Upstream version 10.39.225.0
[platform/framework/web/crosswalk.git] / src / chrome / browser / sync / sessions / sessions_sync_manager.cc
1 // Copyright 2014 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 #include "chrome/browser/sync/sessions/sessions_sync_manager.h"
6
7 #include "chrome/browser/chrome_notification_types.h"
8 #include "chrome/browser/profiles/profile.h"
9 #include "chrome/browser/sync/glue/synced_tab_delegate.h"
10 #include "chrome/browser/sync/glue/synced_window_delegate.h"
11 #include "chrome/browser/sync/sessions/sessions_util.h"
12 #include "chrome/browser/sync/sessions/synced_window_delegates_getter.h"
13 #include "chrome/common/url_constants.h"
14 #include "components/sync_driver/local_device_info_provider.h"
15 #include "content/public/browser/favicon_status.h"
16 #include "content/public/browser/navigation_entry.h"
17 #include "content/public/browser/notification_details.h"
18 #include "content/public/browser/notification_service.h"
19 #include "content/public/browser/notification_source.h"
20 #include "content/public/common/url_constants.h"
21 #include "sync/api/sync_error.h"
22 #include "sync/api/sync_error_factory.h"
23 #include "sync/api/sync_merge_result.h"
24 #include "sync/api/time.h"
25
26 using content::NavigationEntry;
27 using sessions::SerializedNavigationEntry;
28 using sync_driver::DeviceInfo;
29 using sync_driver::LocalDeviceInfoProvider;
30 using syncer::SyncChange;
31 using syncer::SyncData;
32
33 namespace browser_sync {
34
35 // Maximum number of favicons to sync.
36 // TODO(zea): pull this from the server.
37 static const int kMaxSyncFavicons = 200;
38
39 // The maximum number of navigations in each direction we care to sync.
40 static const int kMaxSyncNavigationCount = 6;
41
42 // The URL at which the set of synced tabs is displayed. We treat it differently
43 // from all other URL's as accessing it triggers a sync refresh of Sessions.
44 static const char kNTPOpenTabSyncURL[] = "chrome://newtab/#open_tabs";
45
46 // Default number of days without activity after which a session is considered
47 // stale and becomes a candidate for garbage collection.
48 static const size_t kDefaultStaleSessionThresholdDays = 14;  // 2 weeks.
49
50 // |local_device| is owned by ProfileSyncService, its lifetime exceeds
51 // lifetime of SessionSyncManager.
52 SessionsSyncManager::SessionsSyncManager(
53     Profile* profile,
54     LocalDeviceInfoProvider* local_device,
55     scoped_ptr<LocalSessionEventRouter> router)
56     : favicon_cache_(profile, kMaxSyncFavicons),
57       local_tab_pool_out_of_sync_(true),
58       sync_prefs_(profile->GetPrefs()),
59       profile_(profile),
60       local_device_(local_device),
61       local_session_header_node_id_(TabNodePool::kInvalidTabNodeID),
62       stale_session_threshold_days_(kDefaultStaleSessionThresholdDays),
63       local_event_router_(router.Pass()),
64       synced_window_getter_(new SyncedWindowDelegatesGetter()) {
65 }
66
67 LocalSessionEventRouter::~LocalSessionEventRouter() {}
68
69 SessionsSyncManager::~SessionsSyncManager() {
70 }
71
72 // Returns the GUID-based string that should be used for
73 // |SessionsSyncManager::current_machine_tag_|.
74 static std::string BuildMachineTag(const std::string& cache_guid) {
75   std::string machine_tag = "session_sync";
76   machine_tag.append(cache_guid);
77   return machine_tag;
78 }
79
80 syncer::SyncMergeResult SessionsSyncManager::MergeDataAndStartSyncing(
81      syncer::ModelType type,
82      const syncer::SyncDataList& initial_sync_data,
83      scoped_ptr<syncer::SyncChangeProcessor> sync_processor,
84      scoped_ptr<syncer::SyncErrorFactory> error_handler) {
85   syncer::SyncMergeResult merge_result(type);
86   DCHECK(session_tracker_.Empty());
87   DCHECK_EQ(0U, local_tab_pool_.Capacity());
88
89   error_handler_ = error_handler.Pass();
90   sync_processor_ = sync_processor.Pass();
91
92   local_session_header_node_id_ = TabNodePool::kInvalidTabNodeID;
93
94   // Make sure we have a machine tag.  We do this now (versus earlier) as it's
95   // a conveniently safe time to assert sync is ready and the cache_guid is
96   // initialized.
97   if (current_machine_tag_.empty()) {
98     InitializeCurrentMachineTag();
99   }
100
101   // SessionDataTypeController ensures that the local device info
102   // is available before activating this datatype.
103   DCHECK(local_device_);
104   const DeviceInfo* local_device_info = local_device_->GetLocalDeviceInfo();
105   if (local_device_info) {
106     current_session_name_ = local_device_info->client_name();
107   } else {
108     merge_result.set_error(error_handler_->CreateAndUploadError(
109         FROM_HERE,
110         "Failed to get local device info."));
111     return merge_result;
112   }
113
114   session_tracker_.SetLocalSessionTag(current_machine_tag_);
115
116   syncer::SyncChangeList new_changes;
117
118   // First, we iterate over sync data to update our session_tracker_.
119   syncer::SyncDataList restored_tabs;
120   if (!InitFromSyncModel(initial_sync_data, &restored_tabs, &new_changes)) {
121     // The sync db didn't have a header node for us. Create one.
