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 a timestamp within the database.
183 * The Notmuch database will not interpret this key nor the timestamp
184 * values at all. It will merely store them together and return the
185 * timestamp when notmuch_database_get_timestamp is called with the
186 * same value for 'key'.
188 * The intention is for the caller to use the timestamp to allow
189 * efficient identification of new messages to be added to the
190 * database. The 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_timestamp with the path of the
197 * directory as 'key' and the originally read mtime as 'value'.
199 * Then, when wanting to check for updates to the directory in the
200 * future, the client can call notmuch_database_get_timestamp and know
201 * that it only needs to add files if the mtime of the directory and
202 * files are newer than the stored timestamp.
204 * Note: The notmuch_database_get_timestamp function does not allow
205 * the caller to distinguish a timestamp of 0 from a non-existent
206 * timestamp. So don't store a timestamp of 0 unless you are
207 * comfortable with that.
211 * NOTMUCH_STATUS_SUCCESS: Timestamp successfully stored in database.
213 * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception
214 * occurred. Timestamp not stored.
217 notmuch_database_set_timestamp (notmuch_database_t *database,
218 const char *key, time_t timestamp);
220 /* Retrieve a timestamp from the database.
222 * Returns the timestamp value previously stored by calling
223 * notmuch_database_set_timestamp with the same value for 'key'.
225 * Returns 0 if no timestamp is stored for 'key' or if any error
226 * occurred querying the database.
229 notmuch_database_get_timestamp (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 /* Find a message with the given message_id.
272 * If the database contains a message with the given message_id, then
273 * a new notmuch_message_t object is returned. The caller should call
274 * notmuch_message_destroy when done with the message.
276 * If no message is found with the given message_id or if an
277 * out-of-memory situation occurs, this function returns NULL.
280 notmuch_database_find_message (notmuch_database_t *database,
281 const char *message_id);
283 /* Create a new query for 'database'.
285 * Here, 'database' should be an open database, (see
286 * notmuch_database_open and notmuch_database_create).
288 * For the query string, we'll document the syntax here more
289 * completely in the future, but it's likely to be a specialized
290 * version of the general Xapian query syntax:
292 * http://xapian.org/docs/queryparser.html
294 * As a special case, passing a length-zero string, (that is ""), will
295 * result in a query that returns all messages in the database.
297 * See notmuch_query_set_sort for controlling the order of results and
298 * notmuch_query_search to actually execute the query.
300 * User should call notmuch_query_destroy when finished with this
303 * Will return NULL if insufficient memory is available.
306 notmuch_query_create (notmuch_database_t *database,
307 const char *query_string);
309 /* Sort values for notmuch_query_set_sort */
311 NOTMUCH_SORT_OLDEST_FIRST,
312 NOTMUCH_SORT_NEWEST_FIRST,
313 NOTMUCH_SORT_MESSAGE_ID
316 /* Specify the sorting desired for this query. */
318 notmuch_query_set_sort (notmuch_query_t *query, notmuch_sort_t sort);
320 /* Execute a query for threads, returning a notmuch_threads_t object
321 * which can be used to iterate over the results. The returned threads
322 * object is owned by the query and as such, will only be valid until
323 * notmuch_query_destroy.
325 * Typical usage might be:
327 * notmuch_query_t *query;
328 * notmuch_threads_t *threads;
329 * notmuch_thread_t *thread;
331 * query = notmuch_query_create (database, query_string);
333 * for (threads = notmuch_query_search_threads (query);
334 * notmuch_threads_has_more (threads);
335 * notmuch_threads_advance (threads))
337 * thread = notmuch_threads_get (threads);
339 * notmuch_thread_destroy (thread);
342 * notmuch_query_destroy (query);
344 * Note: If you are finished with a thread before its containing
345 * query, you can call notmuch_thread_destroy to clean up some memory
346 * sooner (as in the above example). Otherwise, if your thread objects
347 * are long-lived, then you don't need to call notmuch_thread_destroy
348 * and all the memory will still be reclaimed when the query is
351 * Note that there's no explicit destructor needed for the
352 * notmuch_threads_t object. (For consistency, we do provide a
353 * notmuch_threads_destroy function, but there's no good reason
354 * to call it if the query is about to be destroyed).
