#!/usr/bin/perl

  # SPDX-License-Identifier: GPL-2.0

  
  use strict;
  use Pod::Usage;
  use Getopt::Long;
  use File::Find;
  use Fcntl ':mode';
  
  my $help;
  my $man;
  my $debug;

  my $prefix="Documentation/ABI";

  
  GetOptions(
  	"debug|d+" => \$debug,

  	"dir=s" => \$prefix,

  	'help|?' => \$help,
  	man => \$man
  ) or pod2usage(2);
  
  pod2usage(1) if $help;
  pod2usage(-exitstatus => 0, -verbose => 2) if $man;

  pod2usage(2) if (scalar @ARGV < 1 || @ARGV > 2);

  my ($cmd, $arg) = @ARGV;

  pod2usage(2) if ($cmd ne "search" && $cmd ne "rest" && $cmd ne "validate");

  pod2usage(2) if ($cmd eq "search" && !$arg);

  
  require Data::Dumper if ($debug);
  
  my %data;
  
  #
  # Displays an error message, printing file name and line
  #
  sub parse_error($$$$) {
  	my ($file, $ln, $msg, $data) = @_;
  
  	print STDERR "file $file#$ln: $msg at
  \t$data";
  }
  
  #
  # Parse an ABI file, storing its contents at %data
  #
  sub parse_abi {
  	my $file = $File::Find::name;
  
  	my $mode = (stat($file))[2];
  	return if ($mode & S_IFDIR);
  	return if ($file =~ m,/README,);
  
  	my $name = $file;
  	$name =~ s,.*/,,;

  	my $nametag = "File $name";
  	$data{$nametag}->{what} = "File $name";
  	$data{$nametag}->{type} = "File";
  	$data{$nametag}->{file} = $name;

  	$data{$nametag}->{filepath} = $file;

  	$data{$nametag}->{is_file} = 1;

  	my $type = $file;
  	$type =~ s,.*/(.*)/.*,$1,;
  
  	my $what;
  	my $new_what;
  	my $tag;
  	my $ln;

  	my $xrefs;

  	my $space;

  	my @labels;
  	my $label;

  
  	print STDERR "Opening $file
  " if ($debug > 1);
  	open IN, $file;
  	while(<IN>) {
  		$ln++;

  		if (m/^(\S+)(:\s*)(.*)/i) {

  			my $new_tag = lc($1);

  			my $sep = $2;
  			my $content = $3;

  			if (!($new_tag =~ m/(what|where|date|kernelversion|contact|description|users)/)) {

  				if ($tag eq "description") {

  					# New "tag" is actually part of
  					# description. Don't consider it a tag
  					$new_tag = "";

  				} elsif ($tag ne "") {

  					parse_error($file, $ln, "tag '$tag' is invalid", $_);
  				}
  			}

  			# Invalid, but it is a common mistake
  			if ($new_tag eq "where") {
  				parse_error($file, $ln, "tag 'Where' is invalid. Should be 'What:' instead", $_);
  				$new_tag = "what";
  			}

  			if ($new_tag =~ m/what/) {

  				$space = "";

  				if ($tag =~ m/what/) {
  					$what .= ", " . $content;
  				} else {

  					parse_error($file, $ln, "What '$what' doesn't have a description", "") if ($what && !$data{$what}->{description});

  					$what = $content;

  					$label = $content;

  					$new_what = 1;
  				}

  				push @labels, [($content, $label)];

  				$tag = $new_tag;

  				push @{$data{$nametag}->{xrefs}}, [($content, $label)] if ($data{$nametag}->{what});

  				next;
  			}

  			if ($tag ne "" && $new_tag) {

  				$tag = $new_tag;

  				if ($new_what) {

  					@{$data{$what}->{label}} = @labels if ($data{$nametag}->{what});
  					@labels = ();
  					$label = "";

  					$new_what = 0;

  					$data{$what}->{type} = $type;
  					$data{$what}->{file} = $name;

  					$data{$what}->{filepath} = $file;

  					print STDERR "\twhat: $what
  " if ($debug > 1);
  				}

  				if (!$what) {
  					parse_error($file, $ln, "'What:' should come first:", $_);
  					next;
  				}
  				if ($tag eq "description") {
  					next if ($content =~ m/^\s*$/);
  					if ($content =~ m/^(\s*)(.*)/) {
  						my $new_content = $2;
  						$space = $new_tag . $sep . $1;
  						while ($space =~ s/\t+/' ' x (length($&) * 8 - length($`) % 8)/e) {}
  						$space =~ s/./ /g;
  						$data{$what}->{$tag} .= "$new_content
  ";
  					}
  				} else {
  					$data{$what}->{$tag} = $content;
  				}

