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1 | # -*-perl-*- |
2 | # |
9796a787 |
3 | # $Id: Info.pm,v 1.2 2004/04/08 01:52:19 mdw Exp $ |
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4 | # |
5 | # Manipulation and reading of Info files |
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 | |
961ce1c2 |
28 | #----- Package preamble ----------------------------------------------------- |
29 | |
30 | package Info; |
31 | use IO; |
32 | use POSIX; |
33 | use Exporter; |
34 | @ISA = qw(Exporter); |
35 | @EXPORT_OK = qw(setpath); |
36 | |
37 | #----- Low-level twiddling -------------------------------------------------- |
38 | |
39 | @infopath = ("/usr/info"); |
40 | |
41 | # --- @setpath(PATH...)@ --- |
42 | # |
43 | # Sets the Info search path. |
44 | |
45 | sub setpath(@) { |
46 | @infopath = @_; |
47 | } |
48 | |
49 | # --- @getname(INFO)@ --- |
50 | # |
51 | # Given the name of an Info manual, find the actual file. |
52 | |
53 | |
54 | sub getname($) { |
55 | my ($file) = @_; |
56 | |
57 | foreach my $p (@infopath) { |
58 | my $f = "$p/$file"; |
59 | |
60 | foreach my $suff ("", "-info", ".info") { |
61 | return $f . $suff if -r $f . $suff; |
62 | return $f . $suff . ".gz" if -r $f . $suff . ".gz"; |
63 | } |
64 | } |
65 | return undef; |
66 | } |
67 | |
68 | # --- @snarf(FILE)@ --- |
69 | # |
70 | # Snarf a file into a string, given its name. Handles compressed files. |
71 | |
72 | sub snarf($) { |
73 | my ($f) = @_; |
74 | local $/ = undef; |
75 | my $snarf; |
76 | |
77 | if ($f =~ /\.gz$/) { |
78 | my $p = IO::Pipe->new(); |
79 | my $kid = fork(); |
80 | defined($kid) or return undef; |
81 | if ($kid == 0) { |
82 | $p->writer(); |
83 | dup2($p->fileno(), 1); |
84 | exec("gzip", "-dc", $f); |
85 | exit(127); |
86 | } |
87 | $p->reader(); |
88 | $snarf = $p->getline(); |
89 | $p->close(); |
90 | waitpid($kid, 0); |
91 | } else { |
92 | my $fh = IO::File->new($f, O_RDONLY) or return undef; |
93 | $snarf = $fh->getline(); |
94 | $fh->close(); |
95 | } |
96 | return $snarf; |
97 | } |
98 | |
99 | #----- An Info-file object -------------------------------------------------- |
100 | |
101 | # --- @node(NAME)@ --- |
102 | # |
103 | # Picks an individual node out of an Info file. |
104 | |
105 | sub node { |
106 | my ($me, $node) = @_; |
107 | my $offset = 0; |
108 | my $file; |
109 | my $chunk; |
110 | |
111 | # --- If there's an index, it will help me find the node --- |
112 | |
113 | if ($me->{index}) { |
114 | $offset = $me->{index}{lc($node)}; |
115 | |
116 | # --- Maybe the offset is into a different file --- |
117 | |
118 | if ($me->{indir}) { |
119 | my $loff = 0; |
120 | PAIR: foreach my $pair (@{$me->{indir}}) { |
121 | if ($pair->[0] <= $offset) { |
122 | ($loff, $file) = @$pair; |
123 | } else { |
124 | last PAIR; |
125 | } |
126 | } |
127 | return undef unless $file; |
128 | $offset -= $loff; |
129 | } |
130 | } |
131 | |
132 | # --- Fetch the file --- |
133 | |
134 | if ($file) { |
135 | my $fn; |
136 | |
137 | $fn = "$me->{dir}/$file", -r $fn or |
138 | $fn = "$me->{dir}/$file.gz", -r $fn or |
139 | return undef; |
140 | |
141 | if ($me->{cache}{$fn}) { |
142 | $file = $me->{cache}{$fn}; |
143 | } else { |
144 | $file = $me->{cache}{$fn} = snarf($fn) or return undef; |
145 | } |
146 | } else { |
147 | $file = $me->{base}; |
148 | } |
149 | |
150 | # --- Dig through the file to find the right node --- |
151 | |
152 | GASP: for (;;) { |
153 | pos $file = $offset; |
154 | if ($file =~ / \G .*\1f\n |
155 | ([^\1f\n]* Node:\ * |
156 | \Q$node\E |
157 | [.,\n\t] [^\1f]*) |
158 | (?:\1f|\Z) /igsx) { |
159 | $chunk = $1; |
160 | last GASP; |
161 | } |
162 | $offset = 0, next GASP if $offset; |
163 | last GASP; |
164 | } |
165 | |
166 | return $chunk; |
167 | } |
168 | |
169 | # --- @load(NAME)@ --- |
170 | # |
171 | # Loads a file into an Info object. |
172 | |
173 | sub load { |
174 | my ($me, $file) = @_; |
175 | my $f = getname($file) or return undef; |
176 | my $c = snarf($f) or return undef; |
177 | |
178 | # --- Read the index, and maybe snarf in the indirection file --- |
179 | |
180 | if (my ($index) = ($c =~ /\1f\nTag Table:\n([^\1f]*)\1f\nEnd Tag Table\n/s)) { |
181 | my %index = (); |
182 | while ($index =~ /Node: *([^\n\7f]*)\7f(\d+)\n/sg) { $index{lc($1)} = $2; } |
183 | $me->{index} = \%index; |
184 | if ($index =~ /^\(Indirect\)/ and |
185 | my ($indir) = ($c =~ /\1f\nIndirect:\n([^\1f]*)\1f\n/s)) { |
186 | my @indir = (); |
187 | while ($indir =~ /([^\n:]*): *(\d+)\n/sg) { push(@indir, [$2, $1]); } |
188 | $me->{indir} = \@indir; |
189 | } |
190 | } |
191 | |
192 | ($me->{dir} = $f) =~ s:/[^/]*$::; |
193 | $me->{base} = $c; |
194 | return $me; |
195 | } |
196 | |
197 | # --- @new([NAME])@ --- |
198 | # |
199 | # Makes a new Info file and returns it to the caller. |
200 | |
201 | sub new { |
202 | my ($class, $file) = @_; |
203 | my $me = bless {}, $class; |
204 | return $me->load($file) if $file; |
205 | return $me; |
206 | } |
207 | |
208 | #----- That's all, folks ---------------------------------------------------- |
209 | |
210 | 1; |