Traverse-FolderTree.ps1

# file named Traverse-FolderTree.ps1
#

Function Traverse-FolderTree
    {
    [CmdletBinding()]
    Param
        (
        [Parameter (Mandatory = $True, Position = 1)]
        [string]$FolderName,

        [switch]$NotFirstRun
        )

    switch ($NotFirstRun)
        {
        $True {Break}
        $False
            {
            # this creates [or resets] a persistent variable in the script scope.
            # when the function finishes the total files & folders can be read outside the function.persistent
            #<# using default Array type
            $script:TFTResults = @{"Files"=@();
                                   "Folders"=@();
                                   "RecurseCount"=[int]0
                                   "TopFolder"=[string]$FolderName}
            #>

            <# using ArrayList instead of default Array type
            $TFTResults = @{"Files"=[System.Collections.ArrayList]@();
                            "Folders"=[System.Collections.ArrayList]@();
                            "RecurseCount"=[int]0}
            #>
            }
        }

    #<# array version
    $FolderList = Get-ChildItem -LiteralPath $FolderName -Directory | Sort-Object directory
    $TFTResults.Folders += $FolderList

    $FileList = Get-ChildItem -LiteralPath $FolderName -File | Sort-Object directory
    $TFTResults.Files += $FileList
    #>

    <# arraylist version
    [System.Collections.ArrayList]$FolderList = Get-ChildItem -LiteralPath $FolderName -Directory | Sort-Object directory
    if ($FolderList.Count -gt 0)
        {
        $TFTResults.Folders.AddRange($FolderList)
        }

    [System.Collections.ArrayList]$FileList = Get-ChildItem -LiteralPath $FolderName -File | Sort-Object directory
    if ($FileList.Count -gt 0)
        {
        $TFTResults.Files.AddRange($FileList)
        }
    #>


    # show what is happening - replace the following with your prefered activity indicator
    #

    <# details
    Write-Output ("")
    Write-Output ("Current folder name   = $FolderName")
    Write-Output ("Current folder depth  = {0,7:N0}" -f $($FolderName.Split("\").Count))
    Write-Output ("")
    Write-Output ("Folders here          = {0,7:N0}" -f $($FolderList.count))
    Write-Output ("Files here            = {0,7:N0}" -f $($FileList.count))
    Write-Output ("")
    Write-Output ("Recurse count         = {0,7:N0}" -f $($TFTResults.RecurseCount))
    Write-Output ("Total folder count    = {0,7:N0}" -f $($TFTResults.Folders.Count))
    Write-Output ("Total file count      = {0,7:N0}" -f $($TFTResults.Files.Count))
    Write-Output ("**********")
    Write-Output ("")
    #>

    #<# progress bar
    # this will bounce around somewhat as it climbs up and down the folder tree
    $Percentage = "{0:N0}" -f (($TFTResults.RecurseCount / $TFTResults.Folders.Count) * 100)
    Write-Progress -Activity "Traversing..." -Status "Percent Complete $Percentage%" -PercentComplete $Percentage
    #>

    #
    #


    foreach ($Folder in $FolderList)
        {
        $TFTResults.RecurseCount += 1
        Traverse-FolderTree $Folder.FullName -NotFirstRun
        }
    }# end of Function Traverse-FolderTree



##########
#$StartingFolder = "D:\New_Downloads\__By-Artist"
# Total folder count     =     118
# Total file count       =   1,610
# - works with both ARRAY and ARRAYLIST
#
#$StartingFolder = "D:\New_Downloads\__By-Artist\Jackie Gleason"
#$StartingFolder = "D:\New_Downloads\__By-Artist\Jackie Gleason\Jackie Gleason - The Romantic Moods of Jackie Gleason 1 (1996)"

#$StartingFolder = "Z:\By_Artist"
# Total folder count  = 8,465
# Total file count    = 75,193
# - fails with ARRAYLIST
# measure-command TFT = 124.141 seconds [with sort-object]
# measure-command TFT = 105.200 seconds [WITHOUT sort-object]
# measure-command GC  =  12.783 seconds
# - GC is faster by about 10x
#
#$StartingFolder = "Z:\By_Artist\Adam_&_the_Ants"
#$StartingFolder = "Z:\By_Artist\Adam_&_the_Ants\Antbox_[Disk_1_of_3]"
#

$StartingFolder = $env:ProgramFiles
# Total folder count     =   3,109
# Total file count       =  29,317
# - this one bounces the progress bar around enormously
#
#$StartingFolder = $env:CommonProgramFiles
##########




#Measure-Command {Get-ChildItem -LiteralPath $StartingFolder -Recurse}
#Measure-Command {Traverse-FolderTree $StartingFolder}
Traverse-FolderTree $StartingFolder

Write-Output ("")
Write-Output ("Starting folder        = $($TFTResults.TopFolder)")
Write-Output ("Total folder count     = {0,7:N0}" -f $($TFTResults.Folders.Count))
Write-Output ("Total file count       = {0,7:N0}" -f $($TFTResults.Files.Count))