Stackable file_util for FileAPIs. Sample code for discussion. Incomplete. Cannot be compiled.

webkit/fileapi/file_system_file_util_base.h

+// Copyright (c) 2011 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 WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_BASE_H_
+#define WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_BASE_H_
+
+#include "base/file_util.h"
+#include "base/singleton.h"
+
+namespace fileapi {
+
+class FileSystemFileUtilBase {
+ public:
+  static FileSystemFileUtilBase* GetInstance();
+  virtual ~FileSystemFileUtilBase() {}
+
+  virtual int CountFilesCreatedAfter(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& path,
+      const base::Time& file_time);
+
+  virtual int64 ComputeDirectorySize(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& root_path);
+
+  virtual int64 ComputeFilesSize(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& directory,
+      const FilePath::StringType& pattern);
+
+  virtual bool Delete(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& path, bool recursive);
+
+#if defined(OS_WIN)
+  virtual bool DeleteAfterReboot(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& path);
+#endif
+
+  virtual bool Move(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& from_path, const FilePath& to_path);
+
+  virtual bool ReplaceFile(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& from_path, const FilePath& to_path);
+
+  virtual bool CopyFile(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& from_path, const FilePath& to_path);
+
+  virtual bool CopyDirectory(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& from_path, const FilePath& to_path,
+      bool recursive);
+
+  virtual bool PathExists(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& path);
+
+  virtual bool PathIsWritable(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& path);
+
+  virtual bool DirectoryExists(
+      const FileSystemOperationContext& fs_context,
+      const FilePath& path);
+
+  // ...

[Dai Mikurube (google.com), 2011/02/10 08:35:12]

FYI: Actually, not all functions in file_util are required here.

1) Need to implement functions required by one of extended file_util stacks
here.
2) No need to override all functions here in child extended file_util stacks,
for example, QuotaFileUtil.

+
+ protected:
+  FileSystemFileUtilBase() {}
+
+ private:
+  friend struct DefaultSingletonTraits<FileSystemFileUtilBase>;
+  DISALLOW_COPY_AND_ASSIGN(FileSystemFileUtilBase);
+}
+
+}  // namespace fileapi
+
+#endif  // WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_BASE_H_