# autoconf -- create `configure' using m4 macros

# Copyright (C) 2003, 2006, 2009-2012 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 Autom4te::C4che;

=head1 NAME

Autom4te::C4che - a single m4 run request

=head1 SYNOPSIS

  use Autom4te::C4che;

=head1 DESCRIPTION

This Perl module handles the cache of M4 runs used by autom4te.

=cut

use Data::Dumper;

use Autom4te::Request;

use Carp;

use strict;

=over 4

=item @request

List of requests.

We cannot declare it "my" as the loading, performed via "do", would

refer to another scope, and @request would not be updated.  It used to

work with "my" vars, and I do not know whether the current behavior

(5.6) is wanted or not.

=cut

use vars qw(@request);

=item C<$req = Autom4te::C4che-E<gt>retrieve (%attr)>

Find a request with the same path and input.

=cut

sub retrieve($%)

{

  my ($self, %attr) = @_;

  foreach (@request)

    {

      # Same path.

      next

	if join ("\n", @{$_->path}) ne join ("\n", @{$attr{path}});

      # Same inputs.

      next

	if join ("\n", @{$_->input}) ne join ("\n", @{$attr{input}});

      # Found it.

      return $_;

    }

  return undef;

}

=item C<$req = Autom4te::C4che-E<gt>register (%attr)>

Create and register a request for these path and input.

=cut

# $REQUEST-OBJ

# register ($SELF, %ATTR)

# -----------------------

# NEW should not be called directly.

# Private.

sub register ($%)

{

  my ($self, %attr) = @_;

  # path and input are the only ID for a request object.

  my $obj = new Autom4te::Request ('path'  => $attr{path},

				   'input' => $attr{input});

  push @request, $obj;

  # Assign an id for cache file.

  $obj->id ("$#request");

  return $obj;

}

=item C<$req = Autom4te::C4che-E<gt>request (%request)>

Get (retrieve or create) a request for the path C<$request{path}> and

the input C<$request{input}>.

=cut

# $REQUEST-OBJ

# request($SELF, %REQUEST)

# ------------------------

sub request ($%)

{

  my ($self, %request) = @_;

  my $req =

    Autom4te::C4che->retrieve (%request)

    || Autom4te::C4che->register (%request);

  # If there are new traces to produce, then we are not valid.

  foreach (@{$request{'macro'}})

    {

      if (! exists ${$req->macro}{$_})

	{

	  ${$req->macro}{$_} = 1;

	  $req->valid (0);

	}

    }

  # It would be great to have $REQ check that it is up to date wrt

  # its dependencies, but that requires getting traces (to fetch the

  # included files), which is out of the scope of Request (currently?).

  return $req;

}

=item C<$string = Autom4te::C4che-E<gt>marshall ()>

Serialize all the current requests.

=cut

# marshall($SELF)

# ---------------

sub marshall ($)

{

  my ($caller) = @_;

  my $res = '';

  my $marshall = Data::Dumper->new ([\@request], [qw (*request)]);

  $marshall->Indent(2)->Terse(0);

  $res = $marshall->Dump . "\n";

  return $res;

}

=item C<Autom4te::C4che-E<gt>save ($file)>

Save the cache in the C<$file> file object.

=cut

# SAVE ($FILE)

# ------------

sub save ($$)

{

  my ($self, $file) = @_;

  confess "cannot save a single request\n"

    if ref ($self);

  $file->seek (0, 0);

  $file->truncate (0);

  print $file

    "# This file was generated.\n",

    "# It contains the lists of macros which have been traced.\n",

    "# It can be safely removed.\n",

    "\n",

    $self->marshall;

}

=item C<Autom4te::C4che-E<gt>load ($file)>

Load the cache from the C<$file> file object.

=cut

# LOAD ($FILE)

# ------------

sub load ($$)

{

  my ($self, $file) = @_;

  my $fname = $file->name;

  confess "cannot load a single request\n"

    if ref ($self);

  my $contents = join "", $file->getlines;

  eval $contents;

  confess "cannot eval $fname: $@\n" if $@;

}

=head1 SEE ALSO

L<Autom4te::Request>

=head1 HISTORY

Written by Akim Demaille E<lt>F<akim@freefriends.org>E<gt>.

=cut

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