# Copyright 2014, 2015 Free Software Foundation, Inc.
#
# This program 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 <http://www.gnu.org/licenses/>.

package Texinfo::Convert::Paragraph;

use DynaLoader;

# same as texi2any.pl, although I don't know what the real requirement
# is for this module.
use 5.00405;
use strict;
use warnings;

require Exporter;

our @ISA = qw(Exporter DynaLoader);

# Items to export into callers namespace by default. Note: do not export
# names by default without a very good reason. Use EXPORT_OK instead.
# Do not simply export all your public functions/methods/constants.

# This allows declaration	use XSParagraph ':all';
# If you do not need this, moving things directly into @EXPORT or @EXPORT_OK
# will save memory.
our %EXPORT_TAGS = ( 'all' => [ qw(
    add_next
    add_text
	
) ] );

our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );

our @EXPORT = qw(
	
);

BEGIN {

my $module = "Texinfo::Convert::XSParagraph::XSParagraph";
our $VERSION = '6.0dev';
# Module interface number, to be changed when the XS interface changes.  
# The value used for the .xs file compilation is set in configure.ac.  
# Both should correspond, but it should be manually changed here to make
# sure that a changed interface has not been missed.
my $XSPARAGRAPH_INTERFACE_VERSION = "1";

# Possible values for TEXINFO_XS environment variable:
#
# TEXINFO_XS=omit         # don't try loading xs at all
# TEXINFO_XS=default      # try xs, libtool and then perl paths, silent fallback
# TEXINFO_XS=libtool      # try xs, libtool only, silent fallback
# TEXINFO_XS=standalone   # try xs, perl paths only, silent fallback
# TEXINFO_XS=warn         # try xs, libtool and then perl paths, warn on failure
# TEXINFO_XS=required     # abort if not loadable, no fallback
# TEXINFO_XS=debug        # voluminuous debugging
#
# Other values are treated at the moment as 'default'.

my $TEXINFO_XS = $ENV{'TEXINFO_XS'};
if (!defined($TEXINFO_XS)) {
  $TEXINFO_XS = '';
}

if ($TEXINFO_XS eq 'omit') {
  # Don't try to use the XS module
  goto FALLBACK;
}

# For verbose information about what's being done
sub _debug($) {
  if ($TEXINFO_XS eq 'debug') {
    my $msg = shift;
    warn $msg . "\n";
  }
}

# For messages to say that XS module couldn't be loaded
sub _fatal($) {
  if ($TEXINFO_XS eq 'debug'
      or $TEXINFO_XS eq 'required'
      or $TEXINFO_XS eq 'warn') {
    my $msg = shift;
    warn $msg . "\n";
  }
}

# We look for the .la and .so files in @INC because this allows us to override
# which modules are used using -I flags to "perl".
sub _find_file($) {
  my $file = shift;
  for my $dir (@INC) {
    _debug "checking $dir/$file";
    if (-f "$dir/$file") {
      _debug "found $dir/$file";
      return ($dir, "$dir/$file");
    }
  }
  return undef;
}

our $disable_XS;
if ($disable_XS) {
  _fatal "use of XS modules was disabled when Texinfo was built";
  goto FALLBACK;
}

my ($libtool_dir, $libtool_archive);
if ($TEXINFO_XS ne 'stand-alone') {
  ($libtool_dir, $libtool_archive) = _find_file("XSParagraph.la");
  if (!$libtool_archive) {
    if ($TEXINFO_XS eq 'libtool') {
      _fatal "XSParagraph: couldn't find Libtool archive file";
      goto FALLBACK;
    }
    _debug "XSParagraph: couldn't find Libtool archive file";
  }
}

my $dlname = undef;
my $dlpath = undef;

# Try perl paths
if (!$libtool_archive) {
  my @modparts = split(/::/,$module);
  my $dlname = $modparts[-1];
  my $modpname = join('/',@modparts);
  # the directories with -L prepended setup directories to
  # be in the search path. Then $dlname is prepended as it is
  # the name really searched for.
  $dlpath = DynaLoader::dl_findfile(map("-L$_/auto/$modpname", @INC), $dlname);
  if (!$dlpath) {
    _fatal "XSParagraph: couldn't find $module";
    goto FALLBACK;
  }
  goto LOAD;
}

my $fh;
open $fh, $libtool_archive;
if (!$fh) {
  _fatal "XSParagraph: couldn't open Libtool archive file";
  goto FALLBACK;
}

