finish moving towards new auto-generated Headers implementation

Everything in one package once more. The bigger API in *this* package is
worth it when we don't have to expose guts to cross package boundaries.

1 files changed, 56 insertions, 0 deletions

diff --git a/field_metadata.go b/field_metadata.go
new file mode 100644
index 0000000..cebd2af
--- /dev/null
+++ b/field_metadata.go
@@ -0,0 +1,56 @@
+/******************************************************************************
+*
+*  Copyright 2018 Stefan Majewsky <majewsky@gmx.net>
+*
+*  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 schwift
+
+//FieldMetadata is a helper type that provides safe access to the metadata headers
+//in a SomethingHeaders instance. It cannot be directly constructed, but each
+//SomethingHeaders type has a method "Metadata" returning this type. For example:
+//
+//    hdr := make(ObjectHeaders)
+//    //the following two statements are equivalent
+//    hdr["X-Object-Meta-Access"] = "strictly confidential"
+//    hdr.Metadata().Set("Access", "strictly confidential")
+type FieldMetadata struct {
+	h headerInterface
+	k string
+}
+
+//Clear works like Headers.Clear(), but prepends the metadata prefix to the key.
+func (m FieldMetadata) Clear(key string) {
+	m.h.Clear(m.k + key)
+}
+
+//Del works like Headers.Del(), but prepends the metadata prefix to the key.
+func (m FieldMetadata) Del(key string) {
+	m.h.Del(m.k + key)
+}
+
+//Get works like Headers.Get(), but prepends the metadata prefix to the key.
+func (m FieldMetadata) Get(key string) string {
+	return m.h.Get(m.k + key)
+}
+
+//Set works like Headers.Set(), but prepends the metadata prefix to the key.
+func (m FieldMetadata) Set(key, value string) {
+	m.h.Set(m.k+key, value)
+}
+
+func (m FieldMetadata) validate() error {
+	return nil
+}