Windows Alpine Overlay Expand/Compress functions

AlpineOverlay.ps1

function Expand-AlpineOverlay
{
    [CmdletBinding()]
    param(
        [Parameter(Mandatory=$true,Position=0)]
        [string] $InputFile,
        [Parameter(Mandatory=$true,Position=1)]
        [string] $Destination,
        [switch] $Force
    )

    if (Test-Path $Destination) {
        if ($Force) {
            Remove-Item $Destination -Recurse -ErrorAction SilentlyContinue | Out-Null
        } else {
            throw "`"$Destination`" already exists!"
        }
    }

    cmd.exe /c "7z.exe x $InputFile -so | 7z x -si -ttar -o`"$Destination`""

    Push-Location
    Set-Location $Destination
    $RootPath = Get-Item .
    $ReparsePoints = Get-ChildItem . -Recurse | `
        Where-Object { $_.Attributes -band [IO.FileAttributes]::ReparsePoint }
    $ReparsePoints | ForEach-Object {
        $Source = $_.FullName
        $Target = $_.Target.Replace('/','\')
        $Target = $Target.Substring($RootPath.FullName.Length)
        Push-Location
        Set-Location $_.Directory
        Remove-Item $Source
        New-Item -ItemType SymbolicLink -Path $Source -Target $Target
        Pop-Location
    }
    Pop-Location
}

function Compress-AlpineOverlay
{
    [CmdletBinding()]
	param(
        [Parameter(Mandatory=$true,Position=0)]
        [string] $InputPath,
        [Parameter(Mandatory=$true,Position=1)]
        [string] $Destination,
        [switch] $Force
    )

    if (-Not (Test-Path $InputPath -PathType 'Container')) {
        throw "`"$InputPath`" does not exist or is not a directory"
    }

    if (-Not $Destination.EndsWith(".tar.gz")) {
        throw "`"$Destination`" does not end in .tar.gz"
    }

    if (-Not $Destination.EndsWith(".apkovl.tar.gz")) {
        Write-Warning -Message "`"$Destination`" does not end in .apkovl.tar.gz"
    }

    if (Test-Path $Destination) {
        if ($Force) {
            Remove-Item $Destination -ErrorAction SilentlyContinue | Out-Null
        } else {
            throw "VM `"$Destination`" already exists!"
        }
    }

    $TarFileName = $Destination.TrimEnd(".gz") | Split-Path -Leaf

    cmd.exe /c "7z a -ttar -snl -so $TarFileName `"$InputPath/*`" | 7z a -si $Destination"
}