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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     bool parsed;
  33     notmuch_query_syntax_t syntax;
  34     Xapian::Query xapian_query;
  35     std::set<std::string> terms;
  36 };
  37
  38 typedef struct _notmuch_mset_messages {
  39     notmuch_messages_t base;
  40     notmuch_database_t *notmuch;
  41     Xapian::MSetIterator iterator;
  42     Xapian::MSetIterator iterator_end;
  43 } notmuch_mset_messages_t;
  44
  45 struct _notmuch_doc_id_set {
  46     unsigned char *bitmap;
  47     unsigned int bound;
  48 };
  49
  50 #define DOCIDSET_WORD(bit) ((bit) / CHAR_BIT)
  51 #define DOCIDSET_BIT(bit) ((bit) % CHAR_BIT)
  52
  53 struct _notmuch_threads {
  54     notmuch_query_t *query;
  55
  56     /* The ordered list of doc ids matched by the query. */
  57     GArray *doc_ids;
  58     /* Our iterator's current position in doc_ids. */
  59     unsigned int doc_id_pos;
  60     /* The set of matched docid's that have not been assigned to a
  61      * thread. Initially, this contains every docid in doc_ids. */
  62     notmuch_doc_id_set_t match_set;
  63 };
  64
  65 /* We need this in the message functions so forward declare. */
  66 static bool
  67 _notmuch_doc_id_set_init (void *ctx,
  68                           notmuch_doc_id_set_t *doc_ids,
  69                           GArray *arr);
  70
  71 static bool
  72 _debug_query (void)
  73 {
  74     char *env = getenv ("NOTMUCH_DEBUG_QUERY");
  75
  76     return (env && strcmp (env, "") != 0);
  77 }
  78
  79 /* Explicit destructor call for placement new */
  80 static int
  81 _notmuch_query_destructor (notmuch_query_t *query)
  82 {
  83     query->xapian_query.~Query();
  84     query->terms.~set<std::string>();
  85     return 0;
  86 }
  87
  88 static notmuch_query_t *
  89 _notmuch_query_constructor (notmuch_database_t *notmuch,
  90                             const char *query_string)
  91 {
  92     notmuch_query_t *query;
  93
  94     if (_debug_query ())
  95         fprintf (stderr, "Query string is:\n%s\n", query_string);
  96
  97     query = talloc (notmuch, notmuch_query_t);
  98     if (unlikely (query == NULL))
  99         return NULL;
 100
 101     new (&query->xapian_query) Xapian::Query ();
 102     new (&query->terms) std::set<std::string> ();
 103     query->parsed = false;
 104
 105     talloc_set_destructor (query, _notmuch_query_destructor);
 106
 107     query->notmuch = notmuch;
 108
 109     if (query_string)
 110         query->query_string = talloc_strdup (query, query_string);
 111     else
 112         query->query_string = NULL;
 113
 114     query->sort = NOTMUCH_SORT_NEWEST_FIRST;
 115
 116     query->exclude_terms = _notmuch_string_list_create (query);
 117
 118     query->omit_excluded = NOTMUCH_EXCLUDE_TRUE;
 119
 120     return query;
 121 }
 122
 123 notmuch_query_t *
 124 notmuch_query_create (notmuch_database_t *notmuch,
 125                       const char *query_string)
 126 {
 127
 128     notmuch_query_t *query;
 129     notmuch_status_t status;
 130
 131     status = notmuch_query_create_with_syntax (notmuch, query_string,
 132                                                NOTMUCH_QUERY_SYNTAX_XAPIAN,
 133                                                &query);
 134     if (status)
 135         return NULL;
 136
 137     return query;
 138 }
 139
 140 notmuch_status_t
 141 notmuch_query_create_with_syntax (notmuch_database_t *notmuch,
 142                                   const char *query_string,
 143                                   notmuch_query_syntax_t syntax,
 144                                   notmuch_query_t **output)
 145 {
 146
 147     notmuch_query_t *query;
 148
 149     if (! output)
 150         return NOTMUCH_STATUS_NULL_POINTER;
 151
 152     query = _notmuch_query_constructor (notmuch, query_string);
 153     if (! query)
 154         return NOTMUCH_STATUS_OUT_OF_MEMORY;
 155
 156     if (syntax == NOTMUCH_QUERY_SYNTAX_SEXP && ! HAVE_SFSEXP) {
 157         _notmuch_database_log (notmuch, "sexp query parser not available");
 158         return NOTMUCH_STATUS_ILLEGAL_ARGUMENT;
 159     }
 160
 161     query->syntax = syntax;
 162
 163     *output = query;
 164
 165     return NOTMUCH_STATUS_SUCCESS;
 166 }
 167
 168 static void
 169 _notmuch_query_cache_terms (notmuch_query_t *query)
 170 {
 171     /* Xapian doesn't support skip_to on terms from a query since
 172      *  they are unordered, so cache a copy of all terms in
 173      *  something searchable.
