// Copyright 2013 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_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_
#define CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_
#include <map>
#include <set>
#include <string>
#include <vector>
#include "base/callback_forward.h"
#include "base/containers/hash_tables.h"
#include "base/containers/scoped_ptr_hash_map.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/scoped_vector.h"
#include "base/memory/weak_ptr.h"
#include "base/values.h"
#include "chrome/browser/sync_file_system/drive_backend/tracker_id_set.h"
#include "chrome/browser/sync_file_system/sync_callbacks.h"
#include "chrome/browser/sync_file_system/sync_status_code.h"
namespace base {
class FilePath;
class SequencedTaskRunner;
class SingleThreadTaskRunner;
}
namespace leveldb {
class DB;
class Env;
class WriteBatch;
}
namespace google_apis {
class ChangeResource;
class FileResource;
class ResourceEntry;
}
namespace tracked_objects {
class Location;
}
namespace sync_file_system {
namespace drive_backend {
class FileDetails;
class FileMetadata;
class FileTracker;
class MetadataDatabaseIndex;
class ServiceMetadata;
struct DatabaseContents {
scoped_ptr<ServiceMetadata> service_metadata;
ScopedVector<FileMetadata> file_metadata;
ScopedVector<FileTracker> file_trackers;
DatabaseContents();
~DatabaseContents();
};
// MetadataDatabase holds and maintains a LevelDB instance and its indexes,
// which holds 1)ServiceMetadata, 2)FileMetadata and 3)FileTracker.
// 1) ServiceMetadata is a singleton in the database which holds information for
// the backend.
// 2) FileMetadata represents a remote-side file and holds latest known
// metadata of the remote file.
// 3) FileTracker represents a synced or to-be-synced file and maintains
// the local-side folder tree.
//
// The term "file" includes files, folders and other resources on Drive.
//
// FileTrackers form a tree structure on the database, which represents the
// FileSystem trees of SyncFileSystem. The tree has a FileTracker named
// sync-root as its root node, and a set of FileTracker named app-root. An
// app-root represents a remote folder for an installed Chrome App and holds all
// synced contents for the App.
//
// One FileMetadata is created for each tracked remote file, which is identified
// by FileID.
// One FileTracker is created for every different {parent tracker, FileID} pair,
// excluding non-app-root inactive parent trackers. Multiple trackers may be
// associated to one FileID when the file has multiple parents. Multiple
// trackers may have the same {parent tracker, title} pair when the associated
// remote files have the same title.
//
// Files have following state:
// - Unknown file
// - Has a dirty inactive tracker and empty synced_details.
// - Is initial state of a tracker, only file_id and parent_tracker_id field
// are known.
// - Folder
// - Is either one of sync-root folder, app-root folder or a regular folder.
// - Sync-root folder holds app-root folders as its direct children, and
// holds entire SyncFileSystem files as its descentants. Its tracker
// should be stored in ServiceMetadata by its tracker_id.
// - App-root folder holds all files for an application as its descendants.
// - File
// - Unsupported file
// - Represents unsupported files such as hosted documents. Must be
// inactive.
//
// Invariants:
// - Any tracker in the database must either:
// - be sync-root,
// - have an app-root as its parent tracker, or
// - have an active tracker as its parent.
// That is, all trackers must be reachable from sync-root via app-root folders
// and active trackers.
//
// - Any active tracker must either:
// - have |needs_folder_listing| flag and dirty flag, or
// - have all children at the stored largest change ID.
//
// - If multiple trackers have the same parent tracker and same title, they
// must not have same |file_id|, and at most one of them may be active.
// - If multiple trackers have the same |file_id|, at most one of them may be
// active.
//
class MetadataDatabase {
public:
typedef std::vector<std::string> FileIDList;
typedef base::Callback<
void(SyncStatusCode status, scoped_ptr<MetadataDatabase> instance)>
CreateCallback;
enum ActivationStatus {
ACTIVATION_PENDING,
ACTIVATION_FAILED_ANOTHER_ACTIVE_TRACKER,
};
enum UpdateOption {
UPDATE_TRACKER_FOR_UNSYNCED_FILE,
UPDATE_TRACKER_FOR_SYNCED_FILE,
};
// The entry point of the MetadataDatabase for production code.
