#!/usr/bin/perl -w
# Check a gnulib module.

# Copyright (C) 2005-2007, 2009-2021 Free Software Foundation, Inc.

# This file is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.


# Read a module description file and derive the set of files
# included directly by any .c or .h file listed in the 'Files:' section.
# Take the union of all such sets for any dependent modules.
# Then, compare that set with the set derived from the names
# listed in the various Files: sections.

# This script makes no attempt to diagnose invalid or empty
# module-description files.

# Written by Jim Meyering

# FIXME:
# for each .m4 file listed in the Files: section(s)
# parse it for AC_LIBSOURCES directives, and accumulate the set
# of files "required" via all AC_LIBSOURCES.
# If this set is not empty, ensure that it contains
# the same (.c and .h only?) files as are listed in the Files: sections.

use strict;
use Getopt::Long;
use File::Basename;
#use Coda;

my $COPYRIGHT_NOTICE = "Copyright (C) 2012 Free Software Foundation, Inc.\n".
"This is free software.  You may redistribute copies of it under the terms of\n".
"the GNU General Public License <https://www.gnu.org/licenses/gpl.html>.\n".
"There is NO WARRANTY, to the extent permitted by law.\n";

(my $VERSION = '$Revision: 1.8 $ ') =~ tr/[0-9].//cd;
(my $ME = $0) =~ s|.*/||;

use constant ST_INIT => 1;
use constant ST_FILES => 2;
use constant ST_DEPENDENTS => 3;

# Parse a module file (returning list of Files: names and
# list of dependent-modules.
# my ($file, $dep) = parse_module_file $module_file;
sub parse_module_file ($)
{
  my ($module_file) = @_;

  open FH, '<', $module_file
    or die "$ME: can't open '$module_file' for reading: $!\n";

  my %file_set;
  my %dep_set;

  my $state = ST_INIT;
  while (defined (my $line = <FH>))
    {
      if ($state eq ST_INIT)
	{
	  if ($line =~ /^Files:$/)
	    {
	      $state = ST_FILES;
	    }
	  elsif ($line =~ /^Depends-on:$/)
	    {
	      $state = ST_DEPENDENTS;
	    }
	}
      else
	{
	  chomp $line;
	  $line =~ s/^\s+//;
	  $line =~ s/\s+$//;
	  if ( ! $line)
	    {
	      $state = ST_INIT;
	      next;
	    }

	  if ($state eq ST_FILES)
	    {
	      $file_set{$line} = 1;
	    }
	  elsif ($state eq ST_DEPENDENTS)
	    {
	      $dep_set{$line} = 1;
	      (my $base = $module_file) =~ s,.*/,,;
	      $line eq $base
		and die "$ME: module $module_file depends on itself\n";
	    }
	}
    }
  close FH;

  # my @t = sort keys %file_set;
  # print "files: @t\n";
  # my @u = sort keys %dep_set;
  # print "dependents: @u\n";

  return (\%file_set, \%dep_set);
}

# Extract the set of files required for this module, including
# those required via dependent modules.

# Files:
# lib/stat.c
# m4/stat.m4
# lib/foo.h
#
# Depends-on:
# some-other-module

sub usage ($)
{
  my ($exit_code) = @_;
  my $STREAM = ($exit_code == 0 ? *STDOUT : *STDERR);
  if ($exit_code != 0)
    {
      print $STREAM "Try '$ME --help' for more information.\n";
    }
  else
    {
      print $STREAM <<EOF;
Usage: $ME [OPTIONS] FILE...

Read a module description file and derive the set of files
included directly by any .c or .h file listed in the 'Files:' section.
Take the union of all such sets for any dependent modules.
Then, compare that set with the set derived from the names
listed in the various Files: sections.

