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