357 notmuch_query_search_threads (notmuch_query_t *query);
359 /* Execute a query for messages, returning a notmuch_messages_t object
360 * which can be used to iterate over the results. The returned
361 * messages object is owned by the query and as such, will only be
362 * valid until notmuch_query_destroy.
364 * The 'first' and 'max_messages' arguments can be used to obtain
365 * partial results from the search. For example, to get results 10 at
366 * a time, pass 'max_messages' as 10 and for 'first' pass the values
367 * 0, 10, 20, etc. As a special case, a value of -1 for 'max_messages'
368 * indicates that no limiting is to be performed. So a search with
369 * 'first' == 0 and 'max_messages' == -1 will return the complete
370 * results of the search.
372 * Typical usage might be:
374 * notmuch_query_t *query;
375 * notmuch_messages_t *messages;
376 * notmuch_message_t *message;
378 * query = notmuch_query_create (database, query_string);
380 * for (messages = notmuch_query_search_messages (query);
381 * notmuch_messages_has_more (messages);
382 * notmuch_messages_advance (messages))
384 * message = notmuch_messages_get (messages);
386 * notmuch_message_destroy (message);
389 * notmuch_query_destroy (query);
391 * Note: If you are finished with a message before its containing
392 * query, you can call notmuch_message_destroy to clean up some memory
393 * sooner (as in the above example). Otherwise, if your message
394 * objects are long-lived, then you don't need to call
395 * notmuch_message_destroy and all the memory will still be reclaimed
396 * when the query is destroyed.
398 * Note that there's no explicit destructor needed for the
399 * notmuch_messages_t object. (For consistency, we do provide a
400 * notmuch_messages_destroy function, but there's no good
401 * reason to call it if the query is about to be destroyed).
404 notmuch_query_search_messages (notmuch_query_t *query,
405 int first, int max_messages);
407 /* Destroy a notmuch_query_t along with any associated resources.
409 * This will in turn destroy any notmuch_threads_t and
410 * notmuch_messages_t objects generated by this query, (and in
411 * turn any notmuch_thrad_t and notmuch_message_t objects generated
412 * from those results, etc.), if such objects haven't already been
416 notmuch_query_destroy (notmuch_query_t *query);
418 /* Does the given notmuch_threads_t object contain any more
421 * When this function returns TRUE, notmuch_threads_get will
422 * return a valid object. Whereas when this function returns FALSE,
423 * notmuch_threads_get will return NULL.
425 * See the documentation of notmuch_query_search_threads for example
426 * code showing how to iterate over a notmuch_threads_t object.
429 notmuch_threads_has_more (notmuch_threads_t *threads);
431 /* Get the current thread from 'threads' as a notmuch_thread_t.
433 * Note: The returned thread belongs to 'threads' and has a lifetime
434 * identical to it (and the query to which it belongs).
436 * See the documentation of notmuch_query_search_threads for example
437 * code showing how to iterate over a notmuch_threads_t object.
439 * If an out-of-memory situation occurs, this function will return
443 notmuch_threads_get (notmuch_threads_t *threads);
445 /* Advance the 'threads' iterator to the next thread.
447 * See the documentation of notmuch_query_search_threads for example
448 * code showing how to iterate over a notmuch_threads_t object.
451 notmuch_threads_advance (notmuch_threads_t *threads);
453 /* Destroy a notmuch_threads_t object.
455 * It's not strictly necessary to call this function. All memory from
456 * the notmuch_threads_t object will be reclaimed when the
457 * containg query object is destroyed.
460 notmuch_threads_destroy (notmuch_threads_t *threads);
462 /* Return an estimate of the number of messages matching a search
464 * This function performs a search and returns Xapian's best
465 * guess as to number of matching messages.
468 notmuch_query_count_messages (notmuch_query_t *query);
470 /* Get the thread ID of 'thread'.
472 * The returned string belongs to 'thread' and as such, should not be
473 * modified by the caller and will only be valid for as long as the
474 * thread is valid, (which is until notmuch_thread_destroy or until
475 * the query from which it derived is destroyed).
478 notmuch_thread_get_thread_id (notmuch_thread_t *thread);
480 /* Get the total number of messages in 'thread'.
482 * This count consists of all messages in the database belonging to
483 * this thread. Contrast with notmuch_thread_get_matched_messages() .
