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###############################################################################
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# (c) Copyright @ 2000, Randy J. Ray <rjray@blackperl.com>
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###############################################################################
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# $Id: Header.pm,v 1.20 2001/04/27 09:05:21 rjray Exp $
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# Description: The RPM::Header class provides access to the RPM Header
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# structure as a tied hash, allowing direct access to the
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# tags in a header as keys, and the content of said tags
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# Global Consts: None.
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# Environment: Just stuff from the RPM config.
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###############################################################################
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use vars qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS $AUTOLOAD);
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use subs qw(new AUTOLOAD filenames);
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use RPM::Constants ':rpmerr';
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$VERSION = do { my @r=(q$Revision: 1.20 $=~/\d+/g); sprintf "%d."."%02d"x$#r,@r };
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@EXPORT_OK = qw(RPM_HEADER_MASK RPM_HEADER_READONLY);
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%EXPORT_TAGS = (all => \@EXPORT_OK);
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($constname = $AUTOLOAD) =~ s/.*:://;
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die "& not defined" if $constname eq 'constant';
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my $val = constant($constname);
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die "Your vendor has not defined RPM macro $constname";
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*$AUTOLOAD = sub { $val };
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tie %hash, $class, @_;
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###############################################################################
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# Description: Glue together the contents of BASENAMES, DIRNAMES and
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# DIRINDEXES to create a single list of fully-qualified
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# Arguments: NAME IN/OUT TYPE DESCRIPTION
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# $self in ref Object of this class
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# Returns: Success: listref
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###############################################################################
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# Each of these three fetches will have already triggered rpm_error, were
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my $base = $self->{BASENAMES} || return undef;
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my $dirs = $self->{DIRNAMES} || return undef;
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my $idxs = $self->{DIRINDEXES} || return undef;
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unless (@$base == @$idxs)
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rpm_error(RPMERR_INTERNAL,
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"Mis-matched elements lists for BASENAMES and DIRINDEXES");
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# The value from DIRNAMES already has the trailing separator
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[ map { "$dirs->[$idxs->[$_]]$base->[$_]" } (0 .. $#$base) ];
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RPM::Header - Access to RPM package headers
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tie %hdr, "RPM::Header", "rpm-3.0.4-0.48.i386.rpm" or die "$RPM::err";
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The B<RPM::Header> package permits access to the header of a package (external
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file or currently installed) as either a tied hash or a blessed hash reference.
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The tags that are present in the header are expressed as keys. Retrieving
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them via C<keys> or C<each> returns the tags in the order in which they
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appear in the header. Keys may be requested without regard for letter case,
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but they are always returned as all upper-case.
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The return value corresponding to each key is a list reference or scalar
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(or C<undef> if the key is not valid), depending on the data-type of the
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key. Each of the header tags are noted with one of C<$> or C<@> in the
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B<RPM::Constants> documentation. The C<defined> keyword should be used
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for testing success versus failure, as empty tags are possible. See the
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C<scalar_tag> test, below.
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This is a significant change from versions prior to 0.27, in which the
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return value was always a list reference. This new approach brings
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B<RPM::Header> more in line with other interfaces to B<rpm> header information.
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B<RPM::Header> objects are also the native return value from keys retrieved
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in the B<RPM::Database> class (see L<RPM::Database>). In these cases, the
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header data is marked read-only, and attempts to alter any of the keys will
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There are also a number of class methods implemented, which are described in
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=head2 Creating an Object
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An object may be created one of two ways:
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tie %h, "RPM::Header", "filename";
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$href = new RPM::Header "filename";
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The latter approach offers more direct access to the class methods, while
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also permitting the usual tied-hash operations such as fetching:
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$href->{tag} # Such as "name" or "version"
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The following methods are available to objects of this class, in addition to
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the tied-hash suite of operations. If the object is a hash instead of a
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hash reference, it can be used to call these methods via:
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(tied %hash)->method_name(...)
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The B<RPM> system attempts to save space by splitting up the file paths into
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the leafs (stored by the tag C<BASENAMES>), the directories (stored under
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C<DIRNAMES>) and indexes into the list of directories (stored under
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C<DIRINDEXES>). As a convenience, this method re-assembles the list of
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filenames and returns it as a list reference. If an error occurs, C<undef>
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will be returned after C<rpm_error> has been called.
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Returns true (1) or false (0), depending on whether the package the header
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object is derived from is a source RPM.
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Return the size of the header, in bytes, within the disk file containing the
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associated package. The value is also returned for those headers within the
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=item scalar_tag(TAG)
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Returns a true/false value (1 or 0) based on whether the value returned by
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the specified tag is a scalar or an array reference. Useful in place of
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using C<ref> to test the fetched values. B<TAG> may be either a string (name)
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or a number (imported from the B<RPM::Constants> tag C<:rpmtag>). This
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method may be called as a class (static) method.
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Given a tag I<TAG>, return the type as a numerical value. The valid types
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can be imported from the B<RPM::Constants> package via the import-tag
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Used internally by B<rpm>.
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The data returned is a single chunk of binary data. It has been converted to
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a single "string" in Perl terms, but may contain nulls within it. The
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B<length()> keyword should return the correct size for the chunk.
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All items are single-character in nature. Note that since Perl does not
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distinguish single characters versus strings in the way that C does, these
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are stored as single-character strings. It is a tradeoff of efficiency over
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All items are integers no larger than 8 bits wide.
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All items are integers no larger than 16 bits wide.
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All items are integers no larger than 32 bits wide.
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=item RPM_STRING_TYPE
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=item RPM_I18NSTRING_TYPE
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=item RPM_STRING_ARRAY_TYPE
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These three are functionally similar from the Perl perspective. Currently,
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B<RPM> does not export data in an I18N format, it will have been converted to
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an ordinary string before being handed to the caller (in this case, before
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the internal Perl/XS code receives it). The distinction between STRING and
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STRING_ARRAY types is only relevant internally. All of these are sequences of
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one or more text strings, returned in the same internal order as they are
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stored within the header.
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The commonly-needed data triple of (B<name>, B<version>, B<release>) may be
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accessed more directly by means of this method. It returns the three values
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on the stack, saving the need for three separate fetches.
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Compare the version of the current header against that in the header
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referenced by C<$other>. The argument should be an object reference, not
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a tied-hash representation of a header. Returns -1, 0 or 1, based on the
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established behavior of other comparison operators (C<cmp> and C<E<lt>=E<gt>>);
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-1 indicates that the calling object is considered less, or older, than the
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passed argument. A value of 1 indicates that the calling object is greater,
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or newer, than the argument. A value of 0 indicates that they are equal.
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If the B<RPM::Header> object is created directly from a file, FTP source
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or HTTP source, then that source is kept for future reference and may be
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retrieved using this accessor. This will be an empty string if the header
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was retrieved from the RPM database, or was built in-memory from data.
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Direct binding to the internal error-management of B<rpm> is still under
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development. At present, most operations generate their diagnostics to
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This is currently regarded as alpha-quality software. The interface is
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subject to change in future releases.
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L<RPM>, L<RPM::Database>, L<RPM::Constants>, L<perl>, L<rpm>
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Randy J. Ray <rjray@blackperl.com>
added
removed
Perl-RPM/RPM/Header.pm
