################################################################################
##
##  $Revision: 19 $
##  $Author: mhx $
##  $Date: 2004/08/16 10:58:27 +0200 $
##
################################################################################
##
##  Version 3.x, Copyright (C) 2004, Marcus Holland-Moritz.
##  Version 2.x, Copyright (C) 2001, Paul Marquess.
##  Version 1.x, Copyright (C) 1999, Kenneth Albanowski.
##
##  This program is free software; you can redistribute it and/or
##  modify it under the same terms as Perl itself.
##
################################################################################

=provides

=implementation

=cut

use strict;

my %opt = (
  quiet     => 0,
  diag      => 1,
  hints     => 1,
  changes   => 1,
  cplusplus => 0,
);

my($ppport) = $0 =~ /([\w.]+)$/;
my $LF = '(?:\r\n|[\r\n])';   # line feed
my $HS = "[ \t]";             # horizontal whitespace

eval {
  require Getopt::Long;
  Getopt::Long::GetOptions(\%opt, qw(
    help quiet diag! hints! changes! cplusplus
    patch=s copy=s diff=s compat-version=s
    list-provided list-unsupported
  )) or usage();
};

if ($@ and grep /^-/, @ARGV) {
  usage() if "@ARGV" =~ /^--?h(?:elp)?$/;
  die "Getopt::Long not found. Please don't use any options.\n";
}

usage() if $opt{help};

if (exists $opt{'compat-version'}) {
  my($r,$v,$s) = eval { parse_version($opt{'compat-version'}) };
  if ($@) {
    die "Invalid version number format: '$opt{'compat-version'}'\n";
  }
  die "Only Perl 5 is supported\n" if $r != 5;
  die "Invalid version number: $opt{'compat-version'}\n" if $v >= 1000 || $v >= 1000;
  $opt{'compat-version'} = sprintf "%d.%03d%03d", $r, $v, $s;
}
else {
  $opt{'compat-version'} = 5;
}

# Never use C comments in this file!!!!!
my $ccs  = '/'.'*';
my $cce  = '*'.'/';
my $rccs = quotemeta $ccs;
my $rcce = quotemeta $cce;

my @files;

if (@ARGV) {
  @files = map { glob $_ } @ARGV;
}
else {
  eval {
    require File::Find;
    File::Find::find(sub {
      $File::Find::name =~ /\.(xs|c|h|cc)$/i
          and push @files, $File::Find::name;
    }, '.');
  };
  if ($@) {
    @files = map { glob $_ } qw(*.xs *.c *.h *.cc);
  }
  my %filter = map { /(.*)\.xs$/ ? ("$1.c" => 1) : () } @files;
  @files = grep { !/\b\Q$ppport\E$/i && !exists $filter{$_} } @files;
}

unless (@files) {
  die "No input files given!\n";
}

my %API = map { /^(\w+)\|([^|]*)\|([^|]*)\|(\w*)$/
                ? ( $1 => { 
                      ($2                  ? ( base     => $2 ) : ()),
                      ($3                  ? ( todo     => $3 ) : ()),
                      (index($4, 'v') >= 0 ? ( varargs  => 1  ) : ()),
                      (index($4, 'p') >= 0 ? ( provided => 1  ) : ()),
                      (index($4, 'n') >= 0 ? ( nothxarg => 1  ) : ()),
                    } )
                : die "invalid spec: $_" } qw(
__PERL_API__
);

if (exists $opt{'list-unsupported'}) {
  my $f;
  for $f (sort { lc $a cmp lc $b } keys %API) {
    next unless $API{$f}{todo};
    print "$f ", '.'x(40-length($f)), " ", format_version($API{$f}{todo}), "\n";
  }
  exit 0;
}

# Scan for possible replacement candidates

my(%replace, %need, %hints, %depends);
my $replace = 0;
my $hint = '';

while (<DATA>) {
  if ($hint) {
    if (m{^\s*\*\s(.*?)\s*$}) {
      $hints{$hint} ||= '';  # suppress warning with older perls
      $hints{$hint} .= "$1\n";
    }
    else {
      $hint = '';
    }
  }
  $hint = $1 if m{^\s*$rccs\sHint:\s+(\w+)\s*$};

