# Copyright © 2007-2009 Raphaël Hertzog <hertzog@debian.org>
#
# 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 2 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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

package Dpkg::Control::Fields;

use strict;
use warnings;

use base qw(Exporter);
use Dpkg::Gettext;
use Dpkg::ErrorHandling;
use Dpkg::Control::Types;
use Dpkg::Checksums qw(@check_supported %check_supported);
use Dpkg::Vendor qw(run_vendor_hook);

our @EXPORT = qw(field_capitalize field_is_official field_is_allowed_in
                 field_transfer_single field_transfer_all
                 field_list_src_dep field_list_pkg_dep field_get_dep_type
                 field_ordered_list field_register
                 field_insert_after field_insert_before);

use constant {
    ALL_PKG => CTRL_INFO_PKG | CTRL_APT_PKG | CTRL_PKG_DEB | CTRL_FILE_STATUS,
    ALL_SRC => CTRL_INFO_SRC | CTRL_APT_SRC | CTRL_PKG_SRC,
    ALL_CHANGES => CTRL_FILE_CHANGES | CTRL_CHANGELOG,
};

# The canonical list of fields

# Note that fields used only in dpkg's available file are not listed
# Deprecated fields of dpkg's status file are also not listed
our %FIELDS = (
    'Architecture' => {
        allowed => (ALL_PKG | ALL_SRC | CTRL_FILE_CHANGES) & (~CTRL_INFO_SRC),
    },
    'Binary' => {
        allowed => CTRL_PKG_SRC | CTRL_FILE_CHANGES,
    },
    'Breaks' => {
        allowed => ALL_PKG,
        dependency => 'union',
        dep_order => 7,
    },
    'Bugs' => {
        allowed => (ALL_PKG | CTRL_INFO_SRC | CTRL_FILE_VENDOR) & (~CTRL_INFO_PKG),
    },
    'Build-Conflicts' => {
        allowed => ALL_SRC,
        dependency => 'union',
        dep_order => 3,
    },
    'Build-Conflicts-Indep' => {
        allowed => ALL_SRC,
        dependency => 'union',
        dep_order => 4,
    },
    'Build-Depends' => {
        allowed => ALL_SRC,
        dependency => 'normal',
        dep_order => 1,
    },
    'Build-Depends-Indep' => {
        allowed => ALL_SRC,
        dependency => 'normal',
        dep_order => 2,
    },
    'Changed-By' => {
        allowed => CTRL_FILE_CHANGES,
    },
    'Changes' => {
        allowed => ALL_CHANGES,
    },
    'Closes' => {
        allowed => ALL_CHANGES,
    },
    'Conffiles' => {
        allowed => CTRL_FILE_STATUS,
    },
    'Config-Version' => {
        allowed => CTRL_FILE_STATUS,
    },
    'Conflicts' => {
        allowed => ALL_PKG,
        dependency => 'union',
        dep_order => 6,
    },
    'Date' => {
        allowed => ALL_CHANGES,
    },
    'Depends' => {
        allowed => ALL_PKG,
        dependency => 'normal',
        dep_order => 2,
    },
    'Description' => {
        allowed => ALL_PKG | CTRL_FILE_CHANGES,
    },
    'Directory' => {
        allowed => CTRL_APT_SRC,
    },
    'Distribution' => {
        allowed => ALL_CHANGES,
    },
    'Enhances' => {
        allowed => ALL_PKG,
        dependency => 'union',
        dep_order => 5,
    },
    'Essential' => {
        allowed => ALL_PKG,
    },
    'Filename' => {
        allowed => CTRL_APT_PKG,
