[pve-devel] [PATCH ha-manager 02/15] tools: add hash set helper subroutines

[Daniel Kral]

Implement helper subroutines, which implement basic set operations done
on hash sets, i.e. hashes with elements set to a true value, e.g. 1.

These will be used for various tasks in the HA Manager colocation rules,
e.g. for verifying the satisfiability of the rules or applying the
colocation rules on the allowed set of nodes.

Signed-off-by: Daniel Kral <d.kral at proxmox.com>
---
If they're useful somewhere else, I can move them to PVE::Tools
post-RFC, but it'd be probably useful to prefix them with `hash_` there.
AFAICS there weren't any other helpers for this with a quick grep over
all projects and `PVE::Tools::array_intersect()` wasn't what I needed.

 src/PVE/HA/Tools.pm | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/src/PVE/HA/Tools.pm b/src/PVE/HA/Tools.pm
index 0f9e9a5..fc3282c 100644
--- a/src/PVE/HA/Tools.pm
+++ b/src/PVE/HA/Tools.pm
@@ -115,6 +115,48 @@ sub write_json_to_file {
     PVE::Tools::file_set_contents($filename, $raw);
 }
 
+sub is_disjoint {
+    my ($hash1, $hash2) = @_;
+
+    for my $key (keys %$hash1) {
+	return 0 if exists($hash2->{$key});
+    }
+
+    return 1;
+};
+
+sub intersect {
+    my ($hash1, $hash2) = @_;
+
+    my $result = { map { $_ => $hash2->{$_} } keys %$hash1 };
+
+    for my $key (keys %$result) {
+	delete $result->{$key} if !defined($result->{$key});
+    }
+
+    return $result;
+};
+
+sub set_difference {
+    my ($hash1, $hash2) = @_;
+
+    my $result = { map { $_ => 1 } keys %$hash1 };
+
+    for my $key (keys %$result) {
+	delete $result->{$key} if defined($hash2->{$key});
+    }
+
+    return $result;
+};
+
+sub union {
+    my ($hash1, $hash2) = @_;
+
+    my $result = { map { $_ => 1 } keys %$hash1, keys %$hash2 };
+
+    return $result;
+};
+
 sub count_fenced_services {
     my ($ss, $node) = @_;
 
-- 
2.39.5