// Copyright 2020 The Tint 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.

#ifndef SRC_TINT_SEM_TYPE_MANAGER_H_
#define SRC_TINT_SEM_TYPE_MANAGER_H_

#include <string>
#include <unordered_map>
#include <utility>

#include "src/tint/sem/type.h"
#include "src/tint/utils/unique_allocator.h"

namespace tint::sem {

/// The type manager holds all the pointers to the known types.
class Manager final : public utils::UniqueAllocator<Type> {
 public:
  /// Iterator is the type returned by begin() and end()
  using Iterator = utils::BlockAllocator<Type>::ConstIterator;

  /// Constructor
  Manager();

  /// Move constructor
  Manager(Manager&&);

  /// Move assignment operator
  /// @param rhs the Manager to move
  /// @return this Manager
  Manager& operator=(Manager&& rhs);

  /// Destructor
  ~Manager();

  /// Wrap returns a new Manager created with the types of `inner`.
  /// The Manager returned by Wrap is intended to temporarily extend the types
  /// of an existing immutable Manager.
  /// As the copied types are owned by `inner`, `inner` must not be destructed
  /// or assigned while using the returned Manager.
  /// TODO(bclayton) - Evaluate whether there are safer alternatives to this
  /// function. See crbug.com/tint/460.
  /// @param inner the immutable Manager to extend
  /// @return the Manager that wraps `inner`
  static Manager Wrap(const Manager& inner) {
    Manager out;
    out.items = inner.items;
    return out;
  }

  /// @returns an iterator to the beginning of the types
  Iterator begin() const { return allocator.Objects().begin(); }
  /// @returns an iterator to the end of the types
  Iterator end() const { return allocator.Objects().end(); }
};

}  // namespace tint::sem

#endif  // SRC_TINT_SEM_TYPE_MANAGER_H_