    },
    'Files' => {
        allowed => CTRL_PKG_SRC | CTRL_FILE_CHANGES,
    },
    'Format' => {
        allowed => CTRL_PKG_SRC | CTRL_FILE_CHANGES,
    },
    'Homepage' => {
        allowed => ALL_SRC | ALL_PKG,
    },
    'Installed-Size' => {
        allowed => ALL_PKG & ~CTRL_INFO_PKG,
    },
    'Installer-Menu-Item' => {
        allowed => ALL_PKG,
    },
    'Kernel-Version' => {
        allowed => ALL_PKG,
    },
    'Origin' => {
        allowed => (ALL_PKG | ALL_SRC) & (~CTRL_INFO_PKG),
    },
    'Maintainer' => {
        allowed => CTRL_PKG_DEB | ALL_SRC | ALL_CHANGES,
    },
    'Multi-Arch' => {
        allowed => ALL_PKG,
    },
    'Package' => {
        allowed => ALL_PKG,
    },
    'Package-Type' => {
        allowed => ALL_PKG,
    },
    'Parent' => {
        allowed => CTRL_FILE_VENDOR,
    },
    'Pre-Depends' => {
        allowed => ALL_PKG,
        dependency => 'normal',
        dep_order => 1,
    },
    'Priority' => {
        allowed => CTRL_INFO_SRC | CTRL_APT_SRC | ALL_PKG,
    },
    'Provides' => {
        allowed => ALL_PKG,
        dependency => 'union',
        dep_order => 9,
    },
    'Recommends' => {
        allowed => ALL_PKG,
        dependency => 'normal',
        dep_order => 3,
    },
    'Replaces' => {
        allowed => ALL_PKG,
        dependency => 'union',
        dep_order => 8,
    },
    'Section' => {
        allowed => CTRL_INFO_SRC | CTRL_APT_SRC | ALL_PKG,
    },
    'Size' => {
        allowed => CTRL_APT_PKG,
    },
    'Source' => {
        allowed => (ALL_PKG | ALL_SRC | ALL_CHANGES) &
                   (~(CTRL_APT_SRC | CTRL_INFO_PKG)),
    },
    'Standards-Version' => {
        allowed => ALL_SRC,
    },
    'Status' => {
        allowed => CTRL_FILE_STATUS,
    },
    'Subarchitecture' => {
        allowed => ALL_PKG,
    },
    'Suggests' => {
        allowed => ALL_PKG,
        dependency => 'normal',
        dep_order => 4,
    },
    'Tag' => {
        allowed => ALL_PKG,
    },
    'Task' => {
        allowed => ALL_PKG,
    },
    'Triggers-Awaited' => {
        allowed => CTRL_FILE_STATUS,
    },
    'Triggers-Pending' => {
        allowed => CTRL_FILE_STATUS,
    },
    'Uploaders' => {
        allowed => ALL_SRC,
    },
    'Urgency' => {
        allowed => ALL_CHANGES,
    },
    'Vcs-Browser' => {
        allowed => ALL_SRC,
    },
    'Vcs-Arch' => {
        allowed => ALL_SRC,
    },
    'Vcs-Bzr' => {
        allowed => ALL_SRC,
    },
    'Vcs-Cvs' => {
        allowed => ALL_SRC,
    },
    'Vcs-Darcs' => {
        allowed => ALL_SRC,
    },
    'Vcs-Git' => {
        allowed => ALL_SRC,
    },
    'Vcs-Hg' => {
        allowed => ALL_SRC,
    },
    'Vcs-Mtn' => {
        allowed => ALL_SRC,
    },
    'Vcs-Svn' => {
        allowed => ALL_SRC,
    },
    'Vendor' => {
        allowed => CTRL_FILE_VENDOR,
    },
    'Vendor-Url' => {
        allowed => CTRL_FILE_VENDOR,
    },
    'Version' => {
        allowed => (ALL_PKG | ALL_SRC | ALL_CHANGES) &
                    (~(CTRL_INFO_SRC | CTRL_INFO_PKG)),
    },
);