  $replace     = $1 if m{^\s*$rccs\s+Replace:\s+(\d+)\s+$rcce\s*$};
  $replace{$2} = $1 if $replace and m{^\s*#\s*define\s+(\w+)(?:\([^)]*\))?\s+(\w+)};
  $replace{$2} = $1 if m{^\s*#\s*define\s+(\w+)(?:\([^)]*\))?\s+(\w+).*$rccs\s+Replace\s+$rcce};
  $replace{$1} = $2 if m{^\s*$rccs\s+Replace (\w+) with (\w+)\s+$rcce\s*$};

  if (m{^\s*$rccs\s+(\w+)\s+depends\s+on\s+(\w+(\s*,\s*\w+)*)\s+$rcce\s*$}) {
    push @{$depends{$1}}, map { s/\s+//g; $_ } split /,/, $2;
  }

  $need{$1} = 1 if m{^#if\s+defined\(NEED_(\w+)(?:_GLOBAL)?\)};
}

if (exists $opt{'list-provided'}) {
  my $f;
  for $f (sort { lc $a cmp lc $b } keys %API) {
    next unless $API{$f}{provided};
    my @flags;
    push @flags, 'explicit' if exists $need{$f};
    push @flags, 'depend'   if exists $depends{$f};
    push @flags, 'hint'     if exists $hints{$f};
    my $flags = @flags ? '  ['.join(', ', @flags).']' : '';
    print "$f$flags\n";
  }
  exit 0;
}

my(%files, %global, %revreplace);
%revreplace = reverse %replace;
my $filename;
my $patch_opened = 0;

for $filename (@files) {
  unless (open IN, "<$filename") {
    warn "Unable to read from $filename: $!\n";
    next;
  }

  info("Scanning $filename ...");

  my $c = do { local $/; <IN> };
  close IN;

  my %file = (orig => $c, changes => 0);

  # temporarily remove C comments from the code
  my @ccom;
  $c =~ s{
    (
        [^"'/]+
      |
        (?:"[^"\\]*(?:\\.[^"\\]*)*" [^"'/]*)+
      |
        (?:'[^'\\]*(?:\\.[^'\\]*)*' [^"'/]*)+
    )
  |
    (/ (?:
        \*[^*]*\*+(?:[^$ccs][^*]*\*+)* /
        |
        /[^\r\n]*
      ))
  }{
    defined $2 and push @ccom, $2;
    defined $1 ? $1 : "$ccs$#ccom$cce";
  }egsx;

  $file{ccom} = \@ccom;
  $file{code} = $c;
  $file{has_inc_ppport} = ($c =~ /#.*include.*\Q$ppport\E/);

  my $func;

  for $func (keys %API) {
    my $match = $func;
    $match .= "|$revreplace{$func}" if exists $revreplace{$func};
    if ($c =~ /\b(?:Perl_)?($match)\b/) {
      $file{uses_replace}{$1}++ if exists $revreplace{$func} && $1 eq $revreplace{$func};
      $file{uses_Perl}{$func}++ if $c =~ /\bPerl_$func\b/;
      if (exists $API{$func}{provided}) {
        if (!exists $API{$func}{base} || $API{$func}{base} > $opt{'compat-version'}) {
          $file{uses}{$func}++;
          push @{$global{uses}{$func}}, $filename;
          my @deps = rec_depend($func);
          if (@deps) {
            $file{uses_deps}{$func} = \@deps;
            for (@deps) {
              $file{uses}{$_} = 0 unless exists $file{uses}{$_};
              push @{$global{uses}{$_}}, $filename;
            }
          }
          for ($func, @deps) {
            if (exists $need{$_}) {
              $file{needs}{$_} = 'static';
              push @{$global{needs}{$_}}, $filename;
            }
          }
        }
      }
      if (exists $API{$func}{todo} && $API{$func}{todo} > $opt{'compat-version'}) {
        if ($c =~ /\b$func\b/) {
          $file{uses_todo}{$func}++;
          push @{$global{uses_todo}{$func}}, $filename;
        }
      }
    }
  }

  while ($c =~ /^$HS*#$HS*define$HS+(NEED_(\w+?)(_GLOBAL)?)\b/mg) {
    if (exists $need{$2}) {
      $file{defined $3 ? 'needed_global' : 'needed_static'}{$2}++;
      push @{$global{defined $3 ? 'needed_global' : 'needed_static'}{$2}}, $filename;
    }
    else {
      warning("Possibly wrong #define $1 in $filename");
    }
  }

