Rework the File System Virtualization Engine

[GoogleCodeExporter]

The file system's virtualization engine should be reviewed and reworked.
The main goal is to make the engine's footprint as small as possible by 
reconsidering the complete implementation of the engine.

One of the main components that possibly can be dropped would be the virtual 
file system table. It might be possible to replace this completely by an 
extremely robust and flexible path-redirecting-engine.
This could dramatically improve performance, because the file system's 
synchronization cycle between guest and host (database) would become obsolete.

During this rework, the engine must also be expanded with an engine rule 
framework, similar to the one in the registry engine.

Original issue reported on code.google.com by simon_al...@hotmail.com on 27 Jun 2010 at 10:42

[GoogleCodeExporter]

The latest series of changes partially broke the virtualization engine.

The following is done already:
- Dropped the virtual file system table (r304)
- Removed synchronization logic between guest and host (r305)
- Removed use of underlying databases (r305)
- Support for engine rule framework (r313, r315, r318, r319)

The rework is still in progress;

Original comment by simon_al...@hotmail.com on 5 Jul 2010 at 7:08

[GoogleCodeExporter]

Currently the engine is partially working again. 'Partially' because the engine 
fails on temporary files, the cause for this is yet to be found. Note that it's 
possible that temporary file were never really supported, in the old engine 
such files were kept untouched.

These are the changes since the last comment:
- r322  Made TransparentRead the default type of virtualization in the file 
system virtualization engine.
- r324  Reintroduced FileRequest
- r325  Made VirtualEnvironment non-static
- r326  Renamed FileAccessRedirector to FileSystemRedirector and made it a 
non-static class
- r328  Moved redirecting logic from FileSystemProvider to VirtualEnvironment
- r329  Added the temporary folder path to the dictionary of system variables in 
FileSystemRedirector
- r330  Implemented support for the RemoveDirectory function
- r331  Added FileRequestResult struct
- r332  Added HostFileSystem class.

Original comment by simon_al...@hotmail.com on 4 Aug 2010 at 8:20

[GoogleCodeExporter]

Support for temporary files was broken due to re-virtualization of the already 
virtualized paths
Fixed in r362

Original comment by simon_al...@hotmail.com on 6 Dec 2010 at 6:11

• Changed state: Fixed
• Added labels: File
• Removed labels: FileSystem