// If |env_override| is non-NULL, internal LevelDB uses |env_override| instead
// of leveldb::Env::Default(). Use leveldb::MemEnv in test code for faster
// testing.
static void Create(base::SequencedTaskRunner* task_runner,
const base::FilePath& database_path,
leveldb::Env* env_override,
const CreateCallback& callback);
static SyncStatusCode CreateForTesting(
scoped_ptr<leveldb::DB> db,
scoped_ptr<MetadataDatabase>* metadata_database_out);
~MetadataDatabase();
static void ClearDatabase(scoped_ptr<MetadataDatabase> metadata_database);
int64 GetLargestFetchedChangeID() const;
int64 GetSyncRootTrackerID() const;
bool HasSyncRoot() const;
// Returns all file metadata for the given |app_id|.
scoped_ptr<base::ListValue> DumpFiles(const std::string& app_id);
// Returns all database data.
scoped_ptr<base::ListValue> DumpDatabase();
// TODO(tzik): Move GetLargestKnownChangeID() to private section, and hide its
// handling in the class, instead of letting user do.
//
// Gets / updates the largest known change ID.
// The largest known change ID is on-memory and not persist over restart.
// This is supposed to use when a task fetches ChangeList in parallel to other
// operation. When a task starts fetching paged ChangeList one by one, it
// should update the largest known change ID on the first round and background
// remaining fetch job.
// Then, when other tasks that update FileMetadata by UpdateByFileResource,
// it should use largest known change ID as the |change_id| that prevents
// FileMetadata from overwritten by ChangeList.
// Also if other tasks try to update a remote resource whose change is not yet
// retrieved the task should fail due to etag check, so we should be fine.
int64 GetLargestKnownChangeID() const;
void UpdateLargestKnownChangeID(int64 change_id);
// Populates empty database with initial data.
// Adds a file metadata and a file tracker for |sync_root_folder|, and adds
// file metadata and file trackers for each |app_root_folders|.
// Newly added tracker for |sync_root_folder| is active and non-dirty.
// Newly added trackers for |app_root_folders| are inactive and non-dirty.
// Trackers for |app_root_folders| are not yet registered as app-roots, but
// are ready to register.
void PopulateInitialData(
int64 largest_change_id,
const google_apis::FileResource& sync_root_folder,
const ScopedVector<google_apis::FileResource>& app_root_folders,
const SyncStatusCallback& callback);
// Returns true if the folder associated to |app_id| is enabled.
bool IsAppEnabled(const std::string& app_id) const;
// Registers existing folder as the app-root for |app_id|. The folder
// must be an inactive folder that does not yet associated to any App.
// This method associates the folder with |app_id| and activates it.
void RegisterApp(const std::string& app_id,
const std::string& folder_id,
const SyncStatusCallback& callback);
// Inactivates the folder associated to the app to disable |app_id|.
// Does nothing if |app_id| is already disabled.
void DisableApp(const std::string& app_id,
const SyncStatusCallback& callback);
// Activates the folder associated to |app_id| to enable |app_id|.
// Does nothing if |app_id| is already enabled.
void EnableApp(const std::string& app_id,
const SyncStatusCallback& callback);
// Unregisters the folder as the app-root for |app_id|. If |app_id| does not
// exist, does nothing. The folder is left as an inactive regular folder.
// Note that the inactivation drops all descendant files since they are no
// longer reachable from sync-root via active folder or app-root.
void UnregisterApp(const std::string& app_id,
const SyncStatusCallback& callback);
// Finds the app-root folder for |app_id|. Returns true if exists.
// Copies the result to |tracker| if it is non-NULL.
bool FindAppRootTracker(const std::string& app_id,
FileTracker* tracker) const;
// Finds the file identified by |file_id|. Returns true if the file is found.
// Copies the metadata identified by |file_id| into |file| if exists and
// |file| is non-NULL.
bool FindFileByFileID(const std::string& file_id, FileMetadata* file) const;
// Finds the tracker identified by |tracker_id|. Returns true if the tracker
// is found.
