ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/AnyEvent/lib/AnyEvent/Handle.pm

Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.5 by elmex, Mon Apr 28 08:01:05 2008 UTC vs.
Revision 1.143 by root, Mon Jul 6 21:02:34 2009 UTC

1	package AnyEvent::Handle;	1	package AnyEvent::Handle;
2		2
3	use warnings;	3	no warnings;
4	use strict;	4	use strict qw(subs vars);
5		5
6	use AnyEvent;	6	use AnyEvent ();
7	use IO::Handle;	7	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		8	use Scalar::Util ();
		9	use Carp ();
		10	use Fcntl ();
8	use Errno qw/EAGAIN EINTR/;	11	use Errno qw(EAGAIN EINTR);
9		12
10	=head1 NAME	13	=head1 NAME
11		14
12	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
13		16
14	=head1 VERSION
15
16	Version 0.01
17
18	=cut	17	=cut
19		18
20	our $VERSION = '0.01';	19	our $VERSION = 4.452;
21		20
22	=head1 SYNOPSIS	21	=head1 SYNOPSIS
23		22
24	use AnyEvent;	23	use AnyEvent;
25	use AnyEvent::Handle;	24	use AnyEvent::Handle;
26		25
27	my $cv = AnyEvent->condvar;	26	my $cv = AnyEvent->condvar;
28		27
29	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	28	my $handle =
30
31	$ae_fh->on_eof (sub { $cv->broadcast });
32
33	$ae_fh->readlines (sub {
34	my ($ae_fh, @lines) = @_;
35	for (@lines) {
36	chomp;
37	print "Line: $_";
38	}
39	});
40
41	# or use the constructor to pass the callback:
42
43	my $ae_fh2 =
44	AnyEvent::Handle->new (	29	AnyEvent::Handle->new (
45	fh => \*STDIN,	30	fh => \*STDIN,
46	on_eof => sub {	31	on_eof => sub {
47	$cv->broadcast;	32	$cv->send;
48	},	33	},
		34	);
		35
		36	# send some request line
		37	$handle->push_write ("getinfo\015\012");
		38
		39	# read the response line
		40	$handle->push_read (line => sub {
		41	my ($handle, $line) = @_;
		42	warn "read line <$line>\n";
		43	$cv->send;
		44	});
		45
		46	$cv->recv;
		47
		48	=head1 DESCRIPTION
		49
		50	This module is a helper module to make it easier to do event-based I/O on
		51	filehandles. For utility functions for doing non-blocking connects and accepts
		52	on sockets see L<AnyEvent::Util>.
		53
		54	The L<AnyEvent::Intro> tutorial contains some well-documented
		55	AnyEvent::Handle examples.
		56
		57	In the following, when the documentation refers to of "bytes" then this
		58	means characters. As sysread and syswrite are used for all I/O, their
		59	treatment of characters applies to this module as well.
		60
		61	All callbacks will be invoked with the handle object as their first
		62	argument.
		63
		64	=head1 METHODS
		65
		66	=over 4
		67
		68	=item $handle = B<new> AnyEvent::TLS fh => $filehandle, key => value...
		69
		70	The constructor supports these arguments (all as C<< key => value >> pairs).
		71
		72	=over 4
		73
		74	=item fh => $filehandle [MANDATORY]
		75
		76	The filehandle this L<AnyEvent::Handle> object will operate on.
		77
		78	NOTE: The filehandle will be set to non-blocking mode (using
		79	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		80	that mode.
		81
		82	=item on_eof => $cb->($handle)
		83
		84	Set the callback to be called when an end-of-file condition is detected,
		85	i.e. in the case of a socket, when the other side has closed the
		86	connection cleanly.
		87
		88	For sockets, this just means that the other side has stopped sending data,
		89	you can still try to write data, and, in fact, one can return from the EOF
		90	callback and continue writing data, as only the read part has been shut
		91	down.
		92
		93	While not mandatory, it is I<highly> recommended to set an EOF callback,
		94	otherwise you might end up with a closed socket while you are still
		95	waiting for data.
		96
		97	If an EOF condition has been detected but no C<on_eof> callback has been
		98	set, then a fatal error will be raised with C<$!> set to <0>.
		99
		100	=item on_error => $cb->($handle, $fatal, $message)
		101
		102	This is the error callback, which is called when, well, some error
		103	occured, such as not being able to resolve the hostname, failure to
		104	connect or a read error.
		105
		106	Some errors are fatal (which is indicated by C<$fatal> being true). On
		107	fatal errors the handle object will be shut down and will not be usable
		108	(but you are free to look at the current C<< ->rbuf >>). Examples of fatal
		109	errors are an EOF condition with active (but unsatisifable) read watchers
		110	(C<EPIPE>) or I/O errors.
		111
		112	AnyEvent::Handle tries to find an appropriate error code for you to check
		113	against, but in some cases (TLS errors), this does not work well. It is
		114	recommended to always output the C<$message> argument in human-readable
		115	error messages (it's usually the same as C<"$!">).
		116
		117	Non-fatal errors can be retried by simply returning, but it is recommended
		118	to simply ignore this parameter and instead abondon the handle object
		119	when this callback is invoked. Examples of non-fatal errors are timeouts
		120	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		121
		122	On callback entrance, the value of C<$!> contains the operating system
		123	error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		124	C<EPROTO>).
		125
		126	While not mandatory, it is I<highly> recommended to set this callback, as
		127	you will not be notified of errors otherwise. The default simply calls
		128	C<croak>.
		129
		130	=item on_read => $cb->($handle)
		131
		132	This sets the default read callback, which is called when data arrives
		133	and no read request is in the queue (unlike read queue callbacks, this
		134	callback will only be called when at least one octet of data is in the
		135	read buffer).
		136
		137	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
		138	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		139	must not enlarge or modify the read buffer, you can only remove data at
		140	the beginning from it.
		141
		142	When an EOF condition is detected then AnyEvent::Handle will first try to
		143	feed all the remaining data to the queued callbacks and C<on_read> before
		144	calling the C<on_eof> callback. If no progress can be made, then a fatal
		145	error will be raised (with C<$!> set to C<EPIPE>).
		146
		147	=item on_drain => $cb->($handle)
		148
		149	This sets the callback that is called when the write buffer becomes empty
		150	(or when the callback is set and the buffer is empty already).
		151
		152	To append to the write buffer, use the C<< ->push_write >> method.
		153
		154	This callback is useful when you don't want to put all of your write data
		155	into the queue at once, for example, when you want to write the contents
		156	of some file to the socket you might not want to read the whole file into
		157	memory and push it into the queue, but instead only read more data from
		158	the file when the write queue becomes empty.