  $files{$filename} = \%file;
}

# Globally resolve NEED_'s
my $need;
for $need (keys %{$global{needs}}) {
  if (@{$global{needs}{$need}} > 1) {
    my @targets = @{$global{needs}{$need}};
    my @t = grep $files{$_}{needed_global}{$need}, @targets;
    @targets = @t if @t;
    @t = grep /\.xs$/i, @targets;
    @targets = @t if @t;
    my $target = shift @targets;
    $files{$target}{needs}{$need} = 'global';
    for (@{$global{needs}{$need}}) {
      $files{$_}{needs}{$need} = 'extern' if $_ ne $target;
    }
  }
}

for $filename (@files) {
  exists $files{$filename} or next;

  info("=== Analyzing $filename ===");

  my %file = %{$files{$filename}};
  my $func;
  my $c = $file{code};

  for $func (sort keys %{$file{uses_Perl}}) {
    if ($API{$func}{varargs}) {
      my $changes = ($c =~ s{\b(Perl_$func\s*\(\s*)(?!aTHX_?)(\)|[^\s)]*\))}
                            { $1 . ($2 eq ')' ? 'aTHX' : 'aTHX_ ') . $2 }ge);
      if ($changes) {
        warning("Doesn't pass interpreter argument aTHX to Perl_$func");
        $file{changes} += $changes;
      }
    }
    else {
      warning("Uses Perl_$func instead of $func");
      $file{changes} += ($c =~ s{\bPerl_$func(\s*)\((\s*aTHX_?)?\s*}
                                {$func$1(}g);
    }
  }

  for $func (sort keys %{$file{uses_replace}}) {
    warning("Uses $func instead of $replace{$func}");
    $file{changes} += ($c =~ s/\b$func\b/$replace{$func}/g);
  }

  for $func (sort keys %{$file{uses}}) {
    next unless $file{uses}{$func};   # if it's only a dependency
    if (exists $file{uses_deps}{$func}) {
      diag("Uses $func, which depends on ", join(', ', @{$file{uses_deps}{$func}}));
    }
    elsif (exists $replace{$func}) {
      warning("Uses $func instead of $replace{$func}");
      $file{changes} += ($c =~ s/\b$func\b/$replace{$func}/g);
    }
    else {
      diag("Uses $func");
    }
    hint($func);
  }

  for $func (sort keys %{$file{uses_todo}}) {
    warning("Uses $func, which may not be portable below perl ",
            format_version($API{$func}{todo}));
  }

  for $func (sort keys %{$file{needed_static}}) {
    my $message = '';
    if (not exists $file{uses}{$func}) {
      $message = "No need to define NEED_$func if $func is never used";
    }
    elsif (exists $file{needs}{$func} && $file{needs}{$func} ne 'static') {
      $message = "No need to define NEED_$func when already needed globally";
    }
    if ($message) {
      diag($message);
      $file{changes} += ($c =~ s/^$HS*#$HS*define$HS+NEED_$func\b.*$LF//mg);
    }
  }

  for $func (sort keys %{$file{needed_global}}) {
    my $message = '';
    if (not exists $global{uses}{$func}) {
      $message = "No need to define NEED_${func}_GLOBAL if $func is never used";
    }
    elsif (exists $file{needs}{$func}) {
      if ($file{needs}{$func} eq 'extern') {
        $message = "No need to define NEED_${func}_GLOBAL when already needed globally";
      }
      elsif ($file{needs}{$func} eq 'static') {
        $message = "No need to define NEED_${func}_GLOBAL when only used in this file";
      }
    }
    if ($message) {
      diag($message);
      $file{changes} += ($c =~ s/^$HS*#$HS*define$HS+NEED_${func}_GLOBAL\b.*$LF//mg);
    }
  }

