460 /* Destroy a notmuch_threads_t object.
462 * It's not strictly necessary to call this function. All memory from
463 * the notmuch_threads_t object will be reclaimed when the
464 * containg query object is destroyed.
467 notmuch_threads_destroy (notmuch_threads_t *threads);
469 /* Return an estimate of the number of messages matching a search
471 * This function performs a search and returns Xapian's best
472 * guess as to number of matching messages.
475 notmuch_query_count_messages (notmuch_query_t *query);
477 /* Get the thread ID of 'thread'.
479 * The returned string belongs to 'thread' and as such, should not be
480 * modified by the caller and will only be valid for as long as the
481 * thread is valid, (which is until notmuch_thread_destroy or until
482 * the query from which it derived is destroyed).
485 notmuch_thread_get_thread_id (notmuch_thread_t *thread);
487 /* Get the total number of messages in 'thread'.
489 * This count consists of all messages in the database belonging to
490 * this thread. Contrast with notmuch_thread_get_matched_messages() .
493 notmuch_thread_get_total_messages (notmuch_thread_t *thread);
495 /* Get a notmuch_messages_t iterator for the top-level messages in
498 * This iterator will not necessarily iterate over all of the messages
499 * in the thread. It will only iterate over the messages in the thread
500 * which are not replies to other messages in the thread.
502 * To iterate over all messages in the thread, the caller will need to
503 * iterate over the result of notmuch_message_get_replies for each
504 * top-level message (and do that recursively for the resulting
508 notmuch_thread_get_toplevel_messages (notmuch_thread_t *thread);
510 /* Get the number of messages in 'thread' that matched the search.
512 * This count includes only the messages in this thread that were
513 * matched by the search from which the thread was created. Contrast
514 * with notmuch_thread_get_total_messages() .
517 notmuch_thread_get_matched_messages (notmuch_thread_t *thread);
519 /* Get the authors of 'thread'
521 * The returned string is a comma-separated list of the names of the
522 * authors of mail messages in the query results that belong to this
525 * The returned string belongs to 'thread' and as such, should not be
526 * modified by the caller and will only be valid for as long as the
527 * thread is valid, (which is until notmuch_thread_destroy or until
528 * the query from which it derived is destroyed).
531 notmuch_thread_get_authors (notmuch_thread_t *thread);
533 /* Get the subject of 'thread'
535 * The subject is taken from the first message (according to the query
536 * order---see notmuch_query_set_sort) in the query results that
537 * belongs to this thread.
539 * The returned string belongs to 'thread' and as such, should not be
540 * modified by the caller and will only be valid for as long as the
541 * thread is valid, (which is until notmuch_thread_destroy or until
542 * the query from which it derived is destroyed).
545 notmuch_thread_get_subject (notmuch_thread_t *thread);
547 /* Get the date of the oldest message in 'thread' as a time_t value.
550 notmuch_thread_get_oldest_date (notmuch_thread_t *thread);
552 /* Get the date of the oldest message in 'thread' as a time_t value.
555 notmuch_thread_get_newest_date (notmuch_thread_t *thread);
557 /* Get the tags for 'thread', returning a notmuch_tags_t object which
558 * can be used to iterate over all tags.
560 * Note: In the Notmuch database, tags are stored on individual
561 * messages, not on threads. So the tags returned here will be all
562 * tags of the messages which matched the search and which belong to
565 * The tags object is owned by the thread and as such, will only be
566 * valid for as long as the thread is valid, (for example, until
567 * notmuch_thread_destroy or until the query from which it derived is
570 * Typical usage might be:
572 * notmuch_thread_t *thread;
573 * notmuch_tags_t *tags;
576 * thread = notmuch_threads_get (threads);
578 * for (tags = notmuch_thread_get_tags (thread);
579 * notmuch_tags_has_more (tags);
580 * notmuch_result_advance (tags))
582 * tag = notmuch_tags_get (tags);
586 * notmuch_thread_destroy (thread);
588 * Note that there's no explicit destructor needed for the
589 * notmuch_tags_t object. (For consistency, we do provide a
590 * notmuch_tags_destroy function, but there's no good reason to call
591 * it if the message is about to be destroyed).
