Future-proof data format used for LocalStorage.

content/renderer/dom_storage/local_storage_cached_area.cc

 // Copyright 2016 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 "content/renderer/dom_storage/local_storage_cached_area.h"
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/rand_util.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/time/time.h"
 #include "content/common/dom_storage/dom_storage_map.h"
 #include "content/common/storage_partition_service.mojom.h"
 #include "content/renderer/dom_storage/local_storage_area.h"
 #include "content/renderer/dom_storage/local_storage_cached_areas.h"
 #include "mojo/public/cpp/bindings/strong_associated_binding.h"
 #include "third_party/WebKit/public/platform/WebURL.h"
 #include "third_party/WebKit/public/web/WebStorageEventDispatcher.h"
 
 namespace content {
 
 namespace {
 
+// Don't change or reorder any of the values in this enum, as these values
+// are serialized on disk.
+enum class StorageFormat : uint8_t { UTF16 = 0 };
+
 base::string16 Uint8VectorToString16(const std::vector<uint8_t>& input) {
-  return base::string16(reinterpret_cast<const base::char16*>(input.data()),
-                        input.size() / sizeof(base::char16));
+  // TODO(mek): Better error recovery when corrupt (or otherwise invalid) data
+  // is detected.
+  if (input.size() % sizeof(base::char16) != 1 ||
+      input[0] != static_cast<uint8_t>(StorageFormat::UTF16)) {
+    VLOG(1) << "Corrupt data in localstorage";
+    return base::string16();
+  }
+  base::string16 result;
+  result.resize(input.size() / sizeof(base::char16));
+  std::memcpy(reinterpret_cast<void*>(&result[0]), input.data() + 1,
+              input.size() - 1);
+  return result;
 }
 
 std::vector<uint8_t> String16ToUint8Vector(const base::string16& input) {
   const uint8_t* data = reinterpret_cast<const uint8_t*>(input.data());
-  return std::vector<uint8_t>(data, data + input.size() * sizeof(base::char16));
+  std::vector<uint8_t> result;
+  result.reserve(input.size() * sizeof(base::char16) + 1);
+  result.push_back(static_cast<uint8_t>(StorageFormat::UTF16));
+  result.insert(result.end(), data, data + input.size() * sizeof(base::char16));
+  return result;
 }
 
 class GetAllCallback : public mojom::LevelDBWrapperGetAllCallback {
  public:
   static mojom::LevelDBWrapperGetAllCallbackAssociatedPtrInfo CreateAndBind(
       const base::Callback<void(bool)>& callback) {
     mojom::LevelDBWrapperGetAllCallbackAssociatedPtrInfo ptr_info;
     auto request = mojo::MakeRequest(&ptr_info);
     mojo::MakeStrongAssociatedBinding(
         base::WrapUnique(new GetAllCallback(callback)), std::move(request));
@@ skipping 315 matching lines @@
 }
 
 void LocalStorageCachedArea::Reset() {
   map_ = NULL;
   ignore_key_mutations_.clear();
   ignore_all_mutations_ = false;
   weak_factory_.InvalidateWeakPtrs();
 }
 
 }  // namespace content