  				next;
  			}

  		}

  		# Store any contents before tags at the database

  		if (!$tag && $data{$nametag}->{what}) {
  			$data{$nametag}->{description} .= $_;

  			next;
  		}

  		if ($tag eq "description") {
  			if (!$data{$what}->{description}) {
  				next if (m/^\s*
  /);
  				if (m/^(\s*)(.*)/) {
  					$space = $1;
  					while ($space =~ s/\t+/' ' x (length($&) * 8 - length($`) % 8)/e) {}
  					$data{$what}->{$tag} .= "$2
  ";
  				}
  			} else {
  				my $content = $_;
  				if (m/^\s*
  /) {
  					$data{$what}->{$tag} .= $content;
  					next;
  				}
  
  				while ($content =~ s/\t+/' ' x (length($&) * 8 - length($`) % 8)/e) {}
  				$space = "" if (!($content =~ s/^($space)//));
  
  				# Compress spaces with tabs
  				$content =~ s<^ {8}> <\t>;
  				$content =~ s<^ {1,7}\t> <\t>;
  				$content =~ s< {1,7}\t> <\t>;
  				$data{$what}->{$tag} .= $content;
  			}
  			next;
  		}

  		if (m/^\s*(.*)/) {
  			$data{$what}->{$tag} .= "
  $1";
  			$data{$what}->{$tag} =~ s/
  +$//;
  			next;
  		}
  
  		# Everything else is error
  		parse_error($file, $ln, "Unexpected line:", $_);
  	}

  	$data{$nametag}->{description} =~ s/^
  +//;

  	close IN;
  }

  #
  # Outputs the book on ReST format
  #

  my %labels;

  sub output_rest {

  	foreach my $what (sort {
  				($data{$a}->{type} eq "File") cmp ($data{$b}->{type} eq "File") ||
  				$a cmp $b
  			       } keys %data) {

  		my $type = $data{$what}->{type};
  		my $file = $data{$what}->{file};

  		my $filepath = $data{$what}->{filepath};

  
  		my $w = $what;
  		$w =~ s/([\(\)\_\-\*\=\^\~\\])/\\$1/g;

  		foreach my $p (@{$data{$what}->{label}}) {
  			my ($content, $label) = @{$p};
  			$label = "abi_" . $label . " ";
  			$label =~ tr/A-Z/a-z/;
  
  			# Convert special chars to "_"
  			$label =~s/([\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\xff])/_/g;
  			$label =~ s,_+,_,g;
  			$label =~ s,_$,,;

  			# Avoid duplicated labels
  			while (defined($labels{$label})) {
  			    my @chars = ("A".."Z", "a".."z");
  			    $label .= $chars[rand @chars];
  			}
  			$labels{$label} = 1;

  			$data{$what}->{label} .= $label;
  
  			printf ".. _%s:
  
  ", $label;
  
  			# only one label is enough
  			last;

  		}

  		$filepath =~ s,.*/(.*/.*),\1,;;
  		$filepath =~ s,[/\-],_,g;;
  		my $fileref = "abi_file_".$filepath;
  
  		if ($type eq "File") {
  			my $bar = $w;
  			$bar =~ s/./-/g;
  
  			print ".. _$fileref:
  
  ";
  			print "$w
  $bar
  
  ";
  		} else {
  			my @names = split /\s*,\s*/,$w;
  
  			my $len = 0;
  
  			foreach my $name (@names) {
  				$len = length($name) if (length($name) > $len);
  			}
  
  			print "What:
  
  ";
  
  			print "+-" . "-" x $len . "-+
  ";
  			foreach my $name (@names) {
  				printf "| %s", $name . " " x ($len - length($name)) . " |
  ";
  				print "+-" . "-" x $len . "-+
  ";
  			}
  			print "
  ";
  		}
  
  		print "Defined on file :ref:`$file <$fileref>`
  
  " if ($type ne "File");

  
  		my $desc = $data{$what}->{description};
  		$desc =~ s/^\s+//;
  
  		# Remove title markups from the description, as they won't work
  		$desc =~ s/
  [\-\*\=\^\~]+
  /
  /g;

  		if (!($desc =~ /^\s*$/)) {
  			if ($desc =~ m/\:
  / || $desc =~ m/
  [\t ]+/  || $desc =~ m/[\x00-\x08\x0b-\x1f\x7b-\xff]/) {
  				# put everything inside a code block
  				$desc =~ s/
  /
   /g;

  				print "::
  
  ";
  				print " $desc
  
  ";
  			} else {
  				# Escape any special chars from description
  				$desc =~s/([\x00-\x08\x0b-\x1f\x21-\x2a\x2d\x2f\x3c-\x40\x5c\x5e-\x60\x7b-\xff])/\\$1/g;

  				print "$desc
  
  ";
  			}

  		} else {

  			print "DESCRIPTION MISSING for $what
  
  " if (!$data{$what}->{is_file});