486 notmuch_thread_get_total_messages (notmuch_thread_t *thread);
488 /* Get a notmuch_messages_t iterator for the top-level messages in
491 * This iterator will not necessarily iterate over all of the messages
492 * in the thread. It will only iterate over the messages in the thread
493 * which are not replies to other messages in the thread.
495 * To iterate over all messages in the thread, the caller will need to
496 * iterate over the result of notmuch_message_get_replies for each
497 * top-level message (and do that recursively for the resulting
501 notmuch_thread_get_toplevel_messages (notmuch_thread_t *thread);
503 /* Get the number of messages in 'thread' that matched the search.
505 * This count includes only the messages in this thread that were
506 * matched by the search from which the thread was created. Contrast
507 * with notmuch_thread_get_total_messages() .
510 notmuch_thread_get_matched_messages (notmuch_thread_t *thread);
512 /* Get the authors of 'thread'
514 * The returned string is a comma-separated list of the names of the
515 * authors of mail messages in the query results that belong to this
518 * The returned string belongs to 'thread' and as such, should not be
519 * modified by the caller and will only be valid for as long as the
520 * thread is valid, (which is until notmuch_thread_destroy or until
521 * the query from which it derived is destroyed).
524 notmuch_thread_get_authors (notmuch_thread_t *thread);
526 /* Get the subject of 'thread'
528 * The subject is taken from the first message (according to the query
529 * order---see notmuch_query_set_sort) in the query results that
530 * belongs to this thread.
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_subject (notmuch_thread_t *thread);
540 /* Get the date of the oldest message in 'thread' as a time_t value.
543 notmuch_thread_get_oldest_date (notmuch_thread_t *thread);
545 /* Get the date of the oldest message in 'thread' as a time_t value.
548 notmuch_thread_get_newest_date (notmuch_thread_t *thread);
550 /* Get the tags for 'thread', returning a notmuch_tags_t object which
551 * can be used to iterate over all tags.
553 * Note: In the Notmuch database, tags are stored on individual
554 * messages, not on threads. So the tags returned here will be all
555 * tags of the messages which matched the search and which belong to
558 * The tags object is owned by the thread and as such, will only be
559 * valid for as long as the thread is valid, (for example, until
560 * notmuch_thread_destroy or until the query from which it derived is
563 * Typical usage might be:
565 * notmuch_thread_t *thread;
566 * notmuch_tags_t *tags;
569 * thread = notmuch_threads_get (threads);
571 * for (tags = notmuch_thread_get_tags (thread);
572 * notmuch_tags_has_more (tags);
573 * notmuch_result_advance (tags))
575 * tag = notmuch_tags_get (tags);
579 * notmuch_thread_destroy (thread);
581 * Note that there's no explicit destructor needed for the
582 * notmuch_tags_t object. (For consistency, we do provide a
583 * notmuch_tags_destroy function, but there's no good reason to call
584 * it if the message is about to be destroyed).
587 notmuch_thread_get_tags (notmuch_thread_t *thread);
589 /* Destroy a notmuch_thread_t object. */
591 notmuch_thread_destroy (notmuch_thread_t *thread);
593 /* Does the given notmuch_messages_t object contain any more
596 * When this function returns TRUE, notmuch_messages_get will return a
597 * valid object. Whereas when this function returns FALSE,
598 * notmuch_messages_get will return NULL.
600 * See the documentation of notmuch_query_search_messages for example
601 * code showing how to iterate over a notmuch_messages_t object.
604 notmuch_messages_has_more (notmuch_messages_t *messages);
606 /* Get the current message from 'messages' as a notmuch_message_t.
608 * Note: The returned message belongs to 'messages' and has a lifetime
609 * identical to it (and the query to which it belongs).
611 * See the documentation of notmuch_query_search_messages for example
612 * code showing how to iterate over a notmuch_messages_t object.
614 * If an out-of-memory situation occurs, this function will return
618 notmuch_messages_get (notmuch_messages_t *messages);
620 /* Advance the 'messages' iterator to the next result.
622 * See the documentation of notmuch_query_search_messages for example
623 * code showing how to iterate over a notmuch_messages_t object.
626 notmuch_messages_advance (notmuch_messages_t *messages);
628 /* Destroy a notmuch_messages_t object.
630 * It's not strictly necessary to call this function. All memory from
631 * the notmuch_messages_t object will be reclaimed when the containing
632 * query object is destroyed.
