Rename Object to EmbeddedObject

pkg/runtime/embedded.go

@@ -0,0 +1,90 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package runtime
+
+import (
+	"gopkg.in/v1/yaml"
+)
+
+// Encode()/Decode() are the canonical way of converting an API object to/from
+// wire format. This file provides utility functions which permit doing so
+// recursively, such that API objects of types known only at run time can be
+// embedded within other API types.
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+func (a *EmbeddedObject) UnmarshalJSON(b []byte) error {
+	// Handle JSON's "null": Decode() doesn't expect it.
+	if len(b) == 4 && string(b) == "null" {
+		a.Object = nil
+		return nil
+	}
+
+	obj, err := Decode(b)
+	if err != nil {
+		return err
+	}
+	a.Object = obj
+	return nil
+}
+
+// MarshalJSON implements the json.Marshaler interface.
+func (a EmbeddedObject) MarshalJSON() ([]byte, error) {
+	if a.Object == nil {
+		// Encode unset/nil objects as JSON's "null".
+		return []byte("null"), nil
+	}
+
+	return Encode(a.Object)
+}
+
+// SetYAML implements the yaml.Setter interface.
+func (a *EmbeddedObject) SetYAML(tag string, value interface{}) bool {
+	if value == nil {
+		a.Object = nil
+		return true
+	}
+	// Why does the yaml package send value as a map[interface{}]interface{}?
+	// It's especially frustrating because encoding/json does the right thing
+	// by giving a []byte. So here we do the embarrasing thing of re-encode and
+	// de-encode the right way.
+	// TODO: Write a version of Decode that uses reflect to turn this value
+	// into an API object.
+	b, err := yaml.Marshal(value)
+	if err != nil {
+		panic("yaml can't reverse its own object")
+	}
+	obj, err := Decode(b)
+	if err != nil {
+		return false
+	}
+	a.Object = obj
+	return true
+}
+
+// GetYAML implements the yaml.Getter interface.
+func (a EmbeddedObject) GetYAML() (tag string, value interface{}) {
+	if a.Object == nil {
+		value = "null"
+		return
+	}
+	// Encode returns JSON, which is conveniently a subset of YAML.
+	v, err := Encode(a.Object)
+	if err != nil {
+		panic("impossible to encode API object!")
+	}
+	return tag, v
+}