[PATCH v3] checkpatch: Add some --strict coding style checks

Joe Perches
2012-03-01T04:24:07Z

Argument alignment across multiple lines should
match the open parenthesis.

Logical continuations should be at the end of
the previous line, not the start of a new line.

These are not required by CodingStyle so make the
tests active only when using --strict.

Improved_by_examples_from: "Bruce W. Allen" <bruce.w.allan@intel.com>
Signed-off-by: Joe Perches <joe@perches.com>
---
V3: Use perl 5.10 features
Use a runtime check of perl version so $balanced_parens
is not used in perl versions that don't support it.
Update memset and min_t checks for newer $balanced_parens
test.
Improve alignment position test.
Add message suggesting perl upgrade.
V2: Scan the entire line for balanced parentheses,
use the position of the last non-balanced open parenthesis.
Allow all space indentation too, checkpatch will complain
in a different message about that if it's too long.

scripts/checkpatch.pl | 94 +++++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 84 insertions(+), 10 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 89d24b3..308e401 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -330,10 +330,15 @@ sub build_types {
}
build_types();

-our $match_balanced_parentheses = qr/(\((?:[^\(\)]+|(-1))*\))/;

our $Typecast = qr{\s*(\(\s*$NonptrType\s*\)){0,1}\s*};
-our $LvalOrFunc = qr{($Lval)\s*($match_balanced_parentheses{0,1})\s*};
+
+# Using $balanced_parens, $LvalOrFunc, or $FuncArg
+# requires at least perl version v5.10.0
+# Any use must be runtime checked with $^V
+
+our $balanced_parens = qr/(\((?:[^\(\)]++|(?-1))*\))/;
+our $LvalOrFunc = qr{($Lval)\s*($balanced_parens{0,1})\s*};
our $FuncArg = qr{$Typecast{0,1}($LvalOrFunc|$Constant)};

sub deparenthesize {
@@ -1330,6 +1335,36 @@ sub check_absolute_file {
}
}

+sub pos_last_openparen {
+ my ($line) = @_;
+
+ my $pos = 0;
+
+ my $opens = $line =~ tr/\(/\(/;
+ my $closes = $line =~ tr/\)/\)/;
+
+ my $last_openparen = 0;
+
+ if (($opens == 0) || ($closes >= $opens)) {
+ return -1;
+ }
+
+ my $len = length($line);
+
+ for ($pos = 0; $pos < $len; $pos++) {
+ my $string = substr($line, $pos);
+ if ($string =~ /^($FuncArg|$balanced_parens)/) {
+ $pos += length($1) - 1;
+ } elsif (substr($line, $pos, 1) eq '(') {
+ $last_openparen = $pos;
+ } elsif (index($string, '(') == -1) {
+ last;
+ }
+ }
+
+ return $last_openparen + 1;
+}
+
sub process {
my $filename = shift;

@@ -1783,6 +1818,37 @@ sub process {
"please, no space before tabs\n" . $herevet);
}

+# check for && or || at the start of a line
+ if ($rawline =~ /^\+\s*(&&|\|\|)/) {
+ CHK("LOGICAL_CONTINUATIONS",
+ "Logical continuations should be on the previous line\n" . $hereprev);
+ }
+
+# check multi-line statement indentation matches previous line
+ if ($^V && $^V ge 5.10.0 &&
+ $prevline =~ /^\+(\t*)(if \(|$Ident\().*(\&\&|\|\||,)\s*$/) {
+ $prevline =~ /^\+(\t*)(.*)$/;
+ my $oldindent = $1;
+ my $rest = $2;
+
+ my $pos = pos_last_openparen($rest);
+ if ($pos >= 0) {
+ $line =~ /^\+([ \t]*)/;
+ my $newindent = $1;
+
+ my $goodtabindent = $oldindent .
+ "\t" x ($pos / 8) .
+ " " x ($pos % 8);
+ my $goodspaceindent = $oldindent . " " x $pos;
+
+ if ($newindent ne $goodtabindent &&
+ $newindent ne $goodspaceindent) {
+ CHK("PARENTHESIS_ALIGNMENT",
+ "Alignment should match open parenthesis\n" . $hereprev);
+ }
+ }
+ }
+
# check for spaces at the beginning of a line.
# Exceptions:
# 1) within comments
@@ -3142,12 +3208,13 @@ sub process {
}

# Check for misused memsets
- if (defined $stat &&
+ if ($^V && $^V ge 5.10.0 &&
+ defined $stat &&
$stat =~ /^\+(?:.*?)\bmemset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*$FuncArg\s*\)/s) {

my $ms_addr = $2;
- my $ms_val = $8;
- my $ms_size = $14;
+ my $ms_val = $7;
+ my $ms_size = $12;

if ($ms_size =~ /^(0x|)0$/i) {
ERROR("MEMSET",
@@ -3159,17 +3226,18 @@ sub process {
}

# typecasts on min/max could be min_t/max_t
- if (defined $stat &&
+ if ($^V && $^V ge 5.10.0 &&
+ defined $stat &&
$stat =~ /^\+(?:.*?)\b(min|max)\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\)/) {
- if (defined $2 || defined $8) {
+ if (defined $2 || defined $7) {
my $call = $1;
my $cast1 = deparenthesize($2);
my $arg1 = $3;
- my $cast2 = deparenthesize($8);
- my $arg2 = $9;
+ my $cast2 = deparenthesize($7);
+ my $arg2 = $8;
my $cast;

- if ($cast1 ne "" && $cast2 ne "") {
+ if ($cast1 ne "" && $cast2 ne "" && $cast1 ne $cast2) {
$cast = "$cast1 or $cast2";
} elsif ($cast1 ne "") {
$cast = $cast1;
@@ -3391,6 +3459,12 @@ sub process {
}

if ($quiet == 0) {
+
+ if ($^V lt 5.10.0) {
+ print("NOTE: perl $^V is not modern enough to detect all possible issues.\n");
+ print("An upgrade to at least perl v5.10.0 is suggested.\n\n");
+ }
+
# If there were whitespace errors which cleanpatch can fix
# then suggest that.
if ($rpt_cleaners) {