 174      */
 175
 176     for (Xapian::TermIterator t = query->xapian_query.get_terms_begin ();
 177          t != query->xapian_query.get_terms_end (); ++t)
 178         query->terms.insert (*t);
 179 }
 180
 181 notmuch_status_t
 182 _notmuch_query_string_to_xapian_query (notmuch_database_t *notmuch,
 183                                        std::string query_string,
 184                                        Xapian::Query &output,
 185                                        std::string &msg)
 186 {
 187     try {
 188         if (query_string == "" || query_string == "*") {
 189             output = Xapian::Query::MatchAll;
 190         } else {
 191             output =
 192                 notmuch->query_parser->
 193                 parse_query (query_string, NOTMUCH_QUERY_PARSER_FLAGS);
 194         }
 195     } catch (const Xapian::Error &error) {
 196         if (! notmuch->exception_reported) {
 197             _notmuch_database_log (notmuch,
 198                                    "A Xapian exception occurred parsing query: %s\n",
 199                                    error.get_msg ().c_str ());
 200             _notmuch_database_log_append (notmuch,
 201                                           "Query string was: %s\n",
 202                                           query_string.c_str ());
 203             notmuch->exception_reported = true;
 204         }
 205
 206         msg = error.get_msg ();
 207         return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 208     }
 209     return NOTMUCH_STATUS_SUCCESS;
 210 }
 211
 212 static notmuch_status_t
 213 _notmuch_query_ensure_parsed_xapian (notmuch_query_t *query)
 214 {
 215     notmuch_status_t status;
 216     std::string msg; /* ignored */
 217
 218     status =  _notmuch_query_string_to_xapian_query (query->notmuch, query->query_string,
 219                                                      query->xapian_query, msg);
 220     if (status)
 221         return status;
 222
 223     query->parsed = true;
 224
 225     _notmuch_query_cache_terms (query);
 226
 227     return NOTMUCH_STATUS_SUCCESS;
 228 }
 229
 230 static notmuch_status_t
 231 _notmuch_query_ensure_parsed_sexpr (notmuch_query_t *query)
 232 {
 233     notmuch_status_t status;
 234
 235     if (query->parsed)
 236         return NOTMUCH_STATUS_SUCCESS;
 237
 238     status = _notmuch_sexp_string_to_xapian_query (query->notmuch, query->query_string,
 239                                                    query->xapian_query);
 240     if (status)
 241         return status;
 242
 243     _notmuch_query_cache_terms (query);
 244     return NOTMUCH_STATUS_SUCCESS;
 245 }
 246
 247 static notmuch_status_t
 248 _notmuch_query_ensure_parsed (notmuch_query_t *query)
 249 {
 250     if (query->parsed)
 251         return NOTMUCH_STATUS_SUCCESS;
 252
 253 #if HAVE_SFSEXP
 254     if (query->syntax == NOTMUCH_QUERY_SYNTAX_SEXP)
 255         return _notmuch_query_ensure_parsed_sexpr (query);
 256 #endif
 257
 258     return _notmuch_query_ensure_parsed_xapian (query);
 259 }
 260
 261 const char *
 262 notmuch_query_get_query_string (const notmuch_query_t *query)
 263 {
 264     return query->query_string;
 265 }
 266
 267 void
 268 notmuch_query_set_omit_excluded (notmuch_query_t *query,
 269                                  notmuch_exclude_t omit_excluded)
 270 {
 271     query->omit_excluded = omit_excluded;
 272 }
 273
 274 void
