sync/engine/directory_update_handler.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 "sync/engine/directory_update_handler.h"
   6
   7 #include "sync/engine/conflict_resolver.h"
   8 #include "sync/engine/process_updates_util.h"
   9 #include "sync/engine/update_applicator.h"
  10 #include "sync/sessions/directory_type_debug_info_emitter.h"
  11 #include "sync/syncable/directory.h"
  12 #include "sync/syncable/model_neutral_mutable_entry.h"
  13 #include "sync/syncable/syncable_model_neutral_write_transaction.h"
  14 #include "sync/syncable/syncable_write_transaction.h"
  15
  16 namespace syncer {
  17
  18 using syncable::SYNCER;
  19
  20 DirectoryUpdateHandler::DirectoryUpdateHandler(
  21     syncable::Directory* dir,
  22     ModelType type,
  23     scoped_refptr<ModelSafeWorker> worker,
  24     DirectoryTypeDebugInfoEmitter* debug_info_emitter)
  25   : dir_(dir),
  26     type_(type),
  27     worker_(worker),
  28     debug_info_emitter_(debug_info_emitter) {}
  29
  30 DirectoryUpdateHandler::~DirectoryUpdateHandler() {}
  31
  32 void DirectoryUpdateHandler::GetDownloadProgress(
  33     sync_pb::DataTypeProgressMarker* progress_marker) const {
  34   dir_->GetDownloadProgress(type_, progress_marker);
  35 }
  36
  37 void DirectoryUpdateHandler::GetDataTypeContext(
  38     sync_pb::DataTypeContext* context) const {
  39   syncable::ModelNeutralWriteTransaction trans(FROM_HERE, SYNCER, dir_);
  40   dir_->GetDataTypeContext(&trans, type_, context);
  41 }
  42
  43 SyncerError DirectoryUpdateHandler::ProcessGetUpdatesResponse(
  44     const sync_pb::DataTypeProgressMarker& progress_marker,
  45     const sync_pb::DataTypeContext& mutated_context,
  46     const SyncEntityList& applicable_updates,
  47     sessions::StatusController* status) {
  48   syncable::ModelNeutralWriteTransaction trans(FROM_HERE, SYNCER, dir_);
  49   if (mutated_context.has_context()) {
  50     sync_pb::DataTypeContext local_context;
  51     dir_->GetDataTypeContext(&trans, type_, &local_context);
  52
  53     // Only update the local context if it is still relevant. If the local
  54     // version is higher, it means a local change happened while the mutation
  55     // was in flight, and the local context takes priority.
  56     if (mutated_context.version() >= local_context.version() &&
  57         local_context.context() != mutated_context.context()) {
  58       dir_->SetDataTypeContext(&trans, type_, mutated_context);
  59       // TODO(zea): trigger the datatype's UpdateDataTypeContext method.
  60     } else if (mutated_context.version() < local_context.version()) {
  61       // A GetUpdates using the old context was in progress when the context was
  62       // set. Fail this get updates cycle, to force a retry.
  63       DVLOG(1) << "GU Context conflict detected, forcing GU retry.";
  64       debug_info_emitter_->EmitUpdateCountersUpdate();
  65       return DATATYPE_TRIGGERED_RETRY;
  66     }
  67   }
  68
  69   // Auto-create permanent folder for the type if the progress marker
  70   // changes from empty to non-empty.
  71   if (IsTypeWithClientGeneratedRoot(type_) &&
  72       dir_->HasEmptyDownloadProgress(type_) &&
  73       IsValidProgressMarker(progress_marker)) {
  74     CreateTypeRoot(&trans);
  75   }
  76
  77   UpdateSyncEntities(&trans, applicable_updates, status);
  78
  79   if (IsValidProgressMarker(progress_marker)) {
  80     ExpireEntriesIfNeeded(&trans, progress_marker);
  81     UpdateProgressMarker(progress_marker);
  82   }
  83
  84   debug_info_emitter_->EmitUpdateCountersUpdate();
  85   return SYNCER_OK;
  86 }
  87
  88 void DirectoryUpdateHandler::CreateTypeRoot(
  89     syncable::ModelNeutralWriteTransaction* trans) {
  90   syncable::ModelNeutralMutableEntry entry(
  91       trans, syncable::CREATE_NEW_TYPE_ROOT, type_);
  92   if (!entry.good()) {
  93     // This will fail only if matching entry already exists, for example
  94     // if the type gets disabled and its progress marker gets cleared,
  95     // then the type gets re-enabled again.
