git.notmuchmail.org Git - notmuch/blob - lib/query.cc

   1 /* query.cc - Support for searching a notmuch database
   2  *
   3  * Copyright © 2009 Carl Worth
   4  *
   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.
   9  *
  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.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see https://www.gnu.org/licenses/ .
  17  *
  18  * Author: Carl Worth <cworth@cworth.org>
  19  */
  20
  21 #include "notmuch-private.h"
  22 #include "database-private.h"
  23
  24 #include <glib.h> /* GHashTable, GPtrArray */
  25
  26 struct _notmuch_query {
  27     notmuch_database_t *notmuch;
  28     const char *query_string;
  29     notmuch_sort_t sort;
  30     notmuch_string_list_t *exclude_terms;
  31     notmuch_exclude_t omit_excluded;
  32     notmuch_bool_t parsed;
  33     Xapian::Query xapian_query;
  34 };
  35
  36 typedef struct _notmuch_mset_messages {
  37     notmuch_messages_t base;
  38     notmuch_database_t *notmuch;
  39     Xapian::MSetIterator iterator;
  40     Xapian::MSetIterator iterator_end;
  41 } notmuch_mset_messages_t;
  42
  43 struct _notmuch_doc_id_set {
  44     unsigned char *bitmap;
  45     unsigned int bound;
  46 };
  47
  48 #define DOCIDSET_WORD(bit) ((bit) / CHAR_BIT)
  49 #define DOCIDSET_BIT(bit) ((bit) % CHAR_BIT)
  50
  51 struct visible _notmuch_threads {
  52     notmuch_query_t *query;
  53
  54     /* The ordered list of doc ids matched by the query. */
  55     GArray *doc_ids;
  56     /* Our iterator's current position in doc_ids. */
  57     unsigned int doc_id_pos;
  58     /* The set of matched docid's that have not been assigned to a
  59      * thread. Initially, this contains every docid in doc_ids. */
  60     notmuch_doc_id_set_t match_set;
  61 };
  62
  63 /* We need this in the message functions so forward declare. */
  64 static notmuch_bool_t
  65 _notmuch_doc_id_set_init (void *ctx,
  66                           notmuch_doc_id_set_t *doc_ids,
  67                           GArray *arr);
  68
  69 static notmuch_bool_t
  70 _debug_query (void)
  71 {
  72     char *env = getenv ("NOTMUCH_DEBUG_QUERY");
  73     return (env && strcmp (env, "") != 0);
  74 }
  75
  76 /* Explicit destructor call for placement new */
  77 static int
  78 _notmuch_query_destructor (notmuch_query_t *query) {
  79     query->xapian_query.~Query();
  80     return 0;
  81 }
  82
  83 notmuch_query_t *
  84 notmuch_query_create (notmuch_database_t *notmuch,
  85                       const char *query_string)
  86 {
  87     notmuch_query_t *query;
  88
  89     if (_debug_query ())
  90         fprintf (stderr, "Query string is:\n%s\n", query_string);
  91
  92     query = talloc (notmuch, notmuch_query_t);
  93     if (unlikely (query == NULL))
  94         return NULL;
  95
  96     new (&query->xapian_query) Xapian::Query ();
  97     query->parsed = FALSE;
  98
  99     talloc_set_destructor (query, _notmuch_query_destructor);
 100
 101     query->notmuch = notmuch;
 102
 103     query->query_string = talloc_strdup (query, query_string);
 104
 105     query->sort = NOTMUCH_SORT_NEWEST_FIRST;
 106
 107     query->exclude_terms = _notmuch_string_list_create (query);
 108
 109     query->omit_excluded = NOTMUCH_EXCLUDE_TRUE;
 110
 111     return query;
 112 }
 113
 114 static notmuch_status_t
 115 _notmuch_query_ensure_parsed (notmuch_query_t *query)
 116 {
 117     if (query->parsed)
 118         return NOTMUCH_STATUS_SUCCESS;
 119
 120     try {
 121         query->xapian_query =
 122             query->notmuch->query_parser->
 123                 parse_query (query->query_string, NOTMUCH_QUERY_PARSER_FLAGS);
 124
 125         query->parsed = TRUE;
 126
 127     } catch (const Xapian::Error &error) {
 128         if (!query->notmuch->exception_reported) {