122     sync_pb::EntitySpecifics specifics;
123     sync_pb::SessionSpecifics* base_specifics = specifics.mutable_session();
124     base_specifics->set_session_tag(current_machine_tag());
125     sync_pb::SessionHeader* header_s = base_specifics->mutable_header();
126     header_s->set_client_name(current_session_name_);
127     header_s->set_device_type(local_device_info->device_type());
128     syncer::SyncData data = syncer::SyncData::CreateLocalData(
129         current_machine_tag(), current_session_name_, specifics);
130     new_changes.push_back(syncer::SyncChange(
131         FROM_HERE, syncer::SyncChange::ACTION_ADD, data));
132   }
133
134 #if defined(OS_ANDROID)
135   std::string sync_machine_tag(BuildMachineTag(
136       local_device_->GetLocalSyncCacheGUID()));
137   if (current_machine_tag_.compare(sync_machine_tag) != 0)
138     DeleteForeignSessionInternal(sync_machine_tag, &new_changes);
139 #endif
140
141   // Check if anything has changed on the local client side.
142   AssociateWindows(RELOAD_TABS, restored_tabs, &new_changes);
143   local_tab_pool_out_of_sync_ = false;
144
145   merge_result.set_error(
146       sync_processor_->ProcessSyncChanges(FROM_HERE, new_changes));
147
148   local_event_router_->StartRoutingTo(this);
149   return merge_result;
150 }
151
152 void SessionsSyncManager::AssociateWindows(
153     ReloadTabsOption option,
154     const syncer::SyncDataList& restored_tabs,
155     syncer::SyncChangeList* change_output) {
156   const std::string local_tag = current_machine_tag();
157   sync_pb::SessionSpecifics specifics;
158   specifics.set_session_tag(local_tag);
159   sync_pb::SessionHeader* header_s = specifics.mutable_header();
160   SyncedSession* current_session = session_tracker_.GetSession(local_tag);
161   current_session->modified_time = base::Time::Now();
162   header_s->set_client_name(current_session_name_);
163   // SessionDataTypeController ensures that the local device info
164   // is available before activating this datatype.
165   DCHECK(local_device_);
166   const DeviceInfo* local_device_info = local_device_->GetLocalDeviceInfo();
167   header_s->set_device_type(local_device_info->device_type());
168
169   session_tracker_.ResetSessionTracking(local_tag);
170   std::set<SyncedWindowDelegate*> windows =
171       synced_window_getter_->GetSyncedWindowDelegates();
172
173   for (std::set<SyncedWindowDelegate*>::const_iterator i =
174            windows.begin(); i != windows.end(); ++i) {
175     // Make sure the window has tabs and a viewable window. The viewable window
176     // check is necessary because, for example, when a browser is closed the
177     // destructor is not necessarily run immediately. This means its possible
178     // for us to get a handle to a browser that is about to be removed. If
179     // the tab count is 0 or the window is NULL, the browser is about to be
180     // deleted, so we ignore it.
181     if (sessions_util::ShouldSyncWindow(*i) &&
182         (*i)->GetTabCount() && (*i)->HasWindow()) {
183       sync_pb::SessionWindow window_s;
184       SessionID::id_type window_id = (*i)->GetSessionId();
185       DVLOG(1) << "Associating window " << window_id << " with "
186                << (*i)->GetTabCount() << " tabs.";
187       window_s.set_window_id(window_id);
188       // Note: We don't bother to set selected tab index anymore. We still
189       // consume it when receiving foreign sessions, as reading it is free, but
190       // it triggers too many sync cycles with too little value to make setting
191       // it worthwhile.
192       if ((*i)->IsTypeTabbed()) {
193         window_s.set_browser_type(
194             sync_pb::SessionWindow_BrowserType_TYPE_TABBED);
195       } else {
196         window_s.set_browser_type(
197             sync_pb::SessionWindow_BrowserType_TYPE_POPUP);
198       }
199
200       bool found_tabs = false;
201       for (int j = 0; j < (*i)->GetTabCount(); ++j) {
202         SessionID::id_type tab_id = (*i)->GetTabIdAt(j);
203         SyncedTabDelegate* synced_tab = (*i)->GetTabAt(j);
204
205         // GetTabAt can return a null tab; in that case just skip it.
206         if (!synced_tab)
207           continue;
208
209         if (!synced_tab->HasWebContents()) {
210           // For tabs without WebContents update the |tab_id|, as it could have
211           // changed after a session restore.
212           // Note: We cannot check if a tab is valid if it has no WebContents.
213           // We assume any such tab is valid and leave the contents of
214           // corresponding sync node unchanged.
215           if (synced_tab->GetSyncId() > TabNodePool::kInvalidTabNodeID &&
216               tab_id > TabNodePool::kInvalidTabID) {
217             AssociateRestoredPlaceholderTab(*synced_tab, tab_id,
218                                             restored_tabs, change_output);
219             found_tabs = true;
220             window_s.add_tab(tab_id);
221           }
222           continue;
223         }
224
225         if (RELOAD_TABS == option)
226           AssociateTab(synced_tab, change_output);
227
228         // If the tab is valid, it would have been added to the tracker either
229         // by the above AssociateTab call (at association time), or by the
230         // change processor calling AssociateTab for all modified tabs.
231         // Therefore, we can key whether this window has valid tabs based on
232         // the tab's presence in the tracker.
233         const SessionTab* tab = NULL;
234         if (session_tracker_.LookupSessionTab(local_tag, tab_id, &tab)) {
235           found_tabs = true;
236           window_s.add_tab(tab_id);
237         }
238       }
239       if (found_tabs) {
240         sync_pb::SessionWindow* header_window = header_s->add_window();
241         *header_window = window_s;
242
243         // Update this window's representation in the synced session tracker.
244         session_tracker_.PutWindowInSession(local_tag, window_id);
245         BuildSyncedSessionFromSpecifics(local_tag,
246                                         window_s,
247                                         current_session->modified_time,
248                                         current_session->windows[window_id]);
249       }
250     }
251   }
252   local_tab_pool_.DeleteUnassociatedTabNodes(change_output);
253   session_tracker_.CleanupSession(local_tag);
254
255   // Always update the header.  Sync takes care of dropping this update
256   // if the entity specifics are identical (i.e windows, client name did
257   // not change).