OPTIONS:

   --help             display this help and exit
   --version          output version information and exit

EOF
    }
  exit $exit_code;
}

sub find_included_lib_files ($)
{
  my ($file) = @_;

  # Special cases...
  my %special_non_dup = ( 'fnmatch_loop.c' => 1,
			  'regex.c' => 1, 'at-func.c' => 1,
			  'vasnprintf.c' => 1
			);
  my %dup_include_ok;
  $dup_include_ok{'vasnprintf.c'}{'isnand-nolibm.h'} = 1;
  $dup_include_ok{'vasnprintf.c'}{'isnanl-nolibm.h'} = 1;
  $dup_include_ok{'vasnprintf.c'}{'fpucw.h'} = 1;
  $dup_include_ok{'gen-uni-tables.c'}{'3level.h'} = 1;
  $dup_include_ok{'csharpexec.c'}{'classpath.c'} = 1;
  $dup_include_ok{'csharpexec.c'}{'classpath.h'} = 1;

  my %inc;
  open FH, '<', $file
    or die "$ME: can't open '$file' for reading: $!\n";

  while (defined (my $line = <FH>))
    {
      # Ignore test-driver code at end of file.
      $line =~ m!^\#if(def)? TEST_!
	and last;

      $line =~ m!^\s*\#\s*include\s+"!
	or next;
      $line =~ s///;
      chomp $line;
      $line =~ s/".*//;
      exists $inc{$line} && ! exists $special_non_dup{$line}
	  && ! exists $dup_include_ok{basename $file}{$line}
	and warn "$ME: $file: duplicate inclusion of $line\n";

      $inc{$line} = 1;
    }
  close FH;

  return \%inc;
}

my %exempt_header =
  (
   # Exempt headers like unlocked-io.h that are '#include'd
   # but not necessarily used.
   'unlocked-io.h' => 1,

   # Give gettext.h a free pass only when included from lib/error.c,
   # since we've made that exception solely to make the error
   # module easier to use -- at RMS's request.
   'lib/error.c:gettext.h' => 1,

   # The full-read module shares code with the full-write module.
   'lib/full-write.c:full-read.h' => 1,

   # The safe-write module shares code with the safe-read module.
   'lib/safe-read.c:safe-write.h' => 1,

   # The use of obstack.h in the hash module is conditional, off by default.
   'lib/hash.c:obstack.h' => 1,

   # C files in the gc module have conditional includes.
   'lib/gc-gnulib.c:des.h' => 1,
   'lib/gc-gnulib.c:arcfour.h' => 1,
   'lib/gc-gnulib.c:arctwo.h' => 1,
   'lib/gc-gnulib.c:md2.h' => 1,
   'lib/gc-gnulib.c:md4.h' => 1,
   'lib/gc-gnulib.c:md5.h' => 1,
   'lib/gc-gnulib.c:rijndael.h' => 1,
   'lib/gc-gnulib.c:sha1.h' => 1,
   'lib/gc-gnulib.c:rijndael-api-fst.h' => 1,
   'lib/gc-gnulib.c:hmac.h' => 1,
   'lib/gc-libgcrypt.c:md2.h' => 1,
  );

sub check_module ($)
{
  my @m = @_;

  my %file;
  my %module_all_files;
  my %dep;
  my %seen_module;

  while (@m)
    {
      my $m = pop @m;
      # warn "M: $m\n";
      exists $seen_module{$m}
	and next;
      $seen_module{$m} = 1;
      my ($file, $dep) = parse_module_file $m;
      push @m, keys %$dep;
      foreach my $f (keys %$file)
	{
	  $module_all_files{$f} = 1;
	}
    }

  my @t = sort keys %module_all_files;
  # warn "ALL files: @t\n";

  # Derive from %module_all_files (by parsing the .c and .h files therein),
  # the list of all #include'd files that reside in lib/.
  foreach my $f (keys %module_all_files)
    {
      $f =~ /\.[ch]$/
	or next;
      # FIXME: this is too naive
      my $inc = find_included_lib_files "../$f";
      foreach my $i (sort keys %$inc)
	{
	  my $lib_file = "lib/$i";
	  exists $exempt_header{"$f:$i"}
	    || exists $exempt_header{$i}
	      and next;
	  !exists $module_all_files{$lib_file} && -f "../lib/$i"
	    and warn "$f: $i is '#include'd, but not "
	      . "listed in module's Files: section\n";
	}
      #my @t = sort keys %$inc;
      #print "** $f: @t\n";
    }
}

{
  GetOptions
    (
     help => sub { usage 0 },
     version => sub { print "$ME version $VERSION\n$COPYRIGHT_NOTICE"; exit },
    ) or usage 1;

  @ARGV < 1
    and (warn "$ME: missing FILE argument\n"), usage 1;

  foreach my $module (@ARGV)
    {
      check_module $module;
    }

  exit 0;
}