 129             _notmuch_database_log (query->notmuch,
 130                                    "A Xapian exception occurred parsing query: %s\n",
 131                                    error.get_msg ().c_str ());
 132             _notmuch_database_log_append (query->notmuch,
 133                                           "Query string was: %s\n",
 134                                           query->query_string);
 135             query->notmuch->exception_reported = TRUE;
 136         }
 137
 138         return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 139     }
 140     return NOTMUCH_STATUS_SUCCESS;
 141 }
 142
 143 const char *
 144 notmuch_query_get_query_string (const notmuch_query_t *query)
 145 {
 146     return query->query_string;
 147 }
 148
 149 void
 150 notmuch_query_set_omit_excluded (notmuch_query_t *query,
 151                                  notmuch_exclude_t omit_excluded)
 152 {
 153     query->omit_excluded = omit_excluded;
 154 }
 155
 156 void
 157 notmuch_query_set_sort (notmuch_query_t *query, notmuch_sort_t sort)
 158 {
 159     query->sort = sort;
 160 }
 161
 162 notmuch_sort_t
 163 notmuch_query_get_sort (const notmuch_query_t *query)
 164 {
 165     return query->sort;
 166 }
 167
 168 void
 169 notmuch_query_add_tag_exclude (notmuch_query_t *query, const char *tag)
 170 {
 171     char *term = talloc_asprintf (query, "%s%s", _find_prefix ("tag"), tag);
 172     _notmuch_string_list_append (query->exclude_terms, term);
 173 }
 174
 175 /* We end up having to call the destructors explicitly because we had
 176  * to use "placement new" in order to initialize C++ objects within a
 177  * block that we allocated with talloc. So C++ is making talloc
 178  * slightly less simple to use, (we wouldn't need
 179  * talloc_set_destructor at all otherwise).
 180  */
 181 static int
 182 _notmuch_messages_destructor (notmuch_mset_messages_t *messages)
 183 {
 184     messages->iterator.~MSetIterator ();
 185     messages->iterator_end.~MSetIterator ();
 186
 187     return 0;
 188 }
 189
 190 /* Return a query that matches messages with the excluded tags
 191  * registered with query.  Any tags that explicitly appear in xquery
 192  * will not be excluded, and will be removed from the list of exclude
 193  * tags.  The caller of this function has to combine the returned
 194  * query appropriately.*/
 195 static Xapian::Query
 196 _notmuch_exclude_tags (notmuch_query_t *query, Xapian::Query xquery)
 197 {
 198     Xapian::Query exclude_query = Xapian::Query::MatchNothing;
 199
 200     for (notmuch_string_node_t *term = query->exclude_terms->head; term;
 201          term = term->next) {
 202         Xapian::TermIterator it = xquery.get_terms_begin ();
 203         Xapian::TermIterator end = xquery.get_terms_end ();
 204         for (; it != end; it++) {
 205             if ((*it).compare (term->string) == 0)
 206                 break;
 207         }
 208         if (it == end)
 209             exclude_query = Xapian::Query (Xapian::Query::OP_OR,
 210                                     exclude_query, Xapian::Query (term->string));
 211         else
 212             term->string = talloc_strdup (query, "");
 213     }
 214     return exclude_query;
 215 }
 216
 217 notmuch_messages_t *
 218 notmuch_query_search_messages (notmuch_query_t *query)
 219 {
 220     notmuch_status_t status;
 221     notmuch_messages_t *messages;
 222     status = notmuch_query_search_messages_st (query, &messages);
 223     if (status)
 224         return NULL;
 225     else
 226         return messages;
 227 }
 228
 229 notmuch_status_t
 230 notmuch_query_search_messages_st (notmuch_query_t *query,
 231                                   notmuch_messages_t **out)
 232 {
 233     return _notmuch_query_search_documents (query, "mail", out);
 234 }
 235
 236 notmuch_status_t
