From 47946f0b85344cf22fe86cbcbfd4f190fce990da Mon Sep 17 00:00:00 2001
From: Ben Soares <b.soares@dundee.ac.uk>
Date: Mon, 5 Aug 2024 19:21:16 +0100
Subject: [PATCH] JAL-3631 update.ps1 has fixed Readlink-f function, works
 across platforms

---
 utils/getdown/bin/update.ps1 |   36 ++++++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 12 deletions(-)

diff --git a/utils/getdown/bin/update.ps1 b/utils/getdown/bin/update.ps1
index 4928573..e771aed 100644
--- a/utils/getdown/bin/update.ps1
+++ b/utils/getdown/bin/update.ps1
@@ -46,20 +46,32 @@ if ( -not ( $userspace -or -$installation ) ) {
 
 # parent dir of this actual script (which should be the getdown appdir/bin). Follow all symlinks.  Like GNU readlink -f
 function Readlink-f {
-  Param($Link)
-  $dirs = @()
-  $dir = Convert-Path $Link
-  while ( $dir ) {
-    $dirs = @( Split-Path $dir -Leaf ) + $dirs
-    $dir = Split-Path $dir -Parent
+  Param(
+    [Parameter(mandatory=$true, ValueFromPipeline=$true)]$Link,
+    [Parameter()]$iteration_count = 1
+  )
+  if ( $iteration_count -ge 100 ) {
+    Write-Error "Readlink-f iterated 100 times"
+    return $Link
   }
-  $real = Get-Item "/"
-  foreach ($d in $dirs) {
-    $real = Join-Path -Path $real -ChildPath $d
-    $item = Get-Item $real
-    if ($item.Target -ne $null) {
-      $real = Convert-Path $item.Target
+  if ( $Link -eq "" -or $Link -eq $null ) {
+    return $null
+  }
+  $path_components = @()
+  $dir = Get-Item $Link
+  while ( $dir -ne $null ) {
+    while ( $dir.Target -ne $null ) {
+      # [System.IO.Path]::Combine caters for a multitude of sins that it's almost impossible to deal with with Join-Path
+      $dir = Get-Item ([System.IO.Path]::GetFullPath( [System.IO.Path]::Combine( (Split-Path $dir -Parent), $dir.Target )))
     }
+    $parent = Split-Path -Path $dir -Parent
+    $path_components = @( (Split-Path -Path $dir -Leaf) ) + $path_components
+    $dir = Readlink-f $parent ($iteration_count + 1)
+  }
+  $real = Get-Item "/"
+  foreach ( $component in $path_components) {
+    # [System.IO.Path]::Combine caters for a multitude of sins that it's almost impossible to deal with with Join-Path
+    $real = Get-Item ([System.IO.Path]::GetFullPath( [System.IO.Path]::Combine( $real, $component )))
   }
   $real
 }
-- 
1.7.10.2