[PATCH 4/5] lib: query make exclude handling non-destructive

[David Bremner]

We filter added exclude at add time, rather than modifying the query by
count search. As noted in the comments, there are several ignored
conditions here. Returning proper status is split into a separate commit
because it is ABI breaking.
---
 lib/query.cc       | 46 ++++++++++++++++++++++++++++------------------
 test/T060-count.sh |  1 -
 2 files changed, 28 insertions(+), 19 deletions(-)

diff --git a/lib/query.cc b/lib/query.cc
index d7cf28f..81e3e01 100644
--- a/lib/query.cc
+++ b/lib/query.cc
@@ -31,6 +31,7 @@ struct _notmuch_query {
     notmuch_exclude_t omit_excluded;
     notmuch_bool_t parsed;
     Xapian::Query xapian_query;
+    std::set<std::string> terms;
 };
 
 typedef struct _notmuch_mset_messages {
@@ -77,6 +78,7 @@ _debug_query (void)
 static int
 _notmuch_query_destructor (notmuch_query_t *query) {
     query->xapian_query.~Query();
+    query->terms.~set<std::string>();
     return 0;
 }
 
@@ -94,6 +96,7 @@ notmuch_query_create (notmuch_database_t *notmuch,
 	return NULL;
 
     new (&query->xapian_query) Xapian::Query ();
+    new (&query->terms) std::set<std::string> ();
     query->parsed = FALSE;
 
     talloc_set_destructor (query, _notmuch_query_destructor);
@@ -121,6 +124,14 @@ _notmuch_query_ensure_parsed (notmuch_query_t *query)
 	query->xapian_query =
 	    query->notmuch->query_parser->
 		parse_query (query->query_string, NOTMUCH_QUERY_PARSER_FLAGS);
+
+	/* apparently Xapian doesn't support skip_to on terms from a query,
+	   so cache a copy of all terms in something searchable */
+
+	for (Xapian::TermIterator t = query->xapian_query.get_terms_begin();
+	     t != query->xapian_query.get_terms_end(); ++t)
+	    query->terms.insert(*t);
+
     } catch (const Xapian::Error &error) {
 	_notmuch_database_log (query->notmuch,
 			       "A Xapian exception occured parsing query: %s\n",
@@ -162,7 +173,17 @@ notmuch_query_get_sort (const notmuch_query_t *query)
 void
 notmuch_query_add_tag_exclude (notmuch_query_t *query, const char *tag)
 {
-    char *term = talloc_asprintf (query, "%s%s", _find_prefix ("tag"), tag);
+    notmuch_status_t status;
+    char *term;
+
+    status = _notmuch_query_ensure_parsed (query);
+    if (status)
+	return; /* XXX report error */
+
+    term = talloc_asprintf (query, "%s%s", _find_prefix ("tag"), tag);
+    if (query->terms.count(term) != 0)
+	return; /* XXX report ignoring exclude? */
+
     _notmuch_string_list_append (query->exclude_terms, term);
 }
 
@@ -182,28 +203,17 @@ _notmuch_messages_destructor (notmuch_mset_messages_t *messages)
 }
 
 /* Return a query that matches messages with the excluded tags
- * registered with query.  Any tags that explicitly appear in xquery
- * will not be excluded, and will be removed from the list of exclude
- * tags.  The caller of this function has to combine the returned
+ * registered with query. The caller of this function has to combine the returned
  * query appropriately.*/
 static Xapian::Query
-_notmuch_exclude_tags (notmuch_query_t *query, Xapian::Query xquery)
+_notmuch_exclude_tags (notmuch_query_t *query)
 {
     Xapian::Query exclude_query = Xapian::Query::MatchNothing;
 
     for (notmuch_string_node_t *term = query->exclude_terms->head; term;
 	 term = term->next) {
-	Xapian::TermIterator it = xquery.get_terms_begin ();
-	Xapian::TermIterator end = xquery.get_terms_end ();
-	for (; it != end; it++) {
-	    if ((*it).compare (term->string) == 0)
-		break;
-	}
-	if (it == end)
-	    exclude_query = Xapian::Query (Xapian::Query::OP_OR,
-				    exclude_query, Xapian::Query (term->string));
-	else
-	    term->string = talloc_strdup (query, "");
+	exclude_query = Xapian::Query (Xapian::Query::OP_OR,
+				       exclude_query, Xapian::Query (term->string));
     }
     return exclude_query;
 }
@@ -274,7 +284,7 @@ _notmuch_query_search_documents (notmuch_query_t *query,
 	messages->base.excluded_doc_ids = NULL;
 
 	if ((query->omit_excluded != NOTMUCH_EXCLUDE_FALSE) && (query->exclude_terms)) {
-	    exclude_query = _notmuch_exclude_tags (query, final_query);
+	    exclude_query = _notmuch_exclude_tags (query);
 
 	    if (query->omit_excluded == NOTMUCH_EXCLUDE_TRUE ||
 		query->omit_excluded == NOTMUCH_EXCLUDE_ALL)
@@ -629,7 +639,7 @@ _notmuch_query_count_documents (notmuch_query_t *query, const char *type, unsign
 					 mail_query, query->xapian_query);
 	}
 
-	exclude_query = _notmuch_exclude_tags (query, final_query);
+	exclude_query = _notmuch_exclude_tags (query);
 
 	final_query = Xapian::Query (Xapian::Query::OP_AND_NOT,
 					 final_query, exclude_query);
diff --git a/test/T060-count.sh b/test/T060-count.sh
index 69ab591..b82583b 100755
--- a/test/T060-count.sh
+++ b/test/T060-count.sh
@@ -127,7 +127,6 @@ test_expect_equal_file EXPECTED OUTPUT.clean
 restore_database
 
 test_begin_subtest "count library function is non-destructive"
-test_subtest_known_broken
 cat<<EOF > EXPECTED
 1: 52 messages
 2: 52 messages
-- 
2.9.3