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 qw(uninitialized);

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, ref $class ? ref $class : $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.

=item $fh->rbuf

Returns the current contents of the read buffer (this is an lvalue, so you
can change the read buffer if you like).

You can use this function to implement your own optimized reader when neither
readline nor sysread are viable candidates, like this:

  # first get the _real_ non-blocking filehandle
  # and fetch a reference to the read buffer
  my $nb_fh = $fh->fh;
  my $buf = \$fh->rbuf;

  for(;;) {
     # now use buffer contents, modifying
     # if necessary to reflect the removed data

     last if $$buf ne ""; # we have leftover data

     # read another buffer full of data
     $fh->readable or die "end of file";
     sysread $nb_fh, $$buf, 8192;
  }

=cut

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

sub rbuf : lvalue {
   tied(${$_[0]})->[3];
}

package Coro::Handle::FH;

no warnings qw(uninitialized);

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 # unused
# 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(shift, join "", @_);
}

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 (length $_[0][3]) {
      my $l = length $_[0][3];
      if ($l <= $len) {
         substr($_[1], $ofs) = $_[0][3]; $_[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:	1.16
Committed:	Sun Mar 24 12:09:05 2002 UTC (22 years, 2 months ago) by root
Branch:	MAIN
Changes since 1.15:	+1 -1 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	1.10	no warnings qw(uninitialized);
22	root	1.9
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	root	1.16	my $_fh = select bless \$self, ref $class ? ref $class : $class; $\| = 1; select $_fh;
49	root	1.1	}
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	root	1.11	=item $fh->rbuf
136	root	1.10
137	root	1.13	Returns the current contents of the read buffer (this is an lvalue, so you
138	root	1.11	can change the read buffer if you like).
139
140	root	1.13	You can use this function to implement your own optimized reader when neither
141	root	1.11	readline nor sysread are viable candidates, like this:
142
143			# first get the _real_ non-blocking filehandle
144	root	1.15	# and fetch a reference to the read buffer
145	root	1.11	my $nb_fh = $fh->fh;
146	root	1.15	my $buf = \$fh->rbuf;
147	root	1.11
148			for(;;) {
149			# now use buffer contents, modifying
150			# if necessary to reflect the removed data
151
152	root	1.15	last if $$buf ne ""; # we have leftover data
153	root	1.11
154			# read another buffer full of data
155			$fh->readable or die "end of file";
156	root	1.15	sysread $nb_fh, $$buf, 8192;
157	root	1.11	}
158	root	1.10
159	root	1.4	=cut
160
161			sub fh {
162	root	1.10	(tied ${$_[0]})->[0];
163			}
164
165	root	1.11	sub rbuf : lvalue {
166			tied(${$_[0]})->[3];
167	root	1.1	}
168
169			package Coro::Handle::FH;
170
171	root	1.10	no warnings qw(uninitialized);
172	root	1.9
173	root	1.1	use Fcntl ();
174			use Errno ();
175			use Carp 'croak';
176
177			use Coro::Event;
178			use Event::Watcher qw(R W E);
179
180	root	1.6	# formerly a hash, but we are speed-critical, so try
181			# to be faster even if it hurts.
182			#
183			# 0 FH
184			# 1 desc
185			# 2 timeout
186			# 3 rb
187	root	1.10	# 4 wb # unused
188	root	1.6	# 5 rw
189			# 6 ww
190
191	root	1.1	sub TIEHANDLE {
192			my $class = shift;
193	root	1.6	my %args = @_;
194	root	1.1
195	root	1.6	my $self = bless [], $class;
196			$self->[0] = $args{fh};
197			$self->[1] = $args{desc};
198			$self->[2] = $args{timeout};
199			$self->[3] = "";
200			$self->[4] = "";
201	root	1.1
202	root	1.6	fcntl $self->[0], &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK
203	root	1.1	or croak "fcntl(O_NONBLOCK): $!";
204
205			$self;
206			}
207
208	root	1.6	sub cleanup {
209			$_[0][3] = "";
210	root	1.7	($_[0][5])->cancel if defined $_[0][5]; $_[0][5] = undef;
211	root	1.6
212			$_[0][4] = "";