 237 _notmuch_query_search_documents (notmuch_query_t *query,
 238                                  const char *type,
 239                                  notmuch_messages_t **out)
 240 {
 241     notmuch_database_t *notmuch = query->notmuch;
 242     const char *query_string = query->query_string;
 243     notmuch_mset_messages_t *messages;
 244     notmuch_status_t status;
 245
 246     status = _notmuch_query_ensure_parsed (query);
 247     if (status)
 248         return status;
 249
 250     messages = talloc (query, notmuch_mset_messages_t);
 251     if (unlikely (messages == NULL))
 252         return NOTMUCH_STATUS_OUT_OF_MEMORY;
 253
 254     try {
 255
 256         messages->base.is_of_list_type = FALSE;
 257         messages->base.iterator = NULL;
 258         messages->notmuch = notmuch;
 259         new (&messages->iterator) Xapian::MSetIterator ();
 260         new (&messages->iterator_end) Xapian::MSetIterator ();
 261
 262         talloc_set_destructor (messages, _notmuch_messages_destructor);
 263
 264         Xapian::Enquire enquire (*notmuch->xapian_db);
 265         Xapian::Query mail_query (talloc_asprintf (query, "%s%s",
 266                                                    _find_prefix ("type"),
 267                                                    type));
 268         Xapian::Query final_query, exclude_query;
 269         Xapian::MSet mset;
 270         Xapian::MSetIterator iterator;
 271
 272         if (strcmp (query_string, "") == 0 ||
 273             strcmp (query_string, "*") == 0)
 274         {
 275             final_query = mail_query;
 276         } else {
 277             final_query = Xapian::Query (Xapian::Query::OP_AND,
 278                                          mail_query, query->xapian_query);
 279         }
 280         messages->base.excluded_doc_ids = NULL;
 281
 282         if ((query->omit_excluded != NOTMUCH_EXCLUDE_FALSE) && (query->exclude_terms)) {
 283             exclude_query = _notmuch_exclude_tags (query, final_query);
 284
 285             if (query->omit_excluded == NOTMUCH_EXCLUDE_TRUE ||
 286                 query->omit_excluded == NOTMUCH_EXCLUDE_ALL)
 287             {
 288                 final_query = Xapian::Query (Xapian::Query::OP_AND_NOT,
 289                                              final_query, exclude_query);
 290             } else { /* NOTMUCH_EXCLUDE_FLAG */
 291                 exclude_query = Xapian::Query (Xapian::Query::OP_AND,
 292                                            exclude_query, final_query);
 293
 294                 enquire.set_weighting_scheme (Xapian::BoolWeight());
 295                 enquire.set_query (exclude_query);
 296
 297                 mset = enquire.get_mset (0, notmuch->xapian_db->get_doccount ());
 298
 299                 GArray *excluded_doc_ids = g_array_new (FALSE, FALSE, sizeof (unsigned int));
 300
 301                 for (iterator = mset.begin (); iterator != mset.end (); iterator++) {
 302                     unsigned int doc_id = *iterator;
 303                     g_array_append_val (excluded_doc_ids, doc_id);
 304                 }
 305                 messages->base.excluded_doc_ids = talloc (messages, _notmuch_doc_id_set);
 306                 _notmuch_doc_id_set_init (query, messages->base.excluded_doc_ids,
 307                                           excluded_doc_ids);
 308                 g_array_unref (excluded_doc_ids);
 309             }
 310         }
 311
 312
 313         enquire.set_weighting_scheme (Xapian::BoolWeight());
 314
 315         switch (query->sort) {
 316         case NOTMUCH_SORT_OLDEST_FIRST:
 317             enquire.set_sort_by_value (NOTMUCH_VALUE_TIMESTAMP, FALSE);
 318             break;
 319         case NOTMUCH_SORT_NEWEST_FIRST:
 320             enquire.set_sort_by_value (NOTMUCH_VALUE_TIMESTAMP, TRUE);
