Revert "Revert 142517 - [Sync] Refactor sync configuration logic."

sync/internal_api/sync_manager.cc

Index: sync/internal_api/sync_manager.cc
diff --git a/sync/internal_api/sync_manager.cc b/sync/internal_api/sync_manager.cc
index b0d9ebb660a8ecb1a0007cc8b8967691c17340f3..e8ba9dd45dcadeb6335191a7f8cb8a61723361e8 100644
--- a/sync/internal_api/sync_manager.cc
+++ b/sync/internal_api/sync_manager.cc
@@ -197,6 +197,11 @@ class SyncManager::SyncInternal
   // went wrong.
   bool SignIn(const SyncCredentials& credentials);
 
+  // Purge from the directory those types with non-empty progress markers
+  // but without initial synced ended set.
+  // Returns false if an error occurred, true otherwise.
+  bool PurgePartiallySyncedTypes();
+
   // Update tokens that we're using in Sync. Email must stay the same.
   void UpdateCredentials(const SyncCredentials& credentials);
 
@@ -357,6 +362,21 @@ class SyncManager::SyncInternal
   // Called only by our NetworkChangeNotifier.
   virtual void OnIPAddressChanged() OVERRIDE;
 
+  ModelTypeSet GetTypesWithEmptyProgressMarkerToken(ModelTypeSet types) {
+    DCHECK(initialized_);
+    syncer::ModelTypeSet result;
+    for (syncer::ModelTypeSet::Iterator i = types.First();
+         i.Good(); i.Inc()) {
+      sync_pb::DataTypeProgressMarker marker;
+      directory()->GetDownloadProgress(i.Get(), &marker);
+
+      if (marker.token().empty())
+        result.Put(i.Get());
+
+    }
+    return result;
+  }
+
   syncer::ModelTypeSet InitialSyncEndedTypes() {
     DCHECK(initialized_);
     return directory()->initial_sync_ended_types();
@@ -751,6 +771,15 @@ syncer::ModelTypeSet SyncManager::InitialSyncEndedTypes() {
   return data_->InitialSyncEndedTypes();
 }
 
+syncer::ModelTypeSet SyncManager::GetTypesWithEmptyProgressMarkerToken(
+    syncer::ModelTypeSet types) {
+  return data_->GetTypesWithEmptyProgressMarkerToken(types);
+}
+
+bool SyncManager::PurgePartiallySyncedTypes() {
+  return data_->PurgePartiallySyncedTypes();
+}
+
 void SyncManager::StartSyncingNormally(
     const syncer::ModelSafeRoutingInfo& routing_info) {
   DCHECK(thread_checker_.CalledOnValidThread());
@@ -924,15 +953,29 @@ bool SyncManager::SyncInternal::Init(
     scheduler_.reset(new SyncScheduler(name_, session_context(), new Syncer()));
   }
 
-  bool signed_in = SignIn(credentials);
+  bool success = SignIn(credentials);
 
-  if (signed_in) {
+  if (success) {
     if (scheduler()) {
       scheduler()->Start(syncer::SyncScheduler::CONFIGURATION_MODE);
     }
 
     initialized_ = true;
 
+    // Unapplied datatypes (those that do not have initial sync ended set) get
+    // re-downloaded during any configuration. But, it's possible for a datatype
+    // to have a progress marker but not have initial sync ended yet, making
+    // it a candidate for migration. This is a problem, as the DataTypeManager
+    // does not support a migration while it's already in the middle of a
+    // configuration. As a result, any partially synced datatype can stall the
+    // DTM, waiting for the configuration to complete, which it never will due
+    // to the migration error. In addition, a partially synced nigori will
+    // trigger the migration logic before the backend is initialized, resulting
+    // in crashes. We therefore detect and purge any partially synced types as
+    // part of initialization.
+    if (!PurgePartiallySyncedTypes())
+      success = false;
+
     // Cryptographer should only be accessed while holding a
     // transaction.  Grabbing the user share for the transaction
     // checks the initialization state, so this must come after
@@ -950,14 +993,14 @@ bool SyncManager::SyncInternal::Init(
   FOR_EACH_OBSERVER(SyncManager::Observer, observers_,
                     OnInitializationComplete(
                         MakeWeakHandle(weak_ptr_factory_.GetWeakPtr()),
-                        signed_in));
+                        success));
 
-  if (!signed_in && testing_mode_ == NON_TEST)
+  if (!success && testing_mode_ == NON_TEST)
     return false;
 
   sync_notifier_->AddObserver(this);
 
-  return signed_in;
+  return success;
 }
 
 void SyncManager::SyncInternal::UpdateCryptographerAndNigori(
@@ -1162,6 +1205,20 @@ bool SyncManager::SyncInternal::SignIn(const SyncCredentials& credentials) {
   return true;
 }
 
+bool SyncManager::SyncInternal::PurgePartiallySyncedTypes() {
+  syncer::ModelTypeSet partially_synced_types =
+      syncer::ModelTypeSet::All();
+  partially_synced_types.RemoveAll(InitialSyncEndedTypes());
+  partially_synced_types.RemoveAll(GetTypesWithEmptyProgressMarkerToken(
+      syncer::ModelTypeSet::All()));
+
+  UMA_HISTOGRAM_COUNTS("Sync.PartiallySyncedTypes",
+                       partially_synced_types.Size());
+  if (partially_synced_types.Empty())
+    return true;
+  return directory()->PurgeEntriesWithTypeIn(partially_synced_types);
+}
+
 void SyncManager::SyncInternal::UpdateCredentials(
     const SyncCredentials& credentials) {
   DCHECK(thread_checker_.CalledOnValidThread());
@@ -2472,20 +2529,4 @@ bool InitialSyncEndedForTypes(syncer::ModelTypeSet types,
   return true;
 }
 
-syncer::ModelTypeSet GetTypesWithEmptyProgressMarkerToken(
-    syncer::ModelTypeSet types,
-    syncer::UserShare* share) {
-  syncer::ModelTypeSet result;
-  for (syncer::ModelTypeSet::Iterator i = types.First();
-       i.Good(); i.Inc()) {
-    sync_pb::DataTypeProgressMarker marker;
-    share->directory->GetDownloadProgress(i.Get(), &marker);
-
-    if (marker.token().empty())
-      result.Put(i.Get());
-
-  }
-  return result;
-}
-
 }  // namespace syncer