Coro/Event/Handle.pm

=head1 NAME

Coro::Handle - non-blocking io with a blocking interface.

=head1 SYNOPSIS

 use Coro::Handle;

=head1 DESCRIPTION

This module implements io-handles in a coroutine-compatible way, that is,
other coroutines can run while reads or writes block on the handle. It
does NOT inherit from IO::Handle but uses tied objects.

=over 4

=cut

package Coro::Handle;

no warnings;

use Errno ();
use base 'Exporter';

$VERSION = 0.45;

@EXPORT = qw(unblock);

=item $fh = new_from_fh Coro::Handle $fhandle [, arg => value...]

Create a new non-blocking io-handle using the given
perl-filehandle. Returns undef if no fhandle is given. The only other
supported argument is "timeout", which sets a timeout for each operation.

=cut

sub new_from_fh {
   my $class = shift;
   my $fh = shift or return;
   my $self = do { local *Coro::Handle };

   my ($package, $filename, $line) = caller;
   $filename =~ s/^.*[\/\\]//;

   tie $self, Coro::Handle::FH, fh => $fh, desc => "$filename:$line", @_;

   my $_fh = select bless \$self, $class; $| = 1; select $_fh;
}

=item $fh = unblock $fh

This is a convinience function that just calls C<new_from_fh> on the given
filehandle. Use it to replace a normal perl filehandle by a non-blocking
equivalent.

=cut

sub unblock($) {
   new_from_fh Coro::Handle $_[0];
}

=item $fh->writable, $fh->readable

Wait until the filehandle is readable or writable (and return true) or
until an error condition happens (and return false).

=cut

sub readable    { Coro::Handle::FH::readable(tied ${$_[0]}) }
sub writable    { Coro::Handle::FH::writable(tied ${$_[0]}) }

=item $fh->readline([$terminator])

Like the builtin of the same name, but allows you to specify the input
record separator in a coroutine-safe manner (i.e. not using a global
variable).

=cut

sub readline    { tied(${+shift})->READLINE(@_) }

=item $fh->autoflush([...])

Always returns true, arguments are being ignored (exists for compatibility
only). Might change in the future.

=cut

sub autoflush   { !0 }

=item $fh->fileno, $fh->close,
$fh->read, $fh->sysread, $fh->syswrite,
$fh->print, $fh->printf

Work like their function equivalents (except read, which works like
sysread. You should not use the read function with Coro::Handles, it will
work but it's not efficient).

=cut

sub read        { Coro::Handle::FH::READ  (tied ${$_[0]}, $_[1], $_[2], $_[3]) }
sub sysread     { Coro::Handle::FH::READ  (tied ${$_[0]}, $_[1], $_[2], $_[3]) }
sub syswrite    { Coro::Handle::FH::WRITE (tied ${$_[0]}, $_[1], $_[2], $_[3]) }
sub print       { Coro::Handle::FH::WRITE (tied ${+shift}, join "", @_) }
sub printf      { Coro::Handle::FH::PRINTF(tied ${+shift}, @_) }
sub fileno      { Coro::Handle::FH::FILENO(tied ${$_[0]}) }
sub close       { Coro::Handle::FH::CLOSE (tied ${$_[0]}) }

=item $fh->timeout([...])

The optional agrument sets the new timeout (in seconds) for this
handle. Returns the current (new) value.

C<0> is a valid timeout, use C<undef> to disable the timeout.

=cut

sub timeout {
   my $self = tied(${$_[0]});
   if (@_ > 1) {
      $self->[2] = $_[1];
      $self->[5]->timeout($_[1]) if $self->[5];
      $self->[6]->timeout($_[1]) if $self->[6];
   }
   $self->[2];
}

=item $fh->fh

Returns the "real" (non-blocking) filehandle. Use this if you want to
do operations on the file handle you cannot do using the Coro::Handle
interface.