 321             break;
 322         case NOTMUCH_SORT_MESSAGE_ID:
 323             enquire.set_sort_by_value (NOTMUCH_VALUE_MESSAGE_ID, FALSE);
 324             break;
 325         case NOTMUCH_SORT_UNSORTED:
 326             break;
 327         }
 328
 329         if (_debug_query ()) {
 330             fprintf (stderr, "Exclude query is:\n%s\n",
 331                      exclude_query.get_description ().c_str ());
 332             fprintf (stderr, "Final query is:\n%s\n",
 333                      final_query.get_description ().c_str ());
 334         }
 335
 336         enquire.set_query (final_query);
 337
 338         mset = enquire.get_mset (0, notmuch->xapian_db->get_doccount ());
 339
 340         messages->iterator = mset.begin ();
 341         messages->iterator_end = mset.end ();
 342
 343         *out = &messages->base;
 344         return NOTMUCH_STATUS_SUCCESS;
 345
 346     } catch (const Xapian::Error &error) {
 347         _notmuch_database_log (notmuch,
 348                                "A Xapian exception occurred performing query: %s\n",
 349                                error.get_msg().c_str());
 350         _notmuch_database_log_append (notmuch,
 351                                "Query string was: %s\n",
 352                                query->query_string);
 353
 354         notmuch->exception_reported = TRUE;
 355         talloc_free (messages);
 356         return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 357     }
 358 }
 359
 360 notmuch_bool_t
 361 _notmuch_mset_messages_valid (notmuch_messages_t *messages)
 362 {
 363     notmuch_mset_messages_t *mset_messages;
 364
 365     mset_messages = (notmuch_mset_messages_t *) messages;
 366
 367     return (mset_messages->iterator != mset_messages->iterator_end);
 368 }
 369
 370 static Xapian::docid
 371 _notmuch_mset_messages_get_doc_id (notmuch_messages_t *messages)
 372 {
 373     notmuch_mset_messages_t *mset_messages;
 374
 375     mset_messages = (notmuch_mset_messages_t *) messages;
 376
 377     if (! _notmuch_mset_messages_valid (&mset_messages->base))
 378         return 0;
 379
 380     return *mset_messages->iterator;
 381 }
 382
 383 notmuch_message_t *
 384 _notmuch_mset_messages_get (notmuch_messages_t *messages)
 385 {
 386     notmuch_message_t *message;
 387     Xapian::docid doc_id;
 388     notmuch_private_status_t status;
 389     notmuch_mset_messages_t *mset_messages;
 390
 391     mset_messages = (notmuch_mset_messages_t *) messages;
 392
 393     if (! _notmuch_mset_messages_valid (&mset_messages->base))
 394         return NULL;
 395
 396     doc_id = *mset_messages->iterator;
 397
 398     message = _notmuch_message_create (mset_messages,
 399                                        mset_messages->notmuch, doc_id,
 400                                        &status);
 401
 402     if (message == NULL &&
 403        status == NOTMUCH_PRIVATE_STATUS_NO_DOCUMENT_FOUND)
 404     {
 405         INTERNAL_ERROR ("a messages iterator contains a non-existent document ID.\n");
 406     }
 407
 408     if (messages->excluded_doc_ids &&
 409         _notmuch_doc_id_set_contains (messages->excluded_doc_ids, doc_id))
 410         notmuch_message_set_flag (message, NOTMUCH_MESSAGE_FLAG_EXCLUDED, TRUE);
 411
 412     return message;
 413 }
 414
 415 void
 416 _notmuch_mset_messages_move_to_next (notmuch_messages_t *messages)
 417 {
 418     notmuch_mset_messages_t *mset_messages;
 419
 420     mset_messages = (notmuch_mset_messages_t *) messages;
 421
 422     mset_messages->iterator++;
 423 }
 424
 425 static notmuch_bool_t
 426 _notmuch_doc_id_set_init (void *ctx,
 427                           notmuch_doc_id_set_t *doc_ids,
 428                           GArray *arr)
 429 {
 430     unsigned int max = 0;
 431     unsigned char *bitmap;
 432