 275 notmuch_query_set_sort (notmuch_query_t *query, notmuch_sort_t sort)
 276 {
 277     query->sort = sort;
 278 }
 279
 280 notmuch_sort_t
 281 notmuch_query_get_sort (const notmuch_query_t *query)
 282 {
 283     return query->sort;
 284 }
 285
 286 notmuch_status_t
 287 notmuch_query_add_tag_exclude (notmuch_query_t *query, const char *tag)
 288 {
 289     notmuch_status_t status;
 290     char *term;
 291
 292     status = _notmuch_query_ensure_parsed (query);
 293     if (status)
 294         return status;
 295
 296     term = talloc_asprintf (query, "%s%s", _find_prefix ("tag"), tag);
 297     if (query->terms.count (term) != 0)
 298         return NOTMUCH_STATUS_IGNORED;
 299
 300     _notmuch_string_list_append (query->exclude_terms, term);
 301     return NOTMUCH_STATUS_SUCCESS;
 302 }
 303
 304 /* We end up having to call the destructors explicitly because we had
 305  * to use "placement new" in order to initialize C++ objects within a
 306  * block that we allocated with talloc. So C++ is making talloc
 307  * slightly less simple to use, (we wouldn't need
 308  * talloc_set_destructor at all otherwise).
 309  */
 310 static int
 311 _notmuch_messages_destructor (notmuch_mset_messages_t *messages)
 312 {
 313     messages->iterator.~MSetIterator ();
 314     messages->iterator_end.~MSetIterator ();
 315
 316     return 0;
 317 }
 318
 319 /* Return a query that matches messages with the excluded tags
 320  * registered with query. The caller of this function has to combine the returned
 321  * query appropriately.*/
 322 static Xapian::Query
 323 _notmuch_exclude_tags (notmuch_query_t *query)
 324 {
 325     Xapian::Query exclude_query = Xapian::Query::MatchNothing;
 326
 327     for (notmuch_string_node_t *term = query->exclude_terms->head; term;
 328          term = term->next) {
 329         exclude_query = Xapian::Query (Xapian::Query::OP_OR,
 330                                        exclude_query, Xapian::Query (term->string));
 331     }
 332     return exclude_query;
 333 }
 334
 335
 336 notmuch_status_t
 337 notmuch_query_search_messages_st (notmuch_query_t *query,
 338                                   notmuch_messages_t **out)
 339 {
 340     return notmuch_query_search_messages (query, out);
 341 }
 342
 343 notmuch_status_t
 344 notmuch_query_search_messages (notmuch_query_t *query,
 345                                notmuch_messages_t **out)
 346 {
 347     return _notmuch_query_search_documents (query, "mail", out);
 348 }
 349
 350 notmuch_status_t
 351 _notmuch_query_search_documents (notmuch_query_t *query,
 352                                  const char *type,
 353                                  notmuch_messages_t **out)
 354 {
 355     notmuch_database_t *notmuch = query->notmuch;
 356     notmuch_mset_messages_t *messages;
 357     notmuch_status_t status;
 358
 359     status = _notmuch_query_ensure_parsed (query);
 360     if (status)
 361         return status;
 362
 363     messages = talloc (query, notmuch_mset_messages_t);
 364     if (unlikely (messages == NULL))
 365         return NOTMUCH_STATUS_OUT_OF_MEMORY;
 366
 367     try {
 368
 369         messages->base.is_of_list_type = false;
 370         messages->base.iterator = NULL;
 371         messages->notmuch = notmuch;
 372         new (&messages->iterator) Xapian::MSetIterator ();
 373         new (&messages->iterator_end) Xapian::MSetIterator ();
 374
