Merge pull request #247 from skippy/fix-class-inheritance

allow Protobuf::Message based classes to be inherited

lib/protobuf/message/fields.rb

@@ -3,117 +3,131 @@ class Message
     module Fields
 
       def self.extended(other)
+        other.extend(ClassMethods)
         ::Protobuf.deprecator.define_deprecated_methods(
           other.singleton_class,
           :get_ext_field_by_name => :get_extension_field,
           :get_ext_field_by_tag => :get_extension_field,
           :get_field_by_name => :get_field,
           :get_field_by_tag => :get_field,
         )
+
+        def inherited(subclass)
+          inherit_fields!(subclass)
+        end
       end
 
-      ##
-      # Field Definition Methods
-      #
+      module ClassMethods
 
-      # Define an optional field.
-      #
-      def optional(type_class, name, tag, options = {})
-        define_field(:optional, type_class, name, tag, options)
-      end
+        ##
+        # Field Definition Methods
+        #
 
-      # Define a repeated field.
-      #
-      def repeated(type_class, name, tag, options = {})
-        define_field(:repeated, type_class, name, tag, options)
-      end
+        # Define an optional field.
+        #
+        def optional(type_class, name, tag, options = {})
+          define_field(:optional, type_class, name, tag, options)
+        end
 
-      # Define a required field.
-      #
-      def required(type_class, name, tag, options = {})
-        define_field(:required, type_class, name, tag, options)
-      end
+        # Define a repeated field.
+        #
+        def repeated(type_class, name, tag, options = {})
+          define_field(:repeated, type_class, name, tag, options)
+        end
 
-      # Define an extension range.
-      #
-      def extensions(range)
-        extension_ranges << range
-      end
+        # Define a required field.
+        #
+        def required(type_class, name, tag, options = {})
+          define_field(:required, type_class, name, tag, options)
+        end
 
-      ##
-      # Field Access Methods
-      #
+        # Define an extension range.
+        #
+        def extensions(range)
+          extension_ranges << range
+        end
 
-      def all_fields
-        @all_fields ||= field_store.values.uniq.sort_by(&:tag)
-      end
+        ##
+        # Field Access Methods
+        #
+        def all_fields
+          @all_fields ||= field_store.values.uniq.sort_by(&:tag)
+        end
 
-      def extension_fields
-        @extension_fields ||= all_fields.select(&:extension?)
-      end
+        def extension_fields
+          @extension_fields ||= all_fields.select(&:extension?)
+        end
 
-      def extension_ranges
-        @extension_ranges ||= []
-      end
+        def extension_ranges
+          @extension_ranges ||= []
+        end
 
-      def extension_tag?(tag)
-        tag.respond_to?(:to_i) && get_extension_field(tag).present?
-      end
+        def extension_tag?(tag)
+          tag.respond_to?(:to_i) && get_extension_field(tag).present?
+        end
 
-      def field_store
-        @field_store ||= {}
-      end
+        def field_store
+          @field_store ||= {}
+        end
 
-      def fields
-        @fields ||= all_fields.reject(&:extension?)
-      end
+        def fields
+          @fields ||= all_fields.reject(&:extension?)
+        end
 
-      def field_tag?(tag, allow_extension = false)
-        tag.respond_to?(:to_i) && get_field(tag, allow_extension).present?
-      end
+        def field_tag?(tag, allow_extension = false)
+          tag.respond_to?(:to_i) && get_field(tag, allow_extension).present?
+        end
 
-      def get_extension_field(name_or_tag)
-        name_or_tag = name_or_tag.to_sym if name_or_tag.respond_to?(:to_sym)
-        field = field_store[name_or_tag]
-        field if field.try(:extension?) { false }
-      end
+        def get_extension_field(name_or_tag)
+          name_or_tag = name_or_tag.to_sym if name_or_tag.respond_to?(:to_sym)
+          field = field_store[name_or_tag]
+          field if field.try(:extension?) { false }
+        end
 
-      def get_field(name_or_tag, allow_extension = false)
-        name_or_tag = name_or_tag.to_sym if name_or_tag.respond_to?(:to_sym)
-        field = field_store[name_or_tag]
+        def get_field(name_or_tag, allow_extension = false)
+          name_or_tag = name_or_tag.to_sym if name_or_tag.respond_to?(:to_sym)
+          field = field_store[name_or_tag]
 