 433     for (unsigned int i = 0; i < arr->len; i++)
 434         max = MAX(max, g_array_index (arr, unsigned int, i));
 435     bitmap = talloc_zero_array (ctx, unsigned char, DOCIDSET_WORD(max) + 1);
 436
 437     if (bitmap == NULL)
 438         return FALSE;
 439
 440     doc_ids->bitmap = bitmap;
 441     doc_ids->bound = max + 1;
 442
 443     for (unsigned int i = 0; i < arr->len; i++) {
 444         unsigned int doc_id = g_array_index (arr, unsigned int, i);
 445         bitmap[DOCIDSET_WORD(doc_id)] |= 1 << DOCIDSET_BIT(doc_id);
 446     }
 447
 448     return TRUE;
 449 }
 450
 451 notmuch_bool_t
 452 _notmuch_doc_id_set_contains (notmuch_doc_id_set_t *doc_ids,
 453                               unsigned int doc_id)
 454 {
 455     if (doc_id >= doc_ids->bound)
 456         return FALSE;
 457     return doc_ids->bitmap[DOCIDSET_WORD(doc_id)] & (1 << DOCIDSET_BIT(doc_id));
 458 }
 459
 460 void
 461 _notmuch_doc_id_set_remove (notmuch_doc_id_set_t *doc_ids,
 462                             unsigned int doc_id)
 463 {
 464     if (doc_id < doc_ids->bound)
 465         doc_ids->bitmap[DOCIDSET_WORD(doc_id)] &= ~(1 << DOCIDSET_BIT(doc_id));
 466 }
 467
 468 /* Glib objects force use to use a talloc destructor as well, (but not
 469  * nearly as ugly as the for messages due to C++ objects). At
 470  * this point, I'd really like to have some talloc-friendly
 471  * equivalents for the few pieces of glib that I'm using. */
 472 static int
 473 _notmuch_threads_destructor (notmuch_threads_t *threads)
 474 {
 475     if (threads->doc_ids)
 476         g_array_unref (threads->doc_ids);
 477
 478     return 0;
 479 }
 480
 481
 482 notmuch_threads_t *
 483 notmuch_query_search_threads (notmuch_query_t *query)
 484 {
 485     notmuch_status_t status;
 486     notmuch_threads_t *threads;
 487     status = notmuch_query_search_threads_st (query, &threads);
 488     if (status)
 489         return NULL;
 490     else
 491         return threads;
 492 }
 493
 494 notmuch_status_t
 495 notmuch_query_search_threads_st (notmuch_query_t *query,
 496                                  notmuch_threads_t **out)
 497 {
 498     notmuch_threads_t *threads;
 499     notmuch_messages_t *messages;
 500     notmuch_status_t status;
 501
 502     threads = talloc (query, notmuch_threads_t);
 503     if (threads == NULL)
 504         return NOTMUCH_STATUS_OUT_OF_MEMORY;
 505     threads->doc_ids = NULL;
 506     talloc_set_destructor (threads, _notmuch_threads_destructor);
 507
 508     threads->query = query;
 509
 510     status = notmuch_query_search_messages_st (query, &messages);
 511     if (status) {
 512         talloc_free (threads);
 513         return status;
 514     }
 515
 516     threads->doc_ids = g_array_new (FALSE, FALSE, sizeof (unsigned int));
 517     while (notmuch_messages_valid (messages)) {
 518         unsigned int doc_id = _notmuch_mset_messages_get_doc_id (messages);
 519         g_array_append_val (threads->doc_ids, doc_id);
 520         notmuch_messages_move_to_next (messages);
 521     }
 522     threads->doc_id_pos = 0;
 523
 524     talloc_free (messages);
 525
 526     if (! _notmuch_doc_id_set_init (threads, &threads->match_set,
 527                                     threads->doc_ids)) {
 528         talloc_free (threads);
 529         return NOTMUCH_STATUS_OUT_OF_MEMORY;
 530     }
 531
 532     *out = threads;
 533     return NOTMUCH_STATUS_SUCCESS;
 534 }
 535
 536 void
 537 notmuch_query_destroy (notmuch_query_t *query)
 538 {
 539     talloc_free (query);
 540 }
 541
 542 notmuch_bool_t
 543 notmuch_threads_valid (notmuch_threads_t *threads)
 544 {
 545     unsigned int doc_id;
 546
 547     if (! threads)
 548         return FALSE;
 549
 550     while (threads->doc_id_pos < threads->doc_ids->len) {
 551         doc_id = g_array_index (threads->doc_ids, unsigned int,
