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/notifier/object_id_invalidation_map.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   ~ConfigurationParams();
  35
  36   // Source for the configuration.
  37   sync_pb::GetUpdatesCallerInfo::GetUpdatesSource source;
  38   // The types that should be downloaded.
  39   ModelTypeSet types_to_download;
  40   // The new routing info (superset of types to be downloaded).
  41   ModelSafeRoutingInfo routing_info;
  42   // Callback to invoke on configuration completion.
  43   base::Closure ready_task;
  44 };
  45
  46 class SYNC_EXPORT_PRIVATE SyncScheduler
  47     : public sessions::SyncSession::Delegate {
  48  public:
  49   enum Mode {
  50     // In this mode, the thread only performs configuration tasks.  This is
  51     // designed to make the case where we want to download updates for a
  52     // specific type only, and not continue syncing until we are moved into
  53     // normal mode.
  54     CONFIGURATION_MODE,
  55     // Resumes polling and allows nudges, drops configuration tasks.  Runs
  56     // through entire sync cycle.
  57     NORMAL_MODE,
  58   };
  59
  60   // All methods of SyncScheduler must be called on the same thread
  61   // (except for RequestEarlyExit()).
  62
  63   SyncScheduler();
  64   virtual ~SyncScheduler();
  65
  66   // Start the scheduler with the given mode.  If the scheduler is
  67   // already started, switch to the given mode, although some
  68   // scheduled tasks from the old mode may still run.
  69   virtual void Start(Mode mode) = 0;
  70
  71   // Schedules the configuration task specified by |params|. Returns true if
  72   // the configuration task executed immediately, false if it had to be
  73   // scheduled for a later attempt. |params.ready_task| is invoked whenever the
  74   // configuration task executes.
  75   // Note: must already be in CONFIGURATION mode.
  76   virtual bool ScheduleConfiguration(const ConfigurationParams& params) = 0;
  77
  78   // Request that the syncer avoid starting any new tasks and prepare for
  79   // shutdown.
  80   virtual void Stop() = 0;
  81
  82   // The meat and potatoes. All three of the following methods will post a
  83   // delayed task to attempt the actual nudge (see ScheduleNudgeImpl).
  84   //
  85   // NOTE: |desired_delay| is best-effort. If a nudge is already scheduled to
  86   // depart earlier than Now() + delay, the scheduler can and will prefer to
  87   // batch the two so that only one nudge is sent (at the earlier time). Also,
  88   // as always with delayed tasks and timers, it's possible the task gets run
  89   // any time after |desired_delay|.
  90
  91   // The LocalNudge indicates that we've made a local change, and that the
  92   // syncer should plan to commit this to the server some time soon.
  93   virtual void ScheduleLocalNudge(
  94       const base::TimeDelta& desired_delay,
  95       ModelTypeSet types,
  96       const tracked_objects::Location& nudge_location) = 0;
  97
  98   // The LocalRefreshRequest occurs when we decide for some reason to manually
  99   // request updates.  This should be used sparingly.  For example, one of its
 100   // uses is to fetch the latest tab sync data when it's relevant to the UI on
 101   // platforms where tab sync is not registered for invalidations.
 102   virtual void ScheduleLocalRefreshRequest(
 103       const base::TimeDelta& desired_delay,
 104       ModelTypeSet types,
 105       const tracked_objects::Location& nudge_location) = 0;
 106
 107   // Invalidations are notifications the server sends to let us know when other
 108   // clients have committed data.  We need to contact the sync server (being
 109   // careful to pass along the "hints" delivered with those invalidations) in
 110   // order to fetch the update.
 111   virtual void ScheduleInvalidationNudge(
 112       const base::TimeDelta& desired_delay,
 113       const ObjectIdInvalidationMap& invalidations,
 114       const tracked_objects::Location& nudge_location) = 0;
 115
 116   // Change status of notifications in the SyncSessionContext.
 117   virtual void SetNotificationsEnabled(bool notifications_enabled) = 0;
 118
 119   virtual base::TimeDelta GetSessionsCommitDelay() const = 0;
 120
 121   // Called when credentials are updated by the user.
 122   virtual void OnCredentialsUpdated() = 0;
 123
 124   // Called when the network layer detects a connection status change.
 125   virtual void OnConnectionStatusChange() = 0;
 126 };
 127
 128 }  // namespace syncer
 129
 130 #endif  // SYNC_ENGINE_SYNC_SCHEDULER_H_