258   sync_pb::EntitySpecifics entity;
259   entity.mutable_session()->CopyFrom(specifics);
260   syncer::SyncData data = syncer::SyncData::CreateLocalData(
261         current_machine_tag(), current_session_name_, entity);
262   change_output->push_back(syncer::SyncChange(
263         FROM_HERE, syncer::SyncChange::ACTION_UPDATE, data));
264 }
265
266 void SessionsSyncManager::AssociateTab(SyncedTabDelegate* const tab,
267                                        syncer::SyncChangeList* change_output) {
268   DCHECK(tab->HasWebContents());
269   SessionID::id_type tab_id = tab->GetSessionId();
270   if (tab->profile() != profile_)
271     return;
272
273   if (tab->IsBeingDestroyed()) {
274     // This tab is closing.
275     TabLinksMap::iterator tab_iter = local_tab_map_.find(tab_id);
276     if (tab_iter == local_tab_map_.end()) {
277       // We aren't tracking this tab (for example, sync setting page).
278       return;
279     }
280     local_tab_pool_.FreeTabNode(tab_iter->second->tab_node_id(),
281                                 change_output);
282     local_tab_map_.erase(tab_iter);
283     return;
284   }
285
286   if (!sessions_util::ShouldSyncTab(*tab))
287     return;
288
289   TabLinksMap::iterator local_tab_map_iter = local_tab_map_.find(tab_id);
290   TabLink* tab_link = NULL;
291
292   if (local_tab_map_iter == local_tab_map_.end()) {
293     int tab_node_id = tab->GetSyncId();
294     // If there is an old sync node for the tab, reuse it.  If this is a new
295     // tab, get a sync node for it.
296     if (!local_tab_pool_.IsUnassociatedTabNode(tab_node_id)) {
297       tab_node_id = local_tab_pool_.GetFreeTabNode(change_output);
298       tab->SetSyncId(tab_node_id);
299     }
300     local_tab_pool_.AssociateTabNode(tab_node_id, tab_id);
301     tab_link = new TabLink(tab_node_id, tab);
302     local_tab_map_[tab_id] = make_linked_ptr<TabLink>(tab_link);
303   } else {
304     // This tab is already associated with a sync node, reuse it.
305     // Note: on some platforms the tab object may have changed, so we ensure
306     // the tab link is up to date.
307     tab_link = local_tab_map_iter->second.get();
308     local_tab_map_iter->second->set_tab(tab);
309   }
310   DCHECK(tab_link);
311   DCHECK_NE(tab_link->tab_node_id(), TabNodePool::kInvalidTabNodeID);
312   DVLOG(1) << "Reloading tab " << tab_id << " from window "
313            << tab->GetWindowId();
314
315   // Write to sync model.
316   sync_pb::EntitySpecifics specifics;
317   LocalTabDelegateToSpecifics(*tab, specifics.mutable_session());
318   syncer::SyncData data = syncer::SyncData::CreateLocalData(
319       TabNodePool::TabIdToTag(current_machine_tag_,
320                                tab_link->tab_node_id()),
321       current_session_name_,
322       specifics);
323   change_output->push_back(syncer::SyncChange(
324       FROM_HERE, syncer::SyncChange::ACTION_UPDATE, data));
325
326   const GURL new_url = GetCurrentVirtualURL(*tab);
327   if (new_url != tab_link->url()) {
328     tab_link->set_url(new_url);
329     favicon_cache_.OnFaviconVisited(new_url, GetCurrentFaviconURL(*tab));
330   }
331
332   session_tracker_.GetSession(current_machine_tag())->modified_time =
333       base::Time::Now();
334 }
335
336 void SessionsSyncManager::RebuildAssociations() {
337   syncer::SyncDataList data(
338       sync_processor_->GetAllSyncData(syncer::SESSIONS));
339   scoped_ptr<syncer::SyncErrorFactory> error_handler(error_handler_.Pass());
340   scoped_ptr<syncer::SyncChangeProcessor> processor(sync_processor_.Pass());
341
342   StopSyncing(syncer::SESSIONS);
343   MergeDataAndStartSyncing(
344       syncer::SESSIONS, data, processor.Pass(), error_handler.Pass());
345 }
346
347 bool SessionsSyncManager::IsValidSessionHeader(
348     const sync_pb::SessionHeader& header) {
349   // Verify that tab IDs appear only once within a session.
350   // Intended to prevent http://crbug.com/360822.
351   std::set<int> session_tab_ids;
352   for (int i = 0; i < header.window_size(); ++i) {
353     const sync_pb::SessionWindow& window = header.window(i);
354     for (int j = 0; j < window.tab_size(); ++j) {
355       const int tab_id = window.tab(j);
356       bool success = session_tab_ids.insert(tab_id).second;
357       if (!success)
358         return false;
359     }
360   }
361
362   return true;
363 }
364
365 void SessionsSyncManager::OnLocalTabModified(SyncedTabDelegate* modified_tab) {
366   const content::NavigationEntry* entry = modified_tab->GetActiveEntry();
367   if (!modified_tab->IsBeingDestroyed() &&
368       entry &&
369       entry->GetVirtualURL().is_valid() &&
370       entry->GetVirtualURL().spec() == kNTPOpenTabSyncURL) {
371     DVLOG(1) << "Triggering sync refresh for sessions datatype.";
372     const syncer::ModelTypeSet types(syncer::SESSIONS);
373     content::NotificationService::current()->Notify(
374         chrome::NOTIFICATION_SYNC_REFRESH_LOCAL,
375         content::Source<Profile>(profile_),
376         content::Details<const syncer::ModelTypeSet>(&types));
377   }
378
379   if (local_tab_pool_out_of_sync_) {
380     // If our tab pool is corrupt, pay the price of a full re-association to
381     // fix things up.  This takes care of the new tab modification as well.