  		}

  		if ($data{$what}->{xrefs}) {
  			printf "Has the following ABI:
  
  ";
  
  			foreach my $p(@{$data{$what}->{xrefs}}) {
  				my ($content, $label) = @{$p};
  				$label = "abi_" . $label . " ";
  				$label =~ tr/A-Z/a-z/;
  
  				# Convert special chars to "_"
  				$label =~s/([\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\xff])/_/g;
  				$label =~ s,_+,_,g;
  				$label =~ s,_$,,;
  
  				# Escape special chars from content
  				$content =~s/([\x00-\x1f\x21-\x2f\x3a-\x40\x7b-\xff])/\\$1/g;
  
  				print "- :ref:`$content <$label>`
  
  ";
  			}
  		}

  	}
  }
  
  #

  # Searches for ABI symbols
  #
  sub search_symbols {
  	foreach my $what (sort keys %data) {
  		next if (!($what =~ m/($arg)/));
  
  		my $type = $data{$what}->{type};
  		next if ($type eq "File");
  
  		my $file = $data{$what}->{filepath};
  
  		my $bar = $what;
  		$bar =~ s/./-/g;
  
  		print "
  $what
  $bar
  
  ";
  
  		my $kernelversion = $data{$what}->{kernelversion};
  		my $contact = $data{$what}->{contact};
  		my $users = $data{$what}->{users};
  		my $date = $data{$what}->{date};
  		my $desc = $data{$what}->{description};
  		$kernelversion =~ s/^\s+//;
  		$contact =~ s/^\s+//;
  		$users =~ s/^\s+//;
  		$users =~ s/
  //g;
  		$date =~ s/^\s+//;
  		$desc =~ s/^\s+//;
  
  		printf "Kernel version:\t\t%s
  ", $kernelversion if ($kernelversion);
  		printf "Date:\t\t\t%s
  ", $date if ($date);
  		printf "Contact:\t\t%s
  ", $contact if ($contact);
  		printf "Users:\t\t\t%s
  ", $users if ($users);
  		print "Defined on file:\t$file
  
  ";
  		print "Description:
  
  $desc";
  	}
  }
  
  
  #

  # Parses all ABI files located at $prefix dir
  #
  find({wanted =>\&parse_abi, no_chdir => 1}, $prefix);
  
  print STDERR Data::Dumper->Dump([\%data], [qw(*data)]) if ($debug);
  
  #

  # Handles the command

  #

  if ($cmd eq "rest") {
  	output_rest;

  } elsif ($cmd eq "search") {

  	search_symbols;
  }

  
  
  __END__
  
  =head1 NAME
  
  abi_book.pl - parse the Linux ABI files and produce a ReST book.
  
  =head1 SYNOPSIS

  B<abi_book.pl> [--debug] [--man] [--help] [--dir=<dir>] <COMAND> [<ARGUMENT>]

  
  Where <COMMAND> can be:
  
  =over 8
  
  B<search> [SEARCH_REGEX] - search for [SEARCH_REGEX] inside ABI

  B<rest>                  - output the ABI in ReST markup language
  
  B<validate>              - validate the ABI contents

  
  =back

  
  =head1 OPTIONS
  
  =over 8

  =item B<--dir>
  
  Changes the location of the ABI search. By default, it uses
  the Documentation/ABI directory.

  =item B<--debug>
  
  Put the script in verbose mode, useful for debugging. Can be called multiple
  times, to increase verbosity.
  
  =item B<--help>
  
  Prints a brief help message and exits.
  
  =item B<--man>
  
  Prints the manual page and exits.
  
  =back
  
  =head1 DESCRIPTION

  Parse the Linux ABI files from ABI DIR (usually located at Documentation/ABI),
  allowing to search for ABI symbols or to produce a ReST book containing
  the Linux ABI documentation.
  
  =head1 EXAMPLES
  
  Search for all stable symbols with the word "usb":
  
  =over 8
  
  $ scripts/get_abi.pl search usb --dir Documentation/ABI/stable
  
  =back
  
  Search for all symbols that match the regex expression "usb.*cap":
  
  =over 8
  
  $ scripts/get_abi.pl search usb.*cap
  
  =back
  
  Output all obsoleted symbols in ReST format
  
  =over 8
  
  $ scripts/get_abi.pl rest --dir Documentation/ABI/obsolete
  
  =back

  
  =head1 BUGS

  Report bugs to Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

  
  =head1 COPYRIGHT

  Copyright (c) 2016-2019 by Mauro Carvalho Chehab <mchehab+samsung@kernel.org>.

  
  License GPLv2: GNU GPL version 2 <http://gnu.org/licenses/gpl.html>.
  
  This is free software: you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law.
  
  =cut