/*
Copyright 2011 Google Inc.

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 blobserver

import (
	"fmt"
	"http"
	"os"
	"sync"

	"camli/jsonconfig"
)

type StorageConstructor func(config jsonconfig.Obj) (Storage, os.Error)
type HandlerConstructor func(config jsonconfig.Obj) (http.Handler, os.Error)

var mapLock sync.Mutex
var storageConstructors = make(map[string]StorageConstructor)
var handlerConstructors = make(map[string]HandlerConstructor)

func RegisterStorageConstructor(typ string, ctor StorageConstructor) {
	mapLock.Lock()
	defer mapLock.Unlock()
	if _, ok := storageConstructors[typ]; ok {
		panic("blobserver: StorageConstructor already registered for type: " + typ)
	}
	storageConstructors[typ] = ctor
}

func CreateStorage(typ string, config jsonconfig.Obj) (Storage, os.Error) {
	mapLock.Lock()
	ctor, ok := storageConstructors[typ]
	mapLock.Unlock()
	if !ok {
		return nil, fmt.Errorf("Storage type %q not known or loaded", typ)
	}
	return ctor(config)
}

func RegisterHandlerConstrutor(typ string, ctor HandlerConstructor) {
	mapLock.Lock()
        defer mapLock.Unlock()
	if _, ok := handlerConstructors[typ]; ok {
                panic("blobserver: HandlerConstrutor already registered for type: " + typ)
        }
	handlerConstructors[typ] = ctor
}