dpkg-1.16.1.1/scripts/Dpkg/Control/Fields.pm - nest-learning-thermostat/5.1/dpkg - Git at Google

 # 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, see <http://www.gnu.org/licenses/>.

 package Dpkg::Control::Fields;

 use strict;
 use warnings;

 our $VERSION = "1.00";

 use base qw(Exporter);
 use Dpkg::Gettext;
 use Dpkg::ErrorHandling;
 use Dpkg::Control::Types;
 use Dpkg::Checksums;
 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_INDEX_PKG | CTRL_PKG_DEB | CTRL_FILE_STATUS,
     ALL_SRC => CTRL_INFO_SRC | CTRL_INDEX_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,
     },
     'Built-Using' => {
         allowed => ALL_PKG,
         dependency => 'union',
         dep_order => 10,
     },
     '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_INDEX_SRC,
     },
     'Distribution' => {
         allowed => ALL_CHANGES,
     },
     'Enhances' => {
         allowed => ALL_PKG,
         dependency => 'union',
         dep_order => 5,
     },
     'Essential' => {
         allowed => ALL_PKG,
     },
     'Filename' => {
         allowed => CTRL_INDEX_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-List' => {
         allowed => ALL_SRC & ~CTRL_INFO_SRC,
     },
     '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_INDEX_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_INDEX_SRC | ALL_PKG,
     },
     'Size' => {
         allowed => CTRL_INDEX_PKG,
     },
     'Source' => {
         allowed => (ALL_PKG | ALL_SRC | ALL_CHANGES) &
                    (~(CTRL_INDEX_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-$_") } checksums_get_list();
 my @sum_fields = map { $_ eq "md5" ? "MD5sum" : field_capitalize($_) }
                  checksums_get_list();
 &field_register($_, CTRL_PKG_SRC | CTRL_FILE_CHANGES) foreach @checksum_fields;
 &field_register($_, CTRL_INDEX_PKG) foreach @sum_fields;

 our %FIELD_ORDER = (
     CTRL_PKG_DEB() => [
         qw(Package Package-Type Source Version Built-Using 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(), qw(Package-List),
         @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_INDEX_PKG is derived from CTRL_PKG_DEB
 $FIELD_ORDER{CTRL_INDEX_PKG()} = [ @{$FIELD_ORDER{CTRL_PKG_DEB()}} ];
 &field_insert_before(CTRL_INDEX_PKG, 'Section', 'Filename', 'Size', @sum_fields);
 # Order for CTRL_INDEX_SRC is derived from CTRL_PKG_SRC
 $FIELD_ORDER{CTRL_INDEX_SRC()} = [ @{$FIELD_ORDER{CTRL_PKG_SRC()}} ];
 @{$FIELD_ORDER{CTRL_INDEX_SRC()}} = map { $_ eq "Source" ? "Package" : $_ }
                                   @{$FIELD_ORDER{CTRL_PKG_SRC()}};
 &field_insert_after(CTRL_INDEX_SRC, "Version", "Priority", "Section");
 &field_insert_before(CTRL_INDEX_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");
     }
 }

 =encoding utf8

 =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 checksums_is_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 treated in a specific manner. When the target
 is not among CTRL_PKG_SRC, CTRL_PKG_DEB or CTRL_FILE_CHANGES, then they
 are alway copied as is (the X- prefix is kept). Otherwise they 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) = @_;
     $field = $_ unless defined $field;
     my ($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 $new;
         } elsif ($to_type != CTRL_PKG_DEB and
 		 $to_type != CTRL_PKG_SRC and
 		 $to_type != CTRL_FILE_CHANGES)
 	{
 	    $to->{$field} = $from->{$field};
 	    return $field;
 	}
     } elsif (not field_is_allowed_in($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;
	# 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, see <http://www.gnu.org/licenses/>.

	package Dpkg::Control::Fields;

	use strict;
	use warnings;

	our $VERSION = "1.00";

	use base qw(Exporter);
	use Dpkg::Gettext;
	use Dpkg::ErrorHandling;
	use Dpkg::Control::Types;
	use Dpkg::Checksums;
	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_INDEX_PKG \| CTRL_PKG_DEB \| CTRL_FILE_STATUS,
	ALL_SRC => CTRL_INFO_SRC \| CTRL_INDEX_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,
	},
	'Built-Using' => {
	allowed => ALL_PKG,
	dependency => 'union',
	dep_order => 10,
	},
	'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_INDEX_SRC,
	},
	'Distribution' => {
	allowed => ALL_CHANGES,
	},
	'Enhances' => {
	allowed => ALL_PKG,
	dependency => 'union',
	dep_order => 5,
	},
	'Essential' => {
	allowed => ALL_PKG,
	},
	'Filename' => {
	allowed => CTRL_INDEX_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-List' => {
	allowed => ALL_SRC & ~CTRL_INFO_SRC,
	},
	'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_INDEX_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_INDEX_SRC \| ALL_PKG,
	},
	'Size' => {
	allowed => CTRL_INDEX_PKG,
	},
	'Source' => {
	allowed => (ALL_PKG \| ALL_SRC \| ALL_CHANGES) &
	(~(CTRL_INDEX_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-$_") } checksums_get_list();
	my @sum_fields = map { $_ eq "md5" ? "MD5sum" : field_capitalize($_) }
	checksums_get_list();
	&field_register($_, CTRL_PKG_SRC \| CTRL_FILE_CHANGES) foreach @checksum_fields;
	&field_register($_, CTRL_INDEX_PKG) foreach @sum_fields;

	our %FIELD_ORDER = (
	CTRL_PKG_DEB() => [
	qw(Package Package-Type Source Version Built-Using 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(), qw(Package-List),
	@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_INDEX_PKG is derived from CTRL_PKG_DEB
	$FIELD_ORDER{CTRL_INDEX_PKG()} = [ @{$FIELD_ORDER{CTRL_PKG_DEB()}} ];
	&field_insert_before(CTRL_INDEX_PKG, 'Section', 'Filename', 'Size', @sum_fields);
	# Order for CTRL_INDEX_SRC is derived from CTRL_PKG_SRC
	$FIELD_ORDER{CTRL_INDEX_SRC()} = [ @{$FIELD_ORDER{CTRL_PKG_SRC()}} ];
	@{$FIELD_ORDER{CTRL_INDEX_SRC()}} = map { $_ eq "Source" ? "Package" : $_ }
	@{$FIELD_ORDER{CTRL_PKG_SRC()}};
	&field_insert_after(CTRL_INDEX_SRC, "Version", "Priority", "Section");
	&field_insert_before(CTRL_INDEX_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");
	}
	}

	=encoding utf8

	=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 checksums_is_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 treated in a specific manner. When the target
	is not among CTRL_PKG_SRC, CTRL_PKG_DEB or CTRL_FILE_CHANGES, then they
	are alway copied as is (the X- prefix is kept). Otherwise they 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) = @_;
	$field = $_ unless defined $field;
	my ($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 $new;
	} elsif ($to_type != CTRL_PKG_DEB and
	$to_type != CTRL_PKG_SRC and
	$to_type != CTRL_FILE_CHANGES)
	{
	$to->{$field} = $from->{$field};
	return $field;
	}
	} elsif (not field_is_allowed_in($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;