cvsimport: complete the cvsps run before starting the import

We now capture the output of cvsps to a tempfile, and then read it in.
cvsps 2.1 works quite a bit "in memory", and only prints its patchset
info once it has finished talking with cvs, but apparently retaining
all that memory allocation. With this patch, cvsps is finished and
reaped before cvsimport start working (and growing). So the footprint
of the whole process is much lower.

Signed-off-by: Martin Langhoff <martin@catalyst.net.nz>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-cvsimport.perl

@@ -529,25 +529,39 @@ if ($opt_A) {
 	write_author_info("$git_dir/cvs-authors");
 }
 
-my $pid = open(CVS,"-|");
-die "Cannot fork: $!\n" unless defined $pid;
-unless($pid) {
-	my @opt;
-	@opt = split(/,/,$opt_p) if defined $opt_p;
-	unshift @opt, '-z', $opt_z if defined $opt_z;
-	unshift @opt, '-q'         unless defined $opt_v;
-	unless (defined($opt_p) && $opt_p =~ m/--no-cvs-direct/) {
-		push @opt, '--cvs-direct';
+
+#
+# run cvsps into a file unless we are getting
+# it passed as a file via $opt_P
+#
+unless ($opt_P) {
+	print "Running cvsps...\n" if $opt_v;
+	my $pid = open(CVSPS,"-|");
+	die "Cannot fork: $!\n" unless defined $pid;
+	unless($pid) {
+		my @opt;
+		@opt = split(/,/,$opt_p) if defined $opt_p;
+		unshift @opt, '-z', $opt_z if defined $opt_z;
+		unshift @opt, '-q'         unless defined $opt_v;
+		unless (defined($opt_p) && $opt_p =~ m/--no-cvs-direct/) {
+			push @opt, '--cvs-direct';
+		}
+		exec("cvsps","--norc",@opt,"-u","-A",'--root',$opt_d,$cvs_tree);
+		die "Could not start cvsps: $!\n";
 	}
-	if ($opt_P) {
-	    exec("cat", $opt_P);
-	} else {
-	    exec("cvsps","--norc",@opt,"-u","-A",'--root',$opt_d,$cvs_tree);
-	    die "Could not start cvsps: $!\n";
+	my ($cvspsfh, $cvspsfile) = tempfile('gitXXXXXX', SUFFIX => '.cvsps',
+					     DIR => File::Spec->tmpdir());
+	while (<CVSPS>) {
+	    print $cvspsfh $_;
 	}
+	close CVSPS;
+	close $cvspsfh;
+	$opt_P = $cvspsfile;
 }
 
 
+open(CVS, "<$opt_P") or die $!;
+
 ## cvsps output:
 #---------------------
 #PatchSet 314