readline-sync/lib/read.ps1

Param(
  [string] $display,
  [switch] $noEchoBack,
  [string] $mask,
  [switch] $keyIn,
  [switch] $encoded
)

$ErrorActionPreference = 'Stop' # for cmdlet
trap {
  # `throw $_` and `Write-Error $_` return exit-code 0
  $Host.UI.WriteErrorLine($_)
  exit 1
}

function decodeDOS ($arg) {
  [Regex]::Replace($arg, '#(\d+);', { [char][int] $args[0].Groups[1].Value })
}

$options = @{}
foreach ($arg in @('display', 'noEchoBack', 'mask', 'keyIn', 'encoded')) {
  $options.Add($arg, (Get-Variable $arg -ValueOnly))
}
if ($options.encoded) {
  $argList = New-Object string[] $options.Keys.Count
  $options.Keys.CopyTo($argList, 0);
  foreach ($arg in $argList) {
    if (($options[$arg] -is [string]) -and ($options[$arg] -ne ''))
      { $options[$arg] = decodeDOS $options[$arg] }
  }
}

[string] $inputTTY = ''
[bool] $isInputLine = $False
[bool] $isEditable = (-not $options.noEchoBack) -and (-not $options.keyIn)

function writeTTY ($text) {
  execWithTTY ('Write-Host ''' + ($text -replace '''', '''''') + ''' -NoNewline')
  $script:isInputLine = $True
}

# Instant method that opens TTY without CreateFile via P/Invoke in .NET Framework
# **NOTE** Don't include special characters of DOS in $command when $getRes is True.
function execWithTTY ($command, $getRes = $False) {
  if ($getRes) {
    $res = (cmd.exe /C "<CON powershell.exe -Command $command")
    if ($LastExitCode -ne 0) { exit 1 }
  } else {
    $command | cmd.exe /C ">CON powershell.exe -Command -"
    if ($LastExitCode -ne 0) { exit 1 }
    $res = ''
  }
  return $res
}

if ($options.display -ne '') {
  writeTTY $options.display
  $options.display = ''
}

if ($options.noEchoBack -and (-not $options.keyIn) -and ($options.mask -eq '*')) {
  $inputTTY = execWithTTY ('$inputTTY = Read-Host -AsSecureString;' +
    '$bstr = [System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($inputTTY);' +
    '[System.Runtime.InteropServices.Marshal]::PtrToStringAuto($bstr)') $True
  return '''' + $inputTTY + ''''
}

if ($options.keyIn) { $reqSize = 1 }
else { $reqSize = 1024 } # dummy

while ($True) {
  if ($isEditable) {
    $chunk = execWithTTY 'Read-Host' $True
    $chunk += "`n"
  } else { # raw
    $chunk = execWithTTY '[System.Console]::ReadKey($True).KeyChar' $True
  }

  if ($chunk -eq '') { break }
  # other ctrl-chars
  $chunk = $chunk -replace '[\x00-\x08\x0b\x0c\x0e-\x1f\x7f]', ''
  if ($chunk -eq '') { continue }

  if (-not $isEditable) {
    $displayTmp = $chunk -replace '[\r\n]', ''
    if ($displayTmp -ne '') {
      if ($options.noEchoBack) {
        if ($options.mask -eq '') { $displayTmp = '' }
        else { $displayTmp = $options.mask * $displayTmp.Length }
      }
      if ($displayTmp -ne '') { writeTTY $displayTmp }
    }
  }

  $inputTTY += $chunk
  if (($inputTTY -match '[\r\n]$') -or
    ($options.keyIn -and ($inputTTY.Length -ge $reqSize))) { break }
}

if ((-not $isEditable) -and (-not ($options.keyIn -and (-not $isInputLine))))
  { execWithTTY 'Write-Host ''''' } # new line

return '''' + $inputTTY + ''''