[pve-devel] [PATCH 1/2] CalendarEvent.pm: implement parser/utils for systemd like calender exents

[Dietmar Maurer]

Not complete, but useful.

Signed-off-by: Dietmar Maurer <dietmar at proxmox.com>
---
 src/Makefile             |   1 +
 src/PVE/CalendarEvent.pm | 217 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 218 insertions(+)
 create mode 100644 src/PVE/CalendarEvent.pm

diff --git a/src/Makefile b/src/Makefile
index a45effb..05344f5 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -7,6 +7,7 @@ MAN1DIR=${MANDIR}/man1/
 PERLDIR=${PREFIX}/share/perl5
 
 LIB_SOURCES=			\
+	CalendarEvent.pm	\
 	OTP.pm			\
 	Ticket.pm		\
 	RESTEnvironment.pm	\
diff --git a/src/PVE/CalendarEvent.pm b/src/PVE/CalendarEvent.pm
new file mode 100644
index 0000000..cda3098
--- /dev/null
+++ b/src/PVE/CalendarEvent.pm
@@ -0,0 +1,217 @@
+package PVE::CalendarEvent;
+
+use strict;
+use warnings;
+use Data::Dumper;
+use Time::Local;
+
+# Note: This class implements a parser/utils for systemd like calender exents
+# Date specification is currently not implemented
+
+my $dow_names = {
+    sun => 0,
+    mon => 1,
+    tue => 2,
+    wed => 3,
+    thu => 4,
+    fri => 5,
+    sat => 6,
+};
+
+# The parser.
+# returns a $calspec hash which can be passed to compute_next_event()
+sub parse_calendar_event {
+    my ($event) = @_;
+
+    my $parse_single_timespec = sub {
+	my ($p, $max, $matchall_ref, $res_hash) = @_;
+
+	if ($p =~ m/^((?:\*|[0-9]+))(?:\/([1-9][0-9]*))?$/) {
+	    my ($start, $repetition) = ($1, $2);
+	    if (defined($repetition)) {
+		$repetition = int($repetition);
+		$start = $start eq '*' ? 0 : int($start);
+		die "value '$start' out of range\n" if $start >= $max;
+		die "repetition '$repetition' out of range\n" if $repetition >= $max;
+		while ($start < $max) {
+		    $res_hash->{$start} = 1;
+		    $start += $repetition;
+		}
+	    } else {
+		if ($start eq '*') {
+		    $$matchall_ref = 1;
+		} else {
+		    $start = int($start);
+		    $res_hash->{$start} = 1;
+		}
+	    }
+	} elsif ($p =~ m/^([0-9]+)\.\.([1-9][0-9]*)$/) {
+	    my ($start, $end) = (int($1), int($2));
+	    die "range start '$start' out of range\n" if $start >= $max;
+	    die "range end '$end' out of range\n" if $end >= $max || $end < $start;
+	    for (my $i = $start; $i <= $end; $i++) {
+		$res_hash->{$i} = 1;
+	    }
+	} else {
+	    die "unable to parse calendar event '$p'\n";
+	}
+    };
+
+    my $h = undef;
+    my $m = undef;
+
+    my $matchall_minutes = 0;
+    my $matchall_hours = 0;
+    my $minutes_hash = {};
+    my $hours_hash = {};
+
+    my $dowsel = join('|', keys %$dow_names);
+
+    my $dow_hash;
+
+    my $parse_dowspec = sub {
+	my ($p) = @_;
+
+	if ($p =~ m/^($dowsel)$/i) {
+	    $dow_hash->{$dow_names->{lc($1)}} = 1;
+	} elsif ($p =~ m/^($dowsel)\.\.($dowsel)$/i) {
+	    my $start = $dow_names->{lc($1)};
+	    my $end = $dow_names->{lc($2)} || 7;
+	    if ($end < $start) {
+		my $t = $start; $start = $end; $end = $t;
+	    }
+	    for (my $i = $start; $i <= $end; $i++) {
+		$dow_hash->{($i % 7)} = 1;
+	    }
+	} else {
+	    die "unable to parse weekday specification '$p'\n";
+	}
+    };
