Original patch by rlarocque@chromium.org at http://codereview.chromium.org/7633077/

chrome/browser/sync/engine/syncapi_internal.cc

+// 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.
+
+#include "chrome/browser/sync/engine/syncapi_internal.h"
+
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/sync/util/cryptographer.h"
+#include "chrome/browser/sync/protocol/password_specifics.pb.h"
+
+using browser_sync::Cryptographer;
+
+namespace sync_api {
+
+sync_pb::PasswordSpecificsData* DecryptPasswordSpecifics(
+    const sync_pb::EntitySpecifics& specifics, Cryptographer* crypto) {
+  if (!specifics.HasExtension(sync_pb::password))
+    return NULL;
+  const sync_pb::PasswordSpecifics& password_specifics =
+      specifics.GetExtension(sync_pb::password);
+  if (!password_specifics.has_encrypted())
+    return NULL;
+  const sync_pb::EncryptedData& encrypted = password_specifics.encrypted();
+  scoped_ptr<sync_pb::PasswordSpecificsData> data(
+      new sync_pb::PasswordSpecificsData);
+  if (!crypto->Decrypt(encrypted, data.get()))
+    return NULL;
+  return data.release();
+}
+
+// The list of names which are reserved for use by the server.
+static const char* kForbiddenServerNames[] = { "", ".", ".." };
+
+// Checks whether |name| is a server-illegal name followed by zero or more space
+// characters.  The three server-illegal names are the empty string, dot, and
+// dot-dot.  Very long names (>255 bytes in UTF-8 Normalization Form C) are
+// also illegal, but are not considered here.
+bool IsNameServerIllegalAfterTrimming(const std::string& name) {
+  size_t untrimmed_count = name.find_last_not_of(' ') + 1;
+  for (size_t i = 0; i < arraysize(kForbiddenServerNames); ++i) {
+    if (name.compare(0, untrimmed_count, kForbiddenServerNames[i]) == 0)
+      return true;
+  }
+  return false;
+}
+
+// Compare the values of two EntitySpecifics, accounting for encryption.
+bool AreSpecificsEqual(const browser_sync::Cryptographer* cryptographer,
+                       const sync_pb::EntitySpecifics& left,
+                       const sync_pb::EntitySpecifics& right) {
+  // Note that we can't compare encrypted strings directly as they are seeded
+  // with a random value.
+  std::string left_plaintext, right_plaintext;
+  if (left.has_encrypted()) {
+    if (!cryptographer->CanDecrypt(left.encrypted())) {
+      NOTREACHED() << "Attempting to compare undecryptable data.";
+      return false;
+    }
+    left_plaintext = cryptographer->DecryptToString(left.encrypted());
+  } else {
+    left_plaintext = left.SerializeAsString();
+  }
+  if (right.has_encrypted()) {
+    if (!cryptographer->CanDecrypt(right.encrypted())) {
+      NOTREACHED() << "Attempting to compare undecryptable data.";
+      return false;
+    }
+    right_plaintext = cryptographer->DecryptToString(right.encrypted());
+  } else {
+    right_plaintext = right.SerializeAsString();
+  }
+  if (left_plaintext == right_plaintext) {
+    return true;
+  }
+  return false;
+}
+
+} // namespace sync_api