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.
5 #ifndef SYNC_ENGINE_SYNC_SCHEDULER_IMPL_H_
6 #define SYNC_ENGINE_SYNC_SCHEDULER_IMPL_H_
11 #include "base/callback.h"
12 #include "base/cancelable_callback.h"
13 #include "base/compiler_specific.h"
14 #include "base/gtest_prod_util.h"
15 #include "base/memory/linked_ptr.h"
16 #include "base/memory/scoped_ptr.h"
17 #include "base/memory/weak_ptr.h"
18 #include "base/threading/non_thread_safe.h"
19 #include "base/time/time.h"
20 #include "base/timer/timer.h"
21 #include "sync/base/sync_export.h"
22 #include "sync/engine/net/server_connection_manager.h"
23 #include "sync/engine/nudge_source.h"
24 #include "sync/engine/sync_scheduler.h"
25 #include "sync/engine/syncer.h"
26 #include "sync/internal_api/public/engine/polling_constants.h"
27 #include "sync/internal_api/public/util/weak_handle.h"
28 #include "sync/sessions/nudge_tracker.h"
29 #include "sync/sessions/sync_session.h"
30 #include "sync/sessions/sync_session_context.h"
34 class BackoffDelayProvider;
37 struct ModelNeutralState;
40 class SYNC_EXPORT_PRIVATE SyncSchedulerImpl
41 : public SyncScheduler,
42 public base::NonThreadSafe {
44 // |name| is a display string to identify the syncer thread. Takes
45 // |ownership of |syncer| and |delay_provider|.
46 SyncSchedulerImpl(const std::string& name,
47 BackoffDelayProvider* delay_provider,
48 sessions::SyncSessionContext* context,
52 virtual ~SyncSchedulerImpl();
54 virtual void Start(Mode mode) OVERRIDE;
55 virtual void ScheduleConfiguration(
56 const ConfigurationParams& params) OVERRIDE;
57 virtual void Stop() OVERRIDE;
58 virtual void ScheduleLocalNudge(
59 const base::TimeDelta& desired_delay,
61 const tracked_objects::Location& nudge_location) OVERRIDE;
62 virtual void ScheduleLocalRefreshRequest(
63 const base::TimeDelta& desired_delay,
65 const tracked_objects::Location& nudge_location) OVERRIDE;
66 virtual void ScheduleInvalidationNudge(
67 const base::TimeDelta& desired_delay,
68 syncer::ModelType type,
69 scoped_ptr<InvalidationInterface> invalidation,
70 const tracked_objects::Location& nudge_location) OVERRIDE;
71 virtual void ScheduleInitialSyncNudge(syncer::ModelType model_type) OVERRIDE;
72 virtual void SetNotificationsEnabled(bool notifications_enabled) OVERRIDE;
74 virtual base::TimeDelta GetSessionsCommitDelay() const OVERRIDE;
76 virtual void OnCredentialsUpdated() OVERRIDE;
77 virtual void OnConnectionStatusChange() OVERRIDE;
79 // SyncSession::Delegate implementation.
80 virtual void OnThrottled(const base::TimeDelta& throttle_duration) OVERRIDE;
81 virtual void OnTypesThrottled(
83 const base::TimeDelta& throttle_duration) OVERRIDE;
84 virtual bool IsCurrentlyThrottled() OVERRIDE;
85 virtual void OnReceivedShortPollIntervalUpdate(
86 const base::TimeDelta& new_interval) OVERRIDE;
87 virtual void OnReceivedLongPollIntervalUpdate(
88 const base::TimeDelta& new_interval) OVERRIDE;
89 virtual void OnReceivedSessionsCommitDelay(
90 const base::TimeDelta& new_delay) OVERRIDE;
91 virtual void OnReceivedClientInvalidationHintBufferSize(int size) OVERRIDE;
92 virtual void OnSyncProtocolError(
93 const SyncProtocolError& sync_protocol_error) OVERRIDE;
94 virtual void OnReceivedGuRetryDelay(const base::TimeDelta& delay) OVERRIDE;
95 virtual void OnReceivedMigrationRequest(syncer::ModelTypeSet types) OVERRIDE;
97 // Returns true if the client is currently in exponential backoff.
98 bool IsBackingOff() const;
102 // Non-canary jobs respect exponential backoff.
104 // Canary jobs bypass exponential backoff, so use with extreme caution.
108 enum PollAdjustType {
109 // Restart the poll interval.
111 // Restart the poll interval only if its length has changed.
