From 8a590a8d71ee7581277ec89e391168169f5a0d3b Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Sat, 19 Jan 2013 19:54:36 +0100
Subject: [PATCH] bex prun: Better allocation of display slots

---
 lib/bin/bex-prun | 94 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 61 insertions(+), 33 deletions(-)

diff --git a/lib/bin/bex-prun b/lib/bin/bex-prun
index 685c8be..162fc8a 100755
--- a/lib/bin/bex-prun
+++ b/lib/bin/bex-prun
@@ -126,8 +126,8 @@ use Curses;
 my $C;
 
 my $nrows;
-my @by_row = ();
-my %by_host = ();
+my @by_row;
+my %by_host;
 
 my %host_state;
 my %host_cnt;
@@ -138,6 +138,22 @@ my %job_cnt;
 my %host_last_fail_job;
 my %host_last_fail_stat;
 
+my @states;
+my %state_to_pri;
+
+BEGIN {
+	@by_row = ();
+	%by_host = ();
+	@states = qw(unknown ready running done failed);
+	%state_to_pri = (
+		'unknown' => 0,
+		'ready' => 1,
+		'done' => 2,
+		'failed' => 3,
+		'running' => 4,
+	);
+}
+
 sub new($) {
 	$C = new Curses;
 	start_color;
@@ -160,7 +176,7 @@ sub new($) {
 
 	%host_state = %host_cnt = ();
 	%job_state = %job_cnt = ();
-	for my $s ('unknown', 'ready', 'running', 'done', 'failed') {
+	for my $s (@states) {
 		$host_cnt{$s} = 0;
 		$job_cnt{'*'}{$s} = 0;
 	}
@@ -193,7 +209,7 @@ sub set_host_status($$$) {
 	if (defined $prev_stat) {
 		$host_cnt{$prev_stat}--;
 	} else {
-		for my $s ('unknown', 'ready', 'running', 'done', 'failed') { $job_cnt{$mach}{$s} = 0; }
+		for my $s (@states) { $job_cnt{$mach}{$s} = 0; }
 	}
 	$host_state{$mach} = $stat;
 	$host_cnt{$stat}++;
@@ -228,41 +244,54 @@ sub refresh_status($) {
 
 sub get_slot($) {
 	my ($mach) = @_;
-	my $s;
-	if (defined ($s = $by_host{$mach})) {
-		delete $s->{'Gone'};
-	} else {
-		my ($best, $besti);
-		for my $i (0..$nrows-1) {
-			my $r = $by_row[$i];
-			if (!defined $r) {
-				$besti = $i;
-				$best = undef;
-				last;
-			} elsif ($r->{'Gone'} && (!$best || $best->{'Gone'} > $r->{'Gone'})) {
-				$besti = $i;
-				$best = $r;
-			}
-		}
-		if ($best) {
-			delete $by_host{$best->{'Host'}};
-		}
-		$s->{'Host'} = $mach;
-		$s->{'Row'} = $besti;
-		$by_host{$mach} = $s;
-		$by_row[$besti] = $s;
+	my $s = $by_host{$mach};
+	if (!defined $s) {
+		$s = $by_host{$mach} = { 'Host' => $mach };
 	}
 	return $s;
 }
 
-my $gone_counter = 1;
-sub delete_slot($) {
+my $place_counter;
+
+sub place_slot($) {
 	my ($s) = @_;
-	$s->{'Gone'} = $gone_counter++;
+	$s->{'LastUpdate'} = $place_counter++;
+	return $s if defined $s->{'Row'};
+
+	my $pri = $state_to_pri{$host_state{$s->{'Host'}}};
+	my ($best, $besti);
+	my $bestpri = -1;
+	for my $i (0..$nrows-1) {
+		my $r = $by_row[$i];
+		if (!defined $r) {
+			$besti = $i;
+			$best = undef;
+			last;
+		}
+		my $rpri = $state_to_pri{$host_state{$r->{'Host'}}};
+		next if $rpri > $pri;
+
+		if ($rpri < $bestpri ||
+		    $rpri == $bestpri && $r->{'LastUpdate'} < $best->{'LastUpdate'}) {
+			# Trick: $best must be defined, as otherwise $bestpri == -1
+			$best = $r;
+			$besti = $i;
+			$bestpri = $rpri;
+		}
+	}
+
+	if ($best) {
+		delete $best->{'Row'};
+	}
+	$s->{'Row'} = $besti;
+	$by_row[$besti] = $s;
+	return $s;
 }
 
 sub redraw_slot($) {
 	my ($s) = @_;
+	my $r = $s->{'Row'} // return;
+	$r++;
 	my $mach = $s->{'Host'};
 	my $stat = $s->{'Status'} // "?";
 	my $jid = $s->{'Job'} // "";
@@ -281,7 +310,6 @@ sub redraw_slot($) {
 			$C->bkgdset(0);
 		}
 	}
-	my $r = $s->{'Row'} + 1;
 	$C->addstr($r, 0, sprintf("%-20.20s", $mach));
 	if ($jcnt->{'failed'}) {
 		$C->bkgdset(COLOR_PAIR(4));
@@ -307,7 +335,6 @@ sub redraw_slot($) {
 
 sub update($$$$) {
 	my ($ui, $mach, $jid, $stat) = @_;
-	my $s = get_slot($mach);
 	given ($stat) {
 		when ('READY') {
 			# Pseudo-state generated internally
@@ -351,9 +378,10 @@ sub update($$$$) {
 			$ui->err("Received unknown job status $stat");
 		}
 	}
+	my $s = get_slot($mach);
 	$s->{'Job'} = $jid;
 	$s->{'Status'} = $stat;
+	place_slot($s);
 	redraw_slot($s);
-	if ($stat eq 'DONE') { delete_slot($s); }
 	$ui->refresh_status;
 }
-- 
2.39.2