/*
Copyright 2015 The Kubernetes Authors.

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 generic

import (
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apiserver/pkg/storage"
	"k8s.io/apiserver/pkg/storage/storagebackend"
	"k8s.io/apiserver/pkg/storage/storagebackend/factory"
	"k8s.io/klog"
)

// StorageDecorator is a function signature for producing a storage.Interface
// and an associated DestroyFunc from given parameters.
type StorageDecorator func(
	config *storagebackend.Config,
	objectType runtime.Object,
	resourcePrefix string,
	keyFunc func(obj runtime.Object) (string, error),
	newListFunc func() runtime.Object,
	getAttrsFunc storage.AttrFunc,
	trigger storage.TriggerPublisherFunc) (storage.Interface, factory.DestroyFunc)

// UndecoratedStorage returns the given a new storage from the given config
// without any decoration.
func UndecoratedStorage(
	config *storagebackend.Config,
	objectType runtime.Object,
	resourcePrefix string,
	keyFunc func(obj runtime.Object) (string, error),
	newListFunc func() runtime.Object,
	getAttrsFunc storage.AttrFunc,
	trigger storage.TriggerPublisherFunc) (storage.Interface, factory.DestroyFunc) {
	return NewRawStorage(config)
}

// NewRawStorage creates the low level kv storage. This is a work-around for current
// two layer of same storage interface.
// TODO: Once cacher is enabled on all registries (event registry is special), we will remove this method.
func NewRawStorage(config *storagebackend.Config) (storage.Interface, factory.DestroyFunc) {
	s, d, err := factory.Create(*config)
	if err != nil {
		klog.Fatalf("Unable to create storage backend: config (%v), err (%v)", config, err)
	}
	return s, d
}