382     RebuildAssociations();
383     DCHECK(!local_tab_pool_out_of_sync_);
384     return;
385   }
386
387   syncer::SyncChangeList changes;
388   // Associate tabs first so the synced session tracker is aware of them.
389   AssociateTab(modified_tab, &changes);
390   // Note, we always associate windows because it's possible a tab became
391   // "interesting" by going to a valid URL, in which case it needs to be added
392   // to the window's tab information.
393   AssociateWindows(DONT_RELOAD_TABS, syncer::SyncDataList(), &changes);
394   sync_processor_->ProcessSyncChanges(FROM_HERE, changes);
395 }
396
397 void SessionsSyncManager::OnFaviconPageUrlsUpdated(
398     const std::set<GURL>& updated_favicon_page_urls) {
399   // TODO(zea): consider a separate container for tabs with outstanding favicon
400   // loads so we don't have to iterate through all tabs comparing urls.
401   for (std::set<GURL>::const_iterator i = updated_favicon_page_urls.begin();
402        i != updated_favicon_page_urls.end(); ++i) {
403     for (TabLinksMap::iterator tab_iter = local_tab_map_.begin();
404          tab_iter != local_tab_map_.end();
405          ++tab_iter) {
406       if (tab_iter->second->url() == *i)
407         favicon_cache_.OnPageFaviconUpdated(*i);
408     }
409   }
410 }
411
412 void SessionsSyncManager::StopSyncing(syncer::ModelType type) {
413   local_event_router_->Stop();
414   sync_processor_.reset(NULL);
415   error_handler_.reset();
416   session_tracker_.Clear();
417   local_tab_map_.clear();
418   local_tab_pool_.Clear();
419   current_machine_tag_.clear();
420   current_session_name_.clear();
421   local_session_header_node_id_ = TabNodePool::kInvalidTabNodeID;
422 }
423
424 syncer::SyncDataList SessionsSyncManager::GetAllSyncData(
425     syncer::ModelType type) const {
426   syncer::SyncDataList list;
427   const SyncedSession* session = NULL;
428   if (!session_tracker_.LookupLocalSession(&session))
429     return syncer::SyncDataList();
430
431   // First construct the header node.
432   sync_pb::EntitySpecifics header_entity;
433   header_entity.mutable_session()->set_session_tag(current_machine_tag());
434   sync_pb::SessionHeader* header_specifics =
435       header_entity.mutable_session()->mutable_header();
436   header_specifics->MergeFrom(session->ToSessionHeader());
437   syncer::SyncData data = syncer::SyncData::CreateLocalData(
438         current_machine_tag(), current_session_name_, header_entity);
439   list.push_back(data);
440
441   SyncedSession::SyncedWindowMap::const_iterator win_iter;
442   for (win_iter = session->windows.begin();
443        win_iter != session->windows.end(); ++win_iter) {
444     std::vector<SessionTab*>::const_iterator tabs_iter;
445     for (tabs_iter = win_iter->second->tabs.begin();
446          tabs_iter != win_iter->second->tabs.end(); ++tabs_iter) {
447       sync_pb::EntitySpecifics entity;
448       sync_pb::SessionSpecifics* specifics = entity.mutable_session();
449       specifics->mutable_tab()->MergeFrom((*tabs_iter)->ToSyncData());
450       specifics->set_session_tag(current_machine_tag_);
451
452       TabLinksMap::const_iterator tab_map_iter = local_tab_map_.find(
453           (*tabs_iter)->tab_id.id());
454       DCHECK(tab_map_iter != local_tab_map_.end());
455       specifics->set_tab_node_id(tab_map_iter->second->tab_node_id());
456       syncer::SyncData data = syncer::SyncData::CreateLocalData(
457           TabNodePool::TabIdToTag(current_machine_tag_,
458                                    specifics->tab_node_id()),
459           current_session_name_,
460           entity);
461       list.push_back(data);
462     }
463   }
464   return list;
465 }
466
467 bool SessionsSyncManager::GetLocalSession(
468     const SyncedSession* * local_session) {
469   if (current_machine_tag_.empty())
470     return false;
471   *local_session = session_tracker_.GetSession(current_machine_tag());
472   return true;
473 }
474
475 syncer::SyncError SessionsSyncManager::ProcessSyncChanges(
476     const tracked_objects::Location& from_here,
477     const syncer::SyncChangeList& change_list) {
478   if (!sync_processor_.get()) {
479     syncer::SyncError error(FROM_HERE,
480                             syncer::SyncError::DATATYPE_ERROR,
481                             "Models not yet associated.",
482                             syncer::SESSIONS);
483     return error;
484   }
485
486   for (syncer::SyncChangeList::const_iterator it = change_list.begin();
487        it != change_list.end(); ++it) {
488     DCHECK(it->IsValid());
489     DCHECK(it->sync_data().GetSpecifics().has_session());
490     const sync_pb::SessionSpecifics& session =
491         it->sync_data().GetSpecifics().session();
492     switch (it->change_type()) {
493       case syncer::SyncChange::ACTION_DELETE:
494         // Deletions are all or nothing (since we only ever delete entire
495         // sessions). Therefore we don't care if it's a tab node or meta node,
496         // and just ensure we've disassociated.
497         if (current_machine_tag() == session.session_tag()) {
498           // Another client has attempted to delete our local data (possibly by
499           // error or a clock is inaccurate). Just ignore the deletion for now
500           // to avoid any possible ping-pong delete/reassociate sequence, but
501           // remember that this happened as our TabNodePool is inconsistent.
502           local_tab_pool_out_of_sync_ = true;
503           LOG(WARNING) << "Local session data deleted. Ignoring until next "
504                        << "local navigation event.";
505         } else if (session.has_header()) {
506           // Disassociate only when header node is deleted. For tab node
507           // deletions, the header node will be updated and foreign tab will
508           // get deleted.