# Look for the line in XSParagraph.la giving the name of the loadable object.
while (my $line = <$fh>) {
  if ($line =~ /^\s*dlname\s*=\s*'([^']+)'\s$/) {
    $dlname = $1;
    last;
  }
}
if (!$dlname) {
  _fatal "XSParagraph: couldn't find name of shared object";
  goto FALLBACK;
}

# The *.so file is under .libs in the source directory.
push @DynaLoader::dl_library_path, $libtool_dir;
push @DynaLoader::dl_library_path, "$libtool_dir/.libs";

$dlpath = DynaLoader::dl_findfile($dlname);
if (!$dlpath) {
  _fatal "XSParagraph: couldn't find $dlname";
  goto FALLBACK;
}

LOAD:

#print STDERR "loadable object is at $dlpath\n";

# Following steps under "bootstrap" in "man DynaLoader".
#bootstrap XSParagraph $VERSION;

# TODO: Execute blib/arch/auto/XSParagraph/XSParagraph.bs ?
# That file is empty.

#my $flags = dl_load_flags $module; # This is 0 in DynaLoader
my $flags = 0;
my $libref = DynaLoader::dl_load_file($dlpath, $flags);
if (!$libref) {
  _fatal "XSParagraph: couldn't load file $dlpath";
  goto FALLBACK;
}
_debug "$dlpath loaded";
my @undefined_symbols = DynaLoader::dl_undef_symbols();
if ($#undefined_symbols+1 != 0) {
  _fatal "XSParagraph: still have undefined symbols after dl_load_file";
}
my $bootname = "boot_$module";
$bootname =~ s/:/_/g;
_debug "looking for $bootname";
my $symref = DynaLoader::dl_find_symbol($libref, $bootname);
if (!$symref) {
  _fatal "XSParagraph: couldn't find $bootname symbol";
  goto FALLBACK;
}
my $boot_fn = DynaLoader::dl_install_xsub("${module}::bootstrap",
                                                $symref, $dlname);

if (!$boot_fn) {
  _fatal "XSParagraph: couldn't bootstrap";
  goto FALLBACK;
}

push @DynaLoader::dl_shared_objects, $dlpath; # record files loaded

# This is the module bootstrap function, which causes all the other
# functions (XSUB's) provided by the module to become available to
# be called from Perl code.
&$boot_fn($module, $XSPARAGRAPH_INTERFACE_VERSION);

if (!Texinfo::Convert::XSParagraph::XSParagraph::init ()) {
  _fatal "XSParagraph: error initializing";
  goto FALLBACK;
}
*Texinfo::Convert::Paragraph:: = *Texinfo::Convert::XSParagraph::XSParagraph::;
goto DONTFALLBACK;

FALLBACK:
  if ($TEXINFO_XS eq 'required') {
    die "unset the TEXINFO_XS environment variable to use the "
       ."pure Perl modules\n";
  } elsif ($TEXINFO_XS eq 'warn' or $TEXINFO_XS eq 'debug') {
    warn "falling back to pure Perl modules\n";
  }
  # Fall back to using the Perl code.
  require Texinfo::Convert::ParagraphNonXS;
  *Texinfo::Convert::Paragraph:: = *Texinfo::Convert::ParagraphNonXS::;
DONTFALLBACK: ;
} # end BEGIN

# NB Don't add more functions down here, because this can cause an error
# with some versions of Perl, connected with the typeglob assignment just
# above.  ("Can't call mro_method_changed_in() on anonymous symbol table").
#
# See http://perl5.git.perl.org/perl.git/commitdiff/03d9f026ae253e9e69212a3cf6f1944437e9f070?hp=ac73ea1ec401df889d312b067f78b618f7ffecc3
#
# (change to Perl interpreter on 22 Oct 2011)


1;
__END__
