mandoline filesystem: add a sqlite3 vfs to proxy filesystem usage.

sql/mojo/sql_test_base.h

+// Copyright 2015 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.
+
+#ifndef SQL_MOJO_SQL_TEST_BASE_H_
+#define SQL_MOJO_SQL_TEST_BASE_H_
+
+#include "base/files/file_path.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/memory/scoped_ptr.h"
+#include "components/filesystem/public/interfaces/file_system.mojom.h"
+#include "mojo/application/public/cpp/application_test_base.h"
+#include "sql/connection.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace sql {
+
+class Connection;
+class ScopedMojoFilesystemVFS;
+
+// Base class for SQL tests.
+//
+// WARNING: We want to run the same gtest based unit test code both against
+// chromium (which uses this implementation here), and the mojo code (which
+// uses a different class named SQLTestBase). These two classes need to have
+// the same interface because we compile time switch them based on a
+// #define. We need to have two different implementations because the mojo
+// version derives from something other than mojo::test::ApplicationTestBase
+// instead of testing::Test.
+class SQLTestBase : public mojo::test::ApplicationTestBase {
+ public:
+  SQLTestBase();
+  ~SQLTestBase() override;
+
+  // Returns the path to the database.
+  base::FilePath db_path();
+
+  // Returns a connection to the database at db_path().
+  sql::Connection& db();
+
+  // Closes the current connection to the database and reopens it.
+  bool Reopen();
+
+  // Proxying method around base::PathExists.
+  bool GetPathExists(const base::FilePath& path);
+
+  // SQLite stores the database size in the header, and if the actual
+  // OS-derived size is smaller, the database is considered corrupt.
+  // [This case is actually a common form of corruption in the wild.]
+  // This helper sets the in-header size to one page larger than the
+  // actual file size.  The resulting file will return SQLITE_CORRUPT
+  // for most operations unless PRAGMA writable_schema is turned ON.
+  //
+  // Returns false if any error occurs accessing the file.
+  bool CorruptSizeInHeaderOfPath(const base::FilePath& path);
+
+  // Writes "Now is the winter of our discontent." to the start of the file.

[Scott Hess - ex-Googler, 2015/06/10 22:35:46]

I don't think the string itself needs to be described.

[Elliot Glaysher, 2015/06/12 22:36:44]

Done.

+  void WriteJunkToDatabase(bool truncate);
+
+  // Sets the database file size to 0.
+  void TruncateDatabase();
+
+  // Overridden from testing::Test:
+  void SetUp() override;
+  void TearDown() override;
+
+ protected:
+  filesystem::FileSystemPtr& files() { return files_; }
+
+ private:
+  filesystem::FileSystemPtr files_;
+
+  scoped_ptr<ScopedMojoFilesystemVFS> vfs_;
+  sql::Connection db_;
+
+  DISALLOW_COPY_AND_ASSIGN(SQLTestBase);
+};
+
+}  // namespace sql
+
+#endif  // SQL_MOJO_SQL_TEST_BASE_H_