+
+    my @parts = split(/\s+/, $event);
+
+    if ($parts[0] =~ m/$dowsel/i) {
+	my $dow_spec = shift @parts;
+	foreach my $p (split(',', $dow_spec)) {
+	    $parse_dowspec->($p);
+	}
+    } else {
+	$dow_hash = { 0 => 1, 1 => 1, 2 => 1, 3 => 1, 4 => 1, 5=> 1, 6 => 1 };
+    }
+
+    if (scalar(@parts) && $parts[0] =~ m/\-/) {
+	my $date_spec = shift @parts;
+	die "date specification not implemented";
+    }
+
+    my $time_spec = shift(@parts) // "00:00";
+    my $chars = "[0-9\*\/\.,]";
+    if ($time_spec =~ m/^($chars+):($chars+)$/) {
+	my ($p1, $p2) = ($1, $2);
+	$parse_single_timespec->($p1, 24, \$matchall_hours, $hours_hash);
+	$parse_single_timespec->($p2, 60, \$matchall_minutes, $minutes_hash);
+    } elsif ($time_spec =~ m/^($chars)+$/) { # minutes only
+	$matchall_hours = 1;
+	foreach my $p (split(',', $event)) {
+	    $parse_single_timespec->($p, 60, \$matchall_minutes, $minutes_hash);
+	}
+
+    } else {
+	die "unable to parse calendar event\n";
+    }
+
+    die "unable to parse calendar event - unused parts\n" if scalar(@parts);
+
+    if ($matchall_hours) {
+	$h = '*';
+    } else {
+	$h = [ sort keys %$hours_hash ];
+    }
+
+    if ($matchall_minutes) {
+	$m = '*';
+    } else {
+	$m = [ sort keys %$minutes_hash ];
+    }
+
+    return { h => $h, m => $m, dow => [ sort keys %$dow_hash ]};
+}
+
+sub compute_next_event {
+    my ($calspec, $last, $utc) = @_;
+
+    my $hspec = $calspec->{h};
+    my $mspec = $calspec->{m};
+    my $dowspec = $calspec->{dow};
+
+    $last += 60; # at least one minute later
+
+    while (1) {
+
+	my ($min, $hour, $mday, $mon, $year, $wday);
+	my $startofday;
+
+	if ($utc) {
+	    (undef, $min, $hour, $mday, $mon, $year, $wday) = gmtime($last);
+	    $startofday = timegm(0, 0, 0, $mday, $mon, $year);
+	} else {
+	    (undef, $min, $hour, $mday, $mon, $year, $wday) = localtime($last);
+	    $startofday = timelocal(0, 0, 0, $mday, $mon, $year);
+	}
+
+	$last = $startofday + $hour*3600 + $min*60;
+
+	my $check_dow = sub {
+	    foreach my $d (@$dowspec) {
+		return $last if $d == $wday;
+		if ($d > $wday) {
+		    return $startofday + ($d-$wday)*86400;
+		}
+	    }
+	    return $startofday + (7-$wday)*86400; # start of next week
+	};
+
+	if ((my $next = $check_dow->()) != $last) {
+	    $last = $next;
+	    next; # repeat
+	}
+
+	my $check_hour = sub {
+	    return $last if $hspec eq '*';
+	    foreach my $h (@$hspec) {
+		return $last if $h == $hour;
+		if ($h > $hour) {
+		    return $startofday + $h*3600;
+		}
+	    }
+	    return $startofday + 24*3600; # test next day
+	};
+
+	if ((my $next = $check_hour->()) != $last) {
+	    $last = $next;
+	    next; # repeat
+	}
+
+	my $check_minute = sub {
+	    return $last if $mspec eq '*';
+	    foreach my $m (@$mspec) {
+		return $last if $m == $min;
+		if ($m > $min) {
+		    return $startofday +$hour*3600 + $m*60;
+		}
+	    }
+	    return $startofday + ($hour + 1)*3600; # test next hour
+	};
+
+	if ((my $next = $check_minute->()) != $last) {
+	    $last = $next;
+	    next; # repeat
+	} else {
+	    return $last;
+	}
+    }
+
+    die "unable to compute next sync time\n";
+}
+
+1;
-- 
2.11.0