115 friend class SyncSchedulerTest;
116 friend class SyncSchedulerWhiteboxTest;
117 friend class SyncerTest;
119 FRIEND_TEST_ALL_PREFIXES(SyncSchedulerTest, TransientPollFailure);
120 FRIEND_TEST_ALL_PREFIXES(SyncSchedulerTest,
121 ServerConnectionChangeDuringBackoff);
122 FRIEND_TEST_ALL_PREFIXES(SyncSchedulerTest,
123 ConnectionChangeCanaryPreemptedByNudge);
124 FRIEND_TEST_ALL_PREFIXES(BackoffTriggersSyncSchedulerTest,
125 FailGetEncryptionKey);
126 FRIEND_TEST_ALL_PREFIXES(SyncSchedulerTest, SuccessfulRetry);
127 FRIEND_TEST_ALL_PREFIXES(SyncSchedulerTest, FailedRetry);
128 FRIEND_TEST_ALL_PREFIXES(SyncSchedulerTest, ReceiveNewRetryDelay);
130 struct SYNC_EXPORT_PRIVATE WaitInterval {
132 // Uninitialized state, should not be set in practice.
134 // We enter a series of increasingly longer WaitIntervals if we experience
135 // repeated transient failures. We retry at the end of each interval.
137 // A server-initiated throttled interval. We do not allow any syncing
138 // during such an interval.
143 WaitInterval(Mode mode, base::TimeDelta length);
145 static const char* GetModeString(Mode mode);
148 base::TimeDelta length;
151 static const char* GetModeString(Mode mode);
153 // Invoke the syncer to perform a nudge job.
154 void DoNudgeSyncSessionJob(JobPriority priority);
156 // Invoke the syncer to perform a configuration job.
157 void DoConfigurationSyncSessionJob(JobPriority priority);
159 // Helper function for Do{Nudge,Configuration}SyncSessionJob.
161 const sessions::ModelNeutralState& model_neutral_state);
163 // Invoke the Syncer to perform a poll job.
164 void DoPollSyncSessionJob();
166 // Helper function to calculate poll interval.
167 base::TimeDelta GetPollInterval();
169 // Adjusts the poll timer to account for new poll interval, and possibly
170 // resets the poll interval, depedning on the flag's value.
171 void AdjustPolling(PollAdjustType type);
173 // Helper to restart waiting with |wait_interval_|'s timer.
174 void RestartWaiting();
176 // Determines if we're allowed to contact the server right now.
177 bool CanRunJobNow(JobPriority priority);
179 // Determines if we're allowed to contact the server right now.
180 bool CanRunNudgeJobNow(JobPriority priority);
182 // If the scheduler's current state supports it, this will create a job based
183 // on the passed in parameters and coalesce it with any other pending jobs,
184 // then post a delayed task to run it. It may also choose to drop the job or
185 // save it for later, depending on the scheduler's current state.
186 void ScheduleNudgeImpl(
187 const base::TimeDelta& delay,
188 const tracked_objects::Location& nudge_location);
190 // Helper to signal listeners about changed retry time.
191 void NotifyRetryTime(base::Time retry_time);
193 // Helper to signal listeners about changed throttled types.
194 void NotifyThrottledTypesChanged(ModelTypeSet types);
196 // Looks for pending work and, if it finds any, run this work at "canary"
200 // At the moment TrySyncSessionJob just posts call to TrySyncSessionJobImpl on
201 // current thread. In the future it will request access token here.
202 void TrySyncSessionJob();
203 void TrySyncSessionJobImpl();
205 // Transitions out of the THROTTLED WaitInterval then calls TryCanaryJob().
208 // Called when a per-type throttling interval expires.
209 void TypeUnthrottle(base::TimeTicks unthrottle_time);
211 // Runs a normal nudge job when the scheduled timer expires.
212 void PerformDelayedNudge();
214 // Attempts to exit EXPONENTIAL_BACKOFF by calling TryCanaryJob().
215 void ExponentialBackoffRetry();
217 // Called when the root cause of the current connection error is fixed.
218 void OnServerConnectionErrorFixed();
220 // Creates a session for a poll and performs the sync.
221 void PollTimerCallback();
223 // Creates a session for a retry and performs the sync.
224 void RetryTimerCallback();
226 // Returns the set of types that are enabled and not currently throttled.
227 ModelTypeSet GetEnabledAndUnthrottledTypes();
229 // Called as we are started to broadcast an initial session snapshot
230 // containing data like initial_sync_ended. Important when the client starts
231 // up and does not need to perform an initial sync.
232 void SendInitialSnapshot();
234 // This is used for histogramming and analysis of ScheduleNudge* APIs.
