scripts/documentation-file-ref-check: rewrite it in perl with auto-fix mode

#!/bin/sh

#!/usr/bin/env perl

# SPDX-License-Identifier: GPL-2.0

#

# Treewide grep for references to files under Documentation, and report

# non-existing files in stderr.

for f in $(git ls-files); do

	for ref in $(grep -ho "Documentation/[A-Za-z0-9_.,~/*+-]*" "$f"); do

		# presume trailing . and , are not part of the name

		ref=${ref%%[.,]}

		# use ls to handle wildcards

		if ! ls $ref >/dev/null 2>&1; then

			echo "$f: $ref" >&2

		fi

	done

done

use warnings;

use strict;

use Getopt::Long qw(:config no_auto_abbrev);

my $scriptname = $0;

$scriptname =~ s,.*/([^/]+/),$1,;

# Parse arguments

my $help = 0;

my $fix = 0;

GetOptions(

	'fix' => \$fix,

	'h|help|usage' => \$help,

);

if ($help != 0) {

    print "$scriptname [--help] [--fix-rst]\n";

    exit -1;

}

# Step 1: find broken references

print "Finding broken references. This may take a while...  " if ($fix);

my %broken_ref;

open IN, "git grep 'Documentation/'|"

     or die "Failed to run git grep";

while (<IN>) {

	next if (!m/^([^:]+):(.*)/);

	my $f = $1;

	my $ln = $2;

	# Makefiles contain nasty expressions to parse docs

	next if ($f =~ m/Makefile/);

	# Skip this script

	next if ($f eq $scriptname);

	if ($ln =~ m,\b(\S*)(Documentation/[A-Za-z0-9\_\.\,\~/\*+-]*),) {

		my $prefix = $1;

		my $ref = $2;

		my $base = $2;

		$ref =~ s/[\,\.]+$//;

		my $fulref = "$prefix$ref";

		$fulref =~ s/^(\<file|ref)://;

		$fulref =~ s/^[\'\`]+//;

		$fulref =~ s,^\$\(.*\)/,,;

		$base =~ s,.*/,,;

		# Remove URL false-positives

		next if ($fulref =~ m/^http/);

		# Check if exists, evaluating wildcards

		next if (grep -e, glob("$ref $fulref"));

		if ($fix) {

			if (!($ref =~ m/(devicetree|scripts|Kconfig|Kbuild)/)) {

				$broken_ref{$ref}++;

			}

		} else {

			print STDERR "$f: $fulref\n";

		}

	}

}

exit 0 if (!$fix);

# Step 2: Seek for file name alternatives

print "Auto-fixing broken references. Please double-check the results\n";

foreach my $ref (keys %broken_ref) {

	my $new =$ref;

	# get just the basename

	$new =~ s,.*/,,;

	# Seek for the same name on another place, as it may have been moved

	my $f="";

	$f = qx(find . -iname $new) if ($new);

	# usual reason for breakage: file renamed to .rst

	if (!$f) {

		$new =~ s/\.txt$/.rst/;

		$f=qx(find . -iname $new) if ($new);

	}

	my @find = split /\s+/, $f;

	if (!$f) {

		print STDERR "ERROR: Didn't find a replacement for $ref\n";

	} elsif (scalar(@find) > 1) {

		print STDERR "WARNING: Won't auto-replace, as found multiple files close to $ref:\n";

		foreach my $j (@find) {

			$j =~ s,^./,,;

			print STDERR "    $j\n";

		}

	} else {

		$f = $find[0];

		$f =~ s,^./,,;

		print "INFO: Replacing $ref to $f\n";

		foreach my $j (qx(git grep -l $ref)) {

			qx(sed "s\@$ref\@$f\@g" -i $j);

		}

	}

}