[Sync] Stop deleting LevelDB files when deleting Directory

chrome/browser/sync/test/integration/single_client_directory_sync_test.cc

 // Copyright (c) 2014 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 "base/files/file_enumerator.h"
+#include "base/files/file_path.h"
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "chrome/browser/sync/test/integration/bookmarks_helper.h"
 #include "chrome/browser/sync/test/integration/single_client_status_change_checker.h"
 #include "chrome/browser/sync/test/integration/sync_test.h"
 #include "chrome/browser/sync/test/integration/updated_progress_marker_checker.h"
 #include "components/browser_sync/profile_sync_service.h"
 #include "components/sync/syncable/directory.h"
 #include "content/public/browser/browser_thread.h"
 #include "sql/test/test_helpers.h"
 #include "url/gurl.h"
 
 using content::BrowserThread;
+using base::FileEnumerator;
+using base::FilePath;
+
+namespace {
+
+// USS ModelTypeStore uses the same folder as the Directory. However, all of its
+// content is in a sub-folder. By not asking for recursive files, this function
+// will avoid seeing any of those, and return iff Directory database files still
+// exist.
+bool FolderContainsFiles(const FilePath& folder) {
+  if (base::DirectoryExists(folder)) {
+    return !FileEnumerator(folder, false, FileEnumerator::FILES).Next().empty();
+  } else {
+    return false;
+  }
+}
 
 class SingleClientDirectorySyncTest : public SyncTest {
  public:
   SingleClientDirectorySyncTest() : SyncTest(SINGLE_CLIENT) {}
   ~SingleClientDirectorySyncTest() override {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SingleClientDirectorySyncTest);
 };
 
@@ skipping 22 matching lines @@
 
   std::string GetDebugMessage() const override {
     return "Sync Unrecoverable Error";
   }
 };
 
 IN_PROC_BROWSER_TEST_F(SingleClientDirectorySyncTest,
                        StopThenDisableDeletesDirectory) {
   ASSERT_TRUE(SetupSync()) << "SetupSync() failed.";
   browser_sync::ProfileSyncService* sync_service = GetSyncService(0);
-  base::FilePath directory_path = sync_service->GetDirectoryPathForTest();
-  ASSERT_TRUE(base::DirectoryExists(directory_path));
+  FilePath directory_path = sync_service->GetDirectoryPathForTest();
+  ASSERT_TRUE(FolderContainsFiles(directory_path));
   sync_service->RequestStop(browser_sync::ProfileSyncService::CLEAR_DATA);
 
   // Wait for StartupController::StartUp()'s tasks to finish.
   base::RunLoop run_loop;
   base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
                                                 run_loop.QuitClosure());
   run_loop.Run();
   // Wait for the directory deletion to finish.
   base::MessageLoop* sync_loop = sync_service->GetSyncLoopForTest();
   ASSERT_TRUE(WaitForExistingTasksOnLoop(sync_loop));
-
-  ASSERT_FALSE(base::DirectoryExists(directory_path));
+  ASSERT_FALSE(FolderContainsFiles(directory_path));
 }
 
 // Verify that when the sync directory's backing store becomes corrupted, we
 // trigger an unrecoverable error and delete the database.
 //
 // If this test fails, see the definition of kNumEntriesRequiredForCorruption
 // for one possible cause.
 IN_PROC_BROWSER_TEST_F(SingleClientDirectorySyncTest,
                        DeleteDirectoryWhenCorrupted) {
   ASSERT_TRUE(SetupClients()) << "SetupClients() failed.";
   // Sync and wait for syncing to complete.
   ASSERT_TRUE(SetupSync()) << "SetupSync() failed.";
   ASSERT_TRUE(UpdatedProgressMarkerChecker(GetSyncService(0)).Wait());
   ASSERT_TRUE(bookmarks_helper::ModelMatchesVerifier(0));
 
   // Flush the directory to the backing store and wait until the flush
   // completes.
   browser_sync::ProfileSyncService* sync_service = GetSyncService(0);
   sync_service->FlushDirectory();
   base::MessageLoop* sync_loop = sync_service->GetSyncLoopForTest();
   ASSERT_TRUE(WaitForExistingTasksOnLoop(sync_loop));
 
   // Now corrupt the database.
-  const base::FilePath directory_path(sync_service->GetDirectoryPathForTest());
-  const base::FilePath sync_db(directory_path.Append(
+  const FilePath directory_path(sync_service->GetDirectoryPathForTest());
+  const FilePath sync_db(directory_path.Append(
       syncer::syncable::Directory::kSyncDatabaseFilename));
   ASSERT_TRUE(sql::test::CorruptSizeInHeaderWithLock(sync_db));
 
   // Write some bookmarks and flush the directory to force sync to
   // notice the corruption.
   const GURL url("https://www.example.com");
   const bookmarks::BookmarkNode* top = bookmarks_helper::AddFolder(
       0, bookmarks_helper::GetOtherNode(0), 0, "top");
   for (int i = 0; i < 100; ++i) {
     ASSERT_TRUE(
         bookmarks_helper::AddURL(0, top, 0, base::Int64ToString(i), url));
   }
   sync_service->FlushDirectory();
 
   // Wait for an unrecoverable error to occur.
   ASSERT_TRUE(SyncUnrecoverableErrorChecker(sync_service).Wait());
   ASSERT_TRUE(sync_service->HasUnrecoverableError());
 
   // Wait until the sync loop has processed any existing tasks and see that the
   // directory no longer exists.
   ASSERT_TRUE(WaitForExistingTasksOnLoop(sync_loop));
-  ASSERT_FALSE(base::DirectoryExists(directory_path));
+  ASSERT_FALSE(FolderContainsFiles(directory_path));
 }
+
+}  // namespace