Use Signal 'ctrl+c' as CancellationTokenSource for sync-over-async calls

signal-cancellation.ps1

using namespace System.Linq.Expressions

#class to register on posix signal and provide a cancellation token
#many signal are working under windows (SIGINT, SIGQUIT ...)
class SignalToken : System.IDisposable {
    hidden [System.Threading.CancellationTokenSource]$cts
    hidden [System.Runtime.InteropServices.PosixSignalRegistration]$reg

    [System.Runtime.InteropServices.PosixSignal]$Signal = [System.Runtime.InteropServices.PosixSignal]::SIGINT
    [System.Threading.CancellationToken]$Token

    SignalToken() {
        $this.Reset()
    }
    SignalToken([System.Runtime.InteropServices.PosixSignal]$signal) {
        $this.Signal = $signal
        $this.Reset()
    }
    
    [void] Reset() {
        if(!($this.cts -and $this.cts.TryReset())) {
            $this.cts = new-object System.Threading.CancellationTokenSource
            $handler = [Expression]::Lambda(
                [System.Action[System.Runtime.InteropServices.PosixSignalContext]],
                [Expression]::Block(
                    [Expression]::Call([Expression]::Constant($this.cts), [System.Threading.CancellationTokenSource].GetMethod("Cancel", [Type]::EmptyTypes))
                ),
                [ParameterExpression[]](
                    [Expression]::Variable([System.Runtime.InteropServices.PosixSignalContext])
                )
            ).Compile()

            $this.reg = [System.Runtime.InteropServices.PosixSignalRegistration]::Create($this.Signal, $handler)
        
            $this.Token = $this.cts.Token
        }
    }

    [void] Dispose() {
        $this.reg.Dispose()
        $this.cts.Dispose()
    }
}

#script block is for demonstation purposes
function Invoke-Demo {
    param()

    begin {
        Write-Host "begin" 
        $signal = [SignalToken]::new()
    }
    process {
        Write-Host "locking for 10sec, press ctrl+c to cancel"
        [System.Threading.Tasks.Task]::Delay(10000, $signal.Token).GetAwaiter().GetResult()

        Write-Host "no cancelletion"

        #demo how to reuse cancellation source
        if($signal.Token.IsCancellationRequested) {
            Write-Host "recreate used cts"
            $signal.Reset()
        }
    }
    end {
        Write-Host "end"
    }
    clean {
        Write-Host "clean"
        $signal.Dispose()
    }
}

Invoke-Demo