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1 | # -*- Mode: cperl; coding: utf-8; cperl-indent-level: 4 -*- |
2 | package CPAN::Queue; |
3 | use strict; |
4 | |
5 | # One use of the queue is to determine if we should or shouldn't |
6 | # announce the availability of a new CPAN module |
7 | |
8 | # Now we try to use it for dependency tracking. For that to happen |
9 | # we need to draw a dependency tree and do the leaves first. This can |
10 | # easily be reached by running CPAN.pm recursively, but we don't want |
11 | # to waste memory and run into deep recursion. So what we can do is |
12 | # this: |
13 | |
14 | # CPAN::Queue is the package where the queue is maintained. Dependencies |
15 | # often have high priority and must be brought to the head of the queue, |
16 | # possibly by jumping the queue if they are already there. My first code |
17 | # attempt tried to be extremely correct. Whenever a module needed |
18 | # immediate treatment, I either unshifted it to the front of the queue, |
19 | # or, if it was already in the queue, I spliced and let it bypass the |
20 | # others. This became a too correct model that made it impossible to put |
21 | # an item more than once into the queue. Why would you need that? Well, |
22 | # you need temporary duplicates as the manager of the queue is a loop |
23 | # that |
24 | # |
25 | # (1) looks at the first item in the queue without shifting it off |
26 | # |
27 | # (2) cares for the item |
28 | # |
29 | # (3) removes the item from the queue, *even if its agenda failed and |
30 | # even if the item isn't the first in the queue anymore* (that way |
31 | # protecting against never ending queues) |
32 | # |
33 | # So if an item has prerequisites, the installation fails now, but we |
34 | # want to retry later. That's easy if we have it twice in the queue. |
35 | # |
36 | # I also expect insane dependency situations where an item gets more |
37 | # than two lives in the queue. Simplest example is triggered by 'install |
38 | # Foo Foo Foo'. People make this kind of mistakes and I don't want to |
39 | # get in the way. I wanted the queue manager to be a dumb servant, not |
40 | # one that knows everything. |
41 | # |
42 | # Who would I tell in this model that the user wants to be asked before |
43 | # processing? I can't attach that information to the module object, |
44 | # because not modules are installed but distributions. So I'd have to |
45 | # tell the distribution object that it should ask the user before |
46 | # processing. Where would the question be triggered then? Most probably |
47 | # in CPAN::Distribution::rematein. |
48 | # Hope that makes sense, my head is a bit off:-) -- AK |
49 | |
50 | use vars qw{ @All $VERSION }; |
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51 | $VERSION = sprintf "%.6f", substr(q$Rev: 1486 $,4)/1000000 + 5.4; |
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52 | |
53 | # CPAN::Queue::new ; |
54 | sub new { |
55 | my($class,@attr) = @_; |
56 | my $self = bless { @attr }, $class; |
57 | push @All, $self; |
58 | CPAN->debug(sprintf("in new All[%s]", |
59 | join("",map {sprintf " %s\[%s]\n",$_->{qmod},$_->{reqtype}} @All), |
60 | )) if $CPAN::DEBUG; |
61 | return $self; |
62 | } |
63 | |
64 | # CPAN::Queue::first ; |
65 | sub first { |
66 | my $obj = $All[0]; |
67 | $obj; |
68 | } |
69 | |
70 | sub as_string { |
71 | my($self) = @_; |
72 | $self->{qmod}; |
73 | } |
74 | |
75 | # r => requires, b => build_requires, c => commandline |
76 | sub reqtype { |
77 | my($self) = @_; |
78 | $self->{reqtype}; |
79 | } |
80 | |
81 | # CPAN::Queue::delete_first ; |
82 | sub delete_first { |
83 | my($class,$what) = @_; |
84 | my $i; |
85 | for my $i (0..$#All) { |
86 | if ( $All[$i]->{qmod} eq $what ) { |
87 | splice @All, $i, 1; |
88 | return; |
89 | } |
90 | } |
91 | } |
92 | |
93 | # CPAN::Queue::jumpqueue ; |
94 | sub jumpqueue { |
95 | my $class = shift; |
96 | my @what = @_; |
97 | CPAN->debug(sprintf("before jumpqueue All[%s] what[%s]", |
98 | join("",map {sprintf " %s\[%s]\n",$_->{qmod},$_->{reqtype}} @All), |
99 | join("",map {sprintf " %s\[%s]",$_->[0],$_->[1]} @what) |
100 | )) if $CPAN::DEBUG; |
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101 | unless (defined $what[0][1]) { |
102 | # apparently it was not the Shell that sent us this enquiry, |
103 | # treat it as commandline |
104 | $what[0][1] = "c"; |
105 | } |
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106 | my $inherit_reqtype = $what[0][1] =~ /^(c|r)$/ ? "r" : "b"; |
107 | WHAT: for my $what_tuple (@what) { |
108 | my($what,$reqtype) = @$what_tuple; |
109 | if ($reqtype eq "r" |
110 | && |
111 | $inherit_reqtype eq "b" |
112 | ) { |
113 | $reqtype = "b"; |
114 | } |
115 | my $jumped = 0; |
116 | for (my $i=0; $i<$#All;$i++) { #prevent deep recursion |
117 | # CPAN->debug("i[$i]this[$All[$i]{qmod}]what[$what]") if $CPAN::DEBUG; |
118 | if ($All[$i]{qmod} eq $what){ |
119 | $jumped++; |
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120 | if ($jumped > 25) { # one's OK if e.g. just processing |
121 | # now; more are OK if user typed |
122 | # it several times |
123 | my $sleep = sprintf "%.1f", $jumped/10; |
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124 | $CPAN::Frontend->mywarn( |
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125 | qq{Warning: Object [$what] queued $jumped times, sleeping $sleep secs!\n} |
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126 | ); |
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127 | $CPAN::Frontend->mysleep($sleep); |
128 | # next WHAT; |
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129 | } |
130 | } |
131 | } |
132 | my $obj = bless { |
133 | qmod => $what, |
134 | reqtype => $reqtype |
135 | }, $class; |
136 | unshift @All, $obj; |
137 | } |
138 | CPAN->debug(sprintf("after jumpqueue All[%s]", |
139 | join("",map {sprintf " %s\[%s]\n",$_->{qmod},$_->{reqtype}} @All) |
140 | )) if $CPAN::DEBUG; |
141 | } |
142 | |
143 | # CPAN::Queue::exists ; |
144 | sub exists { |
145 | my($self,$what) = @_; |
146 | my @all = map { $_->{qmod} } @All; |
147 | my $exists = grep { $_->{qmod} eq $what } @All; |
148 | # warn "in exists what[$what] all[@all] exists[$exists]"; |
149 | $exists; |
150 | } |
151 | |
152 | # CPAN::Queue::delete ; |
153 | sub delete { |
154 | my($self,$mod) = @_; |
155 | @All = grep { $_->{qmod} ne $mod } @All; |
156 | } |
157 | |
158 | # CPAN::Queue::nullify_queue ; |
159 | sub nullify_queue { |
160 | @All = (); |
161 | } |
162 | |
163 | 1; |
164 | |
165 | __END__ |
166 | |
167 | =head1 LICENSE |
168 | |
169 | This program is free software; you can redistribute it and/or |
170 | modify it under the same terms as Perl itself. |
171 | |
172 | =cut |