509           DisassociateForeignSession(session.session_tag());
510         }
511         continue;
512       case syncer::SyncChange::ACTION_ADD:
513       case syncer::SyncChange::ACTION_UPDATE:
514         if (current_machine_tag() == session.session_tag()) {
515           // We should only ever receive a change to our own machine's session
516           // info if encryption was turned on. In that case, the data is still
517           // the same, so we can ignore.
518           LOG(WARNING) << "Dropping modification to local session.";
519           return syncer::SyncError();
520         }
521         UpdateTrackerWithForeignSession(
522             session, syncer::SyncDataRemote(it->sync_data()).GetModifiedTime());
523         break;
524       default:
525         NOTREACHED() << "Processing sync changes failed, unknown change type.";
526     }
527   }
528
529   content::NotificationService::current()->Notify(
530       chrome::NOTIFICATION_FOREIGN_SESSION_UPDATED,
531       content::Source<Profile>(profile_),
532       content::NotificationService::NoDetails());
533   return syncer::SyncError();
534 }
535
536 syncer::SyncChange SessionsSyncManager::TombstoneTab(
537     const sync_pb::SessionSpecifics& tab) {
538   if (!tab.has_tab_node_id()) {
539     LOG(WARNING) << "Old sessions node without tab node id; can't tombstone.";
540     return syncer::SyncChange();
541   } else {
542     return syncer::SyncChange(
543         FROM_HERE,
544         SyncChange::ACTION_DELETE,
545         SyncData::CreateLocalDelete(
546             TabNodePool::TabIdToTag(current_machine_tag(),
547                                      tab.tab_node_id()),
548             syncer::SESSIONS));
549   }
550 }
551
552 bool SessionsSyncManager::GetAllForeignSessions(
553     std::vector<const SyncedSession*>* sessions) {
554   return session_tracker_.LookupAllForeignSessions(sessions);
555 }
556
557 bool SessionsSyncManager::InitFromSyncModel(
558     const syncer::SyncDataList& sync_data,
559     syncer::SyncDataList* restored_tabs,
560     syncer::SyncChangeList* new_changes) {
561   bool found_current_header = false;
562   for (syncer::SyncDataList::const_iterator it = sync_data.begin();
563        it != sync_data.end();
564        ++it) {
565     const syncer::SyncData& data = *it;
566     DCHECK(data.GetSpecifics().has_session());
567     const sync_pb::SessionSpecifics& specifics = data.GetSpecifics().session();
568     if (specifics.session_tag().empty() ||
569            (specifics.has_tab() && (!specifics.has_tab_node_id() ||
570                                     !specifics.tab().has_tab_id()))) {
571       syncer::SyncChange tombstone(TombstoneTab(specifics));
572       if (tombstone.IsValid())
573         new_changes->push_back(tombstone);
574     } else if (specifics.session_tag() != current_machine_tag()) {
575       UpdateTrackerWithForeignSession(
576           specifics, syncer::SyncDataRemote(data).GetModifiedTime());
577     } else {
578       // This is previously stored local session information.
579       if (specifics.has_header() && !found_current_header) {
580         // This is our previous header node, reuse it.
581         found_current_header = true;
582         if (specifics.header().has_client_name())
583           current_session_name_ = specifics.header().client_name();
584       } else {
585         if (specifics.has_header() || !specifics.has_tab()) {
586           LOG(WARNING) << "Found more than one session header node with local "
587                        << "tag.";
588           syncer::SyncChange tombstone(TombstoneTab(specifics));
589           if (tombstone.IsValid())
590             new_changes->push_back(tombstone);
591         } else {
592           // This is a valid old tab node, add it to the pool so it can be
593           // reused for reassociation.
594           local_tab_pool_.AddTabNode(specifics.tab_node_id());
595           restored_tabs->push_back(*it);
596         }
597       }
598     }
599   }
600   return found_current_header;
601 }
602
603 void SessionsSyncManager::UpdateTrackerWithForeignSession(
604     const sync_pb::SessionSpecifics& specifics,
605     const base::Time& modification_time) {
606   std::string foreign_session_tag = specifics.session_tag();
607   DCHECK_NE(foreign_session_tag, current_machine_tag());
608
609   SyncedSession* foreign_session =
610       session_tracker_.GetSession(foreign_session_tag);
611   if (specifics.has_header()) {
612     // Read in the header data for this foreign session.
613     // Header data contains window information and ordered tab id's for each
614     // window.
615
616     if (!IsValidSessionHeader(specifics.header())) {
617       LOG(WARNING) << "Ignoring foreign session node with invalid header "
618                    << "and tag " << foreign_session_tag << ".";
619       return;
620     }
621
622     // Load (or create) the SyncedSession object for this client.
623     const sync_pb::SessionHeader& header = specifics.header();
624     PopulateSessionHeaderFromSpecifics(header,
625                                        modification_time,
626                                        foreign_session);
627
628     // Reset the tab/window tracking for this session (must do this before
629     // we start calling PutWindowInSession and PutTabInWindow so that all
630     // unused tabs/windows get cleared by the CleanupSession(...) call).
631     session_tracker_.ResetSessionTracking(foreign_session_tag);
632
633     // Process all the windows and their tab information.
634     int num_windows = header.window_size();
635     DVLOG(1) << "Associating " << foreign_session_tag << " with "
636              << num_windows << " windows.";
637
638     for (int i = 0; i < num_windows; ++i) {
639       const sync_pb::SessionWindow& window_s = header.window(i);
640       SessionID::id_type window_id = window_s.window_id();
641       session_tracker_.PutWindowInSession(foreign_session_tag,
642                                           window_id);
643       BuildSyncedSessionFromSpecifics(foreign_session_tag,
644                                       window_s,
645                                       modification_time,
646                                       foreign_session->windows[window_id]);
647     }
648     // Delete any closed windows and unused tabs as necessary.
