blob: 4271095d27d58ebede6fcc7ba3ebc2ce5544f381 [file] [log] [blame]
// 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.
#include <memory>
#include <set>
#include <string>
#include <unordered_map>
#include "base/callback.h"
#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/observer_list.h"
#include "base/sequence_checker.h"
#include "components/sync/model/sync_data.h"
#include "components/sync/model/syncable_service.h"
#include "components/sync_preferences/unknown_user_pref_accessor.h"
namespace base {
class Value;
namespace sync_pb {
class PreferenceSpecifics;
namespace sync_preferences {
class PrefModelAssociatorClient;
class PrefServiceSyncable;
class SyncedPrefObserver;
// Contains all preference sync related logic.
// TODO(sync): Merge this into PrefService once we separate the profile
// PrefService from the local state PrefService.
class PrefModelAssociator : public syncer::SyncableService {
// Constructs a PrefModelAssociator initializing the |client_| and |type_|
// instance variable. |client| and |accessor| are not owned by this object
// and the caller must ensure they outlive the PrefModelAssociator.
PrefModelAssociator(const PrefModelAssociatorClient* client,
syncer::ModelType type,
UnknownUserPrefAccessor* accessor);
~PrefModelAssociator() override;
// See description above field for details.
bool models_associated() const { return models_associated_; }
// syncer::SyncableService implementation.
void WaitUntilReadyToSync(base::OnceClosure done) override;
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_factory) override;
void StopSyncing(syncer::ModelType type) override;
syncer::SyncError ProcessSyncChanges(
const base::Location& from_here,
const syncer::SyncChangeList& change_list) override;
// Note for GetAllSyncData: This will build a model of all preferences
// registered as syncable with user controlled data. We do not track any
// information for preferences not registered locally as syncable and do not
// inform the syncer of non-user controlled preferences.
syncer::SyncDataList GetAllSyncData(syncer::ModelType type) const override;
// TODO(tschumann): Replace the RegisterPref() call with a
// VerifyPersistedPrefType() method. All pref registration checks are now
// done via the registry; no need to duplicate that concept.
// Register a preference with the specified name for syncing. We do not care
// about the type at registration time, but when changes arrive from the
// syncer, we check if they can be applied and if not drop them.
// Note: This should only be called at profile startup time (before sync
// begins).
void RegisterPref(const std::string& name);
// Process a local preference change. This can trigger new SyncChanges being
// sent to the syncer.
void ProcessPrefChange(const std::string& name);
// TODO(tschumann): Remove the associator's dependency on PrefServiceSyncable.
// It's only needed for calling OnIsSyncingChanged. This logic can be moved
// onto the associator: PrefServiceSyncable forwards the registration calls.
void SetPrefService(PrefServiceSyncable* pref_service);
// Merges the local_value into the supplied server_value and returns
// the result (caller takes ownership). If there is a conflict, the server
// value always takes precedence. Note that only certain preferences will
// actually be merged, all others will return a copy of the server value. See
// the method's implementation for details.
std::unique_ptr<base::Value> MergePreference(const std::string& name,
const base::Value& local_value,
const base::Value& server_value);
// Fills |sync_data| with a sync representation of the preference data
// provided.
bool CreatePrefSyncData(const std::string& name,
const base::Value& value,
syncer::SyncData* sync_data) const;
// Returns true if the pref under the given name is pulled down from sync.
// Note this does not refer to SYNCABLE_PREF.
bool IsPrefSynced(const std::string& name) const;
// Returns true if the specified preference is registered for syncing.
bool IsPrefRegistered(const std::string& name) const;
// Adds a SyncedPrefObserver to watch for changes to a specific pref.
void AddSyncedPrefObserver(const std::string& name,
SyncedPrefObserver* observer);
// Removes a SyncedPrefObserver from a pref's list of observers.
void RemoveSyncedPrefObserver(const std::string& name,
SyncedPrefObserver* observer);
// Returns the PrefModelAssociatorClient for this object.
const PrefModelAssociatorClient* client() const { return client_; }
friend class PrefServiceSyncableTest;
// Create an association for a given preference. If |sync_pref| is valid,
// signifying that sync has data for this preference, we reconcile their data
// with ours and append a new UPDATE SyncChange to |sync_changes|. If
// sync_pref is not set, we append an ADD SyncChange to |sync_changes| with
// the current preference data.
// Note: We do not modify the sync data for preferences that are either
// controlled by policy (are not user modifiable) or have their default value
// (are not user controlled).
void InitPrefAndAssociate(const syncer::SyncData& sync_pref,
const std::string& pref_name,
syncer::SyncChangeList* sync_changes);
static std::unique_ptr<base::Value> MergeListValues(
const base::Value& from_value,
const base::Value& to_value);
static base::Value MergeDictionaryValues(const base::Value& from_value,
const base::Value& to_value);
// Extract preference value from sync specifics.
static base::Value* ReadPreferenceSpecifics(
const sync_pb::PreferenceSpecifics& specifics);
void NotifySyncedPrefObservers(const std::string& path, bool from_sync) const;
// Do we have an active association between the preferences and sync models?
// Set when start syncing, reset in StopSyncing. While this is not set, we
// ignore any local preference changes (when we start syncing we will look
// up the most recent values anyways).
bool models_associated_ = false;
// Whether we're currently processing changes from the syncer. While this is
// true, we ignore any local preference changes, since we triggered them.
bool processing_syncer_changes_ = false;
// A set of preference names.
typedef std::set<std::string> PreferenceSet;
// All preferences that have registered as being syncable with this profile.
PreferenceSet registered_preferences_;
// The preferences that are currently synced (excludes those preferences
// that have never had sync data and currently have default values or are
// policy controlled).
// Note: this set never decreases, only grows to eventually match
// registered_preferences_ as more preferences are synced. It determines
// whether a preference change should update an existing sync node or create
// a new sync node.
PreferenceSet synced_preferences_;
// The PrefService we are syncing to.
PrefServiceSyncable* pref_service_ = nullptr;
// A pref accessor to access prefs which might not be registered.
UnknownUserPrefAccessor* pref_accessor_;
// Sync's syncer::SyncChange handler. We push all our changes through this.
std::unique_ptr<syncer::SyncChangeProcessor> sync_processor_;
// Sync's error handler. We use this to create sync errors.
std::unique_ptr<syncer::SyncErrorFactory> sync_error_factory_;
// The datatype that this associator is responible for, either PREFERENCES or
syncer::ModelType type_;
// Map prefs to lists of observers. Observers will receive notification when
// a pref changes, including the detail of whether or not the change came
// from sync.
using SyncedPrefObserverList =
std::unordered_map<std::string, std::unique_ptr<SyncedPrefObserverList>>
const PrefModelAssociatorClient* client_; // Weak.
} // namespace sync_preferences