sync: Implement per-type update processing

sync/engine/process_updates_util.h

+// Copyright 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.
+
+#ifndef SYNC_ENGINE_PROCESS_UPDATES_UTIL_H_
+#define SYNC_ENGINE_PROCESS_UPDATES_UTIL_H_
+
+#include <map>
+#include <vector>
+
+#include "base/compiler_specific.h"
+#include "sync/base/sync_export.h"
+#include "sync/engine/syncer_types.h"
+#include "sync/internal_api/public/base/model_type.h"
+
+namespace sync_pb {
+class GetUpdatesResponse;
+class SyncEntity;
+}
+
+namespace syncer {
+
+namespace sessions {
+class StatusController;
+}
+
+namespace syncable {
+class ModelNeutralWriteTransaction;
+class Directory;
+}
+
+class Cryptographer;
+
+// TODO(rlarocque): Move these definitions somewhere else?
+typedef std::vector<const sync_pb::SyncEntity*> SyncEntityList;
+typedef std::map<ModelType, SyncEntityList> TypeSyncEntityMap;
+
+// Given a GetUpdates response, iterates over all the returned items and
+// divides them according to their type.  Outputs a map from model types to
+// received SyncEntities.  The output map will have entries (possibly empty)
+// for all types in |requested_types|.
+void PartitionUpdatesByType(
+    const sync_pb::GetUpdatesResponse& updates,
+    ModelTypeSet requested_types,
+    TypeSyncEntityMap* updates_by_type);
+
+// Processes all the updates associated with a single ModelType.
+void ProcessDownloadedUpdates(
+    syncable::Directory* dir,
+    syncable::ModelNeutralWriteTransaction* trans,
+    ModelType type,
+    const SyncEntityList& applicable_updates,
+    sessions::StatusController* status);
+
+// Checks whether or not an update is fit for processing.
+//
+// The answer may be "no" if the update appears invalid, or it's not releveant
+// (ie. a delete for an item we've never heard of), or other reasons.
+VerifyResult VerifyUpdate(
+    syncable::ModelNeutralWriteTransaction* trans,
+    const sync_pb::SyncEntity& entry,
+    ModelType requested_type);
+
+// If the update passes a series of checks, this function will copy
+// the SyncEntity's data into the SERVER side of the syncable::Directory.
+void ProcessUpdate(
+    const sync_pb::SyncEntity& proto_update,
+    const Cryptographer* cryptographer,
+    syncable::ModelNeutralWriteTransaction* const trans);
+
+}  // namespace syncer
+
+#endif  // SYNC_ENGINE_PROCESS_UPDATES_UTIL_H_