235 // SyncScheduler is the ultimate choke-point for all such invocations (with
236 // and without InvalidationState variants, all NudgeSources, etc) and as such
237 // is the most flexible place to do this bookkeeping.
238 void UpdateNudgeTimeRecords(ModelTypeSet types);
240 // For certain methods that need to worry about X-thread posting.
241 WeakHandle<SyncSchedulerImpl> weak_handle_this_;
244 const std::string name_;
246 // Set in Start(), unset in Stop().
249 // Modifiable versions of kDefaultLongPollIntervalSeconds which can be
250 // updated by the server.
251 base::TimeDelta syncer_short_poll_interval_seconds_;
252 base::TimeDelta syncer_long_poll_interval_seconds_;
254 // Server-tweakable sessions commit delay.
255 base::TimeDelta sessions_commit_delay_;
257 // Periodic timer for polling. See AdjustPolling.
258 base::RepeatingTimer<SyncSchedulerImpl> poll_timer_;
260 // The mode of operation.
263 // Current wait state. Null if we're not in backoff and not throttled.
264 scoped_ptr<WaitInterval> wait_interval_;
266 scoped_ptr<BackoffDelayProvider> delay_provider_;
268 // The event that will wake us up.
269 base::OneShotTimer<SyncSchedulerImpl> pending_wakeup_timer_;
271 // An event that fires when data type throttling expires.
272 base::OneShotTimer<SyncSchedulerImpl> type_unthrottle_timer_;
274 // Storage for variables related to an in-progress configure request. Note
275 // that (mode_ != CONFIGURATION_MODE) \implies !pending_configure_params_.
276 scoped_ptr<ConfigurationParams> pending_configure_params_;
278 // If we have a nudge pending to run soon, it will be listed here.
279 base::TimeTicks scheduled_nudge_time_;
281 // Keeps track of work that the syncer needs to handle.
282 sessions::NudgeTracker nudge_tracker_;
284 // Invoked to run through the sync cycle.
285 scoped_ptr<Syncer> syncer_;
287 sessions::SyncSessionContext* session_context_;
289 // A map tracking LOCAL NudgeSource invocations of ScheduleNudge* APIs,
290 // organized by datatype. Each datatype that was part of the types requested
291 // in the call will have its TimeTicks value updated.
292 typedef std::map<ModelType, base::TimeTicks> ModelTypeTimeMap;
293 ModelTypeTimeMap last_local_nudges_by_model_type_;
295 // Used as an "anti-reentrancy defensive assertion".
296 // While true, it is illegal for any new scheduling activity to take place.
297 // Ensures that higher layers don't break this law in response to events that
298 // take place during a sync cycle. We call this out because such violations
299 // could result in tight sync loops hitting sync servers.
300 bool no_scheduling_allowed_;
302 // crbug/251307. This is a workaround for M29. crbug/259913 tracks proper fix
304 // The issue is that poll job runs after few hours of inactivity and therefore
305 // will always fail with auth error because of expired access token. Once
306 // fresh access token is requested poll job is not retried.
307 // The change is to remember that poll timer just fired and retry poll job
308 // after credentials are updated.
309 bool do_poll_after_credentials_updated_;
311 // TryJob might get called for multiple reasons. It should only call
312 // DoPollSyncSessionJob after some time since the last attempt.
313 // last_poll_reset_ keeps track of when was last attempt.
314 base::TimeTicks last_poll_reset_;
316 // next_sync_session_job_priority_ defines which priority will be used next
317 // time TrySyncSessionJobImpl is called. CANARY_PRIORITY allows syncer to run
318 // even if scheduler is in exponential backoff. This is needed for events that
319 // have chance of resolving previous error (e.g. network connection change
320 // after NETWORK_UNAVAILABLE error).
321 // It is reset back to NORMAL_PRIORITY on every call to TrySyncSessionJobImpl.
322 JobPriority next_sync_session_job_priority_;
324 // One-shot timer for scheduling GU retry according to delay set by server.
325 base::OneShotTimer<SyncSchedulerImpl> retry_timer_;
327 base::WeakPtrFactory<SyncSchedulerImpl> weak_ptr_factory_;
329 // A second factory specially for weak_handle_this_, to allow the handle
330 // to be const and alleviate threading concerns.
331 base::WeakPtrFactory<SyncSchedulerImpl> weak_ptr_factory_for_weak_handle_;
333 DISALLOW_COPY_AND_ASSIGN(SyncSchedulerImpl);
336 } // namespace syncer
338 #endif // SYNC_ENGINE_SYNC_SCHEDULER_IMPL_H_