 375         talloc_set_destructor (messages, _notmuch_messages_destructor);
 376
 377         Xapian::Enquire enquire (*notmuch->xapian_db);
 378         Xapian::Query mail_query (talloc_asprintf (query, "%s%s",
 379                                                    _find_prefix ("type"),
 380                                                    type));
 381         Xapian::Query final_query, exclude_query;
 382         Xapian::MSet mset;
 383         Xapian::MSetIterator iterator;
 384
 385         final_query = Xapian::Query (Xapian::Query::OP_AND,
 386                                      mail_query, query->xapian_query);
 387
 388         messages->base.excluded_doc_ids = NULL;
 389
 390         if ((query->omit_excluded != NOTMUCH_EXCLUDE_FALSE) && (query->exclude_terms)) {
 391             exclude_query = _notmuch_exclude_tags (query);
 392
 393             if (query->omit_excluded == NOTMUCH_EXCLUDE_TRUE ||
 394                 query->omit_excluded == NOTMUCH_EXCLUDE_ALL) {
 395                 final_query = Xapian::Query (Xapian::Query::OP_AND_NOT,
 396                                              final_query, exclude_query);
 397             } else { /* NOTMUCH_EXCLUDE_FLAG */
 398                 exclude_query = Xapian::Query (Xapian::Query::OP_AND,
 399                                                exclude_query, final_query);
 400
 401                 enquire.set_weighting_scheme (Xapian::BoolWeight ());
 402                 enquire.set_query (exclude_query);
 403
 404                 mset = enquire.get_mset (0, notmuch->xapian_db->get_doccount ());
 405
 406                 GArray *excluded_doc_ids = g_array_new (false, false, sizeof (unsigned int));
 407
 408                 for (iterator = mset.begin (); iterator != mset.end (); iterator++) {
 409                     unsigned int doc_id = *iterator;
 410                     g_array_append_val (excluded_doc_ids, doc_id);
 411                 }
 412                 messages->base.excluded_doc_ids = talloc (messages, _notmuch_doc_id_set);
 413                 _notmuch_doc_id_set_init (query, messages->base.excluded_doc_ids,
 414                                           excluded_doc_ids);
 415                 g_array_unref (excluded_doc_ids);
 416             }
 417         }
 418
 419
 420         enquire.set_weighting_scheme (Xapian::BoolWeight ());
 421
 422         switch (query->sort) {
 423         case NOTMUCH_SORT_OLDEST_FIRST:
 424             enquire.set_sort_by_value (NOTMUCH_VALUE_TIMESTAMP, false);
 425             break;
 426         case NOTMUCH_SORT_NEWEST_FIRST:
 427             enquire.set_sort_by_value (NOTMUCH_VALUE_TIMESTAMP, true);
 428             break;
 429         case NOTMUCH_SORT_MESSAGE_ID:
 430             enquire.set_sort_by_value (NOTMUCH_VALUE_MESSAGE_ID, false);
 431             break;
 432         case NOTMUCH_SORT_UNSORTED:
 433             break;
 434         }
 435
 436         if (_debug_query ()) {
 437             fprintf (stderr, "Exclude query is:\n%s\n",
 438                      exclude_query.get_description ().c_str ());
 439             fprintf (stderr, "Final query is:\n%s\n",
 440                      final_query.get_description ().c_str ());
 441         }
 442
 443         enquire.set_query (final_query);
 444
 445         mset = enquire.get_mset (0, notmuch->xapian_db->get_doccount ());
 446
 447         messages->iterator = mset.begin ();
 448         messages->iterator_end = mset.end ();
 449
 450         *out = &messages->base;
 451         return NOTMUCH_STATUS_SUCCESS;
 452
 453     } catch (const Xapian::Error &error) {
 454         _notmuch_database_log (notmuch,
 455                                "A Xapian exception occurred performing query: %s\n",
 456                                error.get_msg ().c_str ());
 457         _notmuch_database_log_append (notmuch,
 458                                       "Query string was: %s\n",
 459                                       query->query_string);
 460
 461         notmuch->exception_reported = true;
 462         talloc_free (messages);
 463         return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 464     }
 465 }
 466
 467 bool
 468 _notmuch_mset_messages_valid (notmuch_messages_t *messages)
 469 {
 470     notmuch_mset_messages_t *mset_messages;
 471
 472     mset_messages = (notmuch_mset_messages_t *) messages;
 473
 474     return (mset_messages->iterator != mset_messages->iterator_end);
 475 }
 476
 477 static Xapian::docid
 478 _notmuch_mset_messages_get_doc_id (notmuch_messages_t *messages)
 479 {
 480     notmuch_mset_messages_t *mset_messages;
 481
 482     mset_messages = (notmuch_mset_messages_t *) messages;
 483
 484     if (! _notmuch_mset_messages_valid (&mset_messages->base))
 485         return 0;
 486
 487     return *mset_messages->iterator;
 488 }
 489
 490 notmuch_message_t *
 491 _notmuch_mset_messages_get (notmuch_messages_t *messages)
 492 {
 493     notmuch_message_t *message;
 494     Xapian::docid doc_id;
 495     notmuch_private_status_t status;
 496     notmuch_mset_messages_t *mset_messages;
 497
 498     mset_messages = (notmuch_mset_messages_t *) messages;
 499
 500     if (! _notmuch_mset_messages_valid (&mset_messages->base))
 501         return NULL;
 502
 503     doc_id = *mset_messages->iterator;
 504
 505     message = _notmuch_message_create (mset_messages,
 506                                        mset_messages->notmuch, doc_id,
 507                                        &status);
 508
 509     if (message == NULL &&
 510         status == NOTMUCH_PRIVATE_STATUS_NO_DOCUMENT_FOUND) {
 511         INTERNAL_ERROR ("a messages iterator contains a non-existent document ID.\n");
 512     }
 513
 514     if (messages->excluded_doc_ids &&
 515         _notmuch_doc_id_set_contains (messages->excluded_doc_ids, doc_id))
 516         notmuch_message_set_flag (message, NOTMUCH_MESSAGE_FLAG_EXCLUDED, true);
 517
 518     return message;
 519 }
 520
 521 void
 522 _notmuch_mset_messages_move_to_next (notmuch_messages_t *messages)
 523 {
 524     notmuch_mset_messages_t *mset_messages;
 525
 526     mset_messages = (notmuch_mset_messages_t *) messages;
 527
 528     mset_messages->iterator++;
 529 }
 530
 531 static bool
 532 _notmuch_doc_id_set_init (void *ctx,
 533                           notmuch_doc_id_set_t *doc_ids,
 534                           GArray *arr)
 535 {
 536     unsigned int max = 0;
 537     unsigned char *bitmap;
 538
 539     for (unsigned int i = 0; i < arr->len; i++)
 540         max = MAX (max, g_array_index (arr, unsigned int, i));
 541     bitmap = talloc_zero_array (ctx, unsigned char, DOCIDSET_WORD (max) + 1);
 542
 543     if (bitmap == NULL)
 544         return false;
 545
 546     doc_ids->bitmap = bitmap;
 547     doc_ids->bound = max + 1;
 548
 549     for (unsigned int i = 0; i < arr->len; i++) {
 550         unsigned int doc_id = g_array_index (arr, unsigned int, i);
 551         bitmap[DOCIDSET_WORD (doc_id)] |= 1 << DOCIDSET_BIT (doc_id);
 552     }
 553
 554     return true;
 555 }
 556
 557 bool
 558 _notmuch_doc_id_set_contains (notmuch_doc_id_set_t *doc_ids,
 559                               unsigned int doc_id)
 560 {
 561     if (doc_id >= doc_ids->bound)
 562         return false;
 563     return doc_ids->bitmap[DOCIDSET_WORD (doc_id)] & (1 << DOCIDSET_BIT (doc_id));
 564 }
 565
 566 void
 567 _notmuch_doc_id_set_remove (notmuch_doc_id_set_t *doc_ids,
 568                             unsigned int doc_id)
 569 {
 570     if (doc_id < doc_ids->bound)
 571         doc_ids->bitmap[DOCIDSET_WORD (doc_id)] &= ~(1 << DOCIDSET_BIT (doc_id));
 572 }
 573
 574 /* Glib objects force use to use a talloc destructor as well, (but not
 575  * nearly as ugly as the for messages due to C++ objects). At
 576  * this point, I'd really like to have some talloc-friendly
 577  * equivalents for the few pieces of glib that I'm using. */
 578 static int
 579 _notmuch_threads_destructor (notmuch_threads_t *threads)
 580 {
 581     if (threads->doc_ids)
 582         g_array_unref (threads->doc_ids);
 583
 584     return 0;
 585 }
 586
 587 notmuch_status_t
 588 notmuch_query_search_threads_st (notmuch_query_t *query, notmuch_threads_t **out)
 589 {
 590     return notmuch_query_search_threads (query, out);
 591 }
 592
 593 notmuch_status_t
 594 notmuch_query_search_threads (notmuch_query_t *query,
 595                               notmuch_threads_t **out)
 596 {
 597     notmuch_threads_t *threads;
 598     notmuch_messages_t *messages;
 599     notmuch_status_t status;
 600
 601     threads = talloc (query, notmuch_threads_t);
 602     if (threads == NULL)
 603         return NOTMUCH_STATUS_OUT_OF_MEMORY;
 604     threads->doc_ids = NULL;
 605     talloc_set_destructor (threads, _notmuch_threads_destructor);
 606
 607     threads->query = query;
 608
 609     status = notmuch_query_search_messages (query, &messages);
 610     if (status) {
 611         talloc_free (threads);
 612         return status;
 613     }
 614
 615     threads->doc_ids = g_array_new (false, false, sizeof (unsigned int));
 616     while (notmuch_messages_valid (messages)) {
 617         unsigned int doc_id = _notmuch_mset_messages_get_doc_id (messages);
 618         g_array_append_val (threads->doc_ids, doc_id);
 619         notmuch_messages_move_to_next (messages);
 620     }
 621     threads->doc_id_pos = 0;
 622
 623     talloc_free (messages);
 624
 625     if (! _notmuch_doc_id_set_init (threads, &threads->match_set,
 626                                     threads->doc_ids)) {
 627         talloc_free (threads);
 628         return NOTMUCH_STATUS_OUT_OF_MEMORY;
 629     }
 630
 631     *out = threads;
 632     return NOTMUCH_STATUS_SUCCESS;
 633 }
 634
 635 void
 636 notmuch_query_destroy (notmuch_query_t *query)
 637 {
 638     talloc_free (query);
 639 }
 640
 641 notmuch_bool_t
 642 notmuch_threads_valid (notmuch_threads_t *threads)
 643 {
 644     unsigned int doc_id;
 645
 646     if (! threads)
 647         return false;
 648
 649     while (threads->doc_id_pos < threads->doc_ids->len) {
 650         doc_id = g_array_index (threads->doc_ids, unsigned int,
 651                                 threads->doc_id_pos);
 652         if (_notmuch_doc_id_set_contains (&threads->match_set, doc_id))