594 notmuch_thread_get_tags (notmuch_thread_t *thread);
596 /* Destroy a notmuch_thread_t object. */
598 notmuch_thread_destroy (notmuch_thread_t *thread);
600 /* Does the given notmuch_messages_t object contain any more
603 * When this function returns TRUE, notmuch_messages_get will return a
604 * valid object. Whereas when this function returns FALSE,
605 * notmuch_messages_get will return NULL.
607 * See the documentation of notmuch_query_search_messages for example
608 * code showing how to iterate over a notmuch_messages_t object.
611 notmuch_messages_has_more (notmuch_messages_t *messages);
613 /* Get the current message from 'messages' as a notmuch_message_t.
615 * Note: The returned message belongs to 'messages' and has a lifetime
616 * identical to it (and the query to which it belongs).
618 * See the documentation of notmuch_query_search_messages for example
619 * code showing how to iterate over a notmuch_messages_t object.
621 * If an out-of-memory situation occurs, this function will return
625 notmuch_messages_get (notmuch_messages_t *messages);
627 /* Advance the 'messages' iterator to the next result.
629 * See the documentation of notmuch_query_search_messages for example
630 * code showing how to iterate over a notmuch_messages_t object.
633 notmuch_messages_advance (notmuch_messages_t *messages);
635 /* Destroy a notmuch_messages_t object.
637 * It's not strictly necessary to call this function. All memory from
638 * the notmuch_messages_t object will be reclaimed when the containing
639 * query object is destroyed.
642 notmuch_messages_destroy (notmuch_messages_t *messages);
644 /* Return a list of tags from all messages.
646 * The resulting list is guaranteed not to contain duplicated tags.
648 * WARNING: You can no longer iterate over messages after calling this
649 * function, because the iterator will point at the end of the list.
650 * We do not have a function to reset the iterator yet and the only
651 * way how you can iterate over the list again is to recreate the
654 * The function returns NULL on error.
657 notmuch_messages_collect_tags (notmuch_messages_t *messages);
659 /* Get the message ID of 'message'.
661 * The returned string belongs to 'message' and as such, should not be
662 * modified by the caller and will only be valid for as long as the
663 * message is valid, (which is until the query from which it derived
666 * This function will not return NULL since Notmuch ensures that every
667 * message has a unique message ID, (Notmuch will generate an ID for a
668 * message if the original file does not contain one).
671 notmuch_message_get_message_id (notmuch_message_t *message);
673 /* Get the thread ID of 'message'.
675 * The returned string belongs to 'message' and as such, should not be
676 * modified by the caller and will only be valid for as long as the
677 * message is valid, (for example, until the user calls
678 * notmuch_message_destroy on 'message' or until a query from which it
679 * derived is destroyed).
681 * This function will not return NULL since Notmuch ensures that every
682 * message belongs to a single thread.
685 notmuch_message_get_thread_id (notmuch_message_t *message);
687 /* Get a notmuch_messages_t iterator for all of the replies to
690 * Note: This call only makes sense if 'message' was ultimately
691 * obtained from a notmuch_thread_t object, (such as by coming
692 * directly from the result of calling notmuch_thread_get_
693 * toplevel_messages or by any number of subsequent
694 * calls to notmuch_message_get_replies).
696 * If 'message' was obtained through some non-thread means, (such as
697 * by a call to notmuch_query_search_messages), then this function
700 * If there are no replies to 'message', this function will return
701 * NULL. (Note that notmuch_messages_has_more will accept that NULL
702 * value as legitimate, and simply return FALSE for it.)