		159
		160	=item timeout => $fractional_seconds
		161
		162	If non-zero, then this enables an "inactivity" timeout: whenever this many
		163	seconds pass without a successful read or write on the underlying file
		164	handle, the C<on_timeout> callback will be invoked (and if that one is
		165	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		166
		167	Note that timeout processing is also active when you currently do not have
		168	any outstanding read or write requests: If you plan to keep the connection
		169	idle then you should disable the timout temporarily or ignore the timeout
		170	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		171	restart the timeout.
		172
		173	Zero (the default) disables this timeout.
		174
		175	=item on_timeout => $cb->($handle)
		176
		177	Called whenever the inactivity timeout passes. If you return from this
		178	callback, then the timeout will be reset as if some activity had happened,
		179	so this condition is not fatal in any way.
		180
		181	=item rbuf_max => <bytes>
		182
		183	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		184	when the read buffer ever (strictly) exceeds this size. This is useful to
		185	avoid some forms of denial-of-service attacks.
		186
		187	For example, a server accepting connections from untrusted sources should
		188	be configured to accept only so-and-so much data that it cannot act on
		189	(for example, when expecting a line, an attacker could send an unlimited
		190	amount of data without a callback ever being called as long as the line
		191	isn't finished).
		192
		193	=item autocork => <boolean>
		194
		195	When disabled (the default), then C<push_write> will try to immediately
		196	write the data to the handle, if possible. This avoids having to register
		197	a write watcher and wait for the next event loop iteration, but can
		198	be inefficient if you write multiple small chunks (on the wire, this
		199	disadvantage is usually avoided by your kernel's nagle algorithm, see
		200	C<no_delay>, but this option can save costly syscalls).
		201
		202	When enabled, then writes will always be queued till the next event loop
		203	iteration. This is efficient when you do many small writes per iteration,
		204	but less efficient when you do a single write only per iteration (or when
		205	the write buffer often is full). It also increases write latency.
		206
		207	=item no_delay => <boolean>
		208
		209	When doing small writes on sockets, your operating system kernel might
		210	wait a bit for more data before actually sending it out. This is called
		211	the Nagle algorithm, and usually it is beneficial.
		212
		213	In some situations you want as low a delay as possible, which can be
		214	accomplishd by setting this option to a true value.
		215
		216	The default is your opertaing system's default behaviour (most likely
		217	enabled), this option explicitly enables or disables it, if possible.
		218
		219	=item read_size => <bytes>
		220
		221	The default read block size (the amount of bytes this module will
		222	try to read during each loop iteration, which affects memory
		223	requirements). Default: C<8192>.
		224
		225	=item low_water_mark => <bytes>
		226
		227	Sets the amount of bytes (default: C<0>) that make up an "empty" write
		228	buffer: If the write reaches this size or gets even samller it is
		229	considered empty.
		230
		231	Sometimes it can be beneficial (for performance reasons) to add data to
		232	the write buffer before it is fully drained, but this is a rare case, as
		233	the operating system kernel usually buffers data as well, so the default
		234	is good in almost all cases.
		235
		236	=item linger => <seconds>
		237
		238	If non-zero (default: C<3600>), then the destructor of the
		239	AnyEvent::Handle object will check whether there is still outstanding
		240	write data and will install a watcher that will write this data to the
		241	socket. No errors will be reported (this mostly matches how the operating
		242	system treats outstanding data at socket close time).
		243
		244	This will not work for partial TLS data that could not be encoded
		245	yet. This data will be lost. Calling the C<stoptls> method in time might
		246	help.
		247
		248	=item peername => $string
		249
		250	A string used to identify the remote site - usually the DNS hostname
		251	(I<not> IDN!) used to create the connection, rarely the IP address.
		252
		253	Apart from being useful in error messages, this string is also used in TLS
		254	peername verification (see C<verify_peername> in L<AnyEvent::TLS>).
		255
		256	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		257
		258	When this parameter is given, it enables TLS (SSL) mode, that means
		259	AnyEvent will start a TLS handshake as soon as the conenction has been
		260	established and will transparently encrypt/decrypt data afterwards.
		261
		262	All TLS protocol errors will be signalled as C<EPROTO>, with an
		263	appropriate error message.
		264
		265	TLS mode requires Net::SSLeay to be installed (it will be loaded
		266	automatically when you try to create a TLS handle): this module doesn't
		267	have a dependency on that module, so if your module requires it, you have
		268	to add the dependency yourself.
		269
		270	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		271	C<accept>, and for the TLS client side of a connection, use C<connect>
		272	mode.
		273
		274	You can also provide your own TLS connection object, but you have
		275	to make sure that you call either C<Net::SSLeay::set_connect_state>
		276	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		277	AnyEvent::Handle. Also, this module will take ownership of this connection
		278	object.
		279
		280	At some future point, AnyEvent::Handle might switch to another TLS
		281	implementation, then the option to use your own session object will go
		282	away.
		283
		284	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		285	passing in the wrong integer will lead to certain crash. This most often
		286	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		287	segmentation fault.
		288
		289	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		290
		291	=item tls_ctx => $anyevent_tls
		292
		293	Use the given C<AnyEvent::TLS> object to create the new TLS connection
		294	(unless a connection object was specified directly). If this parameter is
		295	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		296
		297	Instead of an object, you can also specify a hash reference with C<< key
		298	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		299	new TLS context object.
		300
		301	=item on_starttls => $cb->($handle, $success[, $error_message])
		302
		303	This callback will be invoked when the TLS/SSL handshake has finished. If
		304	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		305	(C<on_stoptls> will not be called in this case).
		306
		307	The session in C<< $handle->{tls} >> can still be examined in this
		308	callback, even when the handshake was not successful.
		309
		310	TLS handshake failures will not cause C<on_error> to be invoked when this
		311	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		312
		313	Without this callback, handshake failures lead to C<on_error> being
		314	called, as normal.
		315
		316	Note that you cannot call C<starttls> right again in this callback. If you
		317	need to do that, start an zero-second timer instead whose callback can
		318	then call C<< ->starttls >> again.
		319
		320	=item on_stoptls => $cb->($handle)
		321
		322	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		323	set, then it will be invoked after freeing the TLS session. If it is not,
		324	then a TLS shutdown condition will be treated like a normal EOF condition
		325	on the handle.
		326
		327	The session in C<< $handle->{tls} >> can still be examined in this
		328	callback.
		329
		330	This callback will only be called on TLS shutdowns, not when the
		331	underlying handle signals EOF.