 552                                 threads->doc_id_pos);
 553         if (_notmuch_doc_id_set_contains (&threads->match_set, doc_id))
 554             break;
 555
 556         threads->doc_id_pos++;
 557     }
 558
 559     return threads->doc_id_pos < threads->doc_ids->len;
 560 }
 561
 562 notmuch_thread_t *
 563 notmuch_threads_get (notmuch_threads_t *threads)
 564 {
 565     unsigned int doc_id;
 566
 567     if (! notmuch_threads_valid (threads))
 568         return NULL;
 569
 570     doc_id = g_array_index (threads->doc_ids, unsigned int,
 571                             threads->doc_id_pos);
 572     return _notmuch_thread_create (threads->query,
 573                                    threads->query->notmuch,
 574                                    doc_id,
 575                                    &threads->match_set,
 576                                    threads->query->exclude_terms,
 577                                    threads->query->omit_excluded,
 578                                    threads->query->sort);
 579 }
 580
 581 void
 582 notmuch_threads_move_to_next (notmuch_threads_t *threads)
 583 {
 584     threads->doc_id_pos++;
 585 }
 586
 587 void
 588 notmuch_threads_destroy (notmuch_threads_t *threads)
 589 {
 590     talloc_free (threads);
 591 }
 592
 593 unsigned int
 594 notmuch_query_count_messages (notmuch_query_t *query)
 595 {
 596     notmuch_status_t status;
 597     unsigned int count;
 598
 599     status = notmuch_query_count_messages_st (query, &count);
 600     return status ? 0 : count;
 601 }
 602
 603 notmuch_status_t
 604 notmuch_query_count_messages_st (notmuch_query_t *query, unsigned *count_out)
 605 {
 606     return _notmuch_query_count_documents (query, "mail", count_out);
 607 }
 608
 609 notmuch_status_t
 610 _notmuch_query_count_documents (notmuch_query_t *query, const char *type, unsigned *count_out)
 611 {
 612     notmuch_database_t *notmuch = query->notmuch;
 613     const char *query_string = query->query_string;
 614     Xapian::doccount count = 0;
 615     notmuch_status_t status;
 616
 617     status = _notmuch_query_ensure_parsed (query);
 618     if (status)
 619         return status;
 620
 621     try {
 622         Xapian::Enquire enquire (*notmuch->xapian_db);
 623         Xapian::Query mail_query (talloc_asprintf (query, "%s%s",
 624                                                    _find_prefix ("type"),
 625                                                    type));
 626         Xapian::Query final_query, exclude_query;
 627         Xapian::MSet mset;
 628
 629         if (strcmp (query_string, "") == 0 ||
 630             strcmp (query_string, "*") == 0)
 631         {
 632             final_query = mail_query;
 633         } else {
 634             final_query = Xapian::Query (Xapian::Query::OP_AND,
 635                                          mail_query, query->xapian_query);
 636         }
 637
 638         exclude_query = _notmuch_exclude_tags (query, final_query);
 639
 640         final_query = Xapian::Query (Xapian::Query::OP_AND_NOT,
 641                                          final_query, exclude_query);
 642
 643         enquire.set_weighting_scheme(Xapian::BoolWeight());
 644         enquire.set_docid_order(Xapian::Enquire::ASCENDING);
 645
 646         if (_debug_query ()) {
 647             fprintf (stderr, "Exclude query is:\n%s\n",
 648                      exclude_query.get_description ().c_str ());
 649             fprintf (stderr, "Final query is:\n%s\n",
 650                      final_query.get_description ().c_str ());
 651         }
 652
 653         enquire.set_query (final_query);
 654
 655         /*
 656          * Set the checkatleast parameter to the number of documents
 657          * in the database to make get_matches_estimated() exact.
