# -*- Mode: cperl; coding: utf-8; cperl-indent-level: 4 -*-
use strict;
package CPAN::Queue::Item;
# CPAN::Queue::Item::new ;
sub new {
my($class,@attr) = @_;
my $self = bless { @attr }, $class;
return $self;
}
sub as_string {
my($self) = @_;
$self->{qmod};
}
# r => requires, b => build_requires, c => commandline
sub reqtype {
my($self) = @_;
$self->{reqtype};
}
sub optional {
my($self) = @_;
$self->{optional};
}
package CPAN::Queue;
# One use of the queue is to determine if we should or shouldn't
# announce the availability of a new CPAN module
# Now we try to use it for dependency tracking. For that to happen
# we need to draw a dependency tree and do the leaves first. This can
# easily be reached by running CPAN.pm recursively, but we don't want
# to waste memory and run into deep recursion. So what we can do is
# this:
# CPAN::Queue is the package where the queue is maintained. Dependencies
# often have high priority and must be brought to the head of the queue,
# possibly by jumping the queue if they are already there. My first code
# attempt tried to be extremely correct. Whenever a module needed
# immediate treatment, I either unshifted it to the front of the queue,
# or, if it was already in the queue, I spliced and let it bypass the
# others. This became a too correct model that made it impossible to put
# an item more than once into the queue. Why would you need that? Well,
# you need temporary duplicates as the manager of the queue is a loop
# that
#
# (1) looks at the first item in the queue without shifting it off
#
# (2) cares for the item
#
# (3) removes the item from the queue, *even if its agenda failed and
# even if the item isn't the first in the queue anymore* (that way
# protecting against never ending queues)
#
# So if an item has prerequisites, the installation fails now, but we
# want to retry later. That's easy if we have it twice in the queue.
#
# I also expect insane dependency situations where an item gets more
# than two lives in the queue. Simplest example is triggered by 'install
# Foo Foo Foo'. People make this kind of mistakes and I don't want to
# get in the way. I wanted the queue manager to be a dumb servant, not
# one that knows everything.
#
# Who would I tell in this model that the user wants to be asked before
# processing? I can't attach that information to the module object,
# because not modules are installed but distributions. So I'd have to
# tell the distribution object that it should ask the user before
# processing. Where would the question be triggered then? Most probably
# in CPAN::Distribution::rematein.
use vars qw{ @All $VERSION };
$VERSION = "5.5003";
# CPAN::Queue::queue_item ;
sub queue_item {
my($class,@attr) = @_;
my $item = "$class\::Item"->new(@attr);
$class->qpush($item);
return 1;
}
# CPAN::Queue::qpush ;
sub qpush {
my($class,$obj) = @_;
push @All, $obj;
CPAN->debug(sprintf("in new All[%s]",
join("",map {sprintf " %s\[%s][%s]\n",$_->{qmod},$_->{reqtype},$_->{optional}} @All),
)) if $CPAN::DEBUG;
}
# CPAN::Queue::first ;
sub first {
my $obj = $All[0];
$obj;
}
# CPAN::Queue::delete_first ;
sub delete_first {
my($class,$what) = @_;
my $i;
for my $i (0..$#All) {
if ( $All[$i]->{qmod} eq $what ) {
splice @All, $i, 1;
last;
}
}
CPAN->debug(sprintf("after delete_first mod[%s] All[%s]",
$what,
join("",map {sprintf " %s\[%s][%s]\n",$_->{qmod},$_->{reqtype},$_->{optional}} @All)
)) if $CPAN::DEBUG;
}
# CPAN::Queue::jumpqueue ;
sub jumpqueue {
my $class = shift;
my @what = @_;
CPAN->debug(sprintf("before jumpqueue All[%s] what[%s]",
join("",map {sprintf " %s\[%s][%s]\n",$_->{qmod},$_->{reqtype},$_->{optional}} @All),
join("",map {sprintf " %s\[%s][%s]\n",$_->{qmod},$_->{reqtype},$_->{optional}} @what),
)) if $CPAN::DEBUG;
unless (defined $what[0]{reqtype}) {
# apparently it was not the Shell that sent us this enquiry,
# treat it as commandline
$what[0]{reqtype} = "c";
}
my $inherit_reqtype = $what[0]{reqtype} =~ /^(c|r)$/ ? "r" : "b";
WHAT: for my $what_tuple (@what) {
my($qmod,$reqtype,$optional) = @$what_tuple{qw(qmod reqtype optional)};
if ($reqtype eq "r"
&&
$inherit_reqtype eq "b"
) {
$reqtype = "b";
}
my $jumped = 0;
for (my $i=0; $i<$#All;$i++) { #prevent deep recursion
if ($All[$i]{qmod} eq $qmod) {
$jumped++;
}
}
# high jumped values are normal for popular modules when
# dealing with large bundles: XML::Simple,
# namespace::autoclean, UNIVERSAL::require
CPAN->debug("qmod[$qmod]jumped[$jumped]") if $CPAN::DEBUG;
my $obj = "$class\::Item"->new(
qmod => $qmod,
reqtype => $reqtype,
optional => !! $optional,
);
unshift @All, $obj;
}
CPAN->debug(sprintf("after jumpqueue All[%s]",
join("",map {sprintf " %s\[%s][%s]\n",$_->{qmod},$_->{reqtype},$_->{optional}} @All)
)) if $CPAN::DEBUG;
}
# CPAN::Queue::exists ;
sub exists {
my($self,$what) = @_;
my @all = map { $_->{qmod} } @All;
my $exists = grep { $_->{qmod} eq $what } @All;
# warn "in exists what[$what] all[@all] exists[$exists]";
$exists;
}
# CPAN::Queue::delete ;
sub delete {
my($self,$mod) = @_;
@All = grep { $_->{qmod} ne $mod } @All;
CPAN->debug(sprintf("after delete mod[%s] All[%s]",
$mod,
join("",map {sprintf " %s\[%s][%s]\n",$_->{qmod},$_->{reqtype},$_->{optional}} @All)
)) if $CPAN::DEBUG;
}
# CPAN::Queue::nullify_queue ;
sub nullify_queue {
@All = ();
}
# CPAN::Queue::size ;
sub size {
return scalar @All;
}
sub reqtype_of {
my($self,$mod) = @_;
my $best = "";
for my $item (grep { $_->{qmod} eq $mod } @All) {
my $c = $item->{reqtype};
if ($c eq "c") {
$best = $c;
last;
} elsif ($c eq "r") {
$best = $c;
} elsif ($c eq "b") {
if ($best eq "") {
$best = $c;
}
} else {
die "Panic: in reqtype_of: reqtype[$c] seen, should never happen";
}
}
return $best;
}
sub iterator {
my $i = 0;
return sub {
until ($All[$i] || $i > $#All) {
$i++;
}
return if $i > $#All;
return $All[$i++]
};
}
1;
__END__
=head1 NAME
CPAN::Queue - internal queue support for CPAN.pm
=head1 LICENSE
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
=cut