		332
		333	=item json => JSON or JSON::XS object
		334
		335	This is the json coder object used by the C<json> read and write types.
		336
		337	If you don't supply it, then AnyEvent::Handle will create and use a
		338	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		339	texts.
		340
		341	Note that you are responsible to depend on the JSON module if you want to
		342	use this functionality, as AnyEvent does not have a dependency itself.
		343
		344	=back
		345
		346	=cut
		347
		348	sub new {
		349	my $class = shift;
		350	my $self = bless { @_ }, $class;
		351
		352	$self->{fh} or Carp::croak "mandatory argument fh is missing";
		353
		354	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		355
		356	$self->{_activity} = AnyEvent->now;
		357	$self->_timeout;
		358
		359	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		360
		361	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		362	if $self->{tls};
		363
		364	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};
		365
		366	$self->start_read
		367	if $self->{on_read};
		368
		369	$self->{fh} && $self
		370	}
		371
		372	sub _shutdown {
		373	my ($self) = @_;
		374
		375	delete @$self{qw(_tw _rw _ww fh wbuf on_read _queue)};
		376	$self->{_eof} = 1; # tell starttls et. al to stop trying
		377
		378	&_freetls;
		379	}
		380
		381	sub _error {
		382	my ($self, $errno, $fatal, $message) = @_;
		383
		384	$self->_shutdown
		385	if $fatal;
		386
		387	$! = $errno;
		388	$message ||= "$!";
		389
		390	if ($self->{on_error}) {
		391	$self->{on_error}($self, $fatal, $message);
		392	} elsif ($self->{fh}) {
		393	Carp::croak "AnyEvent::Handle uncaught error: $message";
		394	}
		395	}
		396
		397	=item $fh = $handle->fh
		398
		399	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		400
		401	=cut
		402
		403	sub fh { $_[0]{fh} }
		404
		405	=item $handle->on_error ($cb)
		406
		407	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		408
		409	=cut
		410
		411	sub on_error {
		412	$_[0]{on_error} = $_[1];
		413	}
		414
		415	=item $handle->on_eof ($cb)
		416
		417	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		418
		419	=cut
		420
		421	sub on_eof {
		422	$_[0]{on_eof} = $_[1];
		423	}
		424
		425	=item $handle->on_timeout ($cb)
		426
		427	Replace the current C<on_timeout> callback, or disables the callback (but
		428	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		429	argument and method.
		430
		431	=cut
		432
		433	sub on_timeout {
		434	$_[0]{on_timeout} = $_[1];
		435	}
		436
		437	=item $handle->autocork ($boolean)
		438
		439	Enables or disables the current autocork behaviour (see C<autocork>
		440	constructor argument). Changes will only take effect on the next write.
		441
		442	=cut
		443
		444	sub autocork {
		445	$_[0]{autocork} = $_[1];
		446	}
		447
		448	=item $handle->no_delay ($boolean)
		449
		450	Enables or disables the C<no_delay> setting (see constructor argument of
		451	the same name for details).
		452
		453	=cut
		454
		455	sub no_delay {
		456	$_[0]{no_delay} = $_[1];
		457
		458	eval {
		459	local $SIG{__DIE__};
		460	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		461	};
		462	}
		463
		464	=item $handle->on_starttls ($cb)
		465
		466	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		467
		468	=cut
		469
		470	sub on_starttls {
		471	$_[0]{on_starttls} = $_[1];
		472	}
		473
		474	=item $handle->on_stoptls ($cb)
		475
		476	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		477
		478	=cut
		479
		480	sub on_starttls {
		481	$_[0]{on_stoptls} = $_[1];
		482	}
		483
		484	#############################################################################
		485
		486	=item $handle->timeout ($seconds)
		487
		488	Configures (or disables) the inactivity timeout.
		489
		490	=cut
		491
		492	sub timeout {
		493	my ($self, $timeout) = @_;
		494
		495	$self->{timeout} = $timeout;
		496	$self->_timeout;
		497	}
		498
		499	# reset the timeout watcher, as neccessary
		500	# also check for time-outs
		501	sub _timeout {
		502	my ($self) = @_;
		503
		504	if ($self->{timeout}) {
		505	my $NOW = AnyEvent->now;
		506
		507	# when would the timeout trigger?
		508	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		509
		510	# now or in the past already?
		511	if ($after <= 0) {
		512	$self->{_activity} = $NOW;
		513
		514	if ($self->{on_timeout}) {
		515	$self->{on_timeout}($self);
		516	} else {
		517	$self->_error (&Errno::ETIMEDOUT);
		518	}
		519
		520	# callback could have changed timeout value, optimise
		521	return unless $self->{timeout};
		522
		523	# calculate new after
		524	$after = $self->{timeout};
		525	}
		526
		527	Scalar::Util::weaken $self;
		528	return unless $self; # ->error could have destroyed $self
		529
		530	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		531	delete $self->{_tw};
		532	$self->_timeout;
		533	});
		534	} else {
		535	delete $self->{_tw};
		536	}
		537	}
		538
		539	#############################################################################
		540
		541	=back
		542
		543	=head2 WRITE QUEUE
		544
		545	AnyEvent::Handle manages two queues per handle, one for writing and one
		546	for reading.
		547
		548	The write queue is very simple: you can add data to its end, and
		549	AnyEvent::Handle will automatically try to get rid of it for you.
		550
		551	When data could be written and the write buffer is shorter then the low
		552	water mark, the C<on_drain> callback will be invoked.
		553
		554	=over 4
		555
		556	=item $handle->on_drain ($cb)
		557
		558	Sets the C<on_drain> callback or clears it (see the description of
		559	C<on_drain> in the constructor).
		560
		561	=cut
		562
		563	sub on_drain {
		564	my ($self, $cb) = @_;
		565
		566	$self->{on_drain} = $cb;
		567
		568	$cb->($self)
		569	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		570	}
		571
		572	=item $handle->push_write ($data)
		573
		574	Queues the given scalar to be written. You can push as much data as you
		575	want (only limited by the available memory), as C<AnyEvent::Handle>
		576	buffers it independently of the kernel.