=cut

sub fh {
   tied(${$_[0]})->{fh};
}

package Coro::Handle::FH;

no warnings;

use Fcntl ();
use Errno ();
use Carp 'croak';

use Coro::Event;
use Event::Watcher qw(R W E);

# formerly a hash, but we are speed-critical, so try
# to be faster even if it hurts.
#
# 0 FH
# 1 desc
# 2 timeout
# 3 rb
# 4 wb
# 5 rw
# 6 ww

sub TIEHANDLE {
   my $class = shift;
   my %args = @_;

   my $self = bless [], $class;
   $self->[0] = $args{fh};
   $self->[1] = $args{desc};
   $self->[2] = $args{timeout};
   $self->[3] = "";
   $self->[4] = "";

   fcntl $self->[0], &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK
      or croak "fcntl(O_NONBLOCK): $!";

   $self;
}

sub cleanup {
   $_[0][3] = "";
   ($_[0][5])->cancel if defined $_[0][5]; $_[0][5] = undef;

   $_[0][4] = "";
   ($_[0][6])->cancel if defined $_[0][6]; $_[0][6] = undef;
}

sub OPEN {
   &cleanup;
   my $self = shift;
   my $r = @_ == 2 ? open $self->[0], $_[0], $_[1]
                   : open $self->[0], $_[0], $_[1], $_[2];
   if ($r) {
      fcntl $self->[0], &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK
         or croak "fcntl(O_NONBLOCK): $!";
   }
   $r;
}

sub PRINT {
   WRITE($_[0], $_[1]);
}

sub PRINTF {
   WRITE(shift, sprintf(shift,@_));
}

sub GETC {
   my $buf;
   READ($_[0], $buf, 1);
   $buf;
}

sub BINMODE {
   binmode $_[0][0];
}

sub TELL {
   use Carp (); Carp::croak("Coro::Handle's don't support tell()");
}

sub SEEK {
   use Carp (); Carp::croak("Coro::Handle's don't support seek()");
}

sub EOF {
   use Carp (); Carp::croak("Coro::Handle's don't support eof()");
}

sub CLOSE {
   &cleanup;
   close $_[0][0];
}

sub DESTROY {
   &cleanup;
}

sub FILENO {
   fileno $_[0][0];
}

# seems to be called for stringification (how weird), at least
# when DumpValue::dumpValue is used to print this.
sub FETCH {
   "$_[0]<$_[0][1]>";
}

sub readable {
   ($_[0][5] ||= Coro::Event->io(
      fd      => $_[0][0],
      desc    => "$_[0][1] R",
      timeout => $_[0][2],
      poll    => R+E,
   ))->next->{Coro::Event}[5] & R;
}

sub writable {
   ($_[0][6] ||= Coro::Event->io(
      fd      => $_[0][0],
      desc    => "$_[0][1] W",
      timeout => $_[0][2],
      poll    => W+E,
   ))->next->{Coro::Event}[5] & W;
}

sub WRITE {
   my $len = defined $_[2] ? $_[2] : length $_[1];
   my $ofs = $_[3];
   my $res = 0;

   while() {
      my $r = syswrite $_[0][0], $_[1], $len, $ofs;
      if (defined $r) {
         $len -= $r;
         $ofs += $r;
         $res += $r;
         last unless $len;
      } elsif ($! != Errno::EAGAIN) {
         last;
      }
      last unless &writable;
   }

   return $res;
}

sub READ {
   my $len = $_[2];
   my $ofs = $_[3];
   my $res = 0;

   # first deplete the read buffer
   if (defined $_[0][3]) {
      my $l = length $_[0][3];
      if ($l <= $len) {
         substr($_[1], $ofs) = $_[0][3]; undef $_[0][3];
         $len -= $l;
         $res += $l;
         return $res unless $len;
      } else {
         substr($_[1], $ofs) = substr($_[0][3], 0, $len);
         substr($_[0][3], 0, $len) = "";
         return $len;
      }
   }

   while() {
      my $r = sysread $_[0][0], $_[1], $len, $ofs;
      if (defined $r) {
         $len -= $r;
         $ofs += $r;
         $res += $r;
         last unless $len && $r;
      } elsif ($! != Errno::EAGAIN) {
         last;
      }
      last unless &readable;
   }

   return $res;
}

sub READLINE {
   my $irs = @_ > 1 ? $_[1] : $/;

   while() {
      my $pos = index $_[0][3], $irs;
      if ($pos >= 0) {
         $pos += length $irs;
         my $res = substr $_[0][3], 0, $pos;
         substr ($_[0][3], 0, $pos) = "";
         return $res;
      }

      my $r = sysread $_[0][0], $_[0][3], 8192, length $_[0][3];
      if (defined $r) {
         return undef unless $r;
      } elsif ($! != Errno::EAGAIN || !&readable) {
         return undef;
      }
   }
}

1;

=head1 BUGS

 - Perl's IO-Handle model is THE bug.

