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1 | # IO::Pipe.pm |
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2 | # |
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3 | # Copyright (c) 1996-8 Graham Barr <gbarr@pobox.com>. All rights reserved. |
4 | # This program is free software; you can redistribute it and/or |
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5 | # modify it under the same terms as Perl itself. |
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6 | |
7 | package IO::Pipe; |
8 | |
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9 | require 5.005_64; |
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10 | |
11 | use IO::Handle; |
12 | use strict; |
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13 | our($VERSION); |
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14 | use Carp; |
15 | use Symbol; |
16 | |
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17 | $VERSION = "1.121"; |
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18 | |
19 | sub new { |
20 | my $type = shift; |
21 | my $class = ref($type) || $type || "IO::Pipe"; |
22 | @_ == 0 || @_ == 2 or croak "usage: new $class [READFH, WRITEFH]"; |
23 | |
24 | my $me = bless gensym(), $class; |
25 | |
26 | my($readfh,$writefh) = @_ ? @_ : $me->handles; |
27 | |
28 | pipe($readfh, $writefh) |
29 | or return undef; |
30 | |
31 | @{*$me} = ($readfh, $writefh); |
32 | |
33 | $me; |
34 | } |
35 | |
36 | sub handles { |
37 | @_ == 1 or croak 'usage: $pipe->handles()'; |
38 | (IO::Pipe::End->new(), IO::Pipe::End->new()); |
39 | } |
40 | |
41 | my $do_spawn = $^O eq 'os2'; |
42 | |
43 | sub _doit { |
44 | my $me = shift; |
45 | my $rw = shift; |
46 | |
47 | my $pid = $do_spawn ? 0 : fork(); |
48 | |
49 | if($pid) { # Parent |
50 | return $pid; |
51 | } |
52 | elsif(defined $pid) { # Child or spawn |
53 | my $fh; |
54 | my $io = $rw ? \*STDIN : \*STDOUT; |
55 | my ($mode, $save) = $rw ? "r" : "w"; |
56 | if ($do_spawn) { |
57 | require Fcntl; |
58 | $save = IO::Handle->new_from_fd($io, $mode); |
59 | # Close in child: |
60 | fcntl(shift, Fcntl::F_SETFD(), 1) or croak "fcntl: $!"; |
61 | $fh = $rw ? ${*$me}[0] : ${*$me}[1]; |
62 | } else { |
63 | shift; |
64 | $fh = $rw ? $me->reader() : $me->writer(); # close the other end |
65 | } |
66 | bless $io, "IO::Handle"; |
67 | $io->fdopen($fh, $mode); |
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68 | $fh->close; |
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69 | |
70 | if ($do_spawn) { |
71 | $pid = eval { system 1, @_ }; # 1 == P_NOWAIT |
72 | my $err = $!; |
73 | |
74 | $io->fdopen($save, $mode); |
75 | $save->close or croak "Cannot close $!"; |
76 | croak "IO::Pipe: Cannot spawn-NOWAIT: $err" if not $pid or $pid < 0; |
77 | return $pid; |
78 | } else { |
79 | exec @_ or |
80 | croak "IO::Pipe: Cannot exec: $!"; |
81 | } |
82 | } |
83 | else { |
84 | croak "IO::Pipe: Cannot fork: $!"; |
85 | } |
86 | |
87 | # NOT Reached |
88 | } |
89 | |
90 | sub reader { |
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91 | @_ >= 1 or croak 'usage: $pipe->reader( [SUB_COMMAND_ARGS] )'; |
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92 | my $me = shift; |
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93 | |
94 | return undef |
95 | unless(ref($me) || ref($me = $me->new)); |
96 | |
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97 | my $fh = ${*$me}[0]; |
98 | my $pid = $me->_doit(0, $fh, @_) |
99 | if(@_); |
100 | |
101 | close ${*$me}[1]; |
102 | bless $me, ref($fh); |
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103 | *$me = *$fh; # Alias self to handle |
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104 | $me->fdopen($fh->fileno,"r") |
105 | unless defined($me->fileno); |
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106 | bless $fh; # Really wan't un-bless here |
107 | ${*$me}{'io_pipe_pid'} = $pid |
108 | if defined $pid; |
109 | |
110 | $me; |
111 | } |
112 | |
113 | sub writer { |
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114 | @_ >= 1 or croak 'usage: $pipe->writer( [SUB_COMMAND_ARGS] )'; |
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115 | my $me = shift; |
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116 | |
117 | return undef |
118 | unless(ref($me) || ref($me = $me->new)); |
119 | |
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120 | my $fh = ${*$me}[1]; |
121 | my $pid = $me->_doit(1, $fh, @_) |
122 | if(@_); |
123 | |
124 | close ${*$me}[0]; |
125 | bless $me, ref($fh); |
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126 | *$me = *$fh; # Alias self to handle |
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127 | $me->fdopen($fh->fileno,"w") |
128 | unless defined($me->fileno); |