  $file{needs_inc_ppport} = keys %{$file{uses}};

  if ($file{needs_inc_ppport}) {
    my $pp = '';

    for $func (sort keys %{$file{needs}}) {
      my $type = $file{needs}{$func};
      next if $type eq 'extern';
      my $suffix = $type eq 'global' ? '_GLOBAL' : '';
      unless (exists $file{"needed_$type"}{$func}) {
        if ($type eq 'global') {
          diag("Files [@{$global{needs}{$func}}] need $func, adding global request");
        }
        else {
          diag("File needs $func, adding static request");
        }
        $pp .= "#define NEED_$func$suffix\n";
      }
    }

    if ($pp && ($c =~ s/^(?=$HS*#$HS*define$HS+NEED_\w+)/$pp/m)) {
      $pp = '';
      $file{changes}++;
    }

    unless ($file{has_inc_ppport}) {
      diag("Needs to include '$ppport'");
      $pp .= qq(#include "$ppport"\n)
    }

    if ($pp) {
      $file{changes} += ($c =~ s/^($HS*#$HS*define$HS+NEED_\w+.*?)^/$1$pp/ms)
                     || ($c =~ s/^(?=$HS*#$HS*include.*\Q$ppport\E)/$pp/m)
                     || ($c =~ s/^($HS*#$HS*include.*XSUB.*\s*?)^/$1$pp/m)
                     || ($c =~ s/^/$pp/);
    }
  }
  else {
    if ($file{has_inc_ppport}) {
      diag("No need to include '$ppport'");
      $file{changes} += ($c =~ s/^$HS*?#$HS*include.*\Q$ppport\E.*?$LF//m);
    }
  }

  # put back in our C comments
  my $ix;
  my $cppc = 0;
  my @ccom = @{$file{ccom}};
  for $ix (0 .. $#ccom) {
    if (!$opt{cplusplus} && $ccom[$ix] =~ s!^//!!) {
      $cppc++;
      $file{changes} += $c =~ s/$rccs$ix$rcce/$ccs$ccom[$ix] $cce/;
    }
    else {
      $c =~ s/$rccs$ix$rcce/$ccom[$ix]/;
    }
  }

  if ($cppc) {
    my $s = $cppc != 1 ? 's' : '';
    warning("Uses $cppc C++ style comment$s, which is not portable");
  }

  if ($file{changes}) {
    if (exists $opt{copy}) {
      my $newfile = "$filename$opt{copy}";
      if (-e $newfile) {
        error("'$newfile' already exists, refusing to write copy of '$filename'");
      }
      else {
        local *F;
        if (open F, ">$newfile") {
          info("Writing copy of '$filename' with changes to '$newfile'");
          print F $c;
          close F;
        }
        else {
          error("Cannot open '$newfile' for writing: $!");
        }
      }
    }
    elsif (exists $opt{patch} || $opt{changes}) {
      if (exists $opt{patch}) {
        unless ($patch_opened) {
          if (open PATCH, ">$opt{patch}") {
            $patch_opened = 1;
          }
          else {
            error("Cannot open '$opt{patch}' for writing: $!");
            delete $opt{patch};
            $opt{changes} = 1;
            goto fallback;
          }
        }
        mydiff(\*PATCH, $filename, $c);
      }
      else {
fallback:
        info("Suggested changes:");
        mydiff(\*STDOUT, $filename, $c);
      }
    }
    else {
      my $s = $file{changes} == 1 ? '' : 's';
      info("$file{changes} potentially required change$s detected");
    }
  }
  else {
    info("Looks good");
  }
}

close PATCH if $patch_opened;

exit 0;