=head1 AUTHOR

 Marc Lehmann <pcg@goof.com>
 http://www.goof.com/pcg/marc/

=cut

Revision:	1.9
Committed:	Mon Sep 24 00:51:19 2001 UTC (25 years, 1 month ago) by root
Branch:	MAIN
Changes since 1.8:	+48 -11 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			Coro::Handle - non-blocking io with a blocking interface.
4
5			=head1 SYNOPSIS
6
7			use Coro::Handle;
8
9			=head1 DESCRIPTION
10
11			This module implements io-handles in a coroutine-compatible way, that is,
12			other coroutines can run while reads or writes block on the handle. It
13			does NOT inherit from IO::Handle but uses tied objects.
14
15			=over 4
16
17			=cut
18
19			package Coro::Handle;
20
21	root	1.9	no warnings;
22
23	root	1.1	use Errno ();
24			use base 'Exporter';
25
26			$VERSION = 0.45;
27
28			@EXPORT = qw(unblock);
29
30			=item $fh = new_from_fh Coro::Handle $fhandle [, arg => value...]
31
32			Create a new non-blocking io-handle using the given
33			perl-filehandle. Returns undef if no fhandle is given. The only other
34			supported argument is "timeout", which sets a timeout for each operation.
35
36			=cut
37
38			sub new_from_fh {
39			my $class = shift;
40			my $fh = shift or return;
41			my $self = do { local *Coro::Handle };
42
43			my ($package, $filename, $line) = caller;
44			$filename =~ s/^.*[\/\\]//;
45
46			tie $self, Coro::Handle::FH, fh => $fh, desc => "$filename:$line", @_;
47
48			my $_fh = select bless \$self, $class; $\| = 1; select $_fh;
49			}
50
51			=item $fh = unblock $fh
52
53			This is a convinience function that just calls C<new_from_fh> on the given
54			filehandle. Use it to replace a normal perl filehandle by a non-blocking
55			equivalent.
56
57			=cut
58
59			sub unblock($) {
60			new_from_fh Coro::Handle $_[0];
61			}
62
63			=item $fh->writable, $fh->readable
64
65			Wait until the filehandle is readable or writable (and return true) or
66			until an error condition happens (and return false).
67
68			=cut
69
70	root	1.5	sub readable { Coro::Handle::FH::readable(tied ${$_[0]}) }
71			sub writable { Coro::Handle::FH::writable(tied ${$_[0]}) }
72	root	1.1
73			=item $fh->readline([$terminator])
74
75			Like the builtin of the same name, but allows you to specify the input
76			record separator in a coroutine-safe manner (i.e. not using a global
77			variable).
78
79			=cut
80
81			sub readline { tied(${+shift})->READLINE(@_) }
82
83			=item $fh->autoflush([...])
84
85			Always returns true, arguments are being ignored (exists for compatibility
86			only). Might change in the future.
87
88			=cut
89
90			sub autoflush { !0 }
91
92	root	1.9	=item $fh->fileno, $fh->close,
93			$fh->read, $fh->sysread, $fh->syswrite,
94			$fh->print, $fh->printf
95
96			Work like their function equivalents (except read, which works like
97			sysread. You should not use the read function with Coro::Handles, it will
98			work but it's not efficient).
99	root	1.1
100			=cut
101
102	root	1.9	sub read { Coro::Handle::FH::READ (tied ${$_[0]}, $_[1], $_[2], $_[3]) }
103			sub sysread { Coro::Handle::FH::READ (tied ${$_[0]}, $_[1], $_[2], $_[3]) }
104			sub syswrite { Coro::Handle::FH::WRITE (tied ${$_[0]}, $_[1], $_[2], $_[3]) }
105			sub print { Coro::Handle::FH::WRITE (tied ${+shift}, join "", @_) }
106			sub printf { Coro::Handle::FH::PRINTF(tied ${+shift}, @_) }
107			sub fileno { Coro::Handle::FH::FILENO(tied ${$_[0]}) }
108			sub close { Coro::Handle::FH::CLOSE (tied ${$_[0]}) }
109	root	1.1
110			=item $fh->timeout([...])
111
112			The optional agrument sets the new timeout (in seconds) for this
113			handle. Returns the current (new) value.
114
115			C<0> is a valid timeout, use C<undef> to disable the timeout.
116
117			=cut
118
119			sub timeout {
120	root	1.4	my $self = tied(${$_[0]});
121	root	1.6	if (@_ > 1) {
122			$self->[2] = $_[1];
123			$self->[5]->timeout($_[1]) if $self->[5];
124			$self->[6]->timeout($_[1]) if $self->[6];
125	root	1.1	}
126	root	1.6	$self->[2];
127	root	1.4	}
128
129			=item $fh->fh
130
131			Returns the "real" (non-blocking) filehandle. Use this if you want to
132			do operations on the file handle you cannot do using the Coro::Handle
133			interface.
134
135			=cut
136
137			sub fh {
138			tied(${$_[0]})->{fh};
139	root	1.1	}
140
141			package Coro::Handle::FH;
142
143	root	1.9	no warnings;
144
145	root	1.1	use Fcntl ();
146			use Errno ();
147			use Carp 'croak';
148
149			use Coro::Event;
150			use Event::Watcher qw(R W E);
151
152	root	1.6	# formerly a hash, but we are speed-critical, so try
153			# to be faster even if it hurts.
154			#
155			# 0 FH
156			# 1 desc
157			# 2 timeout
158			# 3 rb
159			# 4 wb
160			# 5 rw
161			# 6 ww
162
163	root	1.1	sub TIEHANDLE {
164			my $class = shift;
165	root	1.6	my %args = @_;
166	root	1.1
167	root	1.6	my $self = bless [], $class;
168			$self->[0] = $args{fh};
169			$self->[1] = $args{desc};
170			$self->[2] = $args{timeout};
171			$self->[3] = "";
172			$self->[4] = "";
173	root	1.1
174	root	1.6	fcntl $self->[0], &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK
175	root	1.1	or croak "fcntl(O_NONBLOCK): $!";
176
177			$self;
178			}
179
180	root	1.6	sub cleanup {
181			$_[0][3] = "";
182	root	1.7	($_[0][5])->cancel if defined $_[0][5]; $_[0][5] = undef;
183	root	1.6
184			$_[0][4] = "";
185	root	1.7	($_[0][6])->cancel if defined $_[0][6]; $_[0][6] = undef;
186	root	1.6	}
187
188	root	1.1	sub OPEN {
189	root	1.6	&cleanup;
190	root	1.1	my $self = shift;
191	root	1.6	my $r = @_ == 2 ? open $self->[0], $_[0], $_[1]
192			: open $self->[0], $_[0], $_[1], $_[2];
193	root	1.1	if ($r) {
194	root	1.6	fcntl $self->[0], &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK
195	root	1.1	or croak "fcntl(O_NONBLOCK): $!";
196			}
197			$r;
198	root	1.9	}
199
200			sub PRINT {
201			WRITE($_[0], $_[1]);
202			}
203
204			sub PRINTF {
205			WRITE(shift, sprintf(shift,@_));
206			}
207
208			sub GETC {
209			my $buf;
210			READ($_[0], $buf, 1);
211			$buf;
212			}
213
214			sub BINMODE {
215			binmode $_[0][0];
216			}
217
218			sub TELL {
219			use Carp (); Carp::croak("Coro::Handle's don't support tell()");
220			}
221
222			sub SEEK {
223			use Carp (); Carp::croak("Coro::Handle's don't support seek()");
