Adding support for start and end key swapping with descending

history.txt

@@ -2,6 +2,7 @@
 
 * Minor enhancements:
   * Adding "couchrest-hash" to Design Docs with aim to improve view update handling.
+  * Using #descending on View object will automatically swap startkey with endkey.
 
 == 1.1.0.beta2
 

lib/couchrest/model/designs/view.rb

@@ -239,11 +239,19 @@ module CouchRest
         end
 
 
-        # The results should be provided in descending order.
+        # The results should be provided in descending order. If the startkey or
+        # endkey query options have already been seen set, calling this method
+        # will automatically swap the options around. If you don't want this,
+        # simply set descending before any other option.
         #
-        # Descending is false by default, this method will enable it and cannot
-        # be undone.
+        # Descending is false by default, and this method cannot
+        # be undone once used, it has no inverse option.
         def descending
+          if query[:startkey] || query[:endkey]
+            query[:startkey], query[:endkey] = query[:endkey], query[:startkey]
+          elsif query[:startkey_docid] || query[:endkey_docid]
+            query[:startkey_docid], query[:endkey_docid] = query[:endkey_docid], query[:startkey_docid]
+          end
           update_query(:descending => true)
         end
 

spec/couchrest/designs/view_spec.rb

@@ -386,6 +386,24 @@ describe "Design View" do
           @obj.should_receive(:update_query).with({:descending => true})
           @obj.descending
         end
+        it "should reverse start and end keys if given" do
+          @obj = @obj.startkey('a').endkey('z')
+          @obj = @obj.descending
+          @obj.query[:endkey].should eql('a')
+          @obj.query[:startkey].should eql('z')
+        end
+        it "should reverse even if start or end nil" do
+          @obj = @obj.startkey('a')
+          @obj = @obj.descending
+          @obj.query[:endkey].should eql('a')
+          @obj.query[:startkey].should be_nil
+        end
+        it "should reverse start_doc and end_doc keys if given" do
+          @obj = @obj.startkey_doc('a').endkey_doc('z')
+          @obj = @obj.descending
+          @obj.query[:endkey_docid].should eql('a')
+          @obj.query[:startkey_docid].should eql('z')
+        end
       end
 
       describe "#limit" do