  96     DVLOG(1) << "Type root folder " << ModelTypeToRootTag(type_)
  97              << " already exists.";
  98     return;
  99   }
 100
 101   entry.PutServerIsDir(true);
 102   entry.PutUniqueServerTag(ModelTypeToRootTag(type_));
 103 }
 104
 105 void DirectoryUpdateHandler::ApplyUpdates(sessions::StatusController* status) {
 106   if (!IsApplyUpdatesRequired()) {
 107     return;
 108   }
 109
 110   // This will invoke handlers that belong to the model and its thread, so we
 111   // switch to the appropriate thread before we start this work.
 112   WorkCallback c = base::Bind(
 113       &DirectoryUpdateHandler::ApplyUpdatesImpl,
 114       // We wait until the callback is executed.  We can safely use Unretained.
 115       base::Unretained(this),
 116       base::Unretained(status));
 117   worker_->DoWorkAndWaitUntilDone(c);
 118
 119   debug_info_emitter_->EmitUpdateCountersUpdate();
 120   debug_info_emitter_->EmitStatusCountersUpdate();
 121 }
 122
 123 void DirectoryUpdateHandler::PassiveApplyUpdates(
 124     sessions::StatusController* status) {
 125   if (!IsApplyUpdatesRequired()) {
 126     return;
 127   }
 128
 129   // Just do the work here instead of deferring to another thread.
 130   ApplyUpdatesImpl(status);
 131
 132   debug_info_emitter_->EmitUpdateCountersUpdate();
 133   debug_info_emitter_->EmitStatusCountersUpdate();
 134 }
 135
 136 SyncerError DirectoryUpdateHandler::ApplyUpdatesImpl(
 137     sessions::StatusController* status) {
 138   syncable::WriteTransaction trans(FROM_HERE, syncable::SYNCER, dir_);
 139
 140   std::vector<int64> handles;
 141   dir_->GetUnappliedUpdateMetaHandles(
 142       &trans,
 143       FullModelTypeSet(type_),
 144       &handles);
 145
 146   // First set of update application passes.
 147   UpdateApplicator applicator(dir_->GetCryptographer(&trans));
 148   applicator.AttemptApplications(&trans, handles);
 149
 150   // The old StatusController counters.
 151   status->increment_num_updates_applied_by(applicator.updates_applied());
 152   status->increment_num_hierarchy_conflicts_by(
 153       applicator.hierarchy_conflicts());
 154   status->increment_num_encryption_conflicts_by(
 155       applicator.encryption_conflicts());
 156
 157   // The new UpdateCounter counters.
 158   UpdateCounters* counters = debug_info_emitter_->GetMutableUpdateCounters();
 159   counters->num_updates_applied += applicator.updates_applied();
 160   counters->num_hierarchy_conflict_application_failures =
 161       applicator.hierarchy_conflicts();
 162   counters->num_encryption_conflict_application_failures +=
 163       applicator.encryption_conflicts();
 164
 165   if (applicator.simple_conflict_ids().size() != 0) {
 166     // Resolve the simple conflicts we just detected.
 167     ConflictResolver resolver;
 168     resolver.ResolveConflicts(&trans,
 169                               dir_->GetCryptographer(&trans),
 170                               applicator.simple_conflict_ids(),
 171                               status,
 172                               counters);
 173
 174     // Conflict resolution sometimes results in more updates to apply.
 175     handles.clear();
 176     dir_->GetUnappliedUpdateMetaHandles(
 177         &trans,
 178         FullModelTypeSet(type_),
 179         &handles);
 180
 181     UpdateApplicator conflict_applicator(dir_->GetCryptographer(&trans));
 182     conflict_applicator.AttemptApplications(&trans, handles);
 183
 184     // We count the number of updates from both applicator passes.
 185     status->increment_num_updates_applied_by(
 186         conflict_applicator.updates_applied());
 187     counters->num_updates_applied += conflict_applicator.updates_applied();
 188
 189     // Encryption conflicts should remain unchanged by the resolution of simple
 190     // conflicts.  Those can only be solved by updating our nigori key bag.
