Index: openacs-4/packages/acs-admin/www/auth/authority-set-sort-order.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-admin/www/auth/authority-set-sort-order.tcl,v
diff -u -r1.5 -r1.6
--- openacs-4/packages/acs-admin/www/auth/authority-set-sort-order.tcl	7 Aug 2017 23:47:45 -0000	1.5
+++ openacs-4/packages/acs-admin/www/auth/authority-set-sort-order.tcl	21 Dec 2018 10:57:48 -0000	1.6
@@ -1,63 +1,52 @@
 ad_page_contract {
-    Move authorities up/down to control sort order
+    Move an authority up or down one step in the authorities sort_order hierarchy
 
     @author Simon Carstensen (simon@collaboraid.biz)
     @creation-date 2003-09-09
     @cvs-id $Id$
 } {
-    authority_id:naturalnum,notnull
-    direction
-}
-
-# Get the authority's sort_order
-db_1row select_sort_order {
-    select sort_order
-    from auth_authorities 
-    where authority_id = :authority_id
-}
-
-if { $direction eq "up" } {
-
-    db_transaction {
-        # Increase next authority's sort_order by one
-        db_dml move_next_authority_down {
-            update auth_authorities 
-            set sort_order = :sort_order
-            where sort_order = (select max(sort_order)
-                                from   auth_authorities
-                                where  sort_order < :sort_order)
+    {authority_id:naturalnum,notnull}
+    {direction:notnull,oneof(up|down)}
+}  -validate {
+    authority_exists -requires {authority_id:naturalnum} {
+        if {![db_0or1row dbqd...check_authority_id {select authority_id, sort_order from auth_authorities where authority_id = :authority_id}]} {
+            ad_complain "Invalid authority"
+            return
         }
-
-        # Decrease authority's sort_order by one
-        db_dml move_authority_up {
-            update auth_authorities 
-            set sort_order = :sort_order - 1
-            where authority_id = :authority_id
-        }
     }
+}
 
-} elseif { $direction eq "down"} {
-
-    db_transaction {
-        # Decrease previous authority's sort_order by one
-        db_dml move_prev_authority_up {
-            update auth_authorities 
-            set sort_order = :sort_order
-            where sort_order = (select min(sort_order)
-                                from   auth_authorities
-                                where  sort_order > :sort_order)
-        }
-
-        # Increase authority's sort_order by one
-        db_dml move_authority_down {
-            update auth_authorities 
-            set sort_order = :sort_order + 1
-            where authority_id = :authority_id;
-        }
+# Determine the authority which is next to the passed in authority
+# in the order hierarchy depending on the direction we want to move it.
+switch -- $direction {
+    "up" {
+        set op "<"
+        set orderby_direction desc
     }
+    "down" {
+        set op ">"
+        set orderby_direction asc
+    }
+}
 
-} 
+set sql [subst {select
+                    authority_id as swap_authority_id,
+                    sort_order as swap_sort_order
+                 from auth_authorities
+                 where sort_order $op :sort_order
+                 order by sort_order $orderby_direction
+                 limit 1}]
 
+if {[db_0or1row dbqd..get_swap_authority $sql]} {
+    # adjust sort_order of the passed in authority
+    set element_arr(sort_order) $swap_sort_order
+    auth::authority::edit -authority_id $authority_id -array element_arr
+    
+    # adjust sort_order of the swap partner authority
+    set element_arr(sort_order) $sort_order
+    auth::authority::edit -authority_id $swap_authority_id -array element_arr
+}
+
 ad_returnredirect .
 ad_script_abort