array_intersect: allow passing list of references for convenience

[pve-common.git] / src / PVE / Tools.pm

diff --git a/src/PVE/Tools.pm b/src/PVE/Tools.pm
index ff01ebd88ca74db036db5dc70725b49236332fce..676647eefb375d8d1ad00e9d06ab404baab9c906 100644 (file)
--- a/src/PVE/Tools.pm
+++ b/src/PVE/Tools.pm
@@ -1654,18 +1654,26 @@ sub dev_t_minor($) {
 sub array_intersect {
     my ($arrays) = @_;
 
-    return [] if @$arrays == 0;
-    return $arrays->[0] if @$arrays == 1;
+    if (!ref($arrays->[0])) {
+       $arrays = [ grep { ref($_) eq 'ARRAY' } @_ ];
+    }
+
+    return [] if scalar(@$arrays) == 0;
+    return $arrays->[0] if scalar(@$arrays) == 1;
 
     my $array_unique = sub {
        my %seen = ();
        return grep { ! $seen{ $_ }++ } @_;
     };
 
-    my $return_arr;
-    @$return_arr = $array_unique->(@{$arrays->[0]});
+    # base idea is to get all unique members from the first array, then
+    # check the common elements with the next (uniquely made) one, only keep
+    # those. Repeat for every array and at the end we only have those left
+    # which exist in all arrays
+    my $return_arr = [ $array_unique->(@{$arrays->[0]}) ];
     for my $i (1 .. $#$arrays) {
        my %count = ();
+       # $return_arr is already unique, explicit at before the loop, implicit below.
        foreach my $element (@$return_arr, $array_unique->(@{$arrays->[$i]})) {
            $count{$element}++;
        }
@@ -1673,6 +1681,7 @@ sub array_intersect {
        foreach my $element (keys %count) {
            push @$return_arr, $element if $count{$element} > 1;
        }
+       last if scalar(@$return_arr) == 0; # empty intersection, early exit
     }
 
     return $return_arr;