#######################################################################

sub mydiff
{
  local *F = shift;
  my($file, $str) = @_;
  my $diff;

  if (exists $opt{diff}) {
    $diff = run_diff($opt{diff}, $file, $str);
  }

  if (!defined $diff and can_use('Text::Diff')) {
    $diff = Text::Diff::diff($file, \$str, { STYLE => 'Unified' });
    $diff = <<HEADER . $diff;
--- $file
+++ $file.patched
HEADER
  }

  if (!defined $diff) {
    $diff = run_diff('diff -u', $file, $str);
  }

  if (!defined $diff) {
    $diff = run_diff('diff', $file, $str);
  }

  if (!defined $diff) {
    error("Cannot generate a diff. Please install Text::Diff or use --copy.");
    return;
  }

  print F $diff;

}

sub run_diff
{
  my($prog, $file, $str) = @_;
  my $tmp = 'dppptemp';
  my $suf = 'aaa';
  my $diff = '';
  local *F;

  while (-e "$tmp.$suf") { $suf++ }
  $tmp = "$tmp.$suf";

  if (open F, ">$tmp") {
    print F $str;
    close F;

    if (open F, "$prog $file $tmp |") {
      while (<F>) {
        s/\Q$tmp\E/$file.patched/;
        $diff .= $_;
      }
      close F;
      unlink $tmp;
      return $diff;
    }

    unlink $tmp;
  }
  else {
    error("Cannot open '$tmp' for writing: $!");
  }

  return undef;
}

sub can_use
{
  eval "use @_;";
  return $@ eq '';
}

sub rec_depend
{
  my $func = shift;
  return () unless exists $depends{$func};
  map { ($_, rec_depend($_)) } @{$depends{$func}};
}

sub parse_version
{
  my $ver = shift;

  if ($ver =~ /^(\d+)\.(\d+)\.(\d+)$/) {
    return ($1, $2, $3);
  }
  elsif ($ver !~ /^\d+\.[\d_]+$/) {
    die "cannot parse version '$ver'\n";
  }

  $ver =~ s/_//g;
  $ver =~ s/$/000000/;

  my($r,$v,$s) = $ver =~ /(\d+)\.(\d{3})(\d{3})/;

  $v = int $v;
  $s = int $s;

  if ($r < 5 || ($r == 5 && $v < 6)) {
    if ($s % 10) {
      die "cannot parse version '$ver'\n";
    }
  }

  return ($r, $v, $s);
}

sub format_version
{
  my $ver = shift;

  $ver =~ s/$/000000/;
  my($r,$v,$s) = $ver =~ /(\d+)\.(\d{3})(\d{3})/;

  $v = int $v;
  $s = int $s;

  if ($r < 5 || ($r == 5 && $v < 6)) {
    if ($s % 10) {
      die "invalid version '$ver'\n";
    }
    $s /= 10;

    $ver = sprintf "%d.%03d", $r, $v;
    $s > 0 and $ver .= sprintf "_%02d", $s;

    return $ver;
  }

  return sprintf "%d.%d.%d", $r, $v, $s;
}

sub info
{
  $opt{quiet} and return;
  print @_, "\n";
}

sub diag
{
  $opt{quiet} and return;
  $opt{diag} and print @_, "\n";
}

sub warning
{
  $opt{quiet} and return;
  print "*** ", @_, "\n";
}

sub error
{
  print "*** ERROR: ", @_, "\n";
}

my %given_hints;
sub hint
{
  $opt{quiet} and return;
  $opt{hints} or return;
  my $func = shift;
  exists $hints{$func} or return;
  $given_hints{$func}++ and return;
  my $hint = $hints{$func};
  $hint =~ s/^/   /mg;
  print "   --- hint for $func ---\n", $hint;
}

sub usage
{
  my($usage) = do { local(@ARGV,$/)=($0); <> } =~ /^=head\d$HS+SYNOPSIS\s*^(.*?)\s*^=/ms;
  my %M = ( 'I' => '*' );
  $usage =~ s/^\s*perl\s+\S+/$^X $0/;
  $usage =~ s/([A-Z])<([^>]+)>/$M{$1}$2$M{$1}/g;

  print <<ENDUSAGE;

Usage: $usage

See perldoc $0 for details.

ENDUSAGE

  exit 2;
}