split get_make_jobserver_status into two functions

I disliked the complexity of the return values, and the boilerplate
code that followed the two calls to the function, to clean/unset
MAKEFLAGS. To solve both, I refactored it into two functions, one simply
tests to see if a jobserver is specified but unavailable, while the other
cleans/unsets MAKEFLAGS.

This loses the ability to pull the jobs-N count out of MAKEFLAGS,
but that was not currently used.

2 files changed, 29 insertions, 43 deletions

diff --git a/Debian/Debhelper/Buildsystem/makefile.pm b/Debian/Debhelper/Buildsystem/makefile.pm
index f21b2cbd..159f7c1e 100644
--- a/Debian/Debhelper/Buildsystem/makefile.pm
+++ b/Debian/Debhelper/Buildsystem/makefile.pm
@@ -7,7 +7,8 @@
 package Debian::Debhelper::Buildsystem::makefile;
 
 use strict;
-use Debian::Debhelper::Dh_Lib qw(escape_shell get_make_jobserver_status);
+use Debian::Debhelper::Dh_Lib qw(escape_shell is_make_jobserver_unavailable
+	clean_makeflags);
 use base 'Debian::Debhelper::Buildsystem';
 
 sub get_makecmd_C {
@@ -37,14 +38,8 @@ sub do_make {
 	# Always clean MAKEFLAGS from unavailable jobserver options. If parallel
 	# is enabled, do more extensive clean up from all job control specific
 	# options
-	my ($status, $makeflags) = get_make_jobserver_status();
-	if ($status eq "jobserver-unavailable" || defined $this->get_parallel()) {
-		if (defined $makeflags) {
-			$ENV{MAKEFLAGS} = $makeflags;
-		}
-		else {
-			delete $ENV{MAKEFLAGS} if exists $ENV{MAKEFLAGS};
-		}
+	if (defined $this->get_parallel() || is_make_jobserver_unavailable()) {
+		clean_makeflags();
 	}
 
 	# Start a new jobserver if parallel building was requested
diff --git a/Debian/Debhelper/Dh_Lib.pm b/Debian/Debhelper/Dh_Lib.pm
index 602b77fb..ac0d8ab4 100644
--- a/Debian/Debhelper/Dh_Lib.pm
+++ b/Debian/Debhelper/Dh_Lib.pm
@@ -16,7 +16,7 @@ use vars qw(@ISA @EXPORT %dh);
 	    &compat &addsubstvar &delsubstvar &excludefile &package_arch
 	    &is_udeb &udeb_filename &debhelper_script_subst &escape_shell
 	    &inhibit_log &load_log &write_log &dpkg_architecture_value
-	    &sourcepackage &get_make_jobserver_status);
+	    &sourcepackage &is_make_jobserver_unavailable &clean_makeflags);
 
 my $max_compat=7;
 
@@ -794,44 +794,35 @@ sub debhelper_script_subst {
 	}
 }
 
-# A helper subroutine for detecting (based on MAKEFLAGS) if make jobserver 
-# is enabled, if it is available or MAKEFLAGS contains "jobs" option.
-# It returns current status (jobserver, jobserver-unavailable or jobs-N where
-# N is number of jobs, 0 if infinite) and MAKEFLAGS cleaned up from 
-# job control options.
-sub get_make_jobserver_status {
-	my $jobsre = qr/(?:^|\s)(?:(?:-j\s*|--jobs(?:=|\s+))(\d+)?|--jobs)\b/;
-	my $status = "";
-	my $makeflags;
+# Checks if make's jobserver is enabled via MAKEFLAGS, but
+# the FD used to communicate with it is actually not available.
+sub is_make_jobserver_unavailable {
+	if (exists $ENV{MAKEFLAGS} && 
+	    $ENV{MAKEFLAGS} =~ /(?:^|\s)--jobserver-fds=(\d+)/) {
+		if (!open(my $in, "<&$1")) {
+			return 1; # unavailable
+		}
+		else {
+			close $in;
+			return 0; # available
+		}
+	}
+
+	return; # no jobserver specified
+}
 
+# Cleans out job control options from MAKEFLAGS.
+sub clean_makeflags {
 	if (exists $ENV{MAKEFLAGS}) {
-		$makeflags = $ENV{MAKEFLAGS};
-		if ($makeflags =~ /(?:^|\s)--jobserver-fds=(\d+)/) {
-			$status = "jobserver";
-			if (!open(my $in, "<&", "$1")) {
-				# Job server is unavailable
-				$status .= "-unavailable";
-			}
-			else {
-				close $in;
-			}
-			# Clean makeflags up
-			$makeflags =~ s/(?:^|\s)--jobserver-fds=\S+//g;
-			$makeflags =~ s/(?:^|\s)-j\b//g;
+		if ($ENV{MAKEFLAGS} =~ /(?:^|\s)--jobserver-fds=(\d+)/) {
+			$ENV{MAKEFLAGS} =~ s/(?:^|\s)--jobserver-fds=\S+//g;
+			$ENV{MAKEFLAGS} =~ s/(?:^|\s)-j\b//g;
 		}
-		elsif (my @m = ($makeflags =~ /$jobsre/g)) {
-			# Job count is specified in MAKEFLAGS. Whenever make reads it, a new
-			# jobserver will be started. Job count returned is 0 if infinite.
-			$status = "jobs-" . (defined $m[$#m] ? $m[$#m] : "0");
-			# Clean makeflags up from "jobs" option(s)
-			$makeflags =~ s/$jobsre//g;
+		else {
+			$ENV{MAKEFLAGS} =~ s/(?:^|\s)(?:(?:-j\s*|--jobs(?:=|\s+))(\d+)?|--jobs)\b//g;
 		}
+		delete $ENV{MAKEFLAGS} if $ENV{MAKEFLAGS} =~ /^\s*$/;
 	}
-	if ($status) {
-		# MAKEFLAGS could be unset if it is empty
-		$makeflags = undef if $makeflags =~ /^\s*$/;
-	}
-	return wantarray ? ($status, $makeflags) : $status;
 }
 
 1