[PATCH v2] checkpatch: add command-line option for TAB size

[Antonio Borneo <borneo.antonio@gmail.com>]

The size of 8 characters used for both TAB and indentation is
embedded as magic value allover the checkpatch script, and this
makes the script less readable.

Replace the magic value 8 with a variable.
From the context of the code it's clear if it is used for
indentation or tabulation, so no need to use two separate
variables.

Add a command-line option "--tab-size" to let the user select a
TAB size value other than 8.
This makes easy to reuse this script by other projects with
different requirements in their coding style (e.g. OpenOCD [1]
requires TAB size of 4 characters [2]).

[1] http://openocd.org/
[2] http://openocd.org/doc/doxygen/html/stylec.html#styleformat

Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Signed-off-by: Erik Ahlén <erik.ahlen@avalonenterprise.com>
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
---
V1 -> V2
	add the command line option

 scripts/checkpatch.pl | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 916a3fbd4d47..90f641bf1895 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -62,6 +62,7 @@ my $conststructsfile = "$D/const_structs.checkpatch";
 my $typedefsfile = "";
 my $color = "auto";
 my $allow_c99_comments = 1; # Can be overridden by --ignore C99_COMMENT_TOLERANCE
+my $tabsize = 8;
 
 sub help {
 	my ($exitcode) = @_;
@@ -96,6 +97,7 @@ Options:
   --show-types               show the specific message type in the output
   --max-line-length=n        set the maximum line length, if exceeded, warn
   --min-conf-desc-length=n   set the min description length, if shorter, warn
+  --tab-size=n               set the number of spaces for tab (default 8)
   --root=PATH                PATH to the kernel tree root
   --no-summary               suppress the per-file summary
   --mailback                 only produce a report in case of warnings/errors
@@ -213,6 +215,7 @@ GetOptions(
 	'list-types!'	=> \$list_types,
 	'max-line-length=i' => \$max_line_length,
 	'min-conf-desc-length=i' => \$min_conf_desc_length,
+	'tab-size=i'	=> \$tabsize,
 	'root=s'	=> \$root,
 	'summary!'	=> \$summary,
 	'mailback!'	=> \$mailback,
@@ -1211,7 +1214,7 @@ sub expand_tabs {
 		if ($c eq "\t") {
 			$res .= ' ';
 			$n++;
-			for (; ($n % 8) != 0; $n++) {
+			for (; ($n % $tabsize) != 0; $n++) {
 				$res .= ' ';
 			}
 			next;
@@ -2224,7 +2227,7 @@ sub string_find_replace {
 sub tabify {
 	my ($leading) = @_;
 
-	my $source_indent = 8;
+	my $source_indent = $tabsize;
 	my $max_spaces_before_tab = $source_indent - 1;
 	my $spaces_to_tab = " " x $source_indent;
 
@@ -3153,7 +3156,7 @@ sub process {
 		next if ($realfile !~ /\.(h|c|pl|dtsi|dts)$/);
 
 # at the beginning of a line any tabs must come first and anything
-# more than 8 must use tabs.
+# more than $tabsize must use tabs.
 		if ($rawline =~ /^\+\s* \t\s*\S/ ||
 		    $rawline =~ /^\+\s*        \s*/) {
 			my $herevet = "$here\n" . cat_vet($rawline) . "\n";
@@ -3172,7 +3175,7 @@ sub process {
 				"please, no space before tabs\n" . $herevet) &&
 			    $fix) {
 				while ($fixed[$fixlinenr] =~
-					   s/(^\+.*) {8,8}\t/$1\t\t/) {}
+					   s/(^\+.*) {$tabsize,$tabsize}\t/$1\t\t/) {}
 				while ($fixed[$fixlinenr] =~
 					   s/(^\+.*) +\t/$1\t/) {}
 			}
@@ -3194,11 +3197,11 @@ sub process {
 		if ($perl_version_ok &&
 		    $sline =~ /^\+\t+( +)(?:$c90_Keywords\b|\{\s*$|\}\s*(?:else\b|while\b|\s*$)|$Declare\s*$Ident\s*[;=])/) {
 			my $indent = length($1);
-			if ($indent % 8) {
+			if ($indent % $tabsize) {
 				if (WARN("TABSTOP",
 					 "Statements should start on a tabstop\n" . $herecurr) &&
 				    $fix) {
-					$fixed[$fixlinenr] =~ s@(^\+\t+) +@$1 . "\t" x ($indent/8)@e;
+					$fixed[$fixlinenr] =~ s@(^\+\t+) +@$1 . "\t" x ($indent/$tabsize)@e;
 				}
 			}
 		}
@@ -3216,8 +3219,8 @@ sub process {
 				my $newindent = $2;
 
 				my $goodtabindent = $oldindent .
-					"\t" x ($pos / 8) .
-					" "  x ($pos % 8);
+					"\t" x ($pos / $tabsize) .
+					" "  x ($pos % $tabsize);
 				my $goodspaceindent = $oldindent . " "  x $pos;
 
 				if ($newindent ne $goodtabindent &&
@@ -3688,11 +3691,11 @@ sub process {
 			#print "line<$line> prevline<$prevline> indent<$indent> sindent<$sindent> check<$check> continuation<$continuation> s<$s> cond_lines<$cond_lines> stat_real<$stat_real> stat<$stat>\n";
 
 			if ($check && $s ne '' &&
-			    (($sindent % 8) != 0 ||
+			    (($sindent % $tabsize) != 0 ||
 			     ($sindent < $indent) ||
 			     ($sindent == $indent &&
 			      ($s !~ /^\s*(?:\}|\{|else\b)/)) ||
-			     ($sindent > $indent + 8))) {
+			     ($sindent > $indent + $tabsize))) {
 				WARN("SUSPECT_CODE_INDENT",
 				     "suspect code indent for conditional statements ($indent, $sindent)\n" . $herecurr . "$stat_real\n");
 			}
-- 
2.21.0