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