text: // Copyright (c) 2012 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_SPELLCHECKER_SPELLCHECK_CUSTOM_DICTIONARY_H_
  #define CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_CUSTOM_DICTIONARY_H_
  
  #include <memory>
  #include <set>
  #include <string>
  
  #include "base/cancelable_callback.h"
  #include "base/files/file_path.h"
  #include "base/macros.h"
  #include "base/memory/weak_ptr.h"
  #include "base/observer_list.h"
  #include "components/spellcheck/browser/spellcheck_dictionary.h"
  #include "components/sync/model/sync_data.h"
  #include "components/sync/model/sync_error.h"
  #include "components/sync/model/sync_merge_result.h"
  #include "components/sync/model/syncable_service.h"
  
  namespace syncer {
  class SyncErrorFactory;
  class SyncChangeProcessor;
  }
  
  namespace tracked_objects {
  class Location;
  }
  
  // Defines a custom dictionary where users can add their own words. All words
  // must be UTF8, between 1 and 99 bytes long, and without leading or trailing
  // ASCII whitespace. The dictionary contains its own checksum when saved on
  // disk. Example dictionary file contents:
  //
  //   bar
  //   foo
  //   checksum_v1 = ec3df4034567e59e119fcf87f2d9bad4
  //
  class SpellcheckCustomDictionary : public SpellcheckDictionary,
                                     public syncer::SyncableService {
   public:
    // A change to the dictionary.
    class Change {
     public:
      Change();
      ~Change();
  
      // Adds |word| in this change.
      void AddWord(const std::string& word);
  
      // Adds |words| in this change.
      void AddWords(const std::set<std::string>& words);
  
      // Removes |word| in this change.
      void RemoveWord(const std::string& word);
  
      // Prepares this change to be applied to |words| by removing duplicate and
      // invalid words from words to be added and removing missing words from
      // words to be removed. Returns a bitmap of |ChangeSanitationResult| values.
      int Sanitize(const std::set<std::string>& words);
  
      // Returns the words to be added in this change.
      const std::set<std::string>& to_add() const { return to_add_; }
  
      // Returns the words to be removed in this change.
      const std::set<std::string>& to_remove() const {
        return to_remove_;
      }
  
      // Returns true if there are no changes to be made. Otherwise returns false.
      bool empty() const { return to_add_.empty() && to_remove_.empty(); }
  
     private:
      // The words to be added.
      std::set<std::string> to_add_;
  
      // The words to be removed.
      std::set<std::string> to_remove_;
  
      DISALLOW_COPY_AND_ASSIGN(Change);
    };
  
    // Interface to implement for dictionary load and change observers.
    class Observer {
     public:
      // Called when the custom dictionary has been loaded.
      virtual void OnCustomDictionaryLoaded() = 0;
  
      // Called when the custom dictionary has been changed.
      virtual void OnCustomDictionaryChanged(const Change& dictionary_change) = 0;
    };
  
    struct LoadFileResult {
      LoadFileResult();
      ~LoadFileResult();
  
      // The contents of the custom dictionary file or its backup. Does not
      // contain data that failed checksum. Does not contain invalid words.
      std::set<std::string> words;
  
      // True when the custom dictionary file on disk has a valid checksum and
      // contains only valid words.
      bool is_valid_file;
  
     private:
      DISALLOW_COPY_AND_ASSIGN(LoadFileResult);
    };
  
    // The dictionary will be saved in |dictionary_directory_name|.
    explicit SpellcheckCustomDictionary(
        const base::FilePath& dictionary_directory_name);
    ~SpellcheckCustomDictionary() override;
  
    // Returns the in-memory cache of words in the custom dictionary.
    const std::set<std::string>& GetWords() const;
  
    // Adds |word| to the dictionary, schedules a write to disk, and notifies
    // observers of the change. Returns true if |word| is valid and not a
    // duplicate. Otherwise returns false.
    bool AddWord(const std::string& word);
  
    // Removes |word| from the dictionary, schedules a write to disk, and notifies
    // observers of the change. Returns true if |word| was found. Otherwise
    // returns false.
    bool RemoveWord(const std::string& word);
  
