[Sync] Initial support for encrypting any datatype (no UI hookup yet).

chrome/browser/sync/syncable/nigori_util.h

+// Copyright (c) 2011 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.
+
+// Various utility methods for nigory-based multi-type encryption.
+
+#ifndef CHROME_BROWSER_SYNC_SYNCABLE_NIGORI_UTIL_H_
+#define CHROME_BROWSER_SYNC_SYNCABLE_NIGORI_UTIL_H_
+#pragma once
+
+#include "chrome/browser/sync/protocol/nigori_specifics.pb.h"
+#include "chrome/browser/sync/syncable/model_type.h"
+
+namespace browser_sync {
+class Cryptographer;
+}
+
+namespace syncable {
+
+class BaseTransaction;
+class ReadTransaction;
+class WriteTransaction;
+
+// Returns the set of datatypes that require encryption as specified by the
+// Sync DB's nigori node. This will never include passwords, as the encryption
+// status of that is always on if passwords are enabled..
+ModelTypeSet GetEncryptedDataTypes(BaseTransaction* const trans);
+
+// Extract the set of encrypted datatypes from a nigori node.
+ModelTypeSet GetEncryptedDataTypesFromNigori(
+    const sync_pb::NigoriSpecifics& nigori);
+
+// Set the encrypted datatypes on the nigori node.
+void FillNigoriEncryptedTypes(const ModelTypeSet& types,
+    sync_pb::NigoriSpecifics* nigori);
+
+// Check if our unsyced changes are encrypted if they need to be based on
+// |encrypted_types|.
+// Returns: true if all unsynced data that should be encrypted is.
+//          false if some unsynced changes need to be encrypted.
+// This method is similar to ProcessUnsyncedChangesForEncryption but does not
+// modify the data and does not care if data is unnecessarily encrypted.
+bool VerifyUnsyncedChangesAreEncrypted(
+    BaseTransaction* const trans,
+    const ModelTypeSet& encrypted_types);
+
+// Processes all unsynced changes and ensures they are appropriately encrypted
+// or unencrypted, based on |encrypted_types|.
+bool ProcessUnsyncedChangesForEncryption(
+    WriteTransaction* const trans,
+    const syncable::ModelTypeSet& encrypted_types,
+    browser_sync::Cryptographer* cryptographer);
+
+// Verifies all data of type |type| is encrypted if |is_encrypted| is true or is
+// unencrypted otherwise.
+bool VerifyDataTypeEncryption(BaseTransaction* const trans,
+                              ModelType type,
+                              bool is_encrypted);
+
+}  // namespace syncable
+
+#endif  // CHROME_BROWSER_SYNC_SYNCABLE_NIGORI_UTIL_H_