1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_ 6 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_ 7 8 #include <map> 9 #include <set> 10 #include <string> 11 12 #include "base/callback_forward.h" 13 #include "base/memory/scoped_ptr.h" 14 #include "base/memory/scoped_vector.h" 15 #include "base/memory/weak_ptr.h" 16 #include "chrome/browser/sync_file_system/drive_backend/tracker_set.h" 17 #include "chrome/browser/sync_file_system/sync_callbacks.h" 18 #include "chrome/browser/sync_file_system/sync_status_code.h" 19 20 namespace base { 21 class FilePath; 22 class SequencedTaskRunner; 23 class SingleThreadTaskRunner; 24 } 25 26 namespace leveldb { 27 class DB; 28 class WriteBatch; 29 } 30 31 namespace google_apis { 32 class ChangeResource; 33 class FileResource; 34 class ResourceEntry; 35 } 36 37 namespace sync_file_system { 38 namespace drive_backend { 39 40 class FileMetadata; 41 class FileTracker; 42 class ServiceMetadata; 43 struct DatabaseContents; 44 45 // MetadataDatabase holds and maintains a LevelDB instance and its indexes, 46 // which holds 1)ServiceMetadata, 2)FileMetadata and 3)FileTracker. 47 // 1) ServiceMetadata is a singleton in the database which holds information for 48 // the backend. 49 // 2) FileMetadata represents a remote-side file and holds latest known 50 // metadata of the remote file. 51 // 3) FileTracker represents a synced or to-be-synced file and maintains 52 // the local-side folder tree. 53 // 54 // The term "file" includes files, folders and other resources on Drive. 55 // 56 // FileTrackers form a tree structure on the database, which represents the 57 // FileSystem trees of SyncFileSystem. The tree has a FileTracker named 58 // sync-root as its root node, and a set of FileTracker named app-root. An 59 // app-root represents a remote folder for an installed Chrome App and holds all 60 // synced contents for the App. 61 // 62 // One FileMetadata is created for each tracked remote file, which is identified 63 // by FileID. 64 // One FileTracker is created for every different {parent tracker, FileID} pair, 65 // excluding non-app-root inactive parent trackers. Multiple trackers may be 66 // associated to one FileID when the file has multiple parents. Multiple 67 // trackers may have the same {parent tracker, title} pair when the associated 68 // remote files have the same title. 69 // 70 // Files have following state: 71 // - Unknown file 72 // - Has a dirty inactive tracker and empty synced_details. 73 // - Is initial state of a tracker, only file_id and parent_tracker_id field 74 // are known. 75 // - Folder 76 // - Is either one of sync-root folder, app-root folder or a regular folder. 77 // - Sync-root folder holds app-root folders as its direct children, and 78 // holds entire SyncFileSystem files as its descentants. Its tracker 79 // should be stored in ServiceMetadata by its tracker_id. 80 // - App-root folder holds all files for an application as its descendants. 81 // - File 82 // - Unsupported file 83 // - Represents unsupported files such as hosted documents. Must be 84 // inactive. 85 // 86 // Invariants: 87 // - Any tracker in the database must either: 88 // - be sync-root, 89 // - have an app-root as its parent tracker, or 90 // - have an active tracker as its parent. 91 // That is, all trackers must be reachable from sync-root via app-root folders 92 // and active trackers. 93 // 94 // - Any active tracker must either: 95 // - have |needs_folder_listing| flag and dirty flag, or 96 // - have all children at the stored largest change ID. 97 // 98 // - If multiple trackers have the same parent tracker and same title, they 99 // must not have same |file_id|, and at most one of them may be active. 100 // - If multiple trackers have the same |file_id|, at most one of them may be 101 // active. 