705 notmuch_message_get_replies (notmuch_message_t *message);
707 /* Get a filename for the email corresponding to 'message'.
709 * The returned filename is an absolute filename, (the initial
710 * component will match notmuch_database_get_path() ).
712 * The returned string belongs to the message so should not be
713 * modified or freed by the caller (nor should it be referenced after
714 * the message is destroyed).
716 * Note: If this message corresponds to multiple files in the mail
717 * store, (that is, multiple files contain identical message IDs),
718 * this function will arbitrarily return a single one of those
722 notmuch_message_get_filename (notmuch_message_t *message);
724 /* Remove a filename for the email corresponding to 'message'.
726 * This removes the association between a filename and a message,
727 * when the last filename is gone, the entire message is removed
731 notmuch_message_remove_filename (notmuch_message_t *message,
732 const char *filename);
735 typedef enum _notmuch_message_flag {
736 NOTMUCH_MESSAGE_FLAG_MATCH,
737 } notmuch_message_flag_t;
739 /* Get a value of a flag for the email corresponding to 'message'. */
741 notmuch_message_get_flag (notmuch_message_t *message,
742 notmuch_message_flag_t flag);
744 /* Set a value of a flag for the email corresponding to 'message'. */
746 notmuch_message_set_flag (notmuch_message_t *message,
747 notmuch_message_flag_t flag, notmuch_bool_t value);
749 /* Get the date of 'message' as a time_t value.
751 * For the original textual representation of the Date header from the
752 * message call notmuch_message_get_header() with a header value of
755 notmuch_message_get_date (notmuch_message_t *message);
757 /* Get the value of the specified header from 'message'.
759 * The value will be read from the actual message file, not from the
760 * notmuch database. The header name is case insensitive.
762 * The returned string belongs to the message so should not be
763 * modified or freed by the caller (nor should it be referenced after
764 * the message is destroyed).
766 * Returns an empty string ("") if the message does not contain a
767 * header line matching 'header'. Returns NULL if any error occurs.
770 notmuch_message_get_header (notmuch_message_t *message, const char *header);
772 /* Get the tags for 'message', returning a notmuch_tags_t object which
773 * can be used to iterate over all tags.
775 * The tags object is owned by the message and as such, will only be
776 * valid for as long as the message is valid, (which is until the
777 * query from which it derived is destroyed).
779 * Typical usage might be:
781 * notmuch_message_t *message;
782 * notmuch_tags_t *tags;
785 * message = notmuch_database_find_message (database, message_id);
787 * for (tags = notmuch_message_get_tags (message);
788 * notmuch_tags_has_more (tags);
789 * notmuch_result_advance (tags))
791 * tag = notmuch_tags_get (tags);
795 * notmuch_message_destroy (message);
797 * Note that there's no explicit destructor needed for the
798 * notmuch_tags_t object. (For consistency, we do provide a
799 * notmuch_tags_destroy function, but there's no good reason to call
800 * it if the message is about to be destroyed).
803 notmuch_message_get_tags (notmuch_message_t *message);
805 /* The longest possible tag value. */
806 #define NOTMUCH_TAG_MAX 200
808 /* Add a tag to the given message.
812 * NOTMUCH_STATUS_SUCCESS: Tag successfully added to message
814 * NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
816 * NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is too long
817 * (exceeds NOTMUCH_TAG_MAX)
820 notmuch_message_add_tag (notmuch_message_t *message, const char *tag);
822 /* Remove a tag from the given message.
826 * NOTMUCH_STATUS_SUCCESS: Tag successfully removed from message
828 * NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
830 * NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is too long
831 * (exceeds NOTMUCH_TAG_MAX)
834 notmuch_message_remove_tag (notmuch_message_t *message, const char *tag);
836 /* Remove all tags from the given message.
838 * See notmuch_message_freeze for an example showing how to safely
839 * replace tag values.
842 notmuch_message_remove_all_tags (notmuch_message_t *message);
844 /* Freeze the current state of 'message' within the database.
