sync: Add non-blocking type encryption support

sync/engine/model_type_entity.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sync/engine/model_type_entity.h"
 #include "sync/syncable/syncable_util.h"
 
 namespace syncer {
 
 scoped_ptr<ModelTypeEntity> ModelTypeEntity::NewLocalItem(
     const std::string& client_tag,
     const sync_pb::EntitySpecifics& specifics,
     base::Time now) {
   return scoped_ptr<ModelTypeEntity>(new ModelTypeEntity(
       1,
       0,
       0,
       kUncommittedVersion,
       true,
       std::string(),  // Sync thread will assign the initial ID.
       syncable::GenerateSyncableHash(GetModelTypeFromSpecifics(specifics),
                                      client_tag),
       client_tag,  // As non-unique name.
       specifics,
       false,
       now,
-      now));
+      now,
+      std::string()));
 }
 
 scoped_ptr<ModelTypeEntity> ModelTypeEntity::FromServerUpdate(
     const std::string& id,
     const std::string& client_tag_hash,
     const std::string& non_unique_name,
     int64 version,
     const sync_pb::EntitySpecifics& specifics,
     bool deleted,
     base::Time ctime,
-    base::Time mtime) {
+    base::Time mtime,
+    const std::string& encryption_key_name) {
   return scoped_ptr<ModelTypeEntity>(new ModelTypeEntity(0,
                                                          0,
                                                          0,
                                                          version,
                                                          true,
                                                          id,
                                                          client_tag_hash,
                                                          non_unique_name,
                                                          specifics,
                                                          deleted,
                                                          ctime,
-                                                         mtime));
+                                                         mtime,
+                                                         encryption_key_name));
 }
 
 ModelTypeEntity::ModelTypeEntity(int64 sequence_number,
                                  int64 commit_requested_sequence_number,
                                  int64 acked_sequence_number,
                                  int64 base_version,
                                  bool is_dirty,
                                  const std::string& id,
                                  const std::string& client_tag_hash,
                                  const std::string& non_unique_name,
                                  const sync_pb::EntitySpecifics& specifics,
                                  bool deleted,
                                  base::Time ctime,
-                                 base::Time mtime)
+                                 base::Time mtime,
+                                 const std::string& encryption_key_name)
     : sequence_number_(sequence_number),
       commit_requested_sequence_number_(commit_requested_sequence_number),
       acked_sequence_number_(acked_sequence_number),
       base_version_(base_version),
       is_dirty_(is_dirty),
       id_(id),
       client_tag_hash_(client_tag_hash),
       non_unique_name_(non_unique_name),
       specifics_(specifics),
       deleted_(deleted),
       ctime_(ctime),
-      mtime_(mtime) {
+      mtime_(mtime),
+      encryption_key_name_(encryption_key_name) {
 }
 
 ModelTypeEntity::~ModelTypeEntity() {
 }
 
 bool ModelTypeEntity::IsWriteRequired() const {
   return is_dirty_;
 }
 
 bool ModelTypeEntity::IsUnsynced() const {
   return sequence_number_ > acked_sequence_number_;
 }
 
 bool ModelTypeEntity::RequiresCommitRequest() const {
   return sequence_number_ > commit_requested_sequence_number_;
 }
 
 bool ModelTypeEntity::UpdateIsReflection(int64 update_version) const {
   return base_version_ >= update_version;
 }
 
 bool ModelTypeEntity::UpdateIsInConflict(int64 update_version) const {
   return IsUnsynced() && !UpdateIsReflection(update_version);
 }
 
 void ModelTypeEntity::ApplyUpdateFromServer(
     int64 update_version,
     bool deleted,
     const sync_pb::EntitySpecifics& specifics,
-    base::Time mtime) {
+    base::Time mtime,
+    const std::string& encryption_key_name) {
   // There was a conflict and the server just won it.
   // This implicitly acks all outstanding commits because a received update
   // will clobber any pending commits on the sync thread.
   acked_sequence_number_ = sequence_number_;
   commit_requested_sequence_number_ = sequence_number_;
 
   base_version_ = update_version;
   specifics_ = specifics;
   mtime_ = mtime;
 }
 
 void ModelTypeEntity::MakeLocalChange(
     const sync_pb::EntitySpecifics& specifics) {
   sequence_number_++;
   specifics_ = specifics;
 }
 
+void ModelTypeEntity::UpdateDesiredEncryptionKey(const std::string& name) {
+  if (encryption_key_name_ == name)
+    return;
+
+  // Schedule commit with the expectation that the worker will re-encrypt with
+  // the latest encryption key as it does.
+  sequence_number_++;
+}
+
 void ModelTypeEntity::Delete() {
   sequence_number_++;
   specifics_.Clear();
   deleted_ = true;
 }
 
 void ModelTypeEntity::InitializeCommitRequestData(
     CommitRequestData* request) const {
   request->id = id_;
   request->client_tag_hash = client_tag_hash_;
   request->sequence_number = sequence_number_;
   request->base_version = base_version_;
   request->ctime = ctime_;
   request->mtime = mtime_;
   request->non_unique_name = non_unique_name_;
   request->deleted = deleted_;
   request->specifics.CopyFrom(specifics_);
 }
 
 void ModelTypeEntity::SetCommitRequestInProgress() {
   commit_requested_sequence_number_ = sequence_number_;
 }
 
-void ModelTypeEntity::ReceiveCommitResponse(const std::string& id,
-                                            int64 sequence_number,
-                                            int64 response_version) {
+void ModelTypeEntity::ReceiveCommitResponse(
+    const std::string& id,
+    int64 sequence_number,
+    int64 response_version,
+    const std::string& encryption_key_name) {
   id_ = id;  // The server can assign us a new ID in a commit response.
   acked_sequence_number_ = sequence_number;
   base_version_ = response_version;
+  encryption_key_name_ = encryption_key_name;
 }
 
 void ModelTypeEntity::ClearTransientSyncState() {
   // If we have any unacknowledged commit requests outstatnding, they've been
   // dropped and we should forget about them.
   commit_requested_sequence_number_ = acked_sequence_number_;
 }
 
 void ModelTypeEntity::ClearSyncState() {
   base_version_ = kUncommittedVersion;
   is_dirty_ = true;
   sequence_number_ = 1;
   commit_requested_sequence_number_ = 0;
   acked_sequence_number_ = 0;
   id_.clear();
 }
 
 }  // namespace syncer