Remove empty directories using msbuild - msbuild

Question

How can I process a path recursively so that once the processing completes there are no empty directories under the path.
For example, say we have C:\Dir1\Dir2\Dir3 and there are no files in any of these directories. The outcome should be the removal of all three directories.
I would like to accomplish this without the use of custom tasks.

Answer 1

Something like this should work, didn't check the performance of counting thousands of files though just to get array length...
<Project DefaultTargets="Foo" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<Target Name="Foo">
<ItemGroup>
<Directories Include="$([System.IO.Directory]::GetDirectories('D:\foo', '*', System.IO.SearchOption.AllDirectories))" />
<Directories>
<Files>$([System.IO.Directory]::GetFiles("%(Directories.Identity)", "*", System.IO.SearchOption.AllDirectories).get_Length())</Files>
</Directories>
</ItemGroup>
<RemoveDir Directories="#(Directories)" Condition="%(Files)=='0'" />
</Target>
</Project>

Answer 2

Using an Exec Task running PowerShell:
MSBuild
<Project DefaultTargets="DefaultTarget" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
<CleanPath>C:\MyDirAboveDir1</CleanPath>
</PropertyGroup>
<Target Name="DefaultTarget">
<Exec Command="PowerShell .\RemoveDir.ps1 '$(CleanPath)'" />
</Target>
</Project>
PowerShell RemoveDir.ps1
Param ([string]$folderpath = $(throw "provide folderpath"))
$folders = Get-ChildItem $folderpath -recurse -force | ? {$_.PSIsContainer}
if ($folders -ne $null)
{
[array]::Reverse($folders)
foreach($folder in $folders)
{
Write-Host "Examining contents of $($folder.fullname)"
$childitems = Get-Childitem $folder.fullname -recurse -force | ? { $_.PSIsContainer -eq $false }
if($childitems -eq $null)
{
"Remove folder: " + $folder.FullName
Remove-Item $folder.FullName -Recurse -Force
}
else
{
Write-host "Files found in $folder, skipping delete"
}
$childitems = $null
}
}
else
{
Write-Host "no sub folders found"
}
Courtesy to Guy Ellis Rocks: Powershell script to remove empty directories