Add CreateFileSystemOperation() method to FileSystemContext

webkit/fileapi/file_system_mount_point_provider.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_MOUNT_POINT_PROVIDER_H_
 #define WEBKIT_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_
 
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/platform_file.h"
 #include "base/file_path.h"
 #include "webkit/fileapi/file_system_types.h"
 
 class GURL;
 
+namespace base {
+class MessageLoopProxy;
+}
+
 namespace fileapi {
 
+class FileSystemCallbackDispatcher;
+class FileSystemContext;
 class FileSystemFileUtil;
+class FileSystemOperationInterface;
 
 // An interface to provide mount-point-specific path-related utilities
 // and specialized FileSystemFileUtil instance.
 class FileSystemMountPointProvider {
  public:
   // Callback for ValidateFileSystemRoot.
   typedef base::Callback<void(base::PlatformFileError error)>
       ValidateFileSystemCallback;
   virtual ~FileSystemMountPointProvider() {}
 
@@ skipping 27 matching lines @@
   // Callable on any thread.
   virtual bool IsRestrictedFileName(const FilePath& filename) const = 0;
 
   // Returns the list of top level directories that are exposed by this
   // provider. This list is used to set appropriate child process file access
   // permissions.
   virtual std::vector<FilePath> GetRootDirectories() const = 0;
 
   // Returns the specialized FileSystemFileUtil for this mount point.
   virtual FileSystemFileUtil* GetFileUtil() = 0;
+
+  // Returns a new instance of the specialized FileSystemOperation for this
+  // mount point based on the given |url|.
+  virtual FileSystemOperationInterface* CreateFileSystemOperation(

[satorux1, 2011/12/27 20:55:34]

There is also FileSystemContext::CreateFileSystemOperation() with a similar
signature. Why do we need the two functions?

Please add comment to the two functions explaining the differences, and why we
need them.

[kinuko, 2012/01/13 08:28:35]

Added some comments why we have both.  We can get rid of
FileSystemContext::CreateFileSystemOperation as it's just a dispatching layer
but it'll add 4-5 more lines at each callsite, and I thought it might not be
really desirable either.  (Open to objections though)

+      const GURL& url,
+      FileSystemCallbackDispatcher* dispatcher,
+      base::MessageLoopProxy* file_proxy,
+      FileSystemContext* context) const = 0;
 };
 
 // An interface to control external file system access permissions.
 class ExternalFileSystemMountPointProvider
     : public FileSystemMountPointProvider {
  public:
   // Grant access to all external file system from extension identified with
   // |extension_id|.
   virtual void GrantFullAccessToExtension(const std::string& extension_id) = 0;
   // Grants access to |virtual_path| from |origin_url|.
   virtual void GrantFileAccessToExtension(
       const std::string& extension_id,
       const FilePath& virtual_path) = 0;
   // Revoke file access from extension identified with |extension_id|.
   virtual void RevokeAccessForExtension(
         const std::string& extension_id) = 0;
   // Adds a new mount point.
   virtual void AddMountPoint(FilePath mount_point) = 0;
   // Remove a mount point.
   virtual void RemoveMountPoint(FilePath mount_point) = 0;
   // Gets virtual path by known filesystem path. Returns false when filesystem
   // path is not exposed by this provider.
   virtual bool GetVirtualPath(const FilePath& filesystem_path,
                               FilePath* virtual_path) = 0;
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_