Fix a race condition in ~RegistryHashStoreContentsWin

services/preferences/tracked/registry_hash_store_contents_win_unittest.cc

 // Copyright (c) 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 "services/preferences/tracked/registry_hash_store_contents_win.h"
 
+#include "base/bind.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/memory/ptr_util.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/test_reg_util_win.h"
+#include "base/threading/thread.h"
 #include "base/values.h"
 #include "base/win/registry.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
 constexpr base::char16 kRegistryPath[] = L"Foo\\TestStore";
 constexpr base::char16 kStoreKey[] = L"test_store_key";
 
 // Hex-encoded MACs are 64 characters long.
 constexpr char kTestStringA[] =
     "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
 constexpr char kTestStringB[] =
     "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb";
 
 constexpr char kAtomicPrefPath[] = "path1";
 constexpr char kSplitPrefPath[] = "extension";
 
 class RegistryHashStoreContentsWinTest : public testing::Test {
  protected:
   RegistryHashStoreContentsWinTest() {}
 
   void SetUp() override {
     ASSERT_NO_FATAL_FAILURE(
         registry_override_manager_.OverrideRegistry(HKEY_CURRENT_USER));
 
-    contents.reset(new RegistryHashStoreContentsWin(kRegistryPath, kStoreKey));
+    contents.reset(
+        new RegistryHashStoreContentsWin(kRegistryPath, kStoreKey, nullptr));
   }
 
   std::unique_ptr<HashStoreContents> contents;
 
  private:
   registry_util::RegistryOverrideManager registry_override_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(RegistryHashStoreContentsWinTest);
 };
 
@@ skipping 64 matching lines @@
   contents->Reset();
 
   stored_mac.clear();
   EXPECT_FALSE(contents->GetMac(kAtomicPrefPath, &stored_mac));
   EXPECT_TRUE(stored_mac.empty());
 
   split_macs.clear();
   EXPECT_FALSE(contents->GetSplitMacs(kSplitPrefPath, &split_macs));
   EXPECT_EQ(0U, split_macs.size());
 }
+
+TEST(RegistryHashStoreContentsWinScopedTest, TestScopedDirsCleared) {
+  std::string stored_mac;
+
+  base::ScopedTempDir temp_dir;
+  ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
+  const base::string16 registry_path =
+      temp_dir.GetPath().DirName().BaseName().LossyDisplayName();
+
+  RegistryHashStoreContentsWin verifying_contents(registry_path, kStoreKey,
+                                                  nullptr);
+
+  scoped_refptr<TempScopedDirRegistryCleaner> temp_scoped_dir_cleaner =
+      base::MakeRefCounted<TempScopedDirRegistryCleaner>();
+  std::unique_ptr<RegistryHashStoreContentsWin> contentsA =
+      base::MakeUnique<RegistryHashStoreContentsWin>(registry_path, kStoreKey,
+                                                     temp_scoped_dir_cleaner);
+  std::unique_ptr<RegistryHashStoreContentsWin> contentsB =
+      base::MakeUnique<RegistryHashStoreContentsWin>(registry_path, kStoreKey,
+                                                     temp_scoped_dir_cleaner);
+
+  contentsA->SetMac(kAtomicPrefPath, kTestStringA);
+  contentsB->SetMac(kAtomicPrefPath, kTestStringB);
+
+  temp_scoped_dir_cleaner = nullptr;
+  EXPECT_TRUE(verifying_contents.GetMac(kAtomicPrefPath, &stored_mac));
+  EXPECT_EQ(kTestStringB, stored_mac);
+
+  contentsB.reset();
+  EXPECT_TRUE(verifying_contents.GetMac(kAtomicPrefPath, &stored_mac));
+  EXPECT_EQ(kTestStringB, stored_mac);
+
+  contentsA.reset();
+  EXPECT_FALSE(verifying_contents.GetMac(kAtomicPrefPath, &stored_mac));
+}
+
+void OffThreadTempScopedDirDestructor(
+    base::string16 registry_path,
+    std::unique_ptr<HashStoreContents> contents) {
+  std::string stored_mac;
+
+  RegistryHashStoreContentsWin verifying_contents(registry_path, kStoreKey,
+                                                  nullptr);
+
+  contents->SetMac(kAtomicPrefPath, kTestStringB);
+  EXPECT_TRUE(verifying_contents.GetMac(kAtomicPrefPath, &stored_mac));
+  EXPECT_EQ(kTestStringB, stored_mac);
+
+  contents.reset();
+  EXPECT_FALSE(verifying_contents.GetMac(kAtomicPrefPath, &stored_mac));
+}
+
+TEST(RegistryHashStoreContentsWinScopedTest, TestScopedDirsClearedMultiThread) {
+  std::string stored_mac;
+
+  base::ScopedTempDir temp_dir;
+  ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
+  const base::string16 registry_path =
+      temp_dir.GetPath().DirName().BaseName().LossyDisplayName();
+
+  RegistryHashStoreContentsWin verifying_contents(registry_path, kStoreKey,
+                                                  nullptr);
+
+  base::Thread test_thread("scoped_dir_cleaner_test_thread");
+  test_thread.StartAndWaitForTesting();
+
+  scoped_refptr<TempScopedDirRegistryCleaner> temp_scoped_dir_cleaner =
+      base::MakeRefCounted<TempScopedDirRegistryCleaner>();
+  std::unique_ptr<RegistryHashStoreContentsWin> contents =
+      base::MakeUnique<RegistryHashStoreContentsWin>(
+          registry_path, kStoreKey, std::move(temp_scoped_dir_cleaner));
+  base::OnceClosure other_thread_closure =
+      base::BindOnce(&OffThreadTempScopedDirDestructor, registry_path,
+                     base::Passed(contents->MakeCopy()));
+
+  contents->SetMac(kAtomicPrefPath, kTestStringA);
+  contents.reset();
+
+  EXPECT_TRUE(verifying_contents.GetMac(kAtomicPrefPath, &stored_mac));
+  EXPECT_EQ(kTestStringA, stored_mac);
+
+  test_thread.task_runner()->PostTask(FROM_HERE,
+                                      std::move(other_thread_closure));
+  test_thread.FlushForTesting();
+
+  EXPECT_FALSE(verifying_contents.GetMac(kAtomicPrefPath, &stored_mac));
+}