-        if field && (allow_extension || !field.extension?)
-          field
-        else
-          nil
+          if field && (allow_extension || !field.extension?)
+            field
+          else
+            nil
+          end
         end
-      end
 
-      def define_field(rule, type_class, field_name, tag, options)
-        raise_if_tag_collision(tag, field_name)
-        raise_if_name_collision(field_name)
+        def define_field(rule, type_class, field_name, tag, options)
+          raise_if_tag_collision(tag, field_name)
+          raise_if_name_collision(field_name)
 
-        field = ::Protobuf::Field.build(self, rule, type_class, field_name, tag, options)
-        field_store[field_name] = field
-        field_store[tag] = field
+          field = ::Protobuf::Field.build(self, rule, type_class, field_name, tag, options)
+          field_store[field_name] = field
+          field_store[tag] = field
 
-        define_method("#{field_name}!") do
-          @values[field_name]
+          define_method("#{field_name}!") do
+            @values[field_name]
+          end
         end
-      end
 
-      def raise_if_tag_collision(tag, field_name)
-        if get_field(tag, true)
-          fail TagCollisionError, %(Field number #{tag} has already been used in "#{name}" by field "#{field_name}".)
+        def raise_if_tag_collision(tag, field_name)
+          if get_field(tag, true)
+            fail TagCollisionError, %(Field number #{tag} has already been used in "#{name}" by field "#{field_name}".)
+          end
         end
-      end
 
-      def raise_if_name_collision(field_name)
-        if get_field(field_name, true)
-          fail DuplicateFieldNameError, %(Field name #{field_name} has already been used in "#{name}".)
+        def raise_if_name_collision(field_name)
+          if get_field(field_name, true)
+            fail DuplicateFieldNameError, %(Field name #{field_name} has already been used in "#{name}".)
+          end
         end
-      end
 
+        def inherit_fields!(subclass)
+          instance_variables.each do |iv|
+            subclass.instance_variable_set(iv, instance_variable_get(iv))
+          end
+        end
+        private :inherit_fields!
+
+      end
     end
   end
 end

spec/functional/class_inheritance_spec.rb

@@ -0,0 +1,52 @@
+require 'spec_helper'
+require 'spec/support/test/resource_service'
+
+RSpec.describe 'works through class inheritance' do
+  module Corp
+    module Protobuf
+      class Error < ::Protobuf::Message
+        required :string, :foo, 1
+      end
+    end
+  end
+  module Corp
+    class ErrorHandler < Corp::Protobuf::Error
+    end
+  end
+
+  let(:args) { { :foo => 'bar' } }
+  let(:parent_class) { Corp::Protobuf::Error }
+  let(:inherited_class) { Corp::ErrorHandler }
+
+  specify '#encode' do
+    expected_result = "\n\x03bar"
+    expected_result.force_encoding(Encoding::BINARY)
+    expect(parent_class.new(args).encode).to eq(expected_result)
+    expect(inherited_class.new(args).encode).to eq(expected_result)
+  end
+
+  specify '#to_hash' do
+    expect(parent_class.new(args).to_hash).to eq(args)
+    expect(inherited_class.new(args).to_hash).to eq(args)
+  end
+
+  specify '#to_json' do
+    expect(parent_class.new(args).to_json).to eq(args.to_json)
+    expect(inherited_class.new(args).to_json).to eq(args.to_json)
+  end
+
+  specify '.encode' do
+    expected_result = "\n\x03bar"
+    expected_result.force_encoding(Encoding::BINARY)
+    expect(parent_class.encode(args)).to eq(expected_result)
+    expect(inherited_class.encode(args)).to eq(expected_result)
+  end
+
+  specify '.decode' do
+    raw_value = "\n\x03bar"
+    raw_value.force_encoding(Encoding::BINARY)
+    expect(parent_class.decode(raw_value).to_hash).to eq(args)
+    expect(inherited_class.decode(raw_value).to_hash).to eq(args)
+  end
+
+end