213	root	1.7	($_[0][6])->cancel if defined $_[0][6]; $_[0][6] = undef;
214	root	1.6	}
215
216	root	1.1	sub OPEN {
217	root	1.6	&cleanup;
218	root	1.1	my $self = shift;
219	root	1.6	my $r = @_ == 2 ? open $self->[0], $_[0], $_[1]
220			: open $self->[0], $_[0], $_[1], $_[2];
221	root	1.1	if ($r) {
222	root	1.6	fcntl $self->[0], &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK
223	root	1.1	or croak "fcntl(O_NONBLOCK): $!";
224			}
225			$r;
226	root	1.9	}
227
228			sub PRINT {
229	root	1.12	WRITE(shift, join "", @_);
230	root	1.9	}
231
232			sub PRINTF {
233			WRITE(shift, sprintf(shift,@_));
234			}
235
236			sub GETC {
237			my $buf;
238			READ($_[0], $buf, 1);
239			$buf;
240			}
241
242			sub BINMODE {
243			binmode $_[0][0];
244			}
245
246			sub TELL {
247			use Carp (); Carp::croak("Coro::Handle's don't support tell()");
248			}
249
250			sub SEEK {
251			use Carp (); Carp::croak("Coro::Handle's don't support seek()");
252			}
253
254			sub EOF {
255			use Carp (); Carp::croak("Coro::Handle's don't support eof()");
256	root	1.1	}
257
258			sub CLOSE {
259	root	1.6	&cleanup;
260			close $_[0][0];
261	root	1.1	}
262
263	root	1.6	sub DESTROY {
264			&cleanup;
265	root	1.1	}
266
267	root	1.6	sub FILENO {
268			fileno $_[0][0];
269	root	1.1	}
270
271	root	1.8	# seems to be called for stringification (how weird), at least
272			# when DumpValue::dumpValue is used to print this.
273			sub FETCH {
274			"$_[0]<$_[0][1]>";
275			}
276
277	root	1.1	sub readable {
278	root	1.6	($_[0][5] \|\|= Coro::Event->io(
279			fd => $_[0][0],
280			desc => "$_[0][1] R",
281			timeout => $_[0][2],
282	root	1.1	poll => R+E,
283	root	1.3	))->next->{Coro::Event}[5] & R;
284	root	1.1	}
285
286	root	1.6	sub writable {
287			($_[0][6] \|\|= Coro::Event->io(
288			fd => $_[0][0],
289			desc => "$_[0][1] W",
290			timeout => $_[0][2],
291			poll => W+E,
292			))->next->{Coro::Event}[5] & W;
293			}
294
295	root	1.1	sub WRITE {
296			my $len = defined $_[2] ? $_[2] : length $_[1];
297			my $ofs = $_[3];
298			my $res = 0;
299
300			while() {
301	root	1.6	my $r = syswrite $_[0][0], $_[1], $len, $ofs;
302	root	1.1	if (defined $r) {
303			$len -= $r;
304			$ofs += $r;
305			$res += $r;
306			last unless $len;
307			} elsif ($! != Errno::EAGAIN) {
308			last;
309			}
310	root	1.6	last unless &writable;
311	root	1.1	}
312
313			return $res;
314			}
315
316			sub READ {
317			my $len = $_[2];
318			my $ofs = $_[3];
319			my $res = 0;
320
321			# first deplete the read buffer
322	root	1.14	if (length $_[0][3]) {
323	root	1.6	my $l = length $_[0][3];
324	root	1.1	if ($l <= $len) {
325	root	1.14	substr($_[1], $ofs) = $_[0][3]; $_[0][3] = "";
326	root	1.1	$len -= $l;
327			$res += $l;
328			return $res unless $len;
329			} else {
330	root	1.6	substr($_[1], $ofs) = substr($_[0][3], 0, $len);
331			substr($_[0][3], 0, $len) = "";
332	root	1.1	return $len;
333			}
334			}
335
336			while() {
337	root	1.6	my $r = sysread $_[0][0], $_[1], $len, $ofs;
338	root	1.1	if (defined $r) {
339			$len -= $r;
340			$ofs += $r;
341			$res += $r;
342			last unless $len && $r;
343			} elsif ($! != Errno::EAGAIN) {
344			last;
345			}
346	root	1.6	last unless &readable;
347	root	1.1	}
348
349			return $res;
350			}
351
352			sub READLINE {
353	root	1.6	my $irs = @_ > 1 ? $_[1] : $/;
354	root	1.1
355			while() {
356	root	1.6	my $pos = index $_[0][3], $irs;
357	root	1.1	if ($pos >= 0) {
358			$pos += length $irs;
359	root	1.6	my $res = substr $_[0][3], 0, $pos;
360			substr ($_[0][3], 0, $pos) = "";
361	root	1.1	return $res;
362			}
363	root	1.6
364			my $r = sysread $_[0][0], $_[0][3], 8192, length $_[0][3];
365	root	1.1	if (defined $r) {
366			return undef unless $r;
367	root	1.6	} elsif ($! != Errno::EAGAIN \|\| !&readable) {
368	root	1.1	return undef;
369			}
370			}
371			}
372
373			1;
374
375			=head1 BUGS
376
377			- Perl's IO-Handle model is THE bug.
378
379			=head1 AUTHOR
380
381			Marc Lehmann <pcg@goof.com>
382			http://www.goof.com/pcg/marc/
383
384			=cut
385