[Sync] Move //components/sync_driver to //components/sync/driver.

components/sync_driver/glue/sync_backend_registrar.h

-// Copyright 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 COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_REGISTRAR_H_
-#define COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_REGISTRAR_H_
-
-#include <stdint.h>
-
-#include <map>
-#include <memory>
-#include <string>
-#include <vector>
-
-#include "base/compiler_specific.h"
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/synchronization/lock.h"
-#include "base/threading/thread.h"
-#include "components/sync/base/model_type.h"
-#include "components/sync/core/sync_manager.h"
-#include "components/sync/engine/model_safe_worker.h"
-
-class Profile;
-
-namespace base {
-class MessageLoop;
-}
-
-namespace syncer {
-struct UserShare;
-}  // namespace syncer
-
-namespace sync_driver {
-class ChangeProcessor;
-class SyncClient;
-}
-
-namespace browser_sync {
-
-class UIModelWorker;
-
-// A class that keep track of the workers, change processors, and
-// routing info for the enabled sync types, and also routes change
-// events to the right processors.
-class SyncBackendRegistrar : public syncer::SyncManager::ChangeDelegate,
-                             public syncer::WorkerLoopDestructionObserver {
- public:
-  // |name| is used for debugging.  Does not take ownership of |profile|.
-  // Must be created on the UI thread.
-  SyncBackendRegistrar(
-      const std::string& name,
-      sync_driver::SyncClient* sync_client,
-      std::unique_ptr<base::Thread> sync_thread,
-      const scoped_refptr<base::SingleThreadTaskRunner>& ui_thread,
-      const scoped_refptr<base::SingleThreadTaskRunner>& db_thread,
-      const scoped_refptr<base::SingleThreadTaskRunner>& file_thread);
-
-  // SyncBackendRegistrar must be destroyed as follows:
-  //
-  //   1) On the UI thread, call RequestWorkerStopOnUIThread().
-  //   2) UI posts task to shut down syncer on sync thread.
-  //   3) If sync is disabled, call ReleaseSyncThread() on the UI thread.
-  //   3) UI posts SyncBackendRegistrar::ShutDown() on sync thread to
-  //      unregister workers from observing destruction of their working loops.
-  //   4) Workers notify registrar when unregistration finishes or working
-  //      loops are destroyed. Registrar destroys itself on last worker
-  //      notification. Sync thread will be stopped if ownership was not
-  //      released.
-  ~SyncBackendRegistrar() override;
-
-  // Adds |type| to set of non-blocking types. These types are assigned to
-  // GROUP_NON_BLOCKING model safe group and will be treated differently in
-  // ModelTypeRegistry. Unlike directory types, non-blocking types always stay
-  // assigned to GROUP_NON_BLOCKING group.
-  void RegisterNonBlockingType(syncer::ModelType type);
-
-  // Informs the SyncBackendRegistrar of the currently enabled set of types.
-  // These types will be placed in the passive group.  This function should be
-  // called exactly once during startup.
-  void SetInitialTypes(syncer::ModelTypeSet initial_types);
-
-  // Informs SyncBackendRegistrar about non-blocking type loaded from local
-  // storage. Initial sync was already performed for this type, therefore its
-  // data shouldn't be downloaded as part of configuration.
-  void AddRestoredNonBlockingType(syncer::ModelType type);
-
-  // Returns whether or not we are currently syncing encryption keys.
-  // Must be called on the UI thread.
-  bool IsNigoriEnabled() const;
-
-  // Removes all types in |types_to_remove| from the routing info and
-  // adds all the types in |types_to_add| to the routing info that are
-  // not already there (initially put in the passive group).
-  // |types_to_remove| and |types_to_add| must be disjoint.  Returns
-  // the set of newly-added types.  Must be called on the UI thread.
-  syncer::ModelTypeSet ConfigureDataTypes(syncer::ModelTypeSet types_to_add,
-                                          syncer::ModelTypeSet types_to_remove);
-
-  // Returns the set of enabled types as of the last configuration. Note that
-  // this might be different from the current types in the routing info due
-  // to DeactiveDataType being called separately from ConfigureDataTypes.
-  syncer::ModelTypeSet GetLastConfiguredTypes() const;
-
-  // Must be called from the UI thread. (See destructor comment.)
-  void RequestWorkerStopOnUIThread();
-
-  // Activates the given data type (which should belong to the given
-  // group) and starts the given change processor.  Must be called
-  // from |group|'s native thread.
-  void ActivateDataType(syncer::ModelType type,
-                        syncer::ModelSafeGroup group,
-                        sync_driver::ChangeProcessor* change_processor,
-                        syncer::UserShare* user_share);
-
-  // Deactivates the given type if necessary.  Must be called from the
-  // UI thread and not |type|'s native thread.  Yes, this is
-  // surprising: see http://crbug.com/92804.
-  void DeactivateDataType(syncer::ModelType type);
-
-  // Returns true only between calls to ActivateDataType(type, ...)
-  // and DeactivateDataType(type).  Used only by tests.
-  bool IsTypeActivatedForTest(syncer::ModelType type) const;
-
-  // SyncManager::ChangeDelegate implementation.  May be called from
-  // any thread.
