[deltacloud-devel] [PATCH core 09/25] Features: allow modifying existing features and their operations

[David Lutterkort]

From: David Lutterkort

---
 server/lib/deltacloud/base_driver/features.rb |   18 ++++++++++++++----
 1 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/server/lib/deltacloud/base_driver/features.rb b/server/lib/deltacloud/base_driver/features.rb
index c6c9126..abe78e3 100644
--- a/server/lib/deltacloud/base_driver/features.rb
+++ b/server/lib/deltacloud/base_driver/features.rb
@@ -5,7 +5,6 @@ module Deltacloud

class FeatureError < StandardError; end
   class DuplicateFeatureDeclError < FeatureError; end
-  class DuplicateFeatureError < FeatureError; end
   class UndeclaredFeatureError < FeatureError; end

class BaseDriver
@@ -40,8 +39,15 @@ module Deltacloud
         @description
       end

+      # Add a new operation or modify an existing one through BLOCK
       def operation(name, &block)
-        @operations << Operation.new(name, &block)
+        unless op = @operations.find { |op| op.name == name }
+          op = Operation.new(name, &block)
+          @operations << op
+        else
+          op.instance_eval(&block) if block_given?
+        end
+        op
       end
     end

@@ -92,10 +98,14 @@ module Deltacloud
     end

# Declare in a driver that it supports a specific feature
+    #
+    # The same feature can be declared multiple times in a driver, so that
+    # it can be changed successively by passing in different blocks.
     def self.feature(collection, name, &block)
       features[collection] ||= []
-      if features[collection].find { |f| f.name == name }
-        raise DuplicateFeatureError
+      if f = features[collection].find { |f| f.name == name }
+        f.instance_eval(&block) if block_given?
+        return f
       end
       unless decl = feature_decl_for(collection, name)
         raise UndeclaredFeatureError, "No feature #{name} for #{collection}"