846 * This means that changes to the message state, (via
847 * notmuch_message_add_tag, notmuch_message_remove_tag, and
848 * notmuch_message_remove_all_tags), will not be committed to the
849 * database until the message is thawed with notmuch_message_thaw.
851 * Multiple calls to freeze/thaw are valid and these calls with
852 * "stack". That is there must be as many calls to thaw as to freeze
853 * before a message is actually thawed.
855 * The ability to do freeze/thaw allows for safe transactions to
856 * change tag values. For example, explicitly setting a message to
857 * have a given set of tags might look like this:
859 * notmuch_message_freeze (message);
861 * notmuch_message_remove_all_tags (message);
863 * for (i = 0; i < NUM_TAGS; i++)
864 * notmuch_message_add_tag (message, tags[i]);
866 * notmuch_message_thaw (message);
868 * With freeze/thaw used like this, the message in the database is
869 * guaranteed to have either the full set of original tag value, or
870 * the full set of new tag values, but nothing in between.
872 * Imagine the example above without freeze/thaw and the operation
873 * somehow getting interrupted. This could result in the message being
874 * left with no tags if the interruption happened after
875 * notmuch_message_remove_all_tags but before notmuch_message_add_tag.
878 notmuch_message_freeze (notmuch_message_t *message);
880 /* Thaw the current 'message', synchronizing any changes that may have
881 * occurred while 'message' was frozen into the notmuch database.
883 * See notmuch_message_freeze for an example of how to use this
884 * function to safely provide tag changes.
886 * Multiple calls to freeze/thaw are valid and these calls with
887 * "stack". That is there must be as many calls to thaw as to freeze
888 * before a message is actually thawed.
892 * NOTMUCH_STATUS_SUCCESS: Message successfully thawed, (or at least
893 * its frozen count has successfully been reduced by 1).
895 * NOTMUCH_STATUS_UNBALANCE_FREEZE_THAW: An attempt was made to thaw
896 * an unfrozen message. That is, there have been an unbalanced
897 * number of calls to notmuch_message_freeze and
898 * notmuch_message_thaw.
901 notmuch_message_thaw (notmuch_message_t *message);
903 /* Destroy a notmuch_message_t object.
905 * It can be useful to call this function in the case of a single
906 * query object with many messages in the result, (such as iterating
907 * over the entire database). Otherwise, it's fine to never call this
908 * function and there will still be no memory leaks. (The memory from
909 * the messages get reclaimed when the containing query is destroyed.)
912 notmuch_message_destroy (notmuch_message_t *message);
914 /* Does the given notmuch_tags_t object contain any more tags.
916 * When this function returns TRUE, notmuch_tags_get will return a
917 * valid string. Whereas when this function returns FALSE,
918 * notmuch_tags_get will return NULL.
920 * See the documentation of notmuch_message_get_tags for example code
921 * showing how to iterate over a notmuch_tags_t object.
924 notmuch_tags_has_more (notmuch_tags_t *tags);
926 /* Get the current tag from 'tags' as a string.
928 * Note: The returned string belongs to 'tags' and has a lifetime
929 * identical to it (and the query to which it ultimately belongs).
931 * See the documentation of notmuch_message_get_tags for example code
932 * showing how to iterate over a notmuch_tags_t object.
935 notmuch_tags_get (notmuch_tags_t *tags);
937 /* Advance the 'tags' iterator to the next tag.
939 * See the documentation of notmuch_message_get_tags for example code
940 * showing how to iterate over a notmuch_tags_t object.
943 notmuch_tags_advance (notmuch_tags_t *tags);
945 /* Destroy a notmuch_tags_t object.
947 * It's not strictly necessary to call this function. All memory from
948 * the notmuch_tags_t object will be reclaimed when the containing
949 * message or query objects are destroyed.
952 notmuch_tags_destroy (notmuch_tags_t *tags);