649     session_tracker_.CleanupSession(foreign_session_tag);
650   } else if (specifics.has_tab()) {
651     const sync_pb::SessionTab& tab_s = specifics.tab();
652     SessionID::id_type tab_id = tab_s.tab_id();
653     SessionTab* tab =
654         session_tracker_.GetTab(foreign_session_tag,
655                                 tab_id,
656                                 specifics.tab_node_id());
657
658     // Update SessionTab based on protobuf.
659     tab->SetFromSyncData(tab_s, modification_time);
660
661     // If a favicon or favicon urls are present, load the URLs and visit
662     // times into the in-memory favicon cache.
663     RefreshFaviconVisitTimesFromForeignTab(tab_s, modification_time);
664
665     // Update the last modified time.
666     if (foreign_session->modified_time < modification_time)
667       foreign_session->modified_time = modification_time;
668   } else {
669     LOG(WARNING) << "Ignoring foreign session node with missing header/tab "
670                  << "fields and tag " << foreign_session_tag << ".";
671   }
672 }
673
674 void SessionsSyncManager::InitializeCurrentMachineTag() {
675   DCHECK(current_machine_tag_.empty());
676   std::string persisted_guid;
677   persisted_guid = sync_prefs_.GetSyncSessionsGUID();
678   if (!persisted_guid.empty()) {
679     current_machine_tag_ = persisted_guid;
680     DVLOG(1) << "Restoring persisted session sync guid: " << persisted_guid;
681   } else {
682     DCHECK(local_device_);
683     std::string cache_guid = local_device_->GetLocalSyncCacheGUID();
684     DCHECK(!cache_guid.empty());
685     current_machine_tag_ = BuildMachineTag(cache_guid);
686     DVLOG(1) << "Creating session sync guid: " << current_machine_tag_;
687     sync_prefs_.SetSyncSessionsGUID(current_machine_tag_);
688   }
689
690   local_tab_pool_.SetMachineTag(current_machine_tag_);
691 }
692
693 // static
694 void SessionsSyncManager::PopulateSessionHeaderFromSpecifics(
695     const sync_pb::SessionHeader& header_specifics,
696     base::Time mtime,
697     SyncedSession* session_header) {
698   if (header_specifics.has_client_name())
699     session_header->session_name = header_specifics.client_name();
700   if (header_specifics.has_device_type()) {
701     switch (header_specifics.device_type()) {
702       case sync_pb::SyncEnums_DeviceType_TYPE_WIN:
703         session_header->device_type = SyncedSession::TYPE_WIN;
704         break;
705       case sync_pb::SyncEnums_DeviceType_TYPE_MAC:
706         session_header->device_type = SyncedSession::TYPE_MACOSX;
707         break;
708       case sync_pb::SyncEnums_DeviceType_TYPE_LINUX:
709         session_header->device_type = SyncedSession::TYPE_LINUX;
710         break;
711       case sync_pb::SyncEnums_DeviceType_TYPE_CROS:
712         session_header->device_type = SyncedSession::TYPE_CHROMEOS;
713         break;
714       case sync_pb::SyncEnums_DeviceType_TYPE_PHONE:
715         session_header->device_type = SyncedSession::TYPE_PHONE;
716         break;
717       case sync_pb::SyncEnums_DeviceType_TYPE_TABLET:
718         session_header->device_type = SyncedSession::TYPE_TABLET;
719         break;
720       case sync_pb::SyncEnums_DeviceType_TYPE_OTHER:
721         // Intentionally fall-through
722       default:
723         session_header->device_type = SyncedSession::TYPE_OTHER;
724         break;
725     }
726   }
727   session_header->modified_time = mtime;
728 }
729
730 // static
731 void SessionsSyncManager::BuildSyncedSessionFromSpecifics(
732     const std::string& session_tag,
733     const sync_pb::SessionWindow& specifics,
734     base::Time mtime,
735     SessionWindow* session_window) {
736   if (specifics.has_window_id())
737     session_window->window_id.set_id(specifics.window_id());
738   if (specifics.has_selected_tab_index())
739     session_window->selected_tab_index = specifics.selected_tab_index();
740   if (specifics.has_browser_type()) {
741     if (specifics.browser_type() ==
742         sync_pb::SessionWindow_BrowserType_TYPE_TABBED) {
743       session_window->type = 1;
744     } else {
745       session_window->type = 2;
746     }
747   }
748   session_window->timestamp = mtime;
749   session_window->tabs.resize(specifics.tab_size(), NULL);
750   for (int i = 0; i < specifics.tab_size(); i++) {
751     SessionID::id_type tab_id = specifics.tab(i);
752     session_tracker_.PutTabInWindow(session_tag,
753                                     session_window->window_id.id(),
754                                     tab_id,
755                                     i);
756   }
757 }
758
759 void SessionsSyncManager::RefreshFaviconVisitTimesFromForeignTab(
760     const sync_pb::SessionTab& tab, const base::Time& modification_time) {
761   // First go through and iterate over all the navigations, checking if any
762   // have valid favicon urls.