		577
		578	=cut
		579
		580	sub _drain_wbuf {
		581	my ($self) = @_;
		582
		583	if (!$self->{_ww} && length $self->{wbuf}) {
		584
		585	Scalar::Util::weaken $self;
		586
		587	my $cb = sub {
		588	my $len = syswrite $self->{fh}, $self->{wbuf};
		589
		590	if ($len >= 0) {
		591	substr $self->{wbuf}, 0, $len, "";
		592
		593	$self->{_activity} = AnyEvent->now;
		594
		595	$self->{on_drain}($self)
		596	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		597	&& $self->{on_drain};
		598
		599	delete $self->{_ww} unless length $self->{wbuf};
		600	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		601	$self->_error ($!, 1);
		602	}
		603	};
		604
		605	# try to write data immediately
		606	$cb->() unless $self->{autocork};
		607
		608	# if still data left in wbuf, we need to poll
		609	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
		610	if length $self->{wbuf};
		611	};
		612	}
		613
		614	our %WH;
		615
		616	sub register_write_type($$) {
		617	$WH{$_[0]} = $_[1];
		618	}
		619
		620	sub push_write {
		621	my $self = shift;
		622
		623	if (@_ > 1) {
		624	my $type = shift;
		625
		626	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		627	->($self, @_);
		628	}
		629
		630	if ($self->{tls}) {
		631	$self->{_tls_wbuf} .= $_[0];
		632
		633	&_dotls ($self);
		634	} else {
		635	$self->{wbuf} .= $_[0];
		636	$self->_drain_wbuf;
		637	}
		638	}
		639
		640	=item $handle->push_write (type => @args)
		641
		642	Instead of formatting your data yourself, you can also let this module do
		643	the job by specifying a type and type-specific arguments.
		644
		645	Predefined types are (if you have ideas for additional types, feel free to
		646	drop by and tell us):
		647
		648	=over 4
		649
		650	=item netstring => $string
		651
		652	Formats the given value as netstring
		653	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		654
		655	=cut
		656
		657	register_write_type netstring => sub {
		658	my ($self, $string) = @_;
		659
		660	(length $string) . ":$string,"
		661	};
		662
		663	=item packstring => $format, $data
		664
		665	An octet string prefixed with an encoded length. The encoding C<$format>
		666	uses the same format as a Perl C<pack> format, but must specify a single
		667	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		668	optional C<!>, C<< < >> or C<< > >> modifier).
		669
		670	=cut
		671
		672	register_write_type packstring => sub {
		673	my ($self, $format, $string) = @_;
		674
		675	pack "$format/a*", $string
		676	};
		677
		678	=item json => $array_or_hashref
		679
		680	Encodes the given hash or array reference into a JSON object. Unless you
		681	provide your own JSON object, this means it will be encoded to JSON text
		682	in UTF-8.
		683
		684	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		685	one end of a handle and read them at the other end without using any
		686	additional framing.
		687
		688	The generated JSON text is guaranteed not to contain any newlines: While
		689	this module doesn't need delimiters after or between JSON texts to be
		690	able to read them, many other languages depend on that.
		691
		692	A simple RPC protocol that interoperates easily with others is to send
		693	JSON arrays (or objects, although arrays are usually the better choice as
		694	they mimic how function argument passing works) and a newline after each
		695	JSON text:
		696
		697	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		698	$handle->push_write ("\012");
		699
		700	An AnyEvent::Handle receiver would simply use the C<json> read type and
		701	rely on the fact that the newline will be skipped as leading whitespace:
		702
		703	$handle->push_read (json => sub { my $array = $_[1]; ... });
		704
		705	Other languages could read single lines terminated by a newline and pass
		706	this line into their JSON decoder of choice.
		707
		708	=cut
		709
		710	register_write_type json => sub {
		711	my ($self, $ref) = @_;
		712
		713	require JSON;
		714
		715	$self->{json} ? $self->{json}->encode ($ref)
		716	: JSON::encode_json ($ref)
		717	};
		718
		719	=item storable => $reference
		720
		721	Freezes the given reference using L<Storable> and writes it to the
		722	handle. Uses the C<nfreeze> format.
		723
		724	=cut
		725
		726	register_write_type storable => sub {
		727	my ($self, $ref) = @_;
		728
		729	require Storable;
		730
		731	pack "w/a*", Storable::nfreeze ($ref)
		732	};
		733
		734	=back
		735
		736	=item $handle->push_shutdown
		737
		738	Sometimes you know you want to close the socket after writing your data
		739	before it was actually written. One way to do that is to replace your
		740	C<on_drain> handler by a callback that shuts down the socket (and set
		741	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		742	replaces the C<on_drain> callback with:
		743
		744	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		745
		746	This simply shuts down the write side and signals an EOF condition to the
		747	the peer.
		748
		749	You can rely on the normal read queue and C<on_eof> handling
		750	afterwards. This is the cleanest way to close a connection.
		751
		752	=cut
		753
		754	sub push_shutdown {
		755	my ($self) = @_;
		756
		757	delete $self->{low_water_mark};
		758	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		759	}
		760
		761	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		762
		763	This function (not method) lets you add your own types to C<push_write>.
		764	Whenever the given C<type> is used, C<push_write> will invoke the code
		765	reference with the handle object and the remaining arguments.
		766
		767	The code reference is supposed to return a single octet string that will
		768	be appended to the write buffer.
		769
		770	Note that this is a function, and all types registered this way will be
		771	global, so try to use unique names.
		772
		773	=cut
		774
		775	#############################################################################
		776
		777	=back
		778
		779	=head2 READ QUEUE
		780
		781	AnyEvent::Handle manages two queues per handle, one for writing and one
		782	for reading.
		783
		784	The read queue is more complex than the write queue. It can be used in two
		785	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		786	a queue.
		787
		788	In the simple case, you just install an C<on_read> callback and whenever
		789	new data arrives, it will be called. You can then remove some data (if
		790	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
		791	leave the data there if you want to accumulate more (e.g. when only a
		792	partial message has been received so far).
		793
		794	In the more complex case, you want to queue multiple callbacks. In this
		795	case, AnyEvent::Handle will call the first queued callback each time new
		796	data arrives (also the first time it is queued) and removes it when it has
		797	done its job (see C<push_read>, below).
		798
		799	This way you can, for example, push three line-reads, followed by reading
		800	a chunk of data, and AnyEvent::Handle will execute them in order.
		801
		802	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		803	the specified number of bytes which give an XML datagram.
		804
		805	# in the default state, expect some header bytes
		806	$handle->on_read (sub {
		807	# some data is here, now queue the length-header-read (4 octets)
		808	shift->unshift_read (chunk => 4, sub {
		809	# header arrived, decode
		810	my $len = unpack "N", $_[1];
		811
		812	# now read the payload
		813	shift->unshift_read (chunk => $len, sub {
		814	my $xml = $_[1];
		815	# handle xml
		816	});
		817	});
		818	});
		819
		820	Example 2: Implement a client for a protocol that replies either with "OK"
		821	and another line or "ERROR" for the first request that is sent, and 64
		822	bytes for the second request. Due to the availability of a queue, we can
		823	just pipeline sending both requests and manipulate the queue as necessary
		824	in the callbacks.
