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

sql/test/test_helpers.h

 // Copyright 2013 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_TEST_TEST_HELPERS_H_
 #define SQL_TEST_TEST_HELPERS_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/files/file_path.h"
 
 // Collection of test-only convenience functions.
 
 namespace base {
 class FilePath;
 }
 
 namespace sql {
 class Connection;
 }
 
 namespace sql {
 namespace test {
 
-// 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.
+unsigned ReadBigEndian(unsigned char* buf, size_t bytes);
+void WriteBigEndian(unsigned val, unsigned char* buf, size_t bytes);
+
+// Raw version of CorruptSizeInHeader that operates on local files. This is
+// exposed because there's a lot of code outside of //sql/ which uses this.
 bool CorruptSizeInHeader(const base::FilePath& db_path) WARN_UNUSED_RESULT;
 
 // Frequently corruption is a result of failure to atomically update
 // pages in different structures.  For instance, if an index update
 // takes effect but the corresponding table update does not.  This
 // helper restores the prior version of a b-tree root after running an
 // update which changed that b-tree.  The named b-tree must exist and
 // must be a leaf node (either index or table).  Returns true if the
 // on-disk file is successfully modified, and the restored page
 // differs from the updated page.
@@ skipping 33 matching lines @@
 
 // Return the results of running "PRAGMA integrity_check" on |db|.
 // TODO(shess): sql::Connection::IntegrityCheck() is basically the
 // same, but not as convenient for testing.  Maybe combine.
 std::string IntegrityCheck(sql::Connection* db) WARN_UNUSED_RESULT;
 
 }  // namespace test
 }  // namespace sql
 
 #endif  // SQL_TEST_TEST_HELPERS_H_