763   for (int i = 0; i < tab.navigation_size(); ++i) {
764     if (!tab.navigation(i).favicon_url().empty()) {
765       const std::string& page_url = tab.navigation(i).virtual_url();
766       const std::string& favicon_url = tab.navigation(i).favicon_url();
767       favicon_cache_.OnReceivedSyncFavicon(GURL(page_url),
768                                            GURL(favicon_url),
769                                            std::string(),
770                                            syncer::TimeToProtoTime(
771                                                modification_time));
772     }
773   }
774 }
775
776 bool SessionsSyncManager::GetSyncedFaviconForPageURL(
777     const std::string& page_url,
778     scoped_refptr<base::RefCountedMemory>* favicon_png) const {
779   return favicon_cache_.GetSyncedFaviconForPageURL(GURL(page_url), favicon_png);
780 }
781
782 void SessionsSyncManager::DeleteForeignSession(const std::string& tag) {
783   syncer::SyncChangeList changes;
784   DeleteForeignSessionInternal(tag, &changes);
785   sync_processor_->ProcessSyncChanges(FROM_HERE, changes);
786 }
787
788 void SessionsSyncManager::DeleteForeignSessionInternal(
789     const std::string& tag, syncer::SyncChangeList* change_output) {
790  if (tag == current_machine_tag()) {
791     LOG(ERROR) << "Attempting to delete local session. This is not currently "
792                << "supported.";
793     return;
794   }
795
796   std::set<int> tab_node_ids_to_delete;
797   session_tracker_.LookupTabNodeIds(tag, &tab_node_ids_to_delete);
798   if (!DisassociateForeignSession(tag)) {
799     // We don't have any data for this session, our work here is done!
800     return;
801   }
802
803   // Prepare deletes for the meta-node as well as individual tab nodes.
804   change_output->push_back(syncer::SyncChange(
805       FROM_HERE,
806       SyncChange::ACTION_DELETE,
807       SyncData::CreateLocalDelete(tag, syncer::SESSIONS)));
808
809   for (std::set<int>::const_iterator it = tab_node_ids_to_delete.begin();
810        it != tab_node_ids_to_delete.end();
811        ++it) {
812     change_output->push_back(syncer::SyncChange(
813         FROM_HERE,
814         SyncChange::ACTION_DELETE,
815         SyncData::CreateLocalDelete(TabNodePool::TabIdToTag(tag, *it),
816                                     syncer::SESSIONS)));
817   }
818   content::NotificationService::current()->Notify(
819       chrome::NOTIFICATION_FOREIGN_SESSION_UPDATED,
820       content::Source<Profile>(profile_),
821       content::NotificationService::NoDetails());
822 }
823
824 bool SessionsSyncManager::DisassociateForeignSession(
825     const std::string& foreign_session_tag) {
826   if (foreign_session_tag == current_machine_tag()) {
827     DVLOG(1) << "Local session deleted! Doing nothing until a navigation is "
828              << "triggered.";
829     return false;
830   }
831   DVLOG(1) << "Disassociating session " << foreign_session_tag;
832   return session_tracker_.DeleteSession(foreign_session_tag);
833 }
834
835 // static
836 GURL SessionsSyncManager::GetCurrentVirtualURL(
837     const SyncedTabDelegate& tab_delegate) {
838   const int current_index = tab_delegate.GetCurrentEntryIndex();
839   const int pending_index = tab_delegate.GetPendingEntryIndex();
840   const NavigationEntry* current_entry =
841       (current_index == pending_index) ?
842       tab_delegate.GetPendingEntry() :
843       tab_delegate.GetEntryAtIndex(current_index);
844   return current_entry->GetVirtualURL();
845 }
846
847 // static
848 GURL SessionsSyncManager::GetCurrentFaviconURL(
849     const SyncedTabDelegate& tab_delegate) {
850   const int current_index = tab_delegate.GetCurrentEntryIndex();
851   const int pending_index = tab_delegate.GetPendingEntryIndex();
852   const NavigationEntry* current_entry =
853       (current_index == pending_index) ?
854       tab_delegate.GetPendingEntry() :
855       tab_delegate.GetEntryAtIndex(current_index);
856   return (current_entry->GetFavicon().valid ?
857           current_entry->GetFavicon().url :
858           GURL());
859 }
860
861 bool SessionsSyncManager::GetForeignSession(
862     const std::string& tag,
863     std::vector<const SessionWindow*>* windows) {
864   return session_tracker_.LookupSessionWindows(tag, windows);
865 }
866
867 bool SessionsSyncManager::GetForeignTab(
868     const std::string& tag,
869     const SessionID::id_type tab_id,
870     const SessionTab** tab) {
871   const SessionTab* synced_tab = NULL;
872   bool success = session_tracker_.LookupSessionTab(tag,
873                                                    tab_id,
874                                                    &synced_tab);
875   if (success)
876     *tab = synced_tab;
877   return success;
878 }
879
880 void SessionsSyncManager::LocalTabDelegateToSpecifics(
881     const SyncedTabDelegate& tab_delegate,
882     sync_pb::SessionSpecifics* specifics) {
883   SessionTab* session_tab = NULL;
884   session_tab =
885       session_tracker_.GetTab(current_machine_tag(),
886                               tab_delegate.GetSessionId(),
887                               tab_delegate.GetSyncId());
888   SetSessionTabFromDelegate(tab_delegate, base::Time::Now(), session_tab);
889   sync_pb::SessionTab tab_s = session_tab->ToSyncData();
890   specifics->set_session_tag(current_machine_tag_);
891   specifics->set_tab_node_id(tab_delegate.GetSyncId());
892   specifics->mutable_tab()->CopyFrom(tab_s);
893 }
894
895 void SessionsSyncManager::AssociateRestoredPlaceholderTab(
896     const SyncedTabDelegate& tab_delegate,
897     SessionID::id_type new_tab_id,
898     const syncer::SyncDataList& restored_tabs,
899     syncer::SyncChangeList* change_output) {
900   DCHECK_NE(tab_delegate.GetSyncId(), TabNodePool::kInvalidTabNodeID);
901   // Rewrite the tab using |restored_tabs| to retrieve the specifics.
902   if (restored_tabs.empty()) {
903     DLOG(WARNING) << "Can't Update tab ID.";
904     return;
905   }
906
907   for (syncer::SyncDataList::const_iterator it = restored_tabs.begin();
908        it != restored_tabs.end();
909        ++it) {
910     if (it->GetSpecifics().session().tab_node_id() !=
911         tab_delegate.GetSyncId()) {
912       continue;
913     }
914
915     sync_pb::EntitySpecifics entity;
916     sync_pb::SessionSpecifics* specifics = entity.mutable_session();
917     specifics->CopyFrom(it->GetSpecifics().session());
918     DCHECK(specifics->has_tab());
919
920     // Update tab node pool with the new association.