my @checksum_fields = map { field_capitalize("Checksums-$_") } @check_supported;
my @sum_fields = map { $_ eq "md5" ? "MD5sum" : field_capitalize($_) }
                 @check_supported;
&field_register($_, CTRL_PKG_SRC | CTRL_FILE_CHANGES) foreach @checksum_fields;
&field_register($_, CTRL_APT_PKG) foreach @sum_fields;

our %FIELD_ORDER = (
    CTRL_PKG_DEB() => [
        qw(Package Package-Type Source Version Kernel-Version Architecture
        Subarchitecture Installer-Menu-Item Essential Origin Bugs
        Maintainer Installed-Size), &field_list_pkg_dep(),
        qw(Section Priority Multi-Arch Homepage Description Tag Task)
    ],
    CTRL_PKG_SRC() => [
        qw(Format Source Binary Architecture Version Origin Maintainer
        Uploaders Homepage Standards-Version Vcs-Browser
        Vcs-Arch Vcs-Bzr Vcs-Cvs Vcs-Darcs Vcs-Git Vcs-Hg Vcs-Mtn
        Vcs-Svn), &field_list_src_dep(), @checksum_fields, qw(Files)
    ],
    CTRL_FILE_CHANGES() => [
        qw(Format Date Source Binary Architecture Version Distribution
        Urgency Maintainer Changed-By Description Closes Changes),
        @checksum_fields, qw(Files)
    ],
    CTRL_CHANGELOG() => [
        qw(Source Version Distribution Urgency Maintainer Date Closes
        Changes Timestamp Header Items Trailer Urgency_comment
        Urgency_lc)
    ],
    CTRL_FILE_STATUS() => [ # Same as fieldinfos in lib/dpkg/parse.c
        qw(Package Essential Status Priority Section Installed-Size Origin
        Maintainer Bugs Architecture Source Version Config-Version
        Replaces Provides Depends Pre-Depends Recommends Suggests Breaks
        Conflicts Enhances Conffiles Description Triggers-Pending
        Triggers-Awaited)
    ],
);
# Order for CTRL_APT_PKG is derived from CTRL_PKG_DEB
$FIELD_ORDER{CTRL_APT_PKG()} = [ @{$FIELD_ORDER{CTRL_PKG_DEB()}} ];
&field_insert_before(CTRL_APT_PKG, 'Section', 'Filename', 'Size', @sum_fields);
# Order for CTRL_APT_SRC is derived from CTRL_PKG_SRC
$FIELD_ORDER{CTRL_APT_SRC()} = [ @{$FIELD_ORDER{CTRL_PKG_SRC()}} ];
@{$FIELD_ORDER{CTRL_APT_SRC()}} = map { $_ eq "Source" ? "Package" : $_ }
                                  @{$FIELD_ORDER{CTRL_PKG_SRC()}};
&field_insert_after(CTRL_APT_SRC, "Version", "Priority", "Section");
&field_insert_before(CTRL_APT_SRC, "Checksums-Md5", "Directory");

# Register vendor specifics fields
foreach my $op (run_vendor_hook("register-custom-fields")) {
    next if not (defined $op and ref $op); # Skip when not implemented by vendor
    my $func = shift @$op;
    if ($func eq "register") {
        &field_register(@$op);
    } elsif ($func eq "insert_before") {
        &field_insert_before(@$op);
    } elsif ($func eq "insert_after") {
        &field_insert_after(@$op);
    } else {
        error("vendor hook register-custom-fields sent bad data: @$op");
    }
}

=head1 NAME

Dpkg::Control::Fields - manage (list of official) control fields

=head1 DESCRIPTION

The modules contains a list of fieldnames with associated meta-data explaining
in which type of control information they are allowed. The types are the
CTRL_* constants exported by Dpkg::Control.

=head1 FUNCTIONS

=over 4

=item my $f = field_capitalize($field_name)

Returns the field name properly capitalized. All characters are lowercase,
except the first of each word (words are separated by a dash in field names).

=cut

sub field_capitalize($) {
    my $field = lc(shift);
    # Some special cases due to history
    return "MD5sum" if $field eq "md5sum";
    return uc($field) if exists $check_supported{$field};
    # Generic case
    return join '-', map { ucfirst } split /-/, $field;
}

=item field_is_official($fname)

Returns true if the field is official and known.

=cut

sub field_is_official($) {
    return exists $FIELDS{field_capitalize($_[0])};
}

=item field_is_allowed_in($fname, @types)

Returns true (1) if the field $fname is allowed in all the types listed in
the list. Note that you can use type sets instead of individual types (ex:
CTRL_FILE_CHANGES | CTRL_CHANGELOG).

field_allowed_in(A|B, C) returns true only if the field is allowed in C
and either A or B.

Undef is returned for non-official fields.

=cut

sub field_is_allowed_in($@) {
    my ($field, @types) = @_;
    $field = field_capitalize($field);
    return undef unless field_is_official($field);

    return 0 if not scalar(@types);
    foreach my $type (@types) {
        next if $type == CTRL_UNKNOWN; # Always allowed
        return 0 unless $FIELDS{$field}{'allowed'} & $type;
    }
    return 1;
}

=item field_transfer_single($from, $to, $field)

If appropriate, copy the value of the field named $field taken from the
$from Dpkg::Control object to the $to Dpkg::Control object.

Official fields are copied only if the field is allowed in both types of
objects. Custom fields are not copied except if the target object matches
the target destination encoded in the field name. The initial X denoting
custom fields can be followed by one or more letters among "S" (Source:
corresponds to CTRL_PKG_SRC), "B" (Binary: corresponds to CTRL_PKG_DEB) or "C"
(Changes: corresponds to CTRL_FILE_CHANGES).

Returns undef if nothing has been copied or the name of the new field
added to $to otherwise.