		825
		826	When the first callback is called and sees an "OK" response, it will
		827	C<unshift> another line-read. This line-read will be queued I<before> the
		828	64-byte chunk callback.
		829
		830	# request one, returns either "OK + extra line" or "ERROR"
		831	$handle->push_write ("request 1\015\012");
		832
		833	# we expect "ERROR" or "OK" as response, so push a line read
		834	$handle->push_read (line => sub {
		835	# if we got an "OK", we have to _prepend_ another line,
		836	# so it will be read before the second request reads its 64 bytes
		837	# which are already in the queue when this callback is called
		838	# we don't do this in case we got an error
		839	if ($_[1] eq "OK") {
49	on_readline => sub {	840	$_[0]->unshift_read (line => sub {
50	my ($ae_fh, @lines) = @_;	841	my $response = $_[1];
51	for (@lines) {	842	...
52	chomp;	843	});
53	print "Line: $_";	844	}
		845	});
		846
		847	# request two, simply returns 64 octets
		848	$handle->push_write ("request 2\015\012");
		849
		850	# simply read 64 bytes, always
		851	$handle->push_read (chunk => 64, sub {
		852	my $response = $_[1];
		853	...
		854	});
		855
		856	=over 4
		857
		858	=cut
		859
		860	sub _drain_rbuf {
		861	my ($self) = @_;
		862
		863	local $self->{_in_drain} = 1;
		864
		865	if (
		866	defined $self->{rbuf_max}
		867	&& $self->{rbuf_max} < length $self->{rbuf}
		868	) {
		869	$self->_error (&Errno::ENOSPC, 1), return;
		870	}
		871
		872	while () {
		873	# we need to use a separate tls read buffer, as we must not receive data while
		874	# we are draining the buffer, and this can only happen with TLS.
		875	$self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
		876
		877	my $len = length $self->{rbuf};
		878
		879	if (my $cb = shift @{ $self->{_queue} }) {
		880	unless ($cb->($self)) {
		881	if ($self->{_eof}) {
		882	# no progress can be made (not enough data and no data forthcoming)
		883	$self->_error (&Errno::EPIPE, 1), return;
54	}	884	}
		885
		886	unshift @{ $self->{_queue} }, $cb;
		887	last;
55	}	888	}
56	);
57
58	$cv->wait;
59
60	=head1 DESCRIPTION
61
62	This module is a helper module to make it easier to do non-blocking I/O
63	on filehandles (and sockets, see L<AnyEvent::Socket>).
64
65	The event loop is provided by L<AnyEvent>.
66
67	=head1 METHODS
68
69	=over 4
70
71	=item B<new (%args)>
72
73	The constructor has these arguments:
74
75	=over 4
76
77	=item fh => $filehandle
78
79	The filehandle this L<AnyEvent::Handle> object will operate on.
80
81	NOTE: The filehandle will be set to non-blocking.
82
83	=item read_block_size => $size
84
85	The default read block size use for reads via the C<on_read>
86	method.
87
88	=item on_read => $cb
89
90	=item on_eof => $cb
91
92	=item on_error => $cb
93
94	These are shortcuts, that will call the corresponding method and set the callback to C<$cb>.
95
96	=item on_readline => $cb
97
98	The C<readlines> method is called with the default seperator and C<$cb> as callback
99	for you.
100
101	=back
102
103	=cut
104
105	sub new {
106	my $this = shift;
107	my $class = ref($this) || $this;
108	my $self = {
109	read_block_size => 4096,
110	rbuf => '',
111	@_
112	};
113	bless $self, $class;
114
115	$self->{fh}->blocking (0) if $self->{fh};
116
117	if ($self->{on_read}) {
118	$self->on_read ($self->{on_read});
119
120	} elsif ($self->{on_readline}) {	889	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	890	last unless $len;
122		891
		892	$self->{on_read}($self);
		893
		894	if (
		895	$len == length $self->{rbuf} # if no data has been consumed
		896	&& !@{ $self->{_queue} } # and the queue is still empty
		897	&& $self->{on_read} # but we still have on_read
		898	) {
		899	# no further data will arrive
		900	# so no progress can be made
		901	$self->_error (&Errno::EPIPE, 1), return
		902	if $self->{_eof};
		903
		904	last; # more data might arrive
		905	}
		906	} else {
		907	# read side becomes idle
		908	delete $self->{_rw} unless $self->{tls};
		909	last;
		910	}
		911	}
		912
123	} elsif ($self->{on_eof}) {	913	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});
125
126	} elsif ($self->{on_error}) {	914	if ($self->{on_eof}) {
127	$self->on_eof ($self->{on_error});	915	$self->{on_eof}($self)
		916	} else {
		917	$self->_error (0, 1, "Unexpected end-of-file");
		918	}
128	}	919	}
129		920
130	return $self	921	# may need to restart read watcher
		922	unless ($self->{_rw}) {
		923	$self->start_read
		924	if $self->{on_read} || @{ $self->{_queue} };
		925	}
131	}	926	}
132		927
133	=item B<fh>	928	=item $handle->on_read ($cb)
134		929
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	930	This replaces the currently set C<on_read> callback, or clears it (when
136		931	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	932	constructor.
138
139	sub fh { $_[0]->{fh} }
140
141	=item B<on_read ($callback)>
142
143	This method installs a C<$callback> that will be called
144	when new data arrived. You can access the read buffer via the C<rbuf>
145	method (see below).
146
147	The first argument of the C<$callback> will be the L<AnyEvent::Handle> object.
148		933
149	=cut	934	=cut
150		935
151	sub on_read {	936	sub on_read {
152	my ($self, $cb) = @_;	937	my ($self, $cb) = @_;
		938
153	$self->{on_read} = $cb;	939	$self->{on_read} = $cb;
		940	$self->_drain_rbuf if $cb && !$self->{_in_drain};
		941	}
154		942
155	unless (defined $self->{on_read}) {	943	=item $handle->rbuf
156	delete $self->{on_read_w};	944
		945	Returns the read buffer (as a modifiable lvalue).
		946
		947	You can access the read buffer directly as the C<< ->{rbuf} >>
		948	member, if you want. However, the only operation allowed on the
		949	read buffer (apart from looking at it) is removing data from its
		950	beginning. Otherwise modifying or appending to it is not allowed and will
		951	lead to hard-to-track-down bugs.
		952
		953	NOTE: The read buffer should only be used or modified if the C<on_read>,
		954	C<push_read> or C<unshift_read> methods are used. The other read methods
		955	automatically manage the read buffer.