921     local_tab_pool_.ReassociateTabNode(tab_delegate.GetSyncId(),
922                                        new_tab_id);
923     TabLink* tab_link = new TabLink(tab_delegate.GetSyncId(),
924                                     &tab_delegate);
925     local_tab_map_[new_tab_id] = make_linked_ptr<TabLink>(tab_link);
926
927     if (specifics->tab().tab_id() == new_tab_id)
928       return;
929
930     // The tab_id changed (e.g due to session restore), so update sync.
931     specifics->mutable_tab()->set_tab_id(new_tab_id);
932     syncer::SyncData data = syncer::SyncData::CreateLocalData(
933         TabNodePool::TabIdToTag(current_machine_tag_,
934                                  specifics->tab_node_id()),
935         current_session_name_,
936         entity);
937     change_output->push_back(syncer::SyncChange(
938         FROM_HERE, syncer::SyncChange::ACTION_UPDATE, data));
939     return;
940   }
941 }
942
943 // static.
944 void SessionsSyncManager::SetSessionTabFromDelegate(
945       const SyncedTabDelegate& tab_delegate,
946       base::Time mtime,
947       SessionTab* session_tab) {
948   DCHECK(session_tab);
949   session_tab->window_id.set_id(tab_delegate.GetWindowId());
950   session_tab->tab_id.set_id(tab_delegate.GetSessionId());
951   session_tab->tab_visual_index = 0;
952   // Use -1 to indicate that the index hasn't been set properly yet.
953   session_tab->current_navigation_index = -1;
954   session_tab->pinned = tab_delegate.IsPinned();
955   session_tab->extension_app_id = tab_delegate.GetExtensionAppId();
956   session_tab->user_agent_override.clear();
957   session_tab->timestamp = mtime;
958   const int current_index = tab_delegate.GetCurrentEntryIndex();
959   const int pending_index = tab_delegate.GetPendingEntryIndex();
960   const int min_index = std::max(0, current_index - kMaxSyncNavigationCount);
961   const int max_index = std::min(current_index + kMaxSyncNavigationCount,
962                                  tab_delegate.GetEntryCount());
963   bool is_supervised = tab_delegate.ProfileIsSupervised();
964   session_tab->navigations.clear();
965
966   for (int i = min_index; i < max_index; ++i) {
967     const NavigationEntry* entry = (i == pending_index) ?
968         tab_delegate.GetPendingEntry() : tab_delegate.GetEntryAtIndex(i);
969     DCHECK(entry);
970     if (!entry->GetVirtualURL().is_valid())
971       continue;
972
973     // Set current_navigation_index to the index in navigations.
974     if (i == current_index)
975       session_tab->current_navigation_index = session_tab->navigations.size();
976
977     session_tab->navigations.push_back(
978         SerializedNavigationEntry::FromNavigationEntry(i, *entry));
979     if (is_supervised) {
980       session_tab->navigations.back().set_blocked_state(
981           SerializedNavigationEntry::STATE_ALLOWED);
982     }
983   }
984
985   // If the current navigation is invalid, set the index to the end of the
986   // navigation array.
987   if (session_tab->current_navigation_index < 0) {
988     session_tab->current_navigation_index =
989         session_tab->navigations.size() - 1;
990   }
991
992   if (is_supervised) {
993     const std::vector<const NavigationEntry*>& blocked_navigations =
994         *tab_delegate.GetBlockedNavigations();
995     int offset = session_tab->navigations.size();
996     for (size_t i = 0; i < blocked_navigations.size(); ++i) {
997       session_tab->navigations.push_back(
998           SerializedNavigationEntry::FromNavigationEntry(
999               i + offset, *blocked_navigations[i]));
1000       session_tab->navigations.back().set_blocked_state(
1001           SerializedNavigationEntry::STATE_BLOCKED);
1002       // TODO(bauerb): Add categories
1003     }
1004   }
1005   session_tab->session_storage_persistent_id.clear();
1006 }
1007
1008 FaviconCache* SessionsSyncManager::GetFaviconCache() {
1009   return &favicon_cache_;
1010 }
1011
1012 SyncedWindowDelegatesGetter*
1013 SessionsSyncManager::GetSyncedWindowDelegatesGetter() const {
1014   return synced_window_getter_.get();
1015 }
1016
1017 void SessionsSyncManager::DoGarbageCollection() {
1018   std::vector<const SyncedSession*> sessions;
1019   if (!GetAllForeignSessions(&sessions))
1020     return;  // No foreign sessions.
1021
1022   // Iterate through all the sessions and delete any with age older than
1023   // |stale_session_threshold_days_|.
1024   syncer::SyncChangeList changes;
1025   for (std::vector<const SyncedSession*>::const_iterator iter =
1026            sessions.begin(); iter != sessions.end(); ++iter) {
1027     const SyncedSession* session = *iter;
1028     int session_age_in_days =
1029         (base::Time::Now() - session->modified_time).InDays();
1030     std::string session_tag = session->session_tag;
1031     if (session_age_in_days > 0 &&  // If false, local clock is not trustworty.
1032         static_cast<size_t>(session_age_in_days) >
1033             stale_session_threshold_days_) {
1034       DVLOG(1) << "Found stale session " << session_tag
1035                << " with age " << session_age_in_days << ", deleting.";
1036       DeleteForeignSessionInternal(session_tag, &changes);
1037     }
1038   }
1039
1040   if (!changes.empty())
1041     sync_processor_->ProcessSyncChanges(FROM_HERE, changes);
1042 }
1043
1044 };  // namespace browser_sync