 191     DCHECK_EQ(conflict_applicator.encryption_conflicts(),
 192               applicator.encryption_conflicts());
 193
 194     // Hierarchy conflicts should also remain unchanged, for reasons that are
 195     // more subtle.  Hierarchy conflicts exist when the application of a pending
 196     // update from the server would make the local folder hierarchy
 197     // inconsistent.  The resolution of simple conflicts could never affect the
 198     // hierarchy conflicting item directly, because hierarchy conflicts are not
 199     // processed by the conflict resolver.  It could, in theory, modify the
 200     // local hierarchy on which hierarchy conflict detection depends.  However,
 201     // the conflict resolution algorithm currently in use does not allow this.
 202     DCHECK_EQ(conflict_applicator.hierarchy_conflicts(),
 203               applicator.hierarchy_conflicts());
 204
 205     // There should be no simple conflicts remaining.  We know this because the
 206     // resolver should have resolved all the conflicts we detected last time
 207     // and, by the two previous assertions, that no conflicts have been
 208     // downgraded from encryption or hierarchy down to simple.
 209     DCHECK(conflict_applicator.simple_conflict_ids().empty());
 210   }
 211
 212   return SYNCER_OK;
 213 }
 214
 215 bool DirectoryUpdateHandler::IsApplyUpdatesRequired() {
 216   if (IsControlType(type_)) {
 217     return false;  // We don't process control types here.
 218   }
 219
 220   return dir_->TypeHasUnappliedUpdates(type_);
 221 }
 222
 223 void DirectoryUpdateHandler::UpdateSyncEntities(
 224     syncable::ModelNeutralWriteTransaction* trans,
 225     const SyncEntityList& applicable_updates,
 226     sessions::StatusController* status) {
 227   UpdateCounters* counters = debug_info_emitter_->GetMutableUpdateCounters();
 228   counters->num_updates_received += applicable_updates.size();
 229   ProcessDownloadedUpdates(dir_, trans, type_,
 230                            applicable_updates, status, counters);
 231 }
 232
 233 bool DirectoryUpdateHandler::IsValidProgressMarker(
 234     const sync_pb::DataTypeProgressMarker& progress_marker) const {
 235   if (progress_marker.token().empty()) {
 236     return false;
 237   }
 238   int field_number = progress_marker.data_type_id();
 239   ModelType model_type = GetModelTypeFromSpecificsFieldNumber(field_number);
 240   if (!IsRealDataType(model_type) || type_ != model_type) {
 241     NOTREACHED()
 242         << "Update handler of type " << ModelTypeToString(type_)
 243         << " asked to process progress marker with invalid type "
 244         << field_number;
 245     return false;
 246   }
 247   return true;
 248 }
 249
 250 void DirectoryUpdateHandler::UpdateProgressMarker(
 251     const sync_pb::DataTypeProgressMarker& progress_marker) {
 252   if (progress_marker.has_gc_directive() || !cached_gc_directive_) {
 253     dir_->SetDownloadProgress(type_, progress_marker);
 254   } else {
 255     sync_pb::DataTypeProgressMarker merged_marker = progress_marker;
 256     merged_marker.mutable_gc_directive()->CopyFrom(*cached_gc_directive_);
 257     dir_->SetDownloadProgress(type_, merged_marker);
 258   }
 259 }
 260
 261 void DirectoryUpdateHandler::ExpireEntriesIfNeeded(
 262     syncable::ModelNeutralWriteTransaction* trans,
 263     const sync_pb::DataTypeProgressMarker& progress_marker) {
 264   if (!cached_gc_directive_) {
 265     sync_pb::DataTypeProgressMarker current_marker;
 266     GetDownloadProgress(&current_marker);
 267     if (current_marker.has_gc_directive()) {
 268       cached_gc_directive_.reset(new sync_pb::GarbageCollectionDirective(
 269           current_marker.gc_directive()));
 270     }
 271   }
 272
 273   if (!progress_marker.has_gc_directive())
 274     return;
 275
 276   const sync_pb::GarbageCollectionDirective& new_gc_directive =
 277       progress_marker.gc_directive();
 278
 279   if (new_gc_directive.has_version_watermark() &&
 280       (!cached_gc_directive_ ||
 281           cached_gc_directive_->version_watermark() <
 282               new_gc_directive.version_watermark())) {
 283     ExpireEntriesByVersion(dir_, trans, type_,
 284                            new_gc_directive.version_watermark());
 285   }
 286
 287   cached_gc_directive_.reset(
 288       new sync_pb::GarbageCollectionDirective(new_gc_directive));
 289 }
 290
 291 }  // namespace syncer