		956
		957	=cut
		958
		959	sub rbuf : lvalue {
		960	$_[0]{rbuf}
		961	}
		962
		963	=item $handle->push_read ($cb)
		964
		965	=item $handle->unshift_read ($cb)
		966
		967	Append the given callback to the end of the queue (C<push_read>) or
		968	prepend it (C<unshift_read>).
		969
		970	The callback is called each time some additional read data arrives.
		971
		972	It must check whether enough data is in the read buffer already.
		973
		974	If not enough data is available, it must return the empty list or a false
		975	value, in which case it will be called repeatedly until enough data is
		976	available (or an error condition is detected).
		977
		978	If enough data was available, then the callback must remove all data it is
		979	interested in (which can be none at all) and return a true value. After returning
		980	true, it will be removed from the queue.
		981
		982	=cut
		983
		984	our %RH;
		985
		986	sub register_read_type($$) {
		987	$RH{$_[0]} = $_[1];
		988	}
		989
		990	sub push_read {
		991	my $self = shift;
		992	my $cb = pop;
		993
		994	if (@_) {
		995	my $type = shift;
		996
		997	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		998	->($self, $cb, @_);
		999	}
		1000
		1001	push @{ $self->{_queue} }, $cb;
		1002	$self->_drain_rbuf unless $self->{_in_drain};
		1003	}
		1004
		1005	sub unshift_read {
		1006	my $self = shift;
		1007	my $cb = pop;
		1008
		1009	if (@_) {
		1010	my $type = shift;
		1011
		1012	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		1013	->($self, $cb, @_);
		1014	}
		1015
		1016
		1017	unshift @{ $self->{_queue} }, $cb;
		1018	$self->_drain_rbuf unless $self->{_in_drain};
		1019	}
		1020
		1021	=item $handle->push_read (type => @args, $cb)
		1022
		1023	=item $handle->unshift_read (type => @args, $cb)
		1024
		1025	Instead of providing a callback that parses the data itself you can chose
		1026	between a number of predefined parsing formats, for chunks of data, lines
		1027	etc.
		1028
		1029	Predefined types are (if you have ideas for additional types, feel free to
		1030	drop by and tell us):
		1031
		1032	=over 4
		1033
		1034	=item chunk => $octets, $cb->($handle, $data)
		1035
		1036	Invoke the callback only once C<$octets> bytes have been read. Pass the
		1037	data read to the callback. The callback will never be called with less
		1038	data.
		1039
		1040	Example: read 2 bytes.
		1041
		1042	$handle->push_read (chunk => 2, sub {
		1043	warn "yay ", unpack "H*", $_[1];
		1044	});
		1045
		1046	=cut
		1047
		1048	register_read_type chunk => sub {
		1049	my ($self, $cb, $len) = @_;
		1050
		1051	sub {
		1052	$len <= length $_[0]{rbuf} or return;
		1053	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		1054	1
		1055	}
		1056	};
		1057
		1058	=item line => [$eol, ]$cb->($handle, $line, $eol)
		1059
		1060	The callback will be called only once a full line (including the end of
		1061	line marker, C<$eol>) has been read. This line (excluding the end of line
		1062	marker) will be passed to the callback as second argument (C<$line>), and
		1063	the end of line marker as the third argument (C<$eol>).
		1064
		1065	The end of line marker, C<$eol>, can be either a string, in which case it
		1066	will be interpreted as a fixed record end marker, or it can be a regex
		1067	object (e.g. created by C<qr>), in which case it is interpreted as a
		1068	regular expression.
		1069
		1070	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		1071	undef), then C<qr|\015?\012|> is used (which is good for most internet
		1072	protocols).
		1073
		1074	Partial lines at the end of the stream will never be returned, as they are
		1075	not marked by the end of line marker.
		1076
		1077	=cut
		1078
		1079	register_read_type line => sub {
		1080	my ($self, $cb, $eol) = @_;
		1081
		1082	if (@_ < 3) {
		1083	# this is more than twice as fast as the generic code below
		1084	sub {
		1085	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1086
		1087	$cb->($_[0], $1, $2);
		1088	1
		1089	}
		1090	} else {
		1091	$eol = quotemeta $eol unless ref $eol;
		1092	$eol = qr|^(.*?)($eol)|s;
		1093
		1094	sub {
		1095	$_[0]{rbuf} =~ s/$eol// or return;
		1096
		1097	$cb->($_[0], $1, $2);
		1098	1
		1099	}
		1100	}
		1101	};
		1102
		1103	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1104
		1105	Makes a regex match against the regex object C<$accept> and returns
		1106	everything up to and including the match.
		1107
		1108	Example: read a single line terminated by '\n'.
		1109
		1110	$handle->push_read (regex => qr<\n>, sub { ... });
		1111
		1112	If C<$reject> is given and not undef, then it determines when the data is
		1113	to be rejected: it is matched against the data when the C<$accept> regex
		1114	does not match and generates an C<EBADMSG> error when it matches. This is
		1115	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1116	receive buffer overflow).
		1117
		1118	Example: expect a single decimal number followed by whitespace, reject
		1119	anything else (not the use of an anchor).
		1120
		1121	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1122
		1123	If C<$skip> is given and not C<undef>, then it will be matched against
		1124	the receive buffer when neither C<$accept> nor C<$reject> match,
		1125	and everything preceding and including the match will be accepted
		1126	unconditionally. This is useful to skip large amounts of data that you
		1127	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1128	have to start matching from the beginning. This is purely an optimisation
		1129	and is usually worth only when you expect more than a few kilobytes.
		1130
		1131	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1132	expect the header to be very large (it isn't in practise, but...), we use
		1133	a skip regex to skip initial portions. The skip regex is tricky in that
		1134	it only accepts something not ending in either \015 or \012, as these are
		1135	required for the accept regex.
