[PATCH 2/5] lib/query: make query parsing lazy again, keep centralized.

[David Bremner]

This is mainly to fix the nasty error path introduced in the last
commit, by moving the parsing into functions where the API is already
set up to return error status.  It preserves the feature of having a
pre-parsed query available for further processing.
---
 lib/query.cc | 35 +++++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/lib/query.cc b/lib/query.cc
index 098ed8f..d7cf28f 100644
--- a/lib/query.cc
+++ b/lib/query.cc
@@ -29,6 +29,7 @@ struct _notmuch_query {
     notmuch_sort_t sort;
     notmuch_string_list_t *exclude_terms;
     notmuch_exclude_t omit_excluded;
+    notmuch_bool_t parsed;
     Xapian::Query xapian_query;
 };
 
@@ -93,6 +94,7 @@ notmuch_query_create (notmuch_database_t *notmuch,
 	return NULL;
 
     new (&query->xapian_query) Xapian::Query ();
+    query->parsed = FALSE;
 
     talloc_set_destructor (query, _notmuch_query_destructor);
 
@@ -106,23 +108,30 @@ notmuch_query_create (notmuch_database_t *notmuch,
 
     query->omit_excluded = NOTMUCH_EXCLUDE_TRUE;
 
+    return query;
+}
+
+static notmuch_status_t
+_notmuch_query_ensure_parsed (notmuch_query_t *query)
+{
+    if (query->parsed)
+	return NOTMUCH_STATUS_SUCCESS;
+
     try {
-	new (&query->xapian_query) Xapian::Query ();
 	query->xapian_query =
-	    notmuch->query_parser->parse_query (query_string, NOTMUCH_QUERY_PARSER_FLAGS);
+	    query->notmuch->query_parser->
+		parse_query (query->query_string, NOTMUCH_QUERY_PARSER_FLAGS);
     } catch (const Xapian::Error &error) {
-	_notmuch_database_log (notmuch,
+	_notmuch_database_log (query->notmuch,
 			       "A Xapian exception occured parsing query: %s\n",
 			       error.get_msg().c_str());
-	_notmuch_database_log_append (notmuch,
+	_notmuch_database_log_append (query->notmuch,
 			       "Query string was: %s\n",
 			       query->query_string);
 
-	talloc_free (query);
-	query = NULL;
+	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
-
-    return query;
+    return NOTMUCH_STATUS_SUCCESS;
 }
 
 const char *
@@ -226,6 +235,11 @@ _notmuch_query_search_documents (notmuch_query_t *query,
     notmuch_database_t *notmuch = query->notmuch;
     const char *query_string = query->query_string;
     notmuch_mset_messages_t *messages;
+    notmuch_status_t status;
+
+    status = _notmuch_query_ensure_parsed (query);
+    if (status)
+	return status;
 
     messages = talloc (query, notmuch_mset_messages_t);
     if (unlikely (messages == NULL))
@@ -592,6 +606,11 @@ _notmuch_query_count_documents (notmuch_query_t *query, const char *type, unsign
     notmuch_database_t *notmuch = query->notmuch;
     const char *query_string = query->query_string;
     Xapian::doccount count = 0;
+    notmuch_status_t status;
+
+    status = _notmuch_query_ensure_parsed (query);
+    if (status)
+	return status;
 
     try {
 	Xapian::Enquire enquire (*notmuch->xapian_db);
-- 
2.9.3