CRX FileSystem Pepper private API

ppapi/cpp/private/ext_crx_file_system_private.h

+// Copyright (c) 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 PPAPI_CPP_PRIVATE_EXTENSION_CRX_FILE_SYSTEM_PRIVATE_H_
+#define PPAPI_CPP_PRIVATE_EXTENSION_CRX_FILE_SYSTEM_PRIVATE_H_
+
+#include "ppapi/c/pp_instance.h"
+#include "ppapi/cpp/file_system.h"
+#include "ppapi/cpp/instance_handle.h"
+
+namespace pp {
+
+class CompletionCallback;
+
+class ExtCrxFileSystemPrivate : public FileSystem {

[yzshen1, 2013/04/30 19:31:19]

It doesn't make sense to inherit from FileSystem. A crx filesystem PP_Resource
is not a filesystem PP_Resource.

[victorhsieh, 2013/04/30 22:04:32]

That's true, but if we don't do this, we'll have to create a new FileRef and
FileIO for this filesystem.  And when we want to add another filesystem (e.g.
gallery), it will have more.  We probably should keep FileRef and FileIO
independent to FileSystem from the API perspective.

I know it's tricky since this inheritance depends on the fact that pp_resource
is used now is simply an id.  But I didn't come up with a better idea.  Thought?

[yzshen1, 2013/05/01 17:45:10]

You could create a subclass of FileRef, say, ExtCrxFileRefPrivate, which adds a
new constructor to take a ExtCrxFileSystemPrivate instead of a FileSystem. You
don't have to do anything to FileIO, because ExtCrxFileRefPrivate is still a
FileRef.
I don't think we want to add different kinds of file system *PP_Resource*. I
wish we could do it by extending FileSystem itself. I suggested before that we
make a private API to create a PPB_FileSystem PP_Resource which is of isolated
type, but not creating a different file system PP_Resource, right?

The problem we encounter here is one reason we should go that way, IMO.

[victorhsieh, 2013/05/02 18:59:06]

Done.

+ public:
+  ExtCrxFileSystemPrivate();
+  explicit ExtCrxFileSystemPrivate(const InstanceHandle& instance);
+  explicit ExtCrxFileSystemPrivate(const ExtCrxFileSystemPrivate& other);
+  virtual ~ExtCrxFileSystemPrivate();
+
+  int32_t Open(const CompletionCallback& cc);
+};
+
+}  // namespace pp
+
+#endif  // PPAPI_CPP_PRIVATE_EXTENSION_CRX_FILE_SYSTEM_PRIVATE_H_