get_maintainer: Prepare for separate MAINTAINERS files

Allow for MAINTAINERS to become a directory and if it is,
read all the files in the directory for maintained sections.

Optionally look for all files named MAINTAINERS in directories
excluding the .git directory by using --find-maintainer-files.

This optional feature adds ~.3 seconds of CPU on an Intel
i5-6200 with an SSD.

Miscellanea:

 - Create a read_maintainer_file subroutine from the existing code
 - Test only the existence of MAINTAINERS, not whether it's a file
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/get_maintainer.pl

@@ -18,6 +18,7 @@ my $V = '0.26';
 
 use Getopt::Long qw(:config no_auto_abbrev);
 use Cwd;
+use File::Find;
 
 my $cur_path = fastgetcwd() . '/';
 my $lk_path = "./";
@@ -58,6 +59,7 @@ my $from_filename = 0;
 my $pattern_depth = 0;
 my $version = 0;
 my $help = 0;
+my $find_maintainer_files = 0;
 
 my $vcs_used = 0;
 
@@ -249,6 +251,7 @@ if (!GetOptions(
 		'sections!' => \$sections,
 		'fe|file-emails!' => \$file_emails,
 		'f|file' => \$from_filename,
+		'find-maintainer-files' => \$find_maintainer_files,
 		'v|version' => \$version,
 		'h|help|usage' => \$help,
 		)) {
@@ -307,10 +310,14 @@ if (!top_of_kernel_tree($lk_path)) {
 
 my @typevalue = ();
 my %keyword_hash;
+my @mfiles = ();
 
-open (my $maint, '<', "${lk_path}MAINTAINERS")
-    or die "$P: Can't open MAINTAINERS: $!\n";
-while (<$maint>) {
+sub read_maintainer_file {
+    my ($file) = @_;
+
+    open (my $maint, '<', "$file")
+	or die "$P: Can't open MAINTAINERS file '$file': $!\n";
+    while (<$maint>) {
 	my $line = $_;
 
 	if ($line =~ m/^([A-Z]):\s*(.*)/) {
@@ -330,13 +337,47 @@ while (<$maint>) {
 		$keyword_hash{@typevalue} = $value;
 	    }
 	    push(@typevalue, "$type:$value");
-    } elsif (!/^(\s)*$/) {
+	} elsif (!(/^\s*$/ || /^\s*\#/)) {
 	    $line =~ s/\n$//g;
 	    push(@typevalue, $line);
 	}
+    }
+    close($maint);
+}
+
+sub find_is_maintainer_file {
+    my ($file) = $_;
+    return if ($file !~ m@/MAINTAINERS$@);
+    $file = $File::Find::name;
+    return if (! -f $file);
+    push(@mfiles, $file);
+}
+
+sub find_ignore_git {
+    return grep { $_ !~ /^\.git$/; } @_;
 }
-close($maint);
 
+if (-d "${lk_path}MAINTAINERS") {
+    opendir(DIR, "${lk_path}MAINTAINERS") or die $!;
+    my @files = readdir(DIR);
+    closedir(DIR);
+    foreach my $file (@files) {
+	push(@mfiles, "${lk_path}MAINTAINERS/$file") if ($file !~ /^\./);
+    }
+}
+
+if ($find_maintainer_files) {
+    find( { wanted => \&find_is_maintainer_file,
+	    preprocess => \&find_ignore_git,
+	    no_chdir => 1,
+	}, "${lk_path}");
+} else {
+    push(@mfiles, "${lk_path}MAINTAINERS") if -f "${lk_path}MAINTAINERS";
+}
+
+foreach my $file (@mfiles) {
+    read_maintainer_file("$file");
+}
 
 #
 # Read mail address map
@@ -873,7 +914,7 @@ sub top_of_kernel_tree {
     if (   (-f "${lk_path}COPYING")
 	&& (-f "${lk_path}CREDITS")
 	&& (-f "${lk_path}Kbuild")
-	&& (-f "${lk_path}MAINTAINERS")
+	&& (-e "${lk_path}MAINTAINERS")
 	&& (-f "${lk_path}Makefile")
 	&& (-f "${lk_path}README")
 	&& (-d "${lk_path}Documentation")