 658          * Set the max parameter to 0 to avoid fetching documents we will discard.
 659          */
 660         mset = enquire.get_mset (0, 0,
 661                                  notmuch->xapian_db->get_doccount ());
 662
 663         count = mset.get_matches_estimated();
 664
 665     } catch (const Xapian::Error &error) {
 666         _notmuch_database_log (notmuch,
 667                                "A Xapian exception occurred performing query: %s\n",
 668                                error.get_msg().c_str());
 669         _notmuch_database_log_append (notmuch,
 670                                       "Query string was: %s\n",
 671                                       query->query_string);
 672         return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 673     }
 674
 675     *count_out = count;
 676     return NOTMUCH_STATUS_SUCCESS;
 677 }
 678
 679 unsigned
 680 notmuch_query_count_threads (notmuch_query_t *query)
 681 {
 682     notmuch_status_t status;
 683     unsigned int count;
 684
 685     status = notmuch_query_count_threads_st (query, &count);
 686     return status ? 0 : count;
 687 }
 688
 689 notmuch_status_t
 690 notmuch_query_count_threads_st (notmuch_query_t *query, unsigned *count)
 691 {
 692     notmuch_messages_t *messages;
 693     GHashTable *hash;
 694     notmuch_sort_t sort;
 695     notmuch_status_t ret = NOTMUCH_STATUS_SUCCESS;
 696
 697     sort = query->sort;
 698     query->sort = NOTMUCH_SORT_UNSORTED;
 699     ret = notmuch_query_search_messages_st (query, &messages);
 700     if (ret)
 701         return ret;
 702     query->sort = sort;
 703     if (messages == NULL)
 704         return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 705
 706     hash = g_hash_table_new_full (g_str_hash, g_str_equal, NULL, NULL);
 707     if (hash == NULL) {
 708         talloc_free (messages);
 709         return NOTMUCH_STATUS_OUT_OF_MEMORY;
 710     }
 711
 712     while (notmuch_messages_valid (messages)) {
 713         notmuch_message_t *message = notmuch_messages_get (messages);
 714         const char *thread_id = notmuch_message_get_thread_id (message);
 715         char *thread_id_copy = talloc_strdup (messages, thread_id);
 716         if (unlikely (thread_id_copy == NULL)) {
 717             notmuch_message_destroy (message);
 718             ret = NOTMUCH_STATUS_OUT_OF_MEMORY;
 719             goto DONE;
 720         }
 721         g_hash_table_insert (hash, thread_id_copy, NULL);
 722         notmuch_message_destroy (message);
 723         notmuch_messages_move_to_next (messages);
 724     }
 725
 726     *count = g_hash_table_size (hash);
 727
 728   DONE:
 729     g_hash_table_unref (hash);
 730     talloc_free (messages);
 731
 732     return ret;
 733 }
 734
 735 notmuch_database_t *
 736 notmuch_query_get_database (const notmuch_query_t *query)
 737 {
 738     return query->notmuch;
 739 }