[Sync] Add plumbing of context from client to server

chrome/browser/sync/glue/generic_change_processor.cc

 // Copyright (c) 2012 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 "chrome/browser/sync/glue/generic_change_processor.h"
 
 #include "base/location.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/public/browser/browser_thread.h"
 #include "sync/api/sync_change.h"
 #include "sync/api/sync_error.h"
 #include "sync/api/syncable_service.h"
 #include "sync/internal_api/public/base_node.h"
 #include "sync/internal_api/public/change_record.h"
 #include "sync/internal_api/public/read_node.h"
 #include "sync/internal_api/public/read_transaction.h"
 #include "sync/internal_api/public/util/unrecoverable_error_handler.h"
 #include "sync/internal_api/public/write_node.h"
 #include "sync/internal_api/public/write_transaction.h"
 #include "sync/syncable/entry.h"  // TODO(tim): Bug 123674.
 
 using content::BrowserThread;
 
 namespace browser_sync {
 
 namespace {
 
+const int kContextSizeLimit = 1024;  // Datatype context size limit.
+
 void SetNodeSpecifics(const sync_pb::EntitySpecifics& entity_specifics,
                       syncer::WriteNode* write_node) {
   if (syncer::GetModelTypeFromSpecifics(entity_specifics) ==
           syncer::PASSWORDS) {
     write_node->SetPasswordSpecifics(
         entity_specifics.password().client_only_encrypted_data());
   } else {
     write_node->SetEntitySpecifics(entity_specifics);
   }
 }
@@ skipping 124 matching lines @@
     syncer::ModelType type) const {
   // This is slow / memory intensive.  Should be used sparingly by datatypes.
   syncer::SyncDataList data;
   GetAllSyncDataReturnError(type, &data);
   return data;
 }
 
 syncer::SyncError GenericChangeProcessor::UpdateDataTypeContext(
     syncer::ModelType type,
     const std::string& context) {
-  NOTIMPLEMENTED();
+  if (context.size() > static_cast<size_t>(kContextSizeLimit)) {
+    return syncer::SyncError(FROM_HERE,
+                             syncer::SyncError::DATATYPE_ERROR,
+                             "Context size limit exceeded.",
+                             type);
+  }
+
+  syncer::WriteTransaction trans(FROM_HERE, share_handle());
+  trans.SetDataTypeContext(type, context);
+
+  // TODO(zea): consider forcing a nudge? For we'll just use the context on
+  // the next organically triggered sync cycle.
   return syncer::SyncError();
 }
 
 syncer::SyncError GenericChangeProcessor::GetAllSyncDataReturnError(
     syncer::ModelType type,
     syncer::SyncDataList* current_sync_data) const {
   DCHECK(CalledOnValidThread());
   std::string type_name = syncer::ModelTypeToString(type);
   syncer::ReadTransaction trans(FROM_HERE, share_handle());
   syncer::ReadNode root(&trans);
@@ skipping 442 matching lines @@
 void GenericChangeProcessor::StartImpl(Profile* profile) {
   DCHECK(CalledOnValidThread());
 }
 
 syncer::UserShare* GenericChangeProcessor::share_handle() const {
   DCHECK(CalledOnValidThread());
   return share_handle_;
 }
 
 }  // namespace browser_sync