// Copies the tracker identified by |tracker_id| into |tracker| if exists and
// |tracker| is non-NULL.
bool FindTrackerByTrackerID(int64 tracker_id, FileTracker* tracker) const;
// Finds the trackers tracking |file_id|. Returns true if the trackers are
// found.
bool FindTrackersByFileID(const std::string& file_id,
TrackerIDSet* trackers) const;
// Finds the set of trackers whose parent's tracker ID is |parent_tracker_id|,
// and who has |title| as its title in the synced_details.
// Copies the tracker set to |trackers| if it is non-NULL.
// Returns true if the trackers are found.
bool FindTrackersByParentAndTitle(
int64 parent_tracker_id,
const std::string& title,
TrackerIDSet* trackers) const;
// Builds the file path for the given tracker. Returns true on success.
// |path| can be NULL.
// The file path is relative to app-root and have a leading path separator.
bool BuildPathForTracker(int64 tracker_id, base::FilePath* path) const;
// Builds the file path for the given tracker for display purpose.
// This may return a path ending with '<unknown>' if the given tracker does
// not have title information (yet). This may return an empty path.
base::FilePath BuildDisplayPathForTracker(const FileTracker& tracker) const;
// Returns false if no registered app exists associated to |app_id|.
// If |full_path| is active, assigns the tracker of |full_path| to |tracker|.
// Otherwise, assigns the nearest active ancestor to |full_path| to |tracker|.
// Also, assigns the full path of |tracker| to |path|.
bool FindNearestActiveAncestor(const std::string& app_id,
const base::FilePath& full_path,
FileTracker* tracker,
base::FilePath* path) const;
// Updates database by |changes|.
// Marks each tracker for modified file as dirty and adds new trackers if
// needed.
void UpdateByChangeList(int64 largest_change_id,
ScopedVector<google_apis::ChangeResource> changes,
const SyncStatusCallback& callback);
// Updates database by |resource|.
// Marks each tracker for modified file as dirty and adds new trackers if
// needed.
void UpdateByFileResource(const google_apis::FileResource& resource,
const SyncStatusCallback& callback);
void UpdateByFileResourceList(
ScopedVector<google_apis::FileResource> resources,
const SyncStatusCallback& callback);
void UpdateByDeletedRemoteFile(const std::string& file_id,
const SyncStatusCallback& callback);
void UpdateByDeletedRemoteFileList(const FileIDList& file_ids,
const SyncStatusCallback& callback);
// Adds new FileTracker and FileMetadata. The database must not have
// |resource| beforehand.
// The newly added tracker under |parent_tracker_id| is active and non-dirty.
// Deactivates existing active tracker if exists that has the same title and
// parent_tracker to the newly added tracker.
void ReplaceActiveTrackerWithNewResource(
int64 parent_tracker_id,
const google_apis::FileResource& resource,
const SyncStatusCallback& callback);
// Adds |child_file_ids| to |folder_id| as its children.
// This method affects the active tracker only.
// If the tracker has no further change to sync, unmarks its dirty flag.
void PopulateFolderByChildList(const std::string& folder_id,
const FileIDList& child_file_ids,
const SyncStatusCallback& callback);
// Updates |synced_details| of the tracker with |updated_details|.
void UpdateTracker(int64 tracker_id,
const FileDetails& updated_details,
const SyncStatusCallback& callback);
// Activates a tracker identified by |parent_tracker_id| and |file_id| if the
// tracker can be activated without inactivating other trackers that have the
// same |file_id| but different paths.
// If |file_id| has another active tracker, the function returns
// ACTIVATION_FAILED_ANOTHER_ACTIVE_TRACKER and does not invoke |callback|.
// If there is another active tracker that has the same path but different
// |file_id|, inactivates the tracker.
// In success case, returns ACTIVATION_PENDING and invokes |callback| upon
// completion.
//
// The tracker to be activated must:
// - have a tracked metadata in the database,
// - have |synced_details| with valid |title|.
ActivationStatus TryActivateTracker(int64 parent_tracker_id,
const std::string& file_id,
const SyncStatusCallback& callback);
// Changes the priority of the tracker to low.
void LowerTrackerPriority(int64 tracker_id);
void PromoteLowerPriorityTrackersToNormal();
// Returns true if there is a normal priority dirty tracker.
