sync/engine/sync_scheduler.h

   1 // Copyright 2012 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 // A class to schedule syncer tasks intelligently.
   6 #ifndef SYNC_ENGINE_SYNC_SCHEDULER_H_
   7 #define SYNC_ENGINE_SYNC_SCHEDULER_H_
   8
   9 #include <string>
  10
  11 #include "base/callback.h"
  12 #include "base/compiler_specific.h"
  13 #include "base/time/time.h"
  14 #include "sync/base/sync_export.h"
  15 #include "sync/engine/nudge_source.h"
  16 #include "sync/internal_api/public/base/invalidation_interface.h"
  17 #include "sync/sessions/sync_session.h"
  18
  19 namespace tracked_objects {
  20 class Location;
  21 }  // namespace tracked_objects
  22
  23 namespace syncer {
  24
  25 struct ServerConnectionEvent;
  26
  27 struct SYNC_EXPORT_PRIVATE ConfigurationParams {
  28   ConfigurationParams();
  29   ConfigurationParams(
  30       const sync_pb::GetUpdatesCallerInfo::GetUpdatesSource& source,
  31       ModelTypeSet types_to_download,
  32       const ModelSafeRoutingInfo& routing_info,
  33       const base::Closure& ready_task,
  34       const base::Closure& retry_task);
  35   ~ConfigurationParams();
  36
  37   // Source for the configuration.
  38   sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source;
  39   // The types that should be downloaded.
  40   ModelTypeSet types_to_download;
  41   // The new routing info (superset of types to be downloaded).
  42   ModelSafeRoutingInfo routing_info;
  43   // Callback to invoke on configuration completion.
  44   base::Closure ready_task;
  45   // Callback to invoke on configuration failure.
  46   base::Closure retry_task;
  47 };
  48
  49 class SYNC_EXPORT_PRIVATE SyncScheduler
  50     : public sessions::SyncSession::Delegate {
  51  public:
  52   enum Mode {
  53     // In this mode, the thread only performs configuration tasks.  This is
  54     // designed to make the case where we want to download updates for a
  55     // specific type only, and not continue syncing until we are moved into
  56     // normal mode.
  57     CONFIGURATION_MODE,
  58     // Resumes polling and allows nudges, drops configuration tasks.  Runs
  59     // through entire sync cycle.
  60     NORMAL_MODE,
  61   };
  62
  63   // All methods of SyncScheduler must be called on the same thread
  64   // (except for RequestEarlyExit()).
  65
  66   SyncScheduler();
  67   ~SyncScheduler() override;
  68
  69   // Start the scheduler with the given mode.  If the scheduler is
  70   // already started, switch to the given mode, although some
  71   // scheduled tasks from the old mode may still run. |last_poll_time| will
  72   // be used to decide what the poll timer should be initialized with.
  73   virtual void Start(Mode mode, base::Time last_poll_time) = 0;
  74
  75   // Schedules the configuration task specified by |params|. Returns true if
  76   // the configuration task executed immediately, false if it had to be
  77   // scheduled for a later attempt. |params.ready_task| is invoked whenever the
  78   // configuration task executes. |params.retry_task| is invoked once if the
  79   // configuration task could not execute. |params.ready_task| will still be
  80   // called when configuration finishes.
  81   // Note: must already be in CONFIGURATION mode.
  82   virtual void ScheduleConfiguration(const ConfigurationParams& params) = 0;
  83
  84   // Request that the syncer avoid starting any new tasks and prepare for
  85   // shutdown.
  86   virtual void Stop() = 0;
  87
  88   // The meat and potatoes. All three of the following methods will post a
  89   // delayed task to attempt the actual nudge (see ScheduleNudgeImpl).
  90   //
  91   // NOTE: |desired_delay| is best-effort. If a nudge is already scheduled to
  92   // depart earlier than Now() + delay, the scheduler can and will prefer to
  93   // batch the two so that only one nudge is sent (at the earlier time). Also,
  94   // as always with delayed tasks and timers, it's possible the task gets run
  95   // any time after |desired_delay|.
  96
  97   // The LocalNudge indicates that we've made a local change, and that the
  98   // syncer should plan to commit this to the server some time soon.
  99   virtual void ScheduleLocalNudge(
 100       ModelTypeSet types,
 101       const tracked_objects::Location& nudge_location) = 0;
 102
 103   // The LocalRefreshRequest occurs when we decide for some reason to manually
 104   // request updates.  This should be used sparingly.  For example, one of its
 105   // uses is to fetch the latest tab sync data when it's relevant to the UI on
 106   // platforms where tab sync is not registered for invalidations.
 107   virtual void ScheduleLocalRefreshRequest(
 108       ModelTypeSet types,
 109       const tracked_objects::Location& nudge_location) = 0;
 110
 111   // Invalidations are notifications the server sends to let us know when other
 112   // clients have committed data.  We need to contact the sync server (being
 113   // careful to pass along the "hints" delivered with those invalidations) in
 114   // order to fetch the update.
 115   virtual void ScheduleInvalidationNudge(
 116       syncer::ModelType type,
 117       scoped_ptr<InvalidationInterface> invalidation,
 118       const tracked_objects::Location& nudge_location) = 0;
 119
 120   // Requests a non-blocking initial sync request for the specified type.
 121   //
 122   // Many types can only complete initial sync while the scheduler is in
 123   // configure mode, but a few of them are able to perform their initial sync
 124   // while the scheduler is in normal mode.  This non-blocking initial sync
 125   // can be requested through this function.
 126   virtual void ScheduleInitialSyncNudge(syncer::ModelType model_type) = 0;
 127
 128   // Change status of notifications in the SyncSessionContext.
 129   virtual void SetNotificationsEnabled(bool notifications_enabled) = 0;
 130
 131   // Called when credentials are updated by the user.
 132   virtual void OnCredentialsUpdated() = 0;
 133
 134   // Called when the network layer detects a connection status change.
 135   virtual void OnConnectionStatusChange() = 0;
 136 };
 137
 138 }  // namespace syncer
 139
 140 #endif  // SYNC_ENGINE_SYNC_SCHEDULER_H_