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// Copyright 2014 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 <map>
#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/timer/timer.h"
#include "components/sync/base/weak_handle.h"
#include "components/sync/driver/configure_context.h"
#include "components/sync/driver/data_type_controller.h"
#include "components/sync/driver/data_type_manager.h"
#include "components/sync/engine/data_type_association_stats.h"
#include "components/sync/engine/shutdown_reason.h"
namespace syncer {
struct ConfigureContext;
// |ModelAssociationManager| does the heavy lifting for doing the actual model
// association. It instructs DataTypeControllers to load models, start
// associating and stopping. Since the operations are async it uses an
// interface to inform DataTypeManager the results of the operations.
// This class is owned by DataTypeManager.
// |ModelAssociationManager| association functions are async. The results of
// those operations are passed back via this interface.
class ModelAssociationManagerDelegate {
// Called right before ModelAssociationManager calls LoadModels. Allows
// directory types to register with sync engine before download starts.
virtual void OnSingleDataTypeWillStart(ModelType type) = 0;
// Called when all desired types are ready to be configured with
// ModelTypeConfigurer. Data type is ready when its progress marker is
// available to configurer. Directory data types are always ready, their
// progress markers are read from directory. USS data type controllers need to
// load model and read data type context first.
// This function is called at most once after each call to
// ModelAssociationManager::Initialize().
virtual void OnAllDataTypesReadyForConfigure() = 0;
// Called when model association (MergeDataAndStartSyncing) has completed
// for |type|, regardless of success or failure.
virtual void OnSingleDataTypeAssociationDone(
ModelType type,
const DataTypeAssociationStats& association_stats) = 0;
// Called when the ModelAssociationManager has decided it must stop |type|,
// likely because it is no longer a desired data type or sync is shutting
// down.
virtual void OnSingleDataTypeWillStop(ModelType type,
const SyncError& error) = 0;
// Called when the ModelAssociationManager has tried to perform model
// association for all desired types and has nothing left to do.
virtual void OnModelAssociationDone(
const DataTypeManager::ConfigureResult& result) = 0;
virtual ~ModelAssociationManagerDelegate() {}
// The class that is responsible for model association.
class ModelAssociationManager {
enum State {
// No configuration is in progress.
// The model association manager has been initialized with a set of desired
// types, but is not actively associating any.
// One or more types from |desired_types_| are in the process of
// associating.
ModelAssociationManager(const DataTypeController::TypeMap* controllers,
ModelAssociationManagerDelegate* delegate);
virtual ~ModelAssociationManager();
// Initializes the state to do the model association in future. This
// should be called before communicating with sync server. A subsequent call
// of Initialize is only allowed if the ModelAssociationManager has invoked
// |OnModelAssociationDone| on the |ModelAssociationManagerDelegate|. After
// this call, there should be several calls to StartAssociationAsync()
// to associate subset of |desired_types| which must be a subset of
// |preferred_types|.
// |preferred_types| contains types selected by user.
void Initialize(ModelTypeSet desired_types,
ModelTypeSet preferred_types,
const ConfigureContext& context);
// Can be called at any time. Synchronously stops all datatypes.
void Stop(ShutdownReason shutdown_reason);
// Should only be called after Initialize to start the actual association.
// |types_to_associate| should be subset of |desired_types| in Initialize().
// When this is completed, |OnModelAssociationDone| will be invoked.
void StartAssociationAsync(const ModelTypeSet& types_to_associate);
// Stops an individual datatype |type| for |shutdown_reason|. |error| must be
// an actual error (i.e. not UNSET).
void StopDatatype(ModelType type,
ShutdownReason shutdown_reason,
SyncError error);
// This is used for TESTING PURPOSE ONLY. The test case can inspect
// and modify the timer.
// TODO(sync) : This would go away if we made this class be able to do
// Dependency injection.
base::OneShotTimer* GetTimerForTesting();
State state() const { return state_; }
// Called at the end of association to reset state to prepare for next
// round of association.
void ResetForNextAssociation();
// Start loading non-running types that are in |desired_types_|.
void LoadEnabledTypes();
// Callback passed to each data type controller on starting association. This
// callback will be invoked when the model association is done.
void TypeStartCallback(ModelType type,
base::TimeTicks type_start_time,
DataTypeController::ConfigureResult start_result,
const SyncMergeResult& local_merge_result,
const SyncMergeResult& syncer_merge_result);
// Callback that will be invoked when the models finish loading. This callback
// will be passed to |LoadModels| function.
void ModelLoadCallback(ModelType type, const SyncError& error);
// Called when all requested types are associated or association times out.
// Will clean up any unfinished types, and update |state_| to be |new_state|
// Finally, it will notify |delegate_| of the configuration result.
void ModelAssociationDone(State new_state);
// A helper to stop an individual datatype.
void StopDatatypeImpl(const SyncError& error,
ShutdownReason shutdown_reason,
DataTypeController* dtc,
DataTypeController::StopCallback callback);
// Calls delegate's OnAllDataTypesReadyForConfigure when all datatypes from
// desired_types_ are ready for configure. Ensures that for every call to
// Initialize callback is called at most once.
// Datatype is ready if either it doesn't require LoadModels before configure
// or LoadModels successfully finished.
void NotifyDelegateIfReadyForConfigure();
State state_;
ConfigureContext configure_context_;
// Data types that are enabled.
ModelTypeSet desired_types_;
// Data types that are requested to associate.
ModelTypeSet requested_types_;
// Data types currently being associated, including types waiting for model
// load.
ModelTypeSet associating_types_;
// Data types that are loaded, i.e. ready to associate.
ModelTypeSet loaded_types_;
// Data types that are associated, i.e. no more action needed during
// reconfiguration if not disabled.
ModelTypeSet associated_types_;
// Time when StartAssociationAsync() is called to associate for a set of data
// types.
base::TimeTicks association_start_time_;
// Set of all registered controllers.
const DataTypeController::TypeMap* controllers_;
// The processor in charge of handling model association results.
ModelAssociationManagerDelegate* delegate_;
// Timer to track and limit how long a datatype takes to model associate.
base::OneShotTimer timer_;
DataTypeManager::ConfigureStatus configure_status_;
bool notified_about_ready_for_configure_;
base::WeakPtrFactory<ModelAssociationManager> weak_ptr_factory_{this};
} // namespace syncer