text: // Copyright 2017 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef CHROME_BROWSER_EXTENSIONS_API_PASSWORDS_PRIVATE_PASSWORDS_PRIVATE_UTILS_H_
  #define CHROME_BROWSER_EXTENSIONS_API_PASSWORDS_PRIVATE_PASSWORDS_PRIVATE_UTILS_H_
  
  #include <functional>
  #include <map>
  #include <string>
  
  #include "base/containers/flat_map.h"
  #include "chrome/common/extensions/api/passwords_private.h"
  
  namespace password_manager {
  struct PasswordForm;
  }  // namespace password_manager
  
  namespace extensions {
  
  // Obtains a collection of URLs from the passed in form. This includes an origin
  // URL used for internal logic, a human friendly string shown to the user as
  // well as a URL that is linked to.
  api::passwords_private::UrlCollection CreateUrlCollectionFromForm(
      const password_manager::PasswordForm& form);
  
  // This class is an id generator for an arbitrary key type. It is used by both
  // PasswordManagerPresenter and PasswordCheckDelegate to create ids send to the
  // UI. It is similar to base::IDMap, but has the following important
  // differences:
  // - IdGenerator owns a copy of the key data, so that clients don't need to
  //   worry about dangling pointers.
  // - Repeated calls to GenerateId with the same |key| are no-ops, and return the
  //   same ids.
  template <typename KeyT,
            typename IdT = int32_t,
            typename KeyCompare = std::less<>>
  class IdGenerator {
   public:
    // This method generates an id corresponding to |key|. Additionally it
    // remembers ids generated in the past, so that this method is idempotent.
    // Furthermore, it is guaranteed that different ids are returned for different
    // |key| arguments. This implies GenerateId(a) == GenerateId(b) if and only if
    // a == b.
    IdT GenerateId(const KeyT& key) {
      auto result = key_cache_.emplace(key, next_id_);
      if (result.second) {
        // In case we haven't seen |key| before, add a pointer to the inserted key
        // and the corresponding id to the |id_cache_|. This insertion should
        // always succeed.
        auto iter = id_cache_.emplace_hint(id_cache_.end(), next_id_,
                                           &result.first->first);
        DCHECK_EQ(&result.first->first, iter->second);
        ++next_id_;
      }
  
      return result.first->second;
    }
  
    // This method tries to return the key corresponding to |id|. In case |id| was
    // not generated by GenerateId() before, this method returns nullptr.
    // Otherwise it returns a pointer p to a key, such that |id| ==
    // GenerateId(*p).
    const KeyT* TryGetKey(IdT id) const {
      auto it = id_cache_.find(id);
      return it != id_cache_.end() ? it->second : nullptr;
    }
  
   private:
    std::map<KeyT, IdT, KeyCompare> key_cache_;
    base::flat_map<IdT, const KeyT*> id_cache_;
    IdT next_id_ = 0;
  };
  
  }  // namespace extensions
  
  #endif  // CHROME_BROWSER_EXTENSIONS_API_PASSWORDS_PRIVATE_PASSWORDS_PRIVATE_UTILS_H_
  