Saritasa.General.psm1

<#
.Synopsis
    Fetches "Preference" variable values from the caller's scope.
.DESCRIPTION
    Script module functions do not automatically inherit their caller's variables, but they can be
    obtained through the $PSCmdlet variable in Advanced Functions. This function is a helper function
    for any script module Advanced Function; by passing in the values of $ExecutionContext.SessionState
    and $PSCmdlet, Get-CallerPreference will set the caller's preference variables locally.
.PARAMETER Cmdlet
    The $PSCmdlet object from a script module Advanced Function.
.PARAMETER SessionState
    The $ExecutionContext.SessionState object from a script module Advanced Function. This is how the
    Get-CallerPreference function sets variables in its callers' scope, even if that caller is in a different
    script module.
.PARAMETER Name
    Optional array of parameter names to retrieve from the caller's scope. Default is to retrieve all
    Preference variables as defined in the about_Preference_Variables help file (as of PowerShell 4.0)
    This parameter may also specify names of variables that are not in the about_Preference_Variables
    help file, and the function will retrieve and set those as well.
.EXAMPLE
    Get-CallerPreference -Cmdlet $PSCmdlet -SessionState $ExecutionContext.SessionState
 
    Imports the default PowerShell preference variables from the caller into the local scope.
.EXAMPLE
    Get-CallerPreference -Cmdlet $PSCmdlet -SessionState $ExecutionContext.SessionState -Name 'ErrorActionPreference','SomeOtherVariable'
 
    Imports only the ErrorActionPreference and SomeOtherVariable variables into the local scope.
.EXAMPLE
    'ErrorActionPreference','SomeOtherVariable' | Get-CallerPreference -Cmdlet $PSCmdlet -SessionState $ExecutionContext.SessionState
 
    Same as Example 2, but sends variable names to the Name parameter via pipeline input.
.INPUTS
    String
.OUTPUTS
    None. This function does not produce pipeline output.
.LINK
    about_Preference_Variables
.NOTES
    Import Preference variables from the caller of a Script Module function
    https://gallery.technet.microsoft.com/scriptcenter/Inherit-Preference-82343b9d
    MICROSOFT LIMITED PUBLIC LICENSE
#>

function Get-CallerPreference
{
    [CmdletBinding(DefaultParameterSetName = 'AllVariables')]
    param (
        [Parameter(Mandatory = $true)]
        [ValidateScript({ $_.GetType().FullName -eq 'System.Management.Automation.PSScriptCmdlet' })]
        $Cmdlet,

        [Parameter(Mandatory = $true)]
        [System.Management.Automation.SessionState]
        $SessionState,

        [Parameter(ParameterSetName = 'Filtered', ValueFromPipeline = $true)]
        [string[]]
        $Name
    )

    begin
    {
        $filterHash = @{}
    }

    process
    {
        if ($null -ne $Name)
        {
            foreach ($string in $Name)
            {
                $filterHash[$string] = $true
            }
        }
    }

    end
    {
        # List of preference variables taken from the about_Preference_Variables help file in PowerShell version 4.0

        $vars = @{
            'ErrorView' = $null
            'FormatEnumerationLimit' = $null
            'LogCommandHealthEvent' = $null
            'LogCommandLifecycleEvent' = $null
            'LogEngineHealthEvent' = $null
            'LogEngineLifecycleEvent' = $null
            'LogProviderHealthEvent' = $null
            'LogProviderLifecycleEvent' = $null
            'MaximumAliasCount' = $null
            'MaximumDriveCount' = $null
            'MaximumErrorCount' = $null
            'MaximumFunctionCount' = $null
            'MaximumHistoryCount' = $null
            'MaximumVariableCount' = $null
            'OFS' = $null
            'OutputEncoding' = $null
            'ProgressPreference' = $null
            'PSDefaultParameterValues' = $null
            'PSEmailServer' = $null
            'PSModuleAutoLoadingPreference' = $null
            'PSSessionApplicationName' = $null
            'PSSessionConfigurationName' = $null
            'PSSessionOption' = $null

            'ErrorActionPreference' = 'ErrorAction'
            'DebugPreference' = 'Debug'
            'ConfirmPreference' = 'Confirm'
            'WhatIfPreference' = 'WhatIf'
            'VerbosePreference' = 'Verbose'
            'WarningPreference' = 'WarningAction'
            'InformationPreference' = 'InformationAction'
        }


        foreach ($entry in $vars.GetEnumerator())
        {
            if (([string]::IsNullOrEmpty($entry.Value) -or -not $Cmdlet.MyInvocation.BoundParameters.ContainsKey($entry.Value)) -and
                ($PSCmdlet.ParameterSetName -eq 'AllVariables' -or $filterHash.ContainsKey($entry.Name)))
            {
                $variable = $Cmdlet.SessionState.PSVariable.Get($entry.Key)

                if ($null -ne $variable)
                {
                    if ($SessionState -eq $ExecutionContext.SessionState)
                    {
                        Set-Variable -Scope 1 -Name $variable.Name -Value $variable.Value -Force -Confirm:$false -WhatIf:$false
                    }
                    else
                    {
                        $SessionState.PSVariable.Set($variable.Name, $variable.Value)
                    }
                }
            }
        }

        if ($PSCmdlet.ParameterSetName -eq 'Filtered')
        {
            foreach ($varName in $filterHash.Keys)
            {
                if (-not $vars.ContainsKey($varName))
                {
                    $variable = $Cmdlet.SessionState.PSVariable.Get($varName)

                    if ($null -ne $variable)
                    {
                        if ($SessionState -eq $ExecutionContext.SessionState)
                        {
                            Set-Variable -Scope 1 -Name $variable.Name -Value $variable.Value -Force -Confirm:$false -WhatIf:$false
                        }
                        else
                        {
                            $SessionState.PSVariable.Set($variable.Name, $variable.Value)
                        }
                    }
                }
            }
        }

    } # end

} # function Get-CallerPreference

<#
.SYNOPSIS
Returns $true if hostname represents local PC.
#>

function Test-IsLocalhost
{
    [CmdletBinding()]
    param
    (
        [string] $ComputerName
    )

    $ComputerName -match "^(\.|localhost|$env:COMPUTERNAME)`$"
}