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1 | # -*-perl-*- |
2 | # |
3 | # $Id: SW.pm,v 1.1 1999/07/30 18:48:05 mdw Exp $ |
4 | # |
5 | # Handling for the `sw' index file |
6 | # |
7 | # (c) 1999 EBI |
8 | # |
9 | |
10 | #----- Licensing notice ----------------------------------------------------- |
11 | # |
12 | # This file is part of sw-tools. |
13 | # |
14 | # sw-tools is free software; you can redistribute it and/or modify |
15 | # it under the terms of the GNU General Public License as published by |
16 | # the Free Software Foundation; either version 2 of the License, or |
17 | # (at your option) any later version. |
18 | # |
19 | # sw-tools is distributed in the hope that it will be useful, |
20 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | # GNU General Public License for more details. |
23 | # |
24 | # You should have received a copy of the GNU General Public License |
25 | # along with sw-tools; if not, write to the Free Software Foundation, |
26 | # Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | |
28 | #----- Revision history ----------------------------------------------------- |
29 | # |
30 | # $Log: SW.pm,v $ |
31 | # Revision 1.1 1999/07/30 18:48:05 mdw |
32 | # Useful bits for the Perl support code. |
33 | # |
34 | |
35 | #----- Package preamble ----------------------------------------------------- |
36 | |
37 | package SW; |
38 | |
39 | use IO; |
40 | use POSIX; |
41 | |
42 | use SWConfig; |
43 | |
44 | #----- Main code ------------------------------------------------------------ |
45 | |
46 | # --- @vcmp(a, b)@ --- |
47 | # |
48 | # Returns < 0, == 0 or > 0 depending on whether a < b, a == b, or a > b, in |
49 | # an ordering of version numbers. A version number is considered to be a |
50 | # sequence of digit strings and words, optionally separated by non-word |
51 | # characters. The digit sequences are compared using a numerical ordering. |
52 | # The words are compared lexically with the exception that a missing word is |
53 | # considered greater than all other strings. |
54 | |
55 | sub vcmp($$) { |
56 | my ($a, $b) = @_; |
57 | my ($aa, $bb); |
58 | my ($ar, $br); |
59 | |
60 | SECTION: while (1) { |
61 | if ($a eq $b) { return 0; } |
62 | |
63 | # --- Extract leading digit sequences --- |
64 | |
65 | ($aa, $ar) = $a =~ /^(\d+)(.*)/; |
66 | ($bb, $br) = $b =~ /^(\d+)(.*)/; |
67 | if ($aa || $bb) { |
68 | if ($aa == $bb) { next SECTION; } |
69 | else { return $aa <=> $bb; } |
70 | } |
71 | |
72 | # --- Extract leading word sequences --- |
73 | |
74 | ($aa, $ar) = $a =~ /^(\w+)(.*)/; |
75 | ($bb, $br) = $b =~ /^(\w+)(.*)/; |
76 | if (defined($aa) || defined($bb)) { |
77 | if ($aa eq $bb) { next SECTION; } |
78 | elsif ($aa eq "") { return +1; } |
79 | elsif ($bb eq "") { return -1; } |
80 | else { return $aa cmp $bb; } |
81 | } |
82 | |
83 | # --- Strip leading non-word sequences --- |
84 | |
85 | ($ar) = $a =~ /^\W+(.*)/; |
86 | ($br) = $b =~ /^\W+(.*)/; |
87 | } continue { |
88 | $a = $ar; |
89 | $b = $br; |
90 | } |
91 | } |
92 | |
93 | # --- @read()@ --- |
94 | # |
95 | # Reads an `sw' index file. Any EOF condition on the file is cleared before |
96 | # reading starts. This allows multiple reads to pick up any extra appends on |
97 | # the file. Returns the number of items read. |
98 | |
99 | sub read { |
100 | my $me = shift; |
101 | my $read = 0; |
102 | |
103 | return unless $me->{fh}; |
104 | |
105 | seek($me->{fh}, 0, 1); # Clear EOF flag |
106 | |
107 | while (my $line = $me->{fh}->getline()) { |
108 | my %map; |
109 | |
110 | $read++; |
111 | |
112 | chomp($line); |
113 | foreach my $f (split(/\s*\;\s*/, $line)) { |
114 | %map = (%map, split(/\s*=\s*|\s+/, $f, 2)); |
115 | } |
116 | |
117 | my $pkg = $map{"package"}; |
118 | unless ($me->{map}{$pkg} && $me->{map}{$pkg}{"date"} gt $map{"date"}) { |
119 | $me->{map}{$pkg} = \%map; |
120 | $me->{dirty}{$pkg} = 1; |
121 | } |
122 | } |
123 | |
124 | return $read; |
125 | } |
126 | |
127 | # --- @write()@ --- |
128 | # |
129 | # Writes an `sw' index file. The old file is moved out of the way while the |
130 | # new one is written a line at a time. If everyone's playing the game right |
131 | # by using append mode, we should be OK. When the initial write is over, I |
132 | # remove the old file, and read and write any more items that were left in |
133 | # it. |
134 | |
135 | sub write { |
136 | my $me = shift; |
137 | my $fh; |
138 | |
139 | unlink($me->{file} . ".old"); |
140 | rename($me->{file}, $me->{file} . ".old") or return undef; |
141 | $fh = IO::File->new($me->{file}, O_APPEND | O_CREAT | O_WRONLY); |
142 | $fh->autoflush(1); |
143 | |
144 | my @which = $me->list(); |
145 | |
146 | ONE_THERES_A_SISSY: for (;;) { |
147 | foreach my $i (@which) { |
148 | my $l = ""; |
149 | foreach my $j (qw(package version maintainer date arch only-arch)) { |
150 | $v = $me->{map}{$i}{$j}; |
151 | $l and $l .= "; "; |
152 | $l .= "$j = $v"; |
153 | } |
154 | $fh->print($l . "\n"); |
155 | } |
156 | |
157 | unlink($me->{file} . ".old"); |
158 | $me->{dirty} = {}; |
159 | $me->read() or last ONE_THERES_A_SISSY; |
160 | @which = |
161 | sort { $me->{map}{$a}{"date"} cmp $me->{map}{$b}{"date"} } |
162 | keys(%{$me->{dirty}}); |
163 | } |
164 | return 1; |
165 | } |
166 | |
167 | # --- @list()@ --- |
168 | # |
169 | # Returns a list of package names. |
170 | |
171 | sub list { |
172 | my $me = shift; |
173 | return sort(keys(%{$me->{map}})); |
174 | } |
175 | |
176 | # --- @get(PKG)@ --- |
177 | # |
178 | # Returns (a reference to) a package's hash entry. |
179 | |
180 | sub get { |
181 | my $me = shift; |
182 | my $pkg = shift; |
183 | return $me->{map}{$pkg}; |
184 | } |
185 | |
186 | # --- @new([NAME])@ --- |
187 | # |
188 | # Opens a package index. |
189 | |
190 | sub new { |
191 | my $class = shift; |
192 | my $file = shift || "$C{prefix}/sw-index"; |
193 | my $me = bless {}, $class; |
194 | my $fh = IO::File->new($file, O_RDONLY); |
195 | $me->{file} = $file; |
196 | $me->{fh} = $fh; |
197 | $me->read(); |
198 | return $me; |
199 | } |
200 | |
201 | #----- That's all, folks ---------------------------------------------------- |
202 | |
203 | 1; |