names_collection.h

/*

 *  Copyright (c) 2022 The WebRTC project authors. All Rights Reserved.

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

*/

#ifndef TEST_PC_E2E_ANALYZER_VIDEO_NAMES_COLLECTION_H_

#define TEST_PC_E2E_ANALYZER_VIDEO_NAMES_COLLECTION_H_

#include <map>

#include <optional>

#include <set>

#include <string>

#include <vector>

#include "absl/strings/string_view.h"

#include "api/array_view.h"

namespace webrtc {

// Contains mapping between string names and unique size_t values (indexes).

// Once the name is added to the collection it is guaranteed:

//   1. Name will have the same index until collection will be destructed

//   2. Adding, removing and re-adding name won't change its index

//

// The name is considered in the collection if it was added and wasn't removed.

// Adding the name when it is in the collection won't change the collection, the

// same as removing the name when it is removed.

//

// Collection will return name's index and name for the index independently from

// was name removed or not. Once the name was added to the collection the index

// will be allocated for it. To check if name is in collection right now user

// has to explicitly call to `HasName` function.

class NamesCollection {

 public:

  NamesCollection() = default;

  explicit NamesCollection(rtc::ArrayView<const std::string> names);

  // Returns amount of currently presented names in the collection.

  size_t size() const { return size_; }

  // Returns amount of all names known to this collection.

  size_t GetKnownSize() const { return names_.size(); }

  // Returns index of the `name` which was known to the collection. Crashes

  // if `name` was never registered in the collection.

  size_t index(absl::string_view name) const { return index_.at(name); }

  // Returns name which was known to the collection for the specified `index`.

  // Crashes if there was no any name registered in the collection for such

  // `index`.

  const std::string& name(size_t index) const { return names_.at(index); }

  // Returns if `name` is currently presented in this collection.

  bool HasName(absl::string_view name) const;

  // Adds specified `name` to the collection if it isn't presented.

  // Returns index which corresponds to specified `name`.

  size_t AddIfAbsent(absl::string_view name);

  // Removes specified `name` from the collection if it is presented.

//

  // After name was removed, collection size will be decreased, but `name` index

  // will be preserved. Collection will return false for `HasName(name)`, but

  // will continue to return previously known index for `index(name)` and return

  // `name` for `name(index(name))`.

//

  // Returns the index of the removed value or std::nullopt if no such `name`

  // registered in the collection.

  std::optional<size_t> RemoveIfPresent(absl::string_view name);

  // Returns a set of indexes for all currently present names in the

  // collection.

  std::set<size_t> GetPresentIndexes() const;

  // Returns a set of all indexes known to the collection including indexes for

  // names that were removed.

  std::set<size_t> GetAllIndexes() const;

 private:

  std::vector<std::string> names_;

  std::vector<bool> removed_;

  std::map<absl::string_view, size_t> index_;

  size_t size_ = 0;

};

}  // namespace webrtc

#endif  // TEST_PC_E2E_ANALYZER_VIDEO_NAMES_COLLECTION_H_