Identify VFS (Sparse) files differently

[acrey1]

Onedrive, Nextcloud, Dropbox, etc. all support Virtual Files, where files are held in the system merely as placeholders, and have actual file sizes of zero. These are also known as sparse files under Windows (link here).

Under the Files tab in MC, these are shown with their un-virtual size:

Nothing happens when any of these are clicked on (or selected -> Download).

Using Get-ChildItem (or dir), the same files are presented with their un-virtual size in brackets:

It would be great to identify these virtual / sparse files differently, and also disable the Download option for these.

[si458]

unfortunately this isnt going to be possible without introducing unnecessary powershell commands
currently we only get this information
{"size":9215,"ctime":"2022-08-12T12:21:54Z","mtime":"2022-08-12T12:21:54Z","atime":"2022-08-12T12:21:54Z"}
this is because the nodejs implemtations of the fs commands are built manually using duktape and these are the only things thats added
if we wanted to add more it would require meshagent changes and those arent simple sadly :(

edit: also if you look at the nodejs implemtation of fsstat they also dont return info about the file being virtual or not
https://nodejs.org/docs/latest-v20.x/api/fs.html#class-fsstats

[acrey1]

Does this help?

fs.stat('sparse-file.txt', (err, stats) => {
  if (err) throw `err;`

  // A file is sparse if the actual allocated blocks are less than 
  // what is required to hold the logical file size.
  // 512 bytes per block is standard on most Unix systems.
  const logicalSize = stats.size;
  const actualAllocated = stats.blocks * 512;
  const isSparse = actualAllocated < logicalSize;

  console.log(`File Size: ${logicalSize} bytes`);
  console.log(`Allocated: ${actualAllocated} bytes`);
  console.log(`Is Sparse: ${isSparse}`); 
  // Note: Mode indicates file type/permissions (e.g., 33188 for regular), 
  // not sparsity [2].
});

[si458]

unfortunately as explained, meshagent uses duktape to convert the JS/Node into C++,
so you have to write the functions manually as you dont have the full FS library written
so this would require a meshagent rewrite/upgrade and a C++ expert

> eval "var abc = require('fs').stat('C:\\DumpStack.log', function(abc,xyz){ });"
Command returned an exception error: TypeError: undefined not callable (property 'stat' of [object Object])