Added first iteration of wait-path

Wait-Path.ps1

@@ -0,0 +1,136 @@
+Function Wait-Path {
+    <#
+    .SYNOPSIS
+        Wait for a path to exist
+
+    .DESCRIPTION
+        Wait for a path to exist
+
+        Default behavior will throw an error if we time out waiting for the path
+        Passthru behavior will return true or false
+        Behaviors above apply to the set of paths; unless all paths test successfully, we error out or return false
+
+    .PARAMETER Path
+        Path(s) to test
+    
+        Note
+            Each path is independently verified with Test-Path.
+            This means you can pass in paths from other providers.
+
+    .PARAMETER Timeout
+        Time to wait before timing out, in seconds
+
+    .PARAMETER Interval
+        Time to wait between each test, in seconds
+
+    .PARAMETER Passthru
+        When specified, return true if we see all specified paths, otherwise return false
+
+        Note:
+            If this is specified and we time out, we return false.
+            If this is not specified and we time out, we throw an error.
+
+    .EXAMPLE
+        Wait-Path \\Path\To\Share -Timeout 30
+
+        # Wait for \\Path\To\Share to exist, test every 1 second (default), time out at 30 seconds.
+
+    .EXAMPLE
+        $TempFile = [System.IO.Path]::GetTempFileName()
+    
+        if ( Wait-Path -Path $TempFile -Interval .5 -passthru )
+        {
+            Set-Content -Path $TempFile -Value "Test!"
+        }
+        else
+        {
+            Throw "Could not find $TempFile"
+        }
+
+        # Create a temp file, wait until we can see that file, testing every .5 seconds, write data to it.
+
+    .EXAMPLE
+        Wait-Path C:\Test, HKLM:\System
+
+        # Wait until C:\Test and HKLM:\System exist
+
+    .FUNCTIONALITY
+        PowerShell Language
+
+    #>
+    [cmdletbinding()]
+    param (
+        [string[]]$Path,
+        [int]$Timeout = 5,
+        [int]$Interval = 1,
+        [switch]$Passthru
+    )
+
+    $StartDate = Get-Date
+    $First = $True
+
+    Do
+    {
+        #Only sleep if this isn't the first run
+            if($First -eq $True)
+            {
+                $First = $False
+            }
+            else
+            {
+                Start-Sleep -Seconds $Interval
+            }
+
+        #Test paths and collect output
+            [bool[]]$Tests = foreach($PathItem in $Path)
+            {
+                Try
+                {
+                    if(Test-Path $PathItem -ErrorAction stop)
+                    {
+                        Write-Verbose "'$PathItem' exists"
+                        $True
+                    }
+                    else
+                    {
+                        Write-Verbose "Waiting for '$PathItem'"
+                        $False
+                    }
+                }
+                Catch
+                {
+                    Write-Error "Error testing path '$PathItem': $_"
+                    $False
+                }
+            }
+
+        # Identify whether we can see everything
+            $Return = $Tests -notcontains $False -and $Tests -contains $True
+
+        # Poor logic, but we break the Until here
+            # Did we time out?
+            # Error if we are not passing through
+            if ( ((Get-Date) - $StartDate).TotalSeconds -gt $Timeout)
+            {
+                if( $Passthru )
+                {
+                    $False
+                    break
+                }
+                else
+                {
+                    Throw "Timed out waiting for paths $($Path -join ", ")"
+                }
+            }
+            elseif($Return)
+            {
+                if( $Passthru )
+                {
+                    $True
+                }
+                break
+            }
+    }
+    Until( $False ) # We break out above
+
+}