		1136
		1137	$handle->push_read (regex =>
		1138	qr<\015\012\015\012>,
		1139	undef, # no reject
		1140	qr<^.*[^\015\012]>,
		1141	sub { ... });
		1142
		1143	=cut
		1144
		1145	register_read_type regex => sub {
		1146	my ($self, $cb, $accept, $reject, $skip) = @_;
		1147
		1148	my $data;
		1149	my $rbuf = \$self->{rbuf};
		1150
		1151	sub {
		1152	# accept
		1153	if ($$rbuf =~ $accept) {
		1154	$data .= substr $$rbuf, 0, $+[0], "";
		1155	$cb->($self, $data);
157	return;	1156	return 1;
		1157	}
		1158
		1159	# reject
		1160	if ($reject && $$rbuf =~ $reject) {
		1161	$self->_error (&Errno::EBADMSG);
		1162	}
		1163
		1164	# skip
		1165	if ($skip && $$rbuf =~ $skip) {
		1166	$data .= substr $$rbuf, 0, $+[0], "";
		1167	}
		1168
		1169	()
158	}	1170	}
159		1171	};
160	$self->{on_read_w} =	1172
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1173	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1174
163	my $rbuf_len = length $self->{rbuf};	1175	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1176
165	if (defined $self->{read_size}) {	1177	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1178
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1179	=cut
168	} else {	1180
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1181	register_read_type netstring => sub {
		1182	my ($self, $cb) = @_;
		1183
		1184	sub {
		1185	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1186	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1187	$self->_error (&Errno::EBADMSG);
170	}	1188	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1189	return;
		1190	}
172		1191
173	if (not defined $l) {	1192	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1193
178	} elsif ($l == 0) {	1194	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1195	my $string = $_[1];
180	delete $self->{on_read_w};	1196	$_[0]->unshift_read (chunk => 1, sub {
181		1197	if ($_[1] eq ",") {
		1198	$cb->($_[0], $string);
182	} else {	1199	} else {
183	$self->{on_read}->($self);	1200	$self->_error (&Errno::EBADMSG);
		1201	}
		1202	});
		1203	});
		1204
		1205	1
		1206	}
		1207	};
		1208
		1209	=item packstring => $format, $cb->($handle, $string)
		1210
		1211	An octet string prefixed with an encoded length. The encoding C<$format>
		1212	uses the same format as a Perl C<pack> format, but must specify a single
		1213	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1214	optional C<!>, C<< < >> or C<< > >> modifier).
		1215
		1216	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1217	EPP uses a prefix of C<N> (4 octtes).
		1218
		1219	Example: read a block of data prefixed by its length in BER-encoded
		1220	format (very efficient).
		1221
		1222	$handle->push_read (packstring => "w", sub {
		1223	my ($handle, $data) = @_;
		1224	});
		1225
		1226	=cut
		1227
		1228	register_read_type packstring => sub {
		1229	my ($self, $cb, $format) = @_;
		1230
		1231	sub {
		1232	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1233	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1234	or return;
		1235
		1236	$format = length pack $format, $len;
		1237
		1238	# bypass unshift if we already have the remaining chunk
		1239	if ($format + $len <= length $_[0]{rbuf}) {
		1240	my $data = substr $_[0]{rbuf}, $format, $len;
		1241	substr $_[0]{rbuf}, 0, $format + $len, "";
		1242	$cb->($_[0], $data);
		1243	} else {
		1244	# remove prefix
		1245	substr $_[0]{rbuf}, 0, $format, "";
		1246
		1247	# read remaining chunk
		1248	$_[0]->unshift_read (chunk => $len, $cb);
		1249	}
		1250
		1251	1
		1252	}
		1253	};
		1254
		1255	=item json => $cb->($handle, $hash_or_arrayref)
		1256
		1257	Reads a JSON object or array, decodes it and passes it to the
		1258	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1259
		1260	If a C<json> object was passed to the constructor, then that will be used
		1261	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1262
		1263	This read type uses the incremental parser available with JSON version
		1264	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1265	dependency on your own: this module will load the JSON module, but
		1266	AnyEvent does not depend on it itself.
		1267
		1268	Since JSON texts are fully self-delimiting, the C<json> read and write
		1269	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1270	the C<json> write type description, above, for an actual example.
		1271
		1272	=cut
		1273
		1274	register_read_type json => sub {
		1275	my ($self, $cb) = @_;
		1276
		1277	my $json = $self->{json} ||=
		1278	eval { require JSON::XS; JSON::XS->new->utf8 }
		1279	|| do { require JSON; JSON->new->utf8 };
		1280
		1281	my $data;
		1282	my $rbuf = \$self->{rbuf};
		1283
		1284	sub {
		1285	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1286
		1287	if ($ref) {
		1288	$self->{rbuf} = $json->incr_text;
		1289	$json->incr_text = "";
		1290	$cb->($self, $ref);
		1291
		1292	1
		1293	} elsif ($@) {
		1294	# error case
		1295	$json->incr_skip;
		1296
		1297	$self->{rbuf} = $json->incr_text;
		1298	$json->incr_text = "";
		1299
		1300	$self->_error (&Errno::EBADMSG);
		1301
		1302	()
		1303	} else {
		1304	$self->{rbuf} = "";
		1305
		1306	()
		1307	}
		1308	}
		1309	};
		1310
		1311	=item storable => $cb->($handle, $ref)
		1312
		1313	Deserialises a L<Storable> frozen representation as written by the
		1314	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1315	data).
		1316
		1317	Raises C<EBADMSG> error if the data could not be decoded.
		1318
		1319	=cut
		1320
		1321	register_read_type storable => sub {
		1322	my ($self, $cb) = @_;
		1323
		1324	require Storable;
		1325
		1326	sub {
		1327	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1328	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1329	or return;
		1330
		1331	my $format = length pack "w", $len;
		1332
		1333	# bypass unshift if we already have the remaining chunk
		1334	if ($format + $len <= length $_[0]{rbuf}) {
		1335	my $data = substr $_[0]{rbuf}, $format, $len;
		1336	substr $_[0]{rbuf}, 0, $format + $len, "";
		1337	$cb->($_[0], Storable::thaw ($data));
		1338	} else {
		1339	# remove prefix
		1340	substr $_[0]{rbuf}, 0, $format, "";
		1341
		1342	# read remaining chunk
		1343	$_[0]->unshift_read (chunk => $len, sub {
		1344	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1345	$cb->($_[0], $ref);
		1346	} else {
		1347	$self->_error (&Errno::EBADMSG);
		1348	}
		1349	});
		1350	}
		1351
		1352	1
		1353	}
		1354	};
		1355
		1356	=back
		1357
		1358	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1359
		1360	This function (not method) lets you add your own types to C<push_read>.
		1361
		1362	Whenever the given C<type> is used, C<push_read> will invoke the code
		1363	reference with the handle object, the callback and the remaining
		1364	arguments.
		1365
		1366	The code reference is supposed to return a callback (usually a closure)
		1367	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1368
		1369	It should invoke the passed callback when it is done reading (remember to
		1370	pass C<$handle> as first argument as all other callbacks do that).
		1371
		1372	Note that this is a function, and all types registered this way will be
		1373	global, so try to use unique names.
		1374
		1375	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1376	search for C<register_read_type>)).