 653             break;
 654
 655         threads->doc_id_pos++;
 656     }
 657
 658     return threads->doc_id_pos < threads->doc_ids->len;
 659 }
 660
 661 notmuch_thread_t *
 662 notmuch_threads_get (notmuch_threads_t *threads)
 663 {
 664     unsigned int doc_id;
 665
 666     if (! notmuch_threads_valid (threads))
 667         return NULL;
 668
 669     doc_id = g_array_index (threads->doc_ids, unsigned int,
 670                             threads->doc_id_pos);
 671     return _notmuch_thread_create (threads->query,
 672                                    threads->query->notmuch,
 673                                    doc_id,
 674                                    &threads->match_set,
 675                                    threads->query->exclude_terms,
 676                                    threads->query->omit_excluded,
 677                                    threads->query->sort);
 678 }
 679
 680 void
 681 notmuch_threads_move_to_next (notmuch_threads_t *threads)
 682 {
 683     threads->doc_id_pos++;
 684 }
 685
 686 void
 687 notmuch_threads_destroy (notmuch_threads_t *threads)
 688 {
 689     talloc_free (threads);
 690 }
 691
 692 notmuch_status_t
 693 notmuch_query_count_messages_st (notmuch_query_t *query, unsigned *count_out)
 694 {
 695     return notmuch_query_count_messages (query, count_out);
 696 }
 697
 698 notmuch_status_t
 699 notmuch_query_count_messages (notmuch_query_t *query, unsigned *count_out)
 700 {
 701     return _notmuch_query_count_documents (query, "mail", count_out);
 702 }
 703
 704 notmuch_status_t
 705 _notmuch_query_count_documents (notmuch_query_t *query, const char *type, unsigned *count_out)
 706 {
 707     notmuch_database_t *notmuch = query->notmuch;
 708     Xapian::doccount count = 0;
 709     notmuch_status_t status;
 710
 711     status = _notmuch_query_ensure_parsed (query);
 712     if (status)
 713         return status;
 714
 715     try {
 716         Xapian::Enquire enquire (*notmuch->xapian_db);
 717         Xapian::Query mail_query (talloc_asprintf (query, "%s%s",
 718                                                    _find_prefix ("type"),
 719                                                    type));
 720         Xapian::Query final_query, exclude_query;
 721         Xapian::MSet mset;
 722
 723         final_query = Xapian::Query (Xapian::Query::OP_AND,
 724                                      mail_query, query->xapian_query);
 725
 726         exclude_query = _notmuch_exclude_tags (query);
 727
 728         final_query = Xapian::Query (Xapian::Query::OP_AND_NOT,
 729                                      final_query, exclude_query);
 730
 731         enquire.set_weighting_scheme (Xapian::BoolWeight ());
 732         enquire.set_docid_order (Xapian::Enquire::ASCENDING);
 733
 734         if (_debug_query ()) {
 735             fprintf (stderr, "Exclude query is:\n%s\n",
 736                      exclude_query.get_description ().c_str ());
 737             fprintf (stderr, "Final query is:\n%s\n",
 738                      final_query.get_description ().c_str ());
 739         }
 740
 741         enquire.set_query (final_query);
 742
 743         /*
 744          * Set the checkatleast parameter to the number of documents
 745          * in the database to make get_matches_estimated() exact.
 746          * Set the max parameter to 1 to avoid fetching documents we will discard.