635 notmuch_messages_destroy (notmuch_messages_t *messages);
637 /* Get the message ID of 'message'.
639 * The returned string belongs to 'message' and as such, should not be
640 * modified by the caller and will only be valid for as long as the
641 * message is valid, (which is until the query from which it derived
644 * This function will not return NULL since Notmuch ensures that every
645 * message has a unique message ID, (Notmuch will generate an ID for a
646 * message if the original file does not contain one).
649 notmuch_message_get_message_id (notmuch_message_t *message);
651 /* Get the thread ID of 'message'.
653 * The returned string belongs to 'message' and as such, should not be
654 * modified by the caller and will only be valid for as long as the
655 * message is valid, (for example, until the user calls
656 * notmuch_message_destroy on 'message' or until a query from which it
657 * derived is destroyed).
659 * This function will not return NULL since Notmuch ensures that every
660 * message belongs to a single thread.
663 notmuch_message_get_thread_id (notmuch_message_t *message);
665 /* Get a notmuch_messages_t iterator for all of the replies to
668 * Note: This call only makes sense if 'message' was ultimately
669 * obtained from a notmuch_thread_t object, (such as by coming
670 * directly from the result of calling notmuch_thread_get_
671 * toplevel_messages or by any number of subsequent
672 * calls to notmuch_message_get_replies).
674 * If 'message' was obtained through some non-thread means, (such as
675 * by a call to notmuch_query_search_messages), then this function
678 * If there are no replies to 'message', this function will return
679 * NULL. (Note that notmuch_messages_has_more will accept that NULL
680 * value as legitimate, and simply return FALSE for it.)
683 notmuch_message_get_replies (notmuch_message_t *message);
685 /* Get the filename for the email corresponding to 'message'.
687 * The returned filename is an absolute filename, (the initial
688 * component will match notmuch_database_get_path() ).
690 * The returned string belongs to the message so should not be
691 * modified or freed by the caller (nor should it be referenced after
692 * the message is destroyed). */
694 notmuch_message_get_filename (notmuch_message_t *message);
696 /* Get the date of 'message' as a time_t value.
698 * For the original textual representation of the Date header from the
699 * message call notmuch_message_get_header() with a header value of
702 notmuch_message_get_date (notmuch_message_t *message);
704 /* Get the value of the specified header from 'message'.
706 * The value will be read from the actual message file, not from the
707 * notmuch database. The header name is case insensitive.
709 * The returned string belongs to the message so should not be
710 * modified or freed by the caller (nor should it be referenced after
711 * the message is destroyed).
713 * Returns an empty string ("") if the message does not contain a
714 * header line matching 'header'. Returns NULL if any error occurs.
717 notmuch_message_get_header (notmuch_message_t *message, const char *header);
719 /* Get the tags for 'message', returning a notmuch_tags_t object which
720 * can be used to iterate over all tags.
722 * The tags object is owned by the message and as such, will only be
723 * valid for as long as the message is valid, (which is until the
724 * query from which it derived is destroyed).
726 * Typical usage might be:
728 * notmuch_message_t *message;
729 * notmuch_tags_t *tags;
732 * message = notmuch_database_find_message (database, message_id);
734 * for (tags = notmuch_message_get_tags (message);
735 * notmuch_tags_has_more (tags);
736 * notmuch_result_advance (tags))
738 * tag = notmuch_tags_get (tags);
742 * notmuch_message_destroy (message);
744 * Note that there's no explicit destructor needed for the
745 * notmuch_tags_t object. (For consistency, we do provide a
746 * notmuch_tags_destroy function, but there's no good reason to call
747 * it if the message is about to be destroyed).
750 notmuch_message_get_tags (notmuch_message_t *message);
752 /* The longest possible tag value. */
753 #define NOTMUCH_TAG_MAX 200
755 /* Add a tag to the given message.
759 * NOTMUCH_STATUS_SUCCESS: Tag successfully added to message
761 * NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
763 * NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is too long
764 * (exceeds NOTMUCH_TAG_MAX)
767 notmuch_message_add_tag (notmuch_message_t *message, const char *tag);
769 /* Remove a tag from the given message.