=cut

sub field_transfer_single($$_) {
    my ($from, $to, $field) = @_;
    my ($from_type, $to_type) = ($from->get_type(), $to->get_type());
    $field = field_capitalize($field);

    if (field_is_allowed_in($field, $from_type, $to_type)) {
        $to->{$field} = $from->{$field};
        return $field;
    } elsif ($field =~ /^X([SBC]*)-/i) {
        my $dest = $1;
        if (($dest =~ /B/i and $to_type == CTRL_PKG_DEB) or
            ($dest =~ /S/i and $to_type == CTRL_PKG_SRC) or
            ($dest =~ /C/i and $to_type == CTRL_FILE_CHANGES))
        {
            my $new = $field;
            $new =~ s/^X([SBC]*)-//i;
            $to->{$new} = $from->{$field};
            return $new;
        }
    } elsif (not field_is_allowed_in($field, $from_type)) {
        warning(_g("unknown information field '%s' in input data in %s"),
                $field, $from->get_option("name") || _g("control information"));
    }
    return undef;
}

=item field_transfer_all($from, $to)

Transfer all appropriate fields from $from to $to. Calls
field_transfer_single() on all fields available in $from.

Returns the list of fields that have been added to $to.

=cut

sub field_transfer_all($$) {
    my ($from, $to) = @_;
    my (@res, $res);
    foreach my $k (keys %$from) {
        $res = field_transfer_single($from, $to, $k);
        push @res, $res if $res and defined wantarray;
    }
    return @res;
}

=item field_ordered_list($type)

Returns an ordered list of fields for a given type of control information.
This list can be used to output the fields in a predictable order.
The list might be empty for types where the order does not matter much.

=cut

sub field_ordered_list($) {
    my ($type) = @_;
    return @{$FIELD_ORDER{$type}} if exists $FIELD_ORDER{$type};
    return ();
}

=item field_list_src_dep()

List of fields that contains dependencies-like information in a source
Debian package.

=cut

sub field_list_src_dep() {
    return sort {
        $FIELDS{$a}{'dep_order'} <=> $FIELDS{$b}{'dep_order'}
    } grep {
        field_is_allowed_in($_, CTRL_PKG_SRC) and
        exists $FIELDS{$_}{'dependency'}
    } keys %FIELDS;
}

=item field_list_pkg_dep()

List of fields that contains dependencies-like information in a binary
Debian package. The fields that express real dependencies are sorted from
the stronger to the weaker.

=cut

sub field_list_pkg_dep() {
    my @keys = keys %FIELDS;
    return sort {
        $FIELDS{$a}{'dep_order'} <=> $FIELDS{$b}{'dep_order'}
    } grep {
        field_is_allowed_in($_, CTRL_PKG_DEB) and
        exists $FIELDS{$_}{'dependency'}
    } @keys;
}

=item field_get_dep_type($field)

Return the type of the dependency expressed by the given field. Can
either be "normal" for a real dependency field (Pre-Depends, Depends, ...)
or "union" for other relation fields sharing the same syntax (Conflicts,
Breaks, ...). Returns undef for fields which are not dependencies.

=cut

sub field_get_dep_type($) {
    my $field = field_capitalize($_[0]);
    return undef unless field_is_official($field);
    return $FIELDS{$field}{'dependency'} if exists $FIELDS{$field}{'dependency'};
    return undef;
}

=item field_register($field, $allowed_types, %opts)

Register a new field as being allowed in control information of specified
types. %opts is optional

=cut

sub field_register($$;@) {
    my ($field, $types, %opts) = @_;
    $field = field_capitalize($field);
    $FIELDS{$field} = {
        allowed => $types,
        %opts
    };
}

=item field_insert_after($type, $ref, @fields)

Place field after another one ($ref) in output of control information of
type $type.

=cut
sub field_insert_after($$@) {
    my ($type, $field, @fields) = @_;
    return 0 if not exists $FIELD_ORDER{$type};
    ($field, @fields) = map { field_capitalize($_) } ($field, @fields);
    @{$FIELD_ORDER{$type}} = map {
        ($_ eq $field) ? ($_, @fields) : $_
    } @{$FIELD_ORDER{$type}};
    return 1;
}

=item field_insert_before($type, $ref, @fields)

Place field before another one ($ref) in output of control information of
type $type.

=cut
sub field_insert_before($$@) {
    my ($type, $field, @fields) = @_;
    return 0 if not exists $FIELD_ORDER{$type};
    ($field, @fields) = map { field_capitalize($_) } ($field, @fields);
    @{$FIELD_ORDER{$type}} = map {
        ($_ eq $field) ? (@fields, $_) : $_
    } @{$FIELD_ORDER{$type}};
    return 1;
}

=back

=head1 AUTHOR

Raphaël Hertzog <hertzog@debian.org>.

=cut

1;