Code to migrate a single directory from the old sandbox to the new.

webkit/fileapi/obfuscated_file_system_file_util.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_OBFUSCATED_FILE_SYSTEM_FILE_UTIL_H_
 #define WEBKIT_FILEAPI_OBFUSCATED_FILE_SYSTEM_FILE_UTIL_H_
 
 #include <map>
 #include <vector>
 
@@ skipping 23 matching lines @@
 // backing file than have a database entry whose backing file is missing.  When
 // doing FSCK operations, if you find a loose backing file with no reference,
 // you may safely delete it.
 //
 // This class is RefCountedThreadSafe because it may gain a reference on the IO
 // thread, but must be deleted on the FILE thread because that's where
 // DropDatabases needs to be called.  References will be held by the
 // SandboxMountPointProvider [and the task it uses to drop the reference] and
 // SandboxMountPointProvider::GetFileSystemRootPathTask.  Without that last one,
 // we wouldn't need ref counting.
+//
+// TODO(ericu): We don't ever update directory mtimes; which operations should
+// do that?
 class ObfuscatedFileSystemFileUtil : public FileSystemFileUtil,
     public base::RefCountedThreadSafe<ObfuscatedFileSystemFileUtil> {
  public:
 
   ObfuscatedFileSystemFileUtil(const FilePath& file_system_directory);
   virtual ~ObfuscatedFileSystemFileUtil();
 
   virtual base::PlatformFileError CreateOrOpen(
       FileSystemOperationContext* context,
       const FilePath& file_path,
@@ skipping 70 matching lines @@
   // that were created by LocalFileSystemFileUtil, not all backing files will
   // actually be in this directory.
   FilePath GetDirectoryForOriginAndType(
       const GURL& origin, FileSystemType type, bool create);
 
   // Gets the topmost directory specific to this origin.  This will
   // contain both the filesystem type subdirectories.  See previous comment
   // about migration; TODO(ericu): implement migration and fix these comments.
   FilePath GetDirectoryForOrigin(const GURL& origin, bool create);
 
+  // This will migrate a filesystem from the old passthrough sandbox into the
+  // new obfuscated one.  It won't obfuscate the old filenames [it will maintain
+  // the old structure, but move it to a new root], but any new files created
+  // will go into the new standard locations.  This will be completely
+  // transparent to the user.  This migration is atomic in that it won't alter
+  // the source data until it's done, and that will be with a single directory
+  // move [the directory with the unguessable name will move into the new
+  // filesystem storage directory].  However, if this fails partway through, it
+  // might leave a seemingly-valid database for this origin.  When it starts up,
+  // it will clear any such database, just in case.
+  bool MigrateFromOldSandbox(
+      const GURL& origin, FileSystemType type, const FilePath& root);
+
+  FilePath::StringType GetDirectoryNameForType(FileSystemType type) const;
+
  protected:
   virtual AbstractFileEnumerator* CreateFileEnumerator(
       FileSystemOperationContext* context,
       const FilePath& root_path) OVERRIDE;
 
  private:
   typedef FileSystemDirectoryDatabase::FileId FileId;
   typedef FileSystemDirectoryDatabase::FileInfo FileInfo;
 
   // Creates a new file, both the underlying backing file and the entry in the
   // database.  file_info is an in-out parameter.  Supply the name and
   // parent_id; supply data_path if you want it to be used as a source from
   // which to COPY data--otherwise leave it empty.  On success, data_path will

[michaeln, 2011/05/20 02:15:16]

please fixup this comment

* make it clear that file_info.data_path is not used as the input

* the comment about how data_path will contain a full path is now stale

[ericu, 2011/05/20 02:23:25]

Done, thanks for catching that.

   // always be set to the full path of a NEW backing file, and handle, if
   // supplied, will hold open PlatformFile for the backing file, which the
   // caller is responsible for closing.
   // Caveat: do not supply handle if you're also supplying a data path.  It was
   // easier not to support this, and no code has needed it so far, so it will
   // DCHECK and handle will hold base::kInvalidPlatformFileValue.
   base::PlatformFileError CreateFile(
       FileSystemOperationContext* context,
       const GURL& origin_url, FileSystemType type,
-      FileInfo* file_info,
+      const FilePath& source_path, FileInfo* file_info,
       int file_flags, base::PlatformFile* handle);
   // Given the filesystem's root URL and a virtual path, produces a real, full
-  // local path to the underlying data file.
+  // local path to the underlying data file.  This does a database lookup, and
+  // verifies that the file exists.
   FilePath GetLocalPath(
       const GURL& origin_url,
       FileSystemType type,
       const FilePath& virtual_path);
+  // This converts from a relative path [as is stored in the FileInfo.data_path
+  // field] to an absolute local path that can be given to the operating system.
+  // It does no checks as to whether the file actually exists; it's pure path
+  // manipulation.
+  FilePath DataPathToLocalPath(
+      const GURL& origin, FileSystemType type, const FilePath& virtual_path);

[michaeln, 2011/05/20 02:15:16]

virtual_path s/b data_path in the arg list

[ericu, 2011/05/20 02:23:25]

Done.

+  // This does the reverse of DataPathToLocalPath.
+  FilePath LocalPathToDataPath(
+      const GURL& origin, FileSystemType type, const FilePath& data_path);
   FileSystemDirectoryDatabase* GetDirectoryDatabase(
       const GURL& origin_url, FileSystemType type);
   void MarkUsed();
   void DropDatabases();
+  bool DestroyDirectoryDatabase(const GURL& origin, FileSystemType type);
 
   typedef std::map<std::string, FileSystemDirectoryDatabase*> DirectoryMap;
   DirectoryMap directories_;
   scoped_ptr<FileSystemOriginDatabase> origin_database_;
   FilePath file_system_directory_;
   base::OneShotTimer<ObfuscatedFileSystemFileUtil> timer_;
 
   DISALLOW_COPY_AND_ASSIGN(ObfuscatedFileSystemFileUtil);
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_OBFUSCATED_FILE_SYSTEM_FILE_UTIL_H_