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129 | bless $fh; # Really wan't un-bless here |
130 | ${*$me}{'io_pipe_pid'} = $pid |
131 | if defined $pid; |
132 | |
133 | $me; |
134 | } |
135 | |
136 | package IO::Pipe::End; |
137 | |
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138 | our(@ISA); |
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139 | |
140 | @ISA = qw(IO::Handle); |
141 | |
142 | sub close { |
143 | my $fh = shift; |
144 | my $r = $fh->SUPER::close(@_); |
145 | |
146 | waitpid(${*$fh}{'io_pipe_pid'},0) |
147 | if(defined ${*$fh}{'io_pipe_pid'}); |
148 | |
149 | $r; |
150 | } |
151 | |
152 | 1; |
153 | |
154 | __END__ |
155 | |
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156 | =head1 NAME |
157 | |
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158 | IO::Pipe - supply object methods for pipes |
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159 | |
160 | =head1 SYNOPSIS |
161 | |
162 | use IO::Pipe; |
163 | |
164 | $pipe = new IO::Pipe; |
165 | |
166 | if($pid = fork()) { # Parent |
167 | $pipe->reader(); |
168 | |
169 | while(<$pipe> { |
170 | .... |
171 | } |
172 | |
173 | } |
174 | elsif(defined $pid) { # Child |
175 | $pipe->writer(); |
176 | |
177 | print $pipe .... |
178 | } |
179 | |
180 | or |
181 | |
182 | $pipe = new IO::Pipe; |
183 | |
184 | $pipe->reader(qw(ls -l)); |
185 | |
186 | while(<$pipe>) { |
187 | .... |
188 | } |
189 | |
190 | =head1 DESCRIPTION |
191 | |
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192 | C<IO::Pipe> provides an interface to creating pipes between |
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193 | processes. |
194 | |
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195 | =head1 CONSTRUCTOR |
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196 | |
197 | =over 4 |
198 | |
199 | =item new ( [READER, WRITER] ) |
200 | |
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201 | Creates a C<IO::Pipe>, which is a reference to a newly created symbol |
202 | (see the C<Symbol> package). C<IO::Pipe::new> optionally takes two |
203 | arguments, which should be objects blessed into C<IO::Handle>, or a |
204 | subclass thereof. These two objects will be used for the system call |
205 | to C<pipe>. If no arguments are given then method C<handles> is called |
206 | on the new C<IO::Pipe> object. |
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207 | |
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208 | These two handles are held in the array part of the GLOB until either |
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209 | C<reader> or C<writer> is called. |
210 | |
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211 | =back |
212 | |
213 | =head1 METHODS |
214 | |
215 | =over 4 |
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216 | |
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217 | =item reader ([ARGS]) |
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218 | |
219 | The object is re-blessed into a sub-class of C<IO::Handle>, and becomes a |
220 | handle at the reading end of the pipe. If C<ARGS> are given then C<fork> |
221 | is called and C<ARGS> are passed to exec. |
222 | |
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223 | =item writer ([ARGS]) |
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224 | |
225 | The object is re-blessed into a sub-class of C<IO::Handle>, and becomes a |
226 | handle at the writing end of the pipe. If C<ARGS> are given then C<fork> |
227 | is called and C<ARGS> are passed to exec. |
228 | |
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229 | =item handles () |
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230 | |
231 | This method is called during construction by C<IO::Pipe::new> |
232 | on the newly created C<IO::Pipe> object. It returns an array of two objects |
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233 | blessed into C<IO::Pipe::End>, or a subclass thereof. |
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234 | |
235 | =back |
236 | |
237 | =head1 SEE ALSO |
238 | |
239 | L<IO::Handle> |
240 | |
241 | =head1 AUTHOR |
242 | |
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243 | Graham Barr. Currently maintained by the Perl Porters. Please report all |
244 | bugs to <perl5-porters@perl.org>. |
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245 | |
246 | =head1 COPYRIGHT |
247 | |
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248 | Copyright (c) 1996-8 Graham Barr <gbarr@pobox.com>. All rights reserved. |
249 | This program is free software; you can redistribute it and/or |
250 | modify it under the same terms as Perl itself. |
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251 | |
252 | =cut |