From ea6ba7479b984b770df7f9325ab6035e1a2f5b13 Mon Sep 17 00:00:00 2001
From: Joey Hess <joey@kitenet.net>
Date: Mon, 26 Apr 2010 19:45:04 -0400
Subject: [PATCH] Memoize architecture comparisons in samearch, and avoid
 calling dpkg-architecture at all for simple comparisons not involving
 architecture wildcards. Closes:# 579317

---
 Debian/Debhelper/Dh_Lib.pm | 33 ++++++++++++++++++++++++++-------
 debian/changelog           |  8 ++++++++
 2 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/Debian/Debhelper/Dh_Lib.pm b/Debian/Debhelper/Dh_Lib.pm
index d9c1d38..421dd99 100644
--- a/Debian/Debhelper/Dh_Lib.pm
+++ b/Debian/Debhelper/Dh_Lib.pm
@@ -638,15 +638,34 @@ sub dpkg_architecture_value {
 }
 
 # Passed an arch and a list of arches to match against, returns true if matched
-sub samearch {
-	my $arch=shift;
-	my @archlist=split(/\s+/,shift);
+{
+	my %knownsame;
 
-	foreach my $a (@archlist) {
-		system("dpkg-architecture", "-a$arch", "-i$a") == 0 && return 1;
+	sub samearch {
+		my $arch=shift;
+		my @archlist=split(/\s+/,shift);
+	
+		foreach my $a (@archlist) {
+			# Avoid expensive dpkg-architecture call to compare
+			# with a simple architecture name. "linux-any" and
+			# other architecture wildcards are (currently)
+			# always hypenated.
+			if ($a !~ /-/) {
+				return 1 if $arch eq $a;
+			}
+			elsif (exists $knownsame{$arch}{$a}) {
+				return 1 if $knownsame{$arch}{$a};
+			}
+			elsif (system("dpkg-architecture", "-a$arch", "-i$a") == 0) {
+				return $knownsame{$arch}{$a}=1;
+			}
+			else {
+				$knownsame{$arch}{$a}=0;
+			}
+		}
+	
+		return 0;
 	}
-
-	return 0;
 }
 
 # Returns source package name
diff --git a/debian/changelog b/debian/changelog
index 970d764..23f76c8 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,11 @@
+debhelper (7.4.19) UNRELEASED; urgency=low
+
+  * Memoize architecture comparisons in samearch, and avoid calling
+    dpkg-architecture at all for simple comparisons not involving
+    architecture wildcards. Closes:# 579317
+
+ -- Joey Hess <joeyh@debian.org>  Mon, 26 Apr 2010 19:35:53 -0400
+
 debhelper (7.4.18) unstable; urgency=low
 
   * dh_gconf: Depend on new gconf2 that uses triggers, and stop
-- 
2.39.5