From 1b0ef2af90507693946085b2f5b979b7df348c83 Mon Sep 17 00:00:00 2001
From: Jakub Narebski <jnareb@gmail.com>
Date: Sat, 8 Nov 2008 22:48:20 +0100
Subject: [PATCH] Remove adaptive, keep stats for deny rules, add clearing
 stats

Remove so called adaptive rules, which meant moving currently matched
deny rules to the front of @filter_deny list.  Better solution I think
would be to rely on rule usage statistics.

Extend deny rule usage statistics, adding average number of rules to
match (excluding cases where there was no match at all).

Add '/FILTER CLEARSTATS' command, to clear (reset) statistics for
rules.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>
---
 SoftSnow_filter.pl | 65 ++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 41 insertions(+), 24 deletions(-)

diff --git a/SoftSnow_filter.pl b/SoftSnow_filter.pl
index 16cbb50..fa256fd 100755
--- a/SoftSnow_filter.pl
+++ b/SoftSnow_filter.pl
@@ -23,13 +23,12 @@ my $filter_file = Xchat::get_info("xchatdir") . "/SoftSnow_filter.conf";
 my $filter_turned_on = 0;  # is filter is turned on
 my $limit_to_server  = ''; # if true limit to given server (host)
 my $use_filter_allow = 0;  # use overrides (ALLOW before DENY)
-my $adaptive_filter  = 1;  # move used (matched) rules earlier
 
 my $filtered_to_window = 0;
 my $filter_window = "(filtered)";
 ### end config ###
 
-my $filter_commands = 'ON|OFF|STATUS|SERVER|SERVERON|ALL|HELP|DEBUG|PRINT|ALLOW|ADD|DELETE|SAVE|LOAD';
+my $filter_commands = 'ON|OFF|STATUS|SERVER|SERVERON|ALL|HELP|DEBUG|CLEARSTATS|PRINT|ALLOW|ADD|DELETE|SAVE|LOAD';
 
 my $filter_help = <<"EOF";
 ${B}/FILTER $filter_commands${B}
@@ -37,6 +36,7 @@ ${B}/FILTER $filter_commands${B}
 /FILTER HELP - prints this help message
 /FILTER STATUS - prints if filter is turned on, and with what limits
 /FILTER DEBUG - shows some info; used in debuggin the filter
+/FILTER CLEARSTATS - reset filter statistics
 /FILTER PRINT - prints all the rules
 /FILTER ALLOW - toggle use of ALLOW rules (before DENY).
 /FILTER SERVER - limits filtering to current server (host)
@@ -140,6 +140,8 @@ my @filter_deny = (
 );
 
 my $nfiltered = 0;
+my $nchecked  = 0;
+my $nallow    = 0;
 my %stats = ();
 
 # return 1 (true) if text given as argument is to be filtered out
@@ -152,29 +154,28 @@ sub isFiltered {
 
 	if ($use_filter_allow) {
 		foreach $regexp (@filter_allow) {
-			return 0 if ($text =~ /$regexp/);
+			if ($text =~ /$regexp/) {
+				$nallow++;
+				return 0;
+			}
 		}
 	}
 
-	if ($adaptive_filter) {
-		for (my $i = 0; $i < @filter_deny; $i++) {
-			if ($text =~ $filter_deny[$i]) {
-				my ($elem) = splice @filter_deny, $i, 1;
-				unshift @filter_deny, $elem;
-
-				$nfiltered++;
-				if (exists $stats{$elem}) {
-					$stats{$elem}++;
-				} else {
-					$stats{$elem} = 1;
-				}
-
-				return 1;
+	my $nrules_checked = 0;
+	foreach $regexp (@filter_deny) {
+		$nrules_checked++;
+
+		if ($text =~ /$regexp/) {
+			# filter statistic
+			$nfiltered++;
+			$nchecked += $nrules_checked;
+			if (exists $stats{$regexp}) {
+				$stats{$regexp}++;
+			} else {
+				$stats{$regexp} = 1;
 			}
-		}
-	} else {
-		foreach $regexp (@filter_deny) {
-			return 1 if ($text =~ /$regexp/);
+
+			return 1;
 		}
 	}
 
@@ -337,14 +338,27 @@ sub cmd_debug {
 	Xchat::printf("%3u %s rules\n", scalar(@filter_allow), "allow");
 	Xchat::printf("%3u %s rules\n", scalar(@filter_deny),  "deny");
 	Xchat::print("\n");
-	Xchat::print("nfiltered = $nfiltered\n");
+	Xchat::print("filtered lines   = $nfiltered\n");
+	Xchat::print("average to match = ".$nchecked/$nfiltered."\n");
 	foreach my $rule (sort { $stats{$b} <=> $stats{$a} } keys %stats) {
-		Xchat::printf("%3u /%s/\n",
-		              $stats{$rule}, $rule);
+		Xchat::printf("%3u [%5.1f%%] /%s/\n",
+		              $stats{$rule}, 100.0*$stats{$rule}/$nfiltered, $rule);
+	}
+	if ($use_filter_allow) {
+		Xchat::print("allow matches    = $nallow\n");
 	}
 	Xchat::print("${B}FILTER DEBUG ----------${B}\n");
 }
 
+sub cmd_clear_stats {
+	$nfiltered = 0;
+	$nchecked  = 0;
+	$nallow    = 0;
+	%stats = ();
+
+	Xchat::print("${B}FILTER${B} stats cleared\n");
+}
+
 sub cmd_server_limit {
 	my $server = shift;
 
@@ -479,6 +493,9 @@ sub filter_command_handler {
 	} elsif ($cmd =~ /^DEBUG$/i || $cmd =~ /^INFO$/i) {
 		cmd_debug();
 
+	} elsif ($cmd =~ /^CLEARSTAT(?:S)?$/i) {
+		cmd_clear_stats();
+
 	} elsif ($cmd =~ /^(?:PRINT|LIST)$/i) {
 		cmd_print_rules();
 
-- 
2.11.4.GIT