102 // 103 class MetadataDatabase { 104 public: 105 typedef std::map<std::string, FileMetadata*> FileByID; 106 typedef std::map<int64, FileTracker*> TrackerByID; 107 typedef std::map<std::string, TrackerSet> TrackersByFileID; 108 typedef std::map<std::string, TrackerSet> TrackersByTitle; 109 typedef std::map<int64, TrackersByTitle> TrackersByParentAndTitle; 110 typedef std::map<std::string, FileTracker*> TrackerByAppID; 111 112 typedef base::Callback< 113 void(SyncStatusCode status, scoped_ptr<MetadataDatabase> instance)> 114 CreateCallback; 115 116 static void Create(base::SequencedTaskRunner* task_runner, 117 const base::FilePath& database_path, 118 const CreateCallback& callback); 119 ~MetadataDatabase(); 120 121 int64 GetLargestChangeID() const; 122 123 // Registers existing folder as the app-root for |app_id|. The folder 124 // must be an inactive folder that does not yet associated to any App. 125 // This method associates the folder with |app_id| and activates it. 126 void RegisterApp(const std::string& app_id, 127 const std::string& folder_id, 128 const SyncStatusCallback& callback); 129 130 // Inactivates the folder associated to the app to disable |app_id|. 131 // Does nothing if |app_id| is already disabled. 132 void DisableApp(const std::string& app_id, 133 const SyncStatusCallback& callback); 134 135 // Activates the folder associated to |app_id| to enable |app_id|. 136 // Does nothing if |app_id| is already enabled. 137 void EnableApp(const std::string& app_id, 138 const SyncStatusCallback& callback); 139 140 // Unregisters the folder as the app-root for |app_id|. If |app_id| does not 141 // exist, does nothing. The folder is left as an inactive regular folder. 142 // Note that the inactivation drops all descendant files since they are no 143 // longer reachable from sync-root via active folder or app-root. 144 void UnregisterApp(const std::string& app_id, 145 const SyncStatusCallback& callback); 146 147 // Finds the app-root folder for |app_id|. Returns true if exists. 148 // Copies the result to |tracker| if it is non-NULL. 149 bool FindAppRootTracker(const std::string& app_id, 150 FileTracker* tracker) const; 151 152 // Finds the file identified by |file_id|. Returns true if the file is found. 153 // Copies the metadata identified by |file_id| into |file| if exists and 154 // |file| is non-NULL. 155 bool FindFileByFileID(const std::string& file_id, FileMetadata* file) const; 156 157 // Finds the tracker identified by |tracker_id|. Returns true if the tracker 158 // is found. 159 // Copies the tracker identified by |tracker_id| into |tracker| if exists and 160 // |tracker| is non-NULL. 161 bool FindTrackerByTrackerID(int64 tracker_id, FileTracker* tracker) const; 162 163 // Finds the trackers tracking |file_id|. Returns true if the trackers are 164 // found. 165 bool FindTrackersByFileID(const std::string& file_id, 166 TrackerSet* trackers) const; 167 168 // Finds the set of trackers whose parent's tracker ID is |parent_tracker_id|, 169 // and who has |title| as its title in the synced_details. 170 // Copies the tracker set to |trackers| if it is non-NULL. 171 size_t FindTrackersByParentAndTitle( 172 int64 parent_tracker_id, 173 const std::string& title, 174 TrackerSet* trackers) const; 175 176 // Builds the file path for the given tracker. Returns true on success. 177 // |path| can be NULL. 178 // The file path is relative to app-root and have a leading path separator. 179 bool BuildPathForTracker(int64 tracker_id, base::FilePath* path) const; 180 181 // Updates database by |changes|. 182 // Marks each tracker for modified file as dirty and adds new trackers if 183 // needed. 