notmuch dump: Fix the sorting of results.

To properly support sorting in notmuch_query we know use an
Enquire object. We also throw in a QueryParser too, so we're
really close to being able to support arbitrary full-text
searches.

I took a look at the supported QueryParser syntax and chose
a set of flags for everything I like, (such as supporting
Boolean operators in either case ("AND" or "and"), supporting
phrase searching, supporting + and - to include/preclude terms,
and supporting a trailing * on any term as a wildcard).

database-private.h

@@ -28,7 +28,7 @@
 struct _notmuch_database {
     char *path;
     Xapian::WritableDatabase *xapian_db;
-    Xapian::TermGenerator *term_gen;
+    Xapian::QueryParser *query_parser;
 };
 
 #endif

database.cc

@@ -67,15 +67,6 @@ prefix_t BOOLEAN_PREFIX[] = {
     { "ref", "R" }
 };
 
-/* Similarly, these value numbers are also chosen to be sup
- * compatible. */
-
-typedef enum {
-    NOTMUCH_VALUE_MESSAGE_ID = 0,
-    NOTMUCH_VALUE_THREAD = 1,
-    NOTMUCH_VALUE_DATE = 2
-} notmuch_value_t;
-
 static const char *
 find_prefix (const char *name)
 {
@@ -459,6 +450,9 @@ notmuch_database_open (const char *path)
     try {
 	notmuch->xapian_db = new Xapian::WritableDatabase (xapian_path,
 							   Xapian::DB_CREATE_OR_OPEN);
+	notmuch->query_parser = new Xapian::QueryParser;
+	notmuch->query_parser->set_default_op (Xapian::Query::OP_AND);
+	notmuch->query_parser->set_database (*notmuch->xapian_db);
     } catch (const Xapian::Error &error) {
 	fprintf (stderr, "A Xapian exception occurred: %s\n",
 		 error.get_msg().c_str());
@@ -478,6 +472,7 @@ notmuch_database_open (const char *path)
 void
 notmuch_database_close (notmuch_database_t *notmuch)
 {
+    delete notmuch->query_parser;
     delete notmuch->xapian_db;
     free (notmuch->path);
     free (notmuch);

notmuch-private.h

@@ -66,6 +66,15 @@ NOTMUCH_BEGIN_DECLS
 #endif
 #endif
 
+/* These value numbers are chosen to be sup compatible (for now at
+ * least). */
+
+typedef enum {
+    NOTMUCH_VALUE_MESSAGE_ID = 0,
+    NOTMUCH_VALUE_THREAD = 1,
+    NOTMUCH_VALUE_DATE = 2
+} notmuch_value_t;
+
 /* xutil.c */
 void *
 xcalloc (size_t nmemb, size_t size);

query.cc

@@ -31,8 +31,8 @@ struct _notmuch_query {
 
 struct _notmuch_results {
     notmuch_database_t *notmuch;
-    Xapian::PostingIterator iterator;
+    Xapian::MSetIterator iterator;
-    Xapian::PostingIterator iterator_end;
+    Xapian::MSetIterator iterator_end;
 };
 
 notmuch_query_t *
@@ -69,8 +69,8 @@ notmuch_query_set_sort (notmuch_query_t *query, notmuch_sort_t sort)
 static int
 _notmuch_results_destructor (notmuch_results_t *results)
 {
-    results->iterator.~PostingIterator ();
+    results->iterator.~MSetIterator ();
-    results->iterator_end.~PostingIterator ();
+    results->iterator_end.~MSetIterator ();
 
     return 0;
 }
@@ -78,6 +78,8 @@ _notmuch_results_destructor (notmuch_results_t *results)
 notmuch_results_t *
 notmuch_query_search (notmuch_query_t *query)
 {
+    notmuch_database_t *notmuch = query->notmuch;
+    const char *query_string = query->query_string;
     notmuch_results_t *results;
 
     results = talloc (query, notmuch_results_t);
@@ -85,19 +87,50 @@ notmuch_query_search (notmuch_query_t *query)
 	return NULL;
 
     try {
-	if (strlen (query->query_string)) {
+	Xapian::Enquire enquire (*notmuch->xapian_db);
-	    fprintf (stderr, "Error: Arbitrary search strings are not supported yet. Come back soon!\n");
+	Xapian::Query mail_query ("Kmail");
-	    exit (1);
+	Xapian::Query string_query, final_query;
+	Xapian::MSet mset;
+	unsigned int flags = (Xapian::QueryParser::FLAG_BOOLEAN &
+			      Xapian::QueryParser::FLAG_PHRASE &
+			      Xapian::QueryParser::FLAG_LOVEHATE &
+			      Xapian::QueryParser::FLAG_BOOLEAN_ANY_CASE &
+			      Xapian::QueryParser::FLAG_WILDCARD);
+
+	if (strcmp (query_string, "") == 0) {
+	    final_query = mail_query;
+	} else {
+	    string_query = notmuch->query_parser->
+		parse_query (query_string, flags);
+	    final_query = Xapian::Query (Xapian::Query::OP_AND,
+					 mail_query, string_query);
 	}
 
-	results->notmuch = query->notmuch;
+	switch (query->sort) {
-	new (&results->iterator) Xapian::PostingIterator ();
+	case NOTMUCH_SORT_DATE_OLDEST_FIRST:
-	new (&results->iterator_end) Xapian::PostingIterator ();
+	    enquire.set_sort_by_value (NOTMUCH_VALUE_DATE, FALSE);
+	    break;
+	case NOTMUCH_SORT_DATE_NEWEST_FIRST:
+	    enquire.set_sort_by_value (NOTMUCH_VALUE_DATE, TRUE);
+	    break;
+	case NOTMUCH_SORT_MESSAGE_ID:
+	    enquire.set_sort_by_value (NOTMUCH_VALUE_MESSAGE_ID, FALSE);
+	    break;
+	}
+
+	enquire.set_query (final_query);
+
+	mset = enquire.get_mset (0, notmuch->xapian_db->get_doccount ());
+
+	results->notmuch = notmuch;
+
+	new (&results->iterator) Xapian::MSetIterator ();
+	new (&results->iterator_end) Xapian::MSetIterator ();
 
 	talloc_set_destructor (results, _notmuch_results_destructor);
 
-	results->iterator = query->notmuch->xapian_db->postlist_begin ("");
+	results->iterator = mset.begin ();
-	results->iterator_end = query->notmuch->xapian_db->postlist_end ("");
+	results->iterator_end = mset.end ();
 
     } catch (const Xapian::Error &error) {
 	fprintf (stderr, "A Xapian exception occurred: %s\n",