		1377
		1378	=item $handle->stop_read
		1379
		1380	=item $handle->start_read
		1381
		1382	In rare cases you actually do not want to read anything from the
		1383	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1384	any queued callbacks will be executed then. To start reading again, call
		1385	C<start_read>.
		1386
		1387	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1388	you change the C<on_read> callback or push/unshift a read callback, and it
		1389	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1390	there are any read requests in the queue.
		1391
		1392	These methods will have no effect when in TLS mode (as TLS doesn't support
		1393	half-duplex connections).
		1394
		1395	=cut
		1396
		1397	sub stop_read {
		1398	my ($self) = @_;
		1399
		1400	delete $self->{_rw} unless $self->{tls};
		1401	}
		1402
		1403	sub start_read {
		1404	my ($self) = @_;
		1405
		1406	unless ($self->{_rw} || $self->{_eof}) {
		1407	Scalar::Util::weaken $self;
		1408
		1409	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1410	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1411	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1412
		1413	if ($len > 0) {
		1414	$self->{_activity} = AnyEvent->now;
		1415
		1416	if ($self->{tls}) {
		1417	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1418
		1419	&_dotls ($self);
		1420	} else {
		1421	$self->_drain_rbuf unless $self->{_in_drain};
		1422	}
		1423
		1424	} elsif (defined $len) {
		1425	delete $self->{_rw};
		1426	$self->{_eof} = 1;
		1427	$self->_drain_rbuf unless $self->{_in_drain};
		1428
		1429	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1430	return $self->_error ($!, 1);
184	}	1431	}
185	});	1432	});
		1433	}
186	}	1434	}
187		1435
188	=item B<on_error ($callback)>	1436	our $ERROR_SYSCALL;
		1437	our $ERROR_WANT_READ;
189		1438
190	Whenever a read or write operation resulted in an error the C<$callback>
191	will be called.
192
193	The first argument of C<$callback> will be the L<AnyEvent::Handle> object itself.
194	The error is given as errno in C<$!>.
195
196	=cut
197
198	sub on_error {	1439	sub _tls_error {
199	$_[0]->{on_error} = $_[1];
200	}
201
202	=item B<on_eof ($callback)>
203
204	Installs the C<$callback> that will be called when the end of file is
205	encountered in a read operation this C<$callback> will be called. The first
206	argument will be the L<AnyEvent::Handle> object itself.
207
208	=cut
209
210	sub on_eof {
211	$_[0]->{on_eof} = $_[1];
212	}
213
214	=item B<rbuf>
215
216	Returns a reference to the read buffer.
217
218	NOTE: The read buffer should only be used or modified if the C<on_read>
219	method is used directly. The C<read> and C<readlines> methods will provide
220	the read data to their callbacks.
221
222	=cut
223
224	sub rbuf : lvalue {
225	$_[0]->{rbuf}
226	}
227
228	=item B<read ($len, $callback)>
229
230	Will read exactly C<$len> bytes from the filehandle and call the C<$callback>
231	if done so. The first argument to the C<$callback> will be the L<AnyEvent::Handle>
232	object itself and the second argument the read data.
233
234	NOTE: This method will override any callbacks installed via the C<on_read> method.
235
236	=cut
237
238	sub read {
239	my ($self, $len, $cb) = @_;	1440	my ($self, $err) = @_;
240		1441
241	$self->{read_cb} = $cb;	1442	return $self->_error ($!, 1)
242	my $old_blk_size = $self->{read_block_size};	1443	if $err == Net::SSLeay::ERROR_SYSCALL ();
243	$self->{read_block_size} = $len;
244		1444
245	$self->on_read (sub {	1445	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";
247		1446
248	if ($len == length $_[0]->{rbuf}) {	1447	# reduce error string to look less scary
249	$_[0]->{read_block_size} = $old_blk_size;	1448	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
250	$_[0]->on_read (undef);	1449
251	$_[0]->{read_cb}->($_[0], (substr $self->{rbuf}, 0, $len, ''));	1450	if ($self->{_on_starttls}) {
		1451	(delete $self->{_on_starttls})->($self, undef, $err);
		1452	&_freetls;
		1453	} else {
		1454	&_freetls;
		1455	$self->_error (&Errno::EPROTO, 1, $err);
		1456	}
		1457	}
		1458
		1459	# poll the write BIO and send the data if applicable
		1460	# also decode read data if possible
		1461	# this is basiclaly our TLS state machine
		1462	# more efficient implementations are possible with openssl,
		1463	# but not with the buggy and incomplete Net::SSLeay.
		1464	sub _dotls {
		1465	my ($self) = @_;
		1466
		1467	my $tmp;
		1468
		1469	if (length $self->{_tls_wbuf}) {
		1470	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
		1471	substr $self->{_tls_wbuf}, 0, $tmp, "";
252	}	1472	}
		1473
		1474	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1475	return $self->_tls_error ($tmp)
		1476	if $tmp != $ERROR_WANT_READ
		1477	&& ($tmp != $ERROR_SYSCALL || $!);
253	});	1478	}
254	}
255		1479
256	=item B<readlines ($callback)>	1480	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1481	unless (length $tmp) {
		1482	$self->{_on_starttls}
		1483	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1484	&_freetls;
257		1485
258	=item B<readlines ($sep, $callback)>	1486	if ($self->{on_stoptls}) {
259		1487	$self->{on_stoptls}($self);
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1488	return;
261	if C<$sep> is not provided. C<$sep> will be used as "line" seperator.	1489	} else {
262		1490	# let's treat SSL-eof as we treat normal EOF
263	The C<$callback> will be called when at least one	1491	delete $self->{_rw};
264	line could be read. The first argument to the C<$callback> will be the L<AnyEvent::Handle>
265	object itself and the rest of the arguments will be the read lines.
266
267	NOTE: This method will override any callbacks installed via the C<on_read> method.
268
269	=cut
270
271	sub readlines {
272	my ($self, $sep, $cb) = @_;
273
274	if (ref $sep) {
275	$cb = $sep;
276	$sep = "\n";
277
278	} elsif (not defined $sep) {
279	$sep = "\n";
280	}
281
282	my $sep_len = length $sep;
283
284	$self->{on_readline} = $cb;
285
286	$self->on_read (sub {
287	my @lines;
288	my $rb = \$_[0]->{rbuf};
289	my $pos;
290	while (($pos = index ($$rb, $sep)) >= 0) {
291	push @lines, substr $$rb, 0, $pos + $sep_len, '';
292	}
293	$self->{on_readline}->($_[0], @lines);
294	});
295	}
296
297	=item B<write ($data)>
298
299	=item B<write ($callback)>
300
301	=item B<write ($data, $callback)>
302
303	This method will write C<$data> to the filehandle and call the C<$callback>
304	afterