relocate list total calculation to support resumptionToken content decision

Author: barmintor

lib/oai/provider/model/activerecord_caching_wrapper.rb

@@ -78,13 +78,7 @@ def next_set(token_string)
       raise ResumptionTokenException.new unless @limit
 
       token = ResumptionToken.parse(token_string)
-      total = model.where(token_conditions(token)).count
-
-      if token.last * @limit + @limit < total
-        select_partial(token)
-      else
-        select_partial(token).tap { |list| list.instance_variable_set(:@token, list.token.next(nil)) }
-      end
+      select_partial(token)
     end
 
     # select a subset of the result set, and return it with a
@@ -102,10 +96,13 @@ def select_partial(token)
 
       raise ResumptionTokenException.new unless oaitoken
 
+      total = model.where(token_conditions(token)).count
+      # token offset should be nil if this is the last set
+      offset = (token.last * @limit + @limit >= total) ? nil : token.last + 1
       PartialResult.new(
         hydrate_records(
           oaitoken.entries.limit(@limit).offset(token.last * @limit)),
-        token.next(token.last + 1)
+        token.next(offset)
       )
     end
 

lib/oai/provider/model/activerecord_wrapper.rb

@@ -129,13 +129,7 @@ def next_set(find_scope, token_string)
       raise OAI::ResumptionTokenException.new unless @limit
 
       token = ResumptionToken.parse(token_string)
-      total = find_scope.where(token_conditions(token)).count
-
-      if @limit < total
-        select_partial(find_scope, token)
-      else # end of result set
-        select_partial(find_scope, token).tap { |list| list.instance_variable_set(:@token, list.token.next(nil)) }
-      end
+      select_partial(find_scope, token)
     end
 
     # select a subset of the result set, and return it with a
@@ -145,8 +139,10 @@ def select_partial(find_scope, token)
         .limit(@limit)
         .order("#{identifier_field} asc")
       raise OAI::ResumptionTokenException.new unless records
-      offset = records.last.send(identifier_field)
 
+      total = find_scope.where(token_conditions(token)).count
+      # token offset should be nil if this is the last set
+      offset = (@limit >= total) ? nil : records.last.send(identifier_field)
       PartialResult.new(records, token.next(offset))
     end