 747          */
 748         mset = enquire.get_mset (0, 1,
 749                                  notmuch->xapian_db->get_doccount ());
 750
 751         count = mset.get_matches_estimated ();
 752
 753     } catch (const Xapian::Error &error) {
 754         _notmuch_database_log (notmuch,
 755                                "A Xapian exception occurred performing query: %s\n",
 756                                error.get_msg ().c_str ());
 757         _notmuch_database_log_append (notmuch,
 758                                       "Query string was: %s\n",
 759                                       query->query_string);
 760         return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 761     }
 762
 763     *count_out = count;
 764     return NOTMUCH_STATUS_SUCCESS;
 765 }
 766
 767 notmuch_status_t
 768 notmuch_query_count_threads_st (notmuch_query_t *query, unsigned *count)
 769 {
 770     return notmuch_query_count_threads (query, count);
 771 }
 772
 773 notmuch_status_t
 774 notmuch_query_count_threads (notmuch_query_t *query, unsigned *count)
 775 {
 776     notmuch_messages_t *messages;
 777     GHashTable *hash;
 778     notmuch_sort_t sort;
 779     notmuch_status_t ret = NOTMUCH_STATUS_SUCCESS;
 780
 781     sort = query->sort;
 782     query->sort = NOTMUCH_SORT_UNSORTED;
 783     ret = notmuch_query_search_messages (query, &messages);
 784     if (ret)
 785         return ret;
 786     query->sort = sort;
 787     if (messages == NULL)
 788         return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 789
 790     hash = g_hash_table_new_full (g_str_hash, g_str_equal, NULL, NULL);
 791     if (hash == NULL) {
 792         talloc_free (messages);
 793         return NOTMUCH_STATUS_OUT_OF_MEMORY;
 794     }
 795
 796     while (notmuch_messages_valid (messages)) {
 797         notmuch_message_t *message = notmuch_messages_get (messages);
 798         const char *thread_id = notmuch_message_get_thread_id (message);
 799         char *thread_id_copy = talloc_strdup (messages, thread_id);
 800         if (unlikely (thread_id_copy == NULL)) {
 801             notmuch_message_destroy (message);
 802             ret = NOTMUCH_STATUS_OUT_OF_MEMORY;
 803             goto DONE;
 804         }
 805         g_hash_table_insert (hash, thread_id_copy, NULL);
 806         notmuch_message_destroy (message);
 807         notmuch_messages_move_to_next (messages);
 808     }
 809
 810     *count = g_hash_table_size (hash);
 811
 812   DONE:
 813     g_hash_table_unref (hash);
 814     talloc_free (messages);
 815
 816     return ret;
 817 }
 818
 819 notmuch_database_t *
 820 notmuch_query_get_database (const notmuch_query_t *query)
 821 {
 822     return query->notmuch;
 823 }
 824
 825 notmuch_status_t
 826 _notmuch_query_expand (notmuch_database_t *notmuch, const char *field, Xapian::Query subquery,
 827                        Xapian::Query &output, std::string &msg)
 828 {
 829     std::set<std::string> terms;
 830     const std::string term_prefix =  _find_prefix (field);
 831
 832     if (_debug_query ()) {
 833         fprintf (stderr, "Expanding subquery:\n%s\n",
 834                  subquery.get_description ().c_str ());
 835     }
 836
 837     try {
 838         Xapian::Enquire enquire (*notmuch->xapian_db);
 839         Xapian::MSet mset;
 840
 841         enquire.set_weighting_scheme (Xapian::BoolWeight ());
 842         enquire.set_query (subquery);
 843
 844         mset = enquire.get_mset (0, notmuch->xapian_db->get_doccount ());
 845
 846         for (Xapian::MSetIterator iterator = mset.begin (); iterator != mset.end (); iterator++) {
 847             Xapian::docid doc_id = *iterator;
 848             Xapian::Document doc = notmuch->xapian_db->get_document (doc_id);
 849             Xapian::TermIterator i = doc.termlist_begin ();
 850
 851             for (i.skip_to (term_prefix);
 852                  i != doc.termlist_end () && ((*i).rfind (term_prefix, 0) == 0); i++) {
 853                 terms.insert (*i);
 854             }
 855         }
 856         output = Xapian::Query (Xapian::Query::OP_OR, terms.begin (), terms.end ());
 857         if (_debug_query ()) {
 858             fprintf (stderr, "Expanded query:\n%s\n",
 859                      subquery.get_description ().c_str ());
 860         }
 861
 862     } catch (const Xapian::Error &error) {
 863         _notmuch_database_log (notmuch,
 864                                "A Xapian exception occurred expanding query: %s\n",
 865                                error.get_msg ().c_str ());
 866         msg = error.get_msg ();
 867         return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 868     }
 869
 870     return NOTMUCH_STATUS_SUCCESS;
 871 }