* src/GenericFilter.py: implement short-circuit if only rule is

Everyone
* src/NameDisplay.py: optimization
* src/PeopleModel.py: optimization of data building


svn: r5810

gramps2/src/GenericFilter.py

@@ -94,6 +94,9 @@ class Rule:
 
     def __init__(self,list):
         self.set_list(list)
+
+    def is_empty(self):
+        return False
     
     def prepare(self,db):
         pass
@@ -136,6 +139,9 @@ class Everyone(Rule):
     category    = _('General filters')
     description = _('Matches everyone in the database')
 
+    def is_empty(self):
+        return True
+
     def apply(self,db,person):
         return True
 
@@ -1902,6 +1908,9 @@ class GenericFilter:
             self.logical_op = 'and'
             self.invert = False
 
+    def is_empty(self):
+        return len(self.flist) == 1 and self.flist[0].is_empty()
+
     def set_logical_op(self,val):
         if val in GenericFilter.logical_functions:
             self.logical_op = val