184 void UpdateByChangeList(ScopedVector<google_apis::ChangeResource> changes, 185 const SyncStatusCallback& callback); 186 187 private: 188 struct DirtyTrackerComparator { 189 bool operator()(const FileTracker* left, 190 const FileTracker* right) const; 191 }; 192 193 typedef std::set<FileTracker*, DirtyTrackerComparator> DirtyTrackers; 194 195 friend class MetadataDatabaseTest; 196 197 explicit MetadataDatabase(base::SequencedTaskRunner* task_runner); 198 static void CreateOnTaskRunner(base::SingleThreadTaskRunner* callback_runner, 199 base::SequencedTaskRunner* task_runner, 200 const base::FilePath& database_path, 201 const CreateCallback& callback); 202 static SyncStatusCode CreateForTesting( 203 scoped_ptr<leveldb::DB> db, 204 scoped_ptr<MetadataDatabase>* metadata_database_out); 205 SyncStatusCode InitializeOnTaskRunner(const base::FilePath& database_path); 206 void BuildIndexes(DatabaseContents* contents); 207 208 // Database manipulation methods. 209 void RegisterTrackerAsAppRoot(const std::string& app_id, 210 int64 tracker_id, 211 leveldb::WriteBatch* batch); 212 void MakeTrackerActive(int64 tracker_id, leveldb::WriteBatch* batch); 213 void MakeTrackerInactive(int64 tracker_id, leveldb::WriteBatch* batch); 214 215 void UnregisterTrackerAsAppRoot(const std::string& app_id, 216 leveldb::WriteBatch* batch); 217 void RemoveAllDescendantTrackers(int64 root_tracker_id, 218 leveldb::WriteBatch* batch); 219 220 void CreateTrackerForParentAndFileID(const FileTracker& parent_tracker, 221 const std::string& file_id, 222 leveldb::WriteBatch* batch); 223 void RemoveTrackerIgnoringSiblings(int64 tracker_id, 224 leveldb::WriteBatch* batch); 225 void MaybeAddTrackersForNewFile(const FileMetadata& file, 226 leveldb::WriteBatch* batch); 227 228 void MarkTrackerSetDirty(TrackerSet* trackers, 229 leveldb::WriteBatch* batch); 230 void MarkTrackersDirtyByFileID(const std::string& file_id, 231 leveldb::WriteBatch* batch); 232 void MarkTrackersDirtyByPath(int64 parent_tracker_id, 233 const std::string& title, 234 leveldb::WriteBatch* batch); 235 236 void EraseTrackerFromFileIDIndex(FileTracker* tracker, 237 leveldb::WriteBatch* batch); 238 void EraseTrackerFromPathIndex(FileTracker* tracker); 239 void EraseFileFromDatabase(const std::string& file_id, 240 leveldb::WriteBatch* batch); 241 242 int64 GetNextTrackerID(leveldb::WriteBatch* batch); 243 244 void WriteToDatabase(scoped_ptr<leveldb::WriteBatch> batch, 245 const SyncStatusCallback& callback); 246 247 scoped_refptr<base::SequencedTaskRunner> task_runner_; 248 scoped_ptr<leveldb::DB> db_; 249 250 scoped_ptr<ServiceMetadata> service_metadata_; 251 252 FileByID file_by_id_; // Owned. 253 TrackerByID tracker_by_id_; // Owned. 254 255 // Maps FileID to trackers. The active tracker must be unique per FileID. 256 // This must be updated when updating |active| field of a tracker. 257 TrackersByFileID trackers_by_file_id_; // Not owned. 258 259 // Maps AppID to the app-root tracker. 260 // This must be updated when a tracker is registered/unregistered as an 261 // app-root. 262 TrackerByAppID app_root_by_app_id_; // Not owned. 263 264 // Maps |tracker_id| to its children grouped by their |title|. 265 // If the title is unknown for a tracker, treats its title as empty. Empty 266 // titled file must not be active. 267 // The active tracker must be unique per its parent_tracker and its title. 268 // This must be updated when updating |title|, |active| or 269 // |parent_tracker_id|. 270 TrackersByParentAndTitle trackers_by_parent_and_title_; 271 272 // Holds all trackers which marked as dirty. 273 // This must be updated when updating |dirty| field of a tracker. 274 DirtyTrackers dirty_trackers_; // Not owned. 275 276 base::WeakPtrFactory<MetadataDatabase> weak_ptr_factory_; 277 278 DISALLOW_COPY_AND_ASSIGN(MetadataDatabase); 279 }; 280 281 } // namespace drive_backend 282 } // namespace sync_file_system 283 284 #endif // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_ 285