// Assigns the dirty tracker if exists and |tracker| is non-NULL.
bool GetNormalPriorityDirtyTracker(FileTracker* tracker) const;
// Returns true if there is a low priority dirty tracker.
bool HasLowPriorityDirtyTracker() const;
bool HasDirtyTracker() const;
size_t CountDirtyTracker() const;
size_t CountFileMetadata() const;
size_t CountFileTracker() const;
bool GetMultiParentFileTrackers(std::string* file_id,
TrackerIDSet* trackers);
bool GetConflictingTrackers(TrackerIDSet* trackers);
// Sets |app_ids| to a list of all registered app ids.
void GetRegisteredAppIDs(std::vector<std::string>* app_ids);
private:
friend class MetadataDatabaseTest;
MetadataDatabase(base::SequencedTaskRunner* task_runner,
const base::FilePath& database_path,
leveldb::Env* env_override);
static void CreateOnTaskRunner(base::SingleThreadTaskRunner* callback_runner,
base::SequencedTaskRunner* task_runner,
const base::FilePath& database_path,
leveldb::Env* env_override,
const CreateCallback& callback);
SyncStatusCode InitializeOnTaskRunner();
void BuildIndexes(DatabaseContents* contents);
// Database manipulation methods.
void RegisterTrackerAsAppRoot(const std::string& app_id,
int64 tracker_id,
leveldb::WriteBatch* batch);
void CreateTrackerForParentAndFileID(const FileTracker& parent_tracker,
const std::string& file_id,
leveldb::WriteBatch* batch);
void CreateTrackerForParentAndFileMetadata(const FileTracker& parent_tracker,
const FileMetadata& file_metadata,
UpdateOption option,
leveldb::WriteBatch* batch);
void CreateTrackerInternal(const FileTracker& parent_tracker,
const std::string& file_id,
const FileDetails* details,
UpdateOption option,
leveldb::WriteBatch* batch);
void MaybeAddTrackersForNewFile(const FileMetadata& file,
UpdateOption option,
leveldb::WriteBatch* batch);
int64 IncrementTrackerID(leveldb::WriteBatch* batch);
bool CanActivateTracker(const FileTracker& tracker);
bool ShouldKeepDirty(const FileTracker& tracker) const;
bool HasDisabledAppRoot(const FileTracker& tracker) const;
bool HasActiveTrackerForFileID(const std::string& file_id) const;
bool HasActiveTrackerForPath(int64 parent_tracker,
const std::string& title) const;
void RemoveUnneededTrackersForMissingFile(const std::string& file_id,
leveldb::WriteBatch* batch);
void UpdateByFileMetadata(const tracked_objects::Location& from_where,
scoped_ptr<FileMetadata> file,
UpdateOption option,
leveldb::WriteBatch* batch);
void WriteToDatabase(scoped_ptr<leveldb::WriteBatch> batch,
const SyncStatusCallback& callback);
bool HasNewerFileMetadata(const std::string& file_id, int64 change_id);
scoped_ptr<base::ListValue> DumpTrackers();
scoped_ptr<base::ListValue> DumpMetadata();
void AttachSyncRoot(const google_apis::FileResource& sync_root_folder,
leveldb::WriteBatch* batch);
void AttachInitialAppRoot(const google_apis::FileResource& app_root_folder,
leveldb::WriteBatch* batch);
void ForceActivateTrackerByPath(int64 parent_tracker_id,
const std::string& title,
const std::string& file_id,
leveldb::WriteBatch* batch);
scoped_refptr<base::SequencedTaskRunner> task_runner_;
base::FilePath database_path_;
leveldb::Env* env_override_;
scoped_ptr<leveldb::DB> db_;
scoped_ptr<ServiceMetadata> service_metadata_;
int64 largest_known_change_id_;
scoped_ptr<MetadataDatabaseIndex> index_;
base::WeakPtrFactory<MetadataDatabase> weak_ptr_factory_;
DISALLOW_COPY_AND_ASSIGN(MetadataDatabase);
};
} // namespace drive_backend
} // namespace sync_file_system
#endif // CHROME_BROWSER_SYNC_FILE_SYSTEM_DRIVE_BACKEND_METADATA_DATABASE_H_