#!/usr/bin/env perl
#
# Clean up include guards in headers
#
# Copyright (C) 2016 Red Hat, Inc.
#
# Authors:
# Markus Armbruster <armbru@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2 or
# (at your option) any later version. See the COPYING file in the
# top-level directory.
#
# Usage: scripts/clean-header-guards.pl [OPTION]... [FILE]...
# -c CC Use a compiler other than cc
# -n Suppress actual cleanup
# -v Show which files are cleaned up, and which are skipped
#
# Does the following:
# - Header files without a recognizable header guard are skipped.
# - Clean up any untidy header guards in-place. Warn if the cleanup
# renames guard symbols, and explain how to find occurrences of these
# symbols that may have to be updated manually.
# - Warn about duplicate header guard symbols. To make full use of
# this warning, you should clean up *all* headers in one run.
# - Warn when preprocessing a header with its guard symbol defined
# produces anything but whitespace. The preprocessor is run like
# "cc -E -DGUARD_H -c -P -", and fed the test program on stdin.
use strict;
use warnings;
use Getopt::Std;
# Stuff we don't want to clean because we import it into our tree:
my $exclude = qr,^(disas/libvixl/|include/standard-headers/
|linux-headers/|pc-bios/|tests/tcg/|tests/multiboot/),x;
# Stuff that is expected to fail the preprocessing test:
my $exclude_cpp = qr,^include/libdecnumber/decNumberLocal.h,;
my %guarded = ();
my %old_guard = ();
our $opt_c = "cc";
our $opt_n = 0;
our $opt_v = 0;
getopts("c:nv");
sub skipping {
my ($fname, $msg, $line1, $line2) = @_;
return if !$opt_v or $fname =~ $exclude;
print "$fname skipped: $msg\n";
print " $line1" if defined $line1;
print " $line2" if defined $line2;
}
sub gripe {
my ($fname, $msg) = @_;
return if $fname =~ $exclude;
print STDERR "$fname: warning: $msg\n";
}
sub slurp {
my ($fname) = @_;
local $/; # slurp
open(my $in, "<", $fname)
or die "can't open $fname for reading: $!";
return <$in>;
}
sub unslurp {
my ($fname, $contents) = @_;
open (my $out, ">", $fname)
or die "can't open $fname for writing: $!";
print $out $contents
or die "error writing $fname: $!";
close $out
or die "error writing $fname: $!";
}
sub fname2guard {
my ($fname) = @_;
$fname =~ tr/a-z/A-Z/;
$fname =~ tr/A-Z0-9/_/cs;
return $fname;
}
sub preprocess {
my ($fname, $guard) = @_;
open(my $pipe, "-|", "$opt_c -E -D$guard -c -P - <$fname")
or die "can't run $opt_c: $!";
while (<$pipe>) {
if ($_ =~ /\S/) {
gripe($fname, "not blank after preprocessing");
last;
}
}
close $pipe
or gripe($fname, "preprocessing failed ($opt_c exit status $?)");
}
for my $fname (@ARGV) {
my $text = slurp($fname);
$text =~ m,\A(\s*\n|\s*//\N*\n|\s*/\*.*?\*/\s*\n)*|,sg;
my $pre = $&;
unless ($text =~ /\G(.*\n)/g) {
$text =~ /\G.*/;
skipping($fname, "no recognizable header guard", "$&\n");
next;
}
my $line1 = $1;
unless ($text =~ /\G(.*\n)/g) {
$text =~ /\G.*/;
skipping($fname, "no recognizable header guard", "$&\n");
next;
}
my $line2 = $1;
my $body = substr($text, pos($text));
unless ($line1 =~ /^\s*\#\s*(if\s*\!\s*defined(\s*\()?|ifndef)\s*
([A-Za-z0-9_]+)/x) {
skipping($fname, "no recognizable header guard", $line1, $line2);
next;
}
my $guard = $3;
unless ($line2 =~ /^\s*\#\s*define\s+([A-Za-z0-9_]+)/) {
skipping($fname, "no recognizable header guard", $line1, $line2);
next;
}
my $guard2 = $1;
unless ($guard2 eq $guard) {
skipping($fname, "mismatched header guard ($guard vs. $guard2) ",
$line1, $line2);
next;
}
unless ($body =~ m,\A((.*\n)*)
([ \t]*\#[ \t]*endif([ \t]*\N*)\n)
((?s)(\s*\n|\s*//\N*\n|\s*/\*.*?\*/\s*\n)*)
\Z,x) {
skipping($fname, "can't find end of header guard");
next;
}
$body = $1;
my $line3 = $3;
my $endif_comment = $4;
my $post = $5;
my $oldg = $guard;
unless ($fname =~ $exclude) {
my @issues = ();
$guard =~ tr/a-z/A-Z/
and push @issues, "contains lowercase letters";
$guard =~ s/^_+//
and push @issues, "is a reserved identifier";
$guard =~ s/(_H)?_*$/_H/
and $& ne "_H" and push @issues, "doesn't end with _H";
unless ($guard =~ /^[A-Z][A-Z0-9_]*_H/) {
skipping($fname, "can't clean up odd guard symbol $oldg\n",
$line1, $line2);
next;
}
my $exp = fname2guard($fname =~ s,.*/,,r);
unless ($guard =~ /\Q$exp\E\Z/) {
$guard = fname2guard($fname =~ s,^include/,,r);
push @issues, "doesn't match the file name";
}
if (@issues and $opt_v) {
print "$fname guard $oldg needs cleanup:\n ",
join(", ", @issues), "\n";
}
}
$old_guard{$guard} = $oldg
if $guard ne $oldg;
if (exists $guarded{$guard}) {
gripe($fname, "guard $guard also used by $guarded{$guard}");
} else {
$guarded{$guard} = $fname;
}
unless ($fname =~ $exclude) {
my $newl1 = "#ifndef $guard\n";
my $newl2 = "#define $guard\n";
my $newl3 = "#endif\n";
$newl3 =~ s,\Z, /* $guard */, if $endif_comment;
if ($line1 ne $newl1 or $line2 ne $newl2 or $line3 ne $newl3) {
$pre =~ s/\n*\Z/\n\n/ if $pre =~ /\N/;
$body =~ s/\A\n*/\n/;
if ($opt_n) {
print "$fname would be cleaned up\n" if $opt_v;
} else {
unslurp($fname, "$pre$newl1$newl2$body$newl3$post");
print "$fname cleaned up\n" if $opt_v;
}
}
}
preprocess($fname, $opt_n ? $oldg : $guard)
unless $fname =~ $exclude or $fname =~ $exclude_cpp;
}
if (%old_guard) {
print STDERR "warning: guard symbol renaming may break things\n";
for my $guard (sort keys %old_guard) {
print STDERR " $old_guard{$guard} -> $guard\n";
}
print STDERR "To find uses that may have to be updated try:\n";
print STDERR " git grep -Ew '", join("|", sort values %old_guard),
"'\n";
}
