Keep only base/extractor.[cc|h].

base/object_factory.h

-// Copyright 2007-2009 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.
-// ========================================================================
-
-#ifndef OMAHA_BASE_OBJECT_FACTORY_H_
-#define OMAHA_BASE_OBJECT_FACTORY_H_
-
-#include <map>
-
-namespace omaha {
-
-// Factory creates instances of objects based on a unique type id.
-//
-// AbstractProduct - base class of the product hierarchy.
-// TypeId - type id for each type in the hierarchy.
-// ProductCreator - callable entity to create objects.
-
-template <class AbstractProduct,
-          typename TypeId,
-          typename ProductCreator = AbstractProduct* (*)()>
-class Factory {
- public:
-  Factory() {}
-
-  // Registers a creator for the type id. Returns true if the creator has
-  // been registered succesfully.
-  bool Register(const TypeId& id, ProductCreator creator) {
-    return id_to_creators_.insert(Map::value_type(id, creator)).second;
-  }
-
-  // Unregisters a type id.
-  bool Unregister(const TypeId& id) {
-    return id_to_creators_.erase(id) == 1;
-  }
-
-  // Creates an instance of the abstract product.
-  AbstractProduct* CreateObject(const TypeId& id) const {
-    typename Map::const_iterator it = id_to_creators_.find(id);
-    if (it != id_to_creators_.end()) {
-      return (it->second)();
-    } else {
-      return NULL;
-    }
-  }
-
- private:
-  typedef std::map<TypeId, ProductCreator> Map;
-  Map id_to_creators_;
-
-  DISALLOW_EVIL_CONSTRUCTORS(Factory);
-};
-
-}  // namespace omaha
-
-#endif  // OMAHA_BASE_OBJECT_FACTORY_H_
-