    // Returns true if the dictionary contains |word|. Otherwise returns false.
    bool HasWord(const std::string& word) const;
  
    // Adds |observer| to be notified of dictionary events and changes.
    void AddObserver(Observer* observer);
  
    // Removes |observer| to stop notifications of dictionary events and changes.
    void RemoveObserver(Observer* observer);
  
    // Returns true if the dictionary has been loaded. Otherwise returns false.
    bool IsLoaded();
  
    // Returns true if the dictionary is being synced. Otherwise returns false.
    bool IsSyncing();
  
    // Overridden from SpellcheckDictionary:
    void Load() override;
  
    // Overridden from syncer::SyncableService:
    syncer::SyncMergeResult MergeDataAndStartSyncing(
        syncer::ModelType type,
        const syncer::SyncDataList& initial_sync_data,
        std::unique_ptr<syncer::SyncChangeProcessor> sync_processor,
        std::unique_ptr<syncer::SyncErrorFactory> sync_error_handler) override;
    void StopSyncing(syncer::ModelType type) override;
    syncer::SyncDataList GetAllSyncData(syncer::ModelType type) const override;
    syncer::SyncError ProcessSyncChanges(
        const tracked_objects::Location& from_here,
        const syncer::SyncChangeList& change_list) override;
  
   private:
    friend class DictionarySyncIntegrationTestHelper;
    friend class SpellcheckCustomDictionaryTest;
  
    // Returns the list of words in the custom spellcheck dictionary at |path|.
    // Validates that the custom dictionary file does not have duplicates and
    // contains only valid words. Must be called on the FILE thread.
    static std::unique_ptr<LoadFileResult> LoadDictionaryFile(
        const base::FilePath& path);
  
    // Applies the change in |dictionary_change| to the custom spellcheck
    // dictionary. Assumes that |dictionary_change| has been sanitized. Must be
    // called on the FILE thread. Takes ownership of |dictionary_change|.
    static void UpdateDictionaryFile(std::unique_ptr<Change> dictionary_change,
                                     const base::FilePath& path);
  
    // The reply point for PostTaskAndReplyWithResult, called when
    // LoadDictionaryFile finishes reading the dictionary file.
    void OnLoaded(std::unique_ptr<LoadFileResult> result);
  
    // Applies the |dictionary_change| to the in-memory copy of the dictionary.
    void Apply(const Change& dictionary_change);
  
    // Schedules a write of the words in |load_file_result| to disk when the
    // custom dictionary file is invalid.
    void FixInvalidFile(std::unique_ptr<LoadFileResult> load_file_result);
  
    // Schedules a write of |dictionary_change| to disk. Takes ownership of
    // |dictionary_change| to pass it to the FILE thread.
    void Save(std::unique_ptr<Change> dictionary_change);
  
    // Notifies the sync service of the |dictionary_change|. Syncs up to the
    // maximum syncable words on the server. Disables syncing of this dictionary
    // if the server contains the maximum number of syncable words.
    syncer::SyncError Sync(const Change& dictionary_change);
  
    // Notifies observers of the dictionary change if the dictionary has been
    // changed.
    void Notify(const Change& dictionary_change);
  
    // In-memory cache of the custom words file.
    std::set<std::string> words_;
  
    // The path to the custom dictionary file.
    base::FilePath custom_dictionary_path_;
  
    // Observers for dictionary load and content changes.
    base::ObserverList<Observer> observers_;
  
    // Used to send local changes to the sync infrastructure.
    std::unique_ptr<syncer::SyncChangeProcessor> sync_processor_;
  
    // Used to send sync-related errors to the sync infrastructure.
    std::unique_ptr<syncer::SyncErrorFactory> sync_error_handler_;
  
    // True if the dictionary has been loaded. Otherwise false.
    bool is_loaded_;
  
    // A post-startup task to fix the invalid custom dictionary file.
    base::CancelableClosure fix_invalid_file_;
  
    // Used to create weak pointers for an instance of this class.
    base::WeakPtrFactory<SpellcheckCustomDictionary> weak_ptr_factory_;
  
    DISALLOW_COPY_AND_ASSIGN(SpellcheckCustomDictionary);
  };
  
  #endif  // CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_CUSTOM_DICTIONARY_H_
  