224			}
225
226			sub EOF {
227			use Carp (); Carp::croak("Coro::Handle's don't support eof()");
228	root	1.1	}
229
230			sub CLOSE {
231	root	1.6	&cleanup;
232			close $_[0][0];
233	root	1.1	}
234
235	root	1.6	sub DESTROY {
236			&cleanup;
237	root	1.1	}
238
239	root	1.6	sub FILENO {
240			fileno $_[0][0];
241	root	1.1	}
242
243	root	1.8	# seems to be called for stringification (how weird), at least
244			# when DumpValue::dumpValue is used to print this.
245			sub FETCH {
246			"$_[0]<$_[0][1]>";
247			}
248
249	root	1.1	sub readable {
250	root	1.6	($_[0][5] \|\|= Coro::Event->io(
251			fd => $_[0][0],
252			desc => "$_[0][1] R",
253			timeout => $_[0][2],
254	root	1.1	poll => R+E,
255	root	1.3	))->next->{Coro::Event}[5] & R;
256	root	1.1	}
257
258	root	1.6	sub writable {
259			($_[0][6] \|\|= Coro::Event->io(
260			fd => $_[0][0],
261			desc => "$_[0][1] W",
262			timeout => $_[0][2],
263			poll => W+E,
264			))->next->{Coro::Event}[5] & W;
265			}
266
267	root	1.1	sub WRITE {
268			my $len = defined $_[2] ? $_[2] : length $_[1];
269			my $ofs = $_[3];
270			my $res = 0;
271
272			while() {
273	root	1.6	my $r = syswrite $_[0][0], $_[1], $len, $ofs;
274	root	1.1	if (defined $r) {
275			$len -= $r;
276			$ofs += $r;
277			$res += $r;
278			last unless $len;
279			} elsif ($! != Errno::EAGAIN) {
280			last;
281			}
282	root	1.6	last unless &writable;
283	root	1.1	}
284
285			return $res;
286			}
287
288			sub READ {
289			my $len = $_[2];
290			my $ofs = $_[3];
291			my $res = 0;
292
293			# first deplete the read buffer
294	root	1.6	if (defined $_[0][3]) {
295			my $l = length $_[0][3];
296	root	1.1	if ($l <= $len) {
297	root	1.6	substr($_[1], $ofs) = $_[0][3]; undef $_[0][3];
298	root	1.1	$len -= $l;
299			$res += $l;
300			return $res unless $len;
301			} else {
302	root	1.6	substr($_[1], $ofs) = substr($_[0][3], 0, $len);
303			substr($_[0][3], 0, $len) = "";
304	root	1.1	return $len;
305			}
306			}
307
308			while() {
309	root	1.6	my $r = sysread $_[0][0], $_[1], $len, $ofs;
310	root	1.1	if (defined $r) {
311			$len -= $r;
312			$ofs += $r;
313			$res += $r;
314			last unless $len && $r;
315			} elsif ($! != Errno::EAGAIN) {
316			last;
317			}
318	root	1.6	last unless &readable;
319	root	1.1	}
320
321			return $res;
322			}
323
324			sub READLINE {
325	root	1.6	my $irs = @_ > 1 ? $_[1] : $/;
326	root	1.1
327			while() {
328	root	1.6	my $pos = index $_[0][3], $irs;
329	root	1.1	if ($pos >= 0) {
330			$pos += length $irs;
331	root	1.6	my $res = substr $_[0][3], 0, $pos;
332			substr ($_[0][3], 0, $pos) = "";
333	root	1.1	return $res;
334			}
335	root	1.6
336			my $r = sysread $_[0][0], $_[0][3], 8192, length $_[0][3];
337	root	1.1	if (defined $r) {
338			return undef unless $r;
339	root	1.6	} elsif ($! != Errno::EAGAIN \|\| !&readable) {
340	root	1.1	return undef;
341			}
342			}
343			}
344
345			1;
346
347			=head1 BUGS
348
349			- Perl's IO-Handle model is THE bug.
350
351			=head1 AUTHOR
352
353			Marc Lehmann <pcg@goof.com>
354			http://www.goof.com/pcg/marc/
355
356			=cut
357