773 * NOTMUCH_STATUS_SUCCESS: Tag successfully removed from message
775 * NOTMUCH_STATUS_NULL_POINTER: The 'tag' argument is NULL
777 * NOTMUCH_STATUS_TAG_TOO_LONG: The length of 'tag' is too long
778 * (exceeds NOTMUCH_TAG_MAX)
781 notmuch_message_remove_tag (notmuch_message_t *message, const char *tag);
783 /* Remove all tags from the given message.
785 * See notmuch_message_freeze for an example showing how to safely
786 * replace tag values.
789 notmuch_message_remove_all_tags (notmuch_message_t *message);
791 /* Freeze the current state of 'message' within the database.
793 * This means that changes to the message state, (via
794 * notmuch_message_add_tag, notmuch_message_remove_tag, and
795 * notmuch_message_remove_all_tags), will not be committed to the
796 * database until the message is thawed with notmuch_message_thaw.
798 * Multiple calls to freeze/thaw are valid and these calls with
799 * "stack". That is there must be as many calls to thaw as to freeze
800 * before a message is actually thawed.
802 * The ability to do freeze/thaw allows for safe transactions to
803 * change tag values. For example, explicitly setting a message to
804 * have a given set of tags might look like this:
806 * notmuch_message_freeze (message);
808 * notmuch_message_remove_all_tags (message);
810 * for (i = 0; i < NUM_TAGS; i++)
811 * notmuch_message_add_tag (message, tags[i]);
813 * notmuch_message_thaw (message);
815 * With freeze/thaw used like this, the message in the database is
816 * guaranteed to have either the full set of original tag value, or
817 * the full set of new tag values, but nothing in between.
819 * Imagine the example above without freeze/thaw and the operation
820 * somehow getting interrupted. This could result in the message being
821 * left with no tags if the interruption happened after
822 * notmuch_message_remove_all_tags but before notmuch_message_add_tag.
825 notmuch_message_freeze (notmuch_message_t *message);
827 /* Thaw the current 'message', synchronizing any changes that may have
828 * occurred while 'message' was frozen into the notmuch database.
830 * See notmuch_message_freeze for an example of how to use this
831 * function to safely provide tag changes.
833 * Multiple calls to freeze/thaw are valid and these calls with
834 * "stack". That is there must be as many calls to thaw as to freeze
835 * before a message is actually thawed.
839 * NOTMUCH_STATUS_SUCCESS: Message successfully thawed, (or at least
840 * its frozen count has successfully been reduced by 1).
842 * NOTMUCH_STATUS_UNBALANCE_FREEZE_THAW: An attempt was made to thaw
843 * an unfrozen message. That is, there have been an unbalanced
844 * number of calls to notmuch_message_freeze and
845 * notmuch_message_thaw.
848 notmuch_message_thaw (notmuch_message_t *message);
850 /* Destroy a notmuch_message_t object.
852 * It can be useful to call this function in the case of a single
853 * query object with many messages in the result, (such as iterating
854 * over the entire database). Otherwise, it's fine to never call this
855 * function and there will still be no memory leaks. (The memory from
856 * the messages get reclaimed when the containing query is destroyed.)
859 notmuch_message_destroy (notmuch_message_t *message);
861 /* Does the given notmuch_tags_t object contain any more tags.
863 * When this function returns TRUE, notmuch_tags_get will return a
864 * valid string. Whereas when this function returns FALSE,
865 * notmuch_tags_get will return NULL.
867 * See the documentation of notmuch_message_get_tags for example code
868 * showing how to iterate over a notmuch_tags_t object.
871 notmuch_tags_has_more (notmuch_tags_t *tags);
873 /* Get the current tag from 'tags' as a string.
875 * Note: The returned string belongs to 'tags' and has a lifetime
876 * identical to it (and the query to which it ultimately belongs).
878 * See the documentation of notmuch_message_get_tags for example code
879 * showing how to iterate over a notmuch_tags_t object.
882 notmuch_tags_get (notmuch_tags_t *tags);
884 /* Advance the 'tags' iterator to the next tag.
886 * See the documentation of notmuch_message_get_tags for example code
887 * showing how to iterate over a notmuch_tags_t object.
890 notmuch_tags_advance (notmuch_tags_t *tags);
892 /* Destroy a notmuch_tags_t object.
894 * It's not strictly necessary to call this function. All memory from
895 * the notmuch_tags_t object will be reclaimed when the containing
896 * message or query objects are destroyed.
899 notmuch_tags_destroy (notmuch_tags_t *tags);