-  void OnChangesApplied(
-      syncer::ModelType model_type,
-      int64_t model_version,
-      const syncer::BaseTransaction* trans,
-      const syncer::ImmutableChangeRecordList& changes) override;
-  void OnChangesComplete(syncer::ModelType model_type) override;
-
-  void GetWorkers(std::vector<scoped_refptr<syncer::ModelSafeWorker>>* out);
-  void GetModelSafeRoutingInfo(syncer::ModelSafeRoutingInfo* out);
-
-  // syncer::WorkerLoopDestructionObserver implementation.
-  void OnWorkerLoopDestroyed(syncer::ModelSafeGroup group) override;
-
-  // Release ownership of |sync_thread_|. Called when sync is disabled.
-  std::unique_ptr<base::Thread> ReleaseSyncThread();
-
-  // Unregister workers from loop destruction observation.
-  void Shutdown();
-
-  base::Thread* sync_thread();
-
- private:
-  typedef std::map<syncer::ModelSafeGroup,
-                   scoped_refptr<syncer::ModelSafeWorker>> WorkerMap;
-  typedef std::map<syncer::ModelType, sync_driver::ChangeProcessor*>
-      ProcessorMap;
-
-  // Add a worker for |group| to the worker map if one can be created.
-  void MaybeAddWorker(syncer::ModelSafeGroup group);
-
-  // Callback after workers unregister from observing destruction of their
-  // working loops.
-  void OnWorkerUnregistrationDone(syncer::ModelSafeGroup group);
-
-  void RemoveWorker(syncer::ModelSafeGroup group);
-
-  // Returns the change processor for the given model, or NULL if none
-  // exists.  Must be called from |group|'s native thread.
-  sync_driver::ChangeProcessor* GetProcessor(syncer::ModelType type) const;
-
-  // Must be called with |lock_| held.  Simply returns the change
-  // processor for the given type, if it exists.  May be called from
-  // any thread.
-  sync_driver::ChangeProcessor* GetProcessorUnsafe(
-      syncer::ModelType type) const;
-
-  // Return true if |model_type| lives on the current thread.  Must be
-  // called with |lock_| held.  May be called on any thread.
-  bool IsCurrentThreadSafeForModel(syncer::ModelType model_type) const;
-
-  // Returns true if the current thread is the native thread for the
-  // given group (or if it is undeterminable).
-  bool IsOnThreadForGroup(syncer::ModelType type,
-                          syncer::ModelSafeGroup group) const;
-
-  // Returns model safe group that should be assigned to type when it is first
-  // configured (before activation). Returns GROUP_PASSIVE for directory types
-  // and GROUP_NON_BLOCKING for non-blocking types.
-  syncer::ModelSafeGroup GetInitialGroupForType(syncer::ModelType type) const;
-
-  // Name used for debugging.
-  const std::string name_;
-
-  // A pointer to the sync client.
-  sync_driver::SyncClient* const sync_client_;
-
-  // Protects all variables below.
-  mutable base::Lock lock_;
-
-  // We maintain ownership of all workers.  In some cases, we need to
-  // ensure shutdown occurs in an expected sequence by Stop()ing
-  // certain workers.  They are guaranteed to be valid because we only
-  // destroy elements of |workers_| after the syncapi has been
-  // destroyed.  Unless a worker is no longer needed because all types
-  // that get routed to it have been disabled (from syncing). In that
-  // case, we'll destroy on demand *after* routing any dependent types
-  // to syncer::GROUP_PASSIVE, so that the syncapi doesn't call into garbage.
-  // If a key is present, it means at least one ModelType that routes
-  // to that model safe group is being synced.
-  WorkerMap workers_;
-  syncer::ModelSafeRoutingInfo routing_info_;
-
-  // The change processors that handle the different data types.
-  ProcessorMap processors_;
-
-  // The types that were enabled as of the last configuration. Updated on each
-  // call to ConfigureDataTypes as well as SetInitialTypes.
-  syncer::ModelTypeSet last_configured_types_;
-
-  // Parks stopped workers because they may still be referenced by syncer.
-  std::vector<scoped_refptr<syncer::ModelSafeWorker>> stopped_workers_;
-
-  // References to the thread task runners that sync depends on.
-  const scoped_refptr<base::SingleThreadTaskRunner> ui_thread_;
-  const scoped_refptr<base::SingleThreadTaskRunner> db_thread_;
-  const scoped_refptr<base::SingleThreadTaskRunner> file_thread_;
-
-  // Declare |sync_thread_| at the end so that it will be destroyed before
-  // objects above because tasks on sync thread depend on those objects,
-  // e.g. Shutdown() depends on |lock_|, SyncManager::Init() depends on
-  // workers, etc.
-  std::unique_ptr<base::Thread> sync_thread_;
-
-  // Set of types with non-blocking implementation (as opposed to directory
-  // based).
-  syncer::ModelTypeSet non_blocking_types_;
-
-  DISALLOW_COPY_AND_ASSIGN(SyncBackendRegistrar);
-};
-
-}  // namespace browser_sync
-
-#endif  // COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_REGISTRAR_H_