Add a AND_NOT subquery.

debexpo/lib/axi.py

@@ -46,6 +46,7 @@ class XapianQuery(object):
         self.stemmer = xapian.Stem("english")
 
         self.terms = []
+        self.not_terms = []
 
     @classmethod
     def tokenize(cls, text):
@@ -79,12 +80,20 @@ class XapianQuery(object):
         for tag in tags:
             self.terms.append('XT'+tag)
 
+    def add_not(self, *terms):
+        """
+        Add terms that should be added to the query as a AND_NOT subquery.
+        """
+        self.not_terms.extend(terms)
+
     def query(self):
         """
         Actually performs the query and return the results as a
         generator.
         """
-        query = xapian.Query(xapian.Query.OP_OR, self.terms)
+        query = xapian.Query(xapian.Query.OP_AND_NOT,
+                             xapian.Query(xapian.Query.OP_OR, self.terms),
+                             xapian.Query(xapian.Query.OP_OR, self.not_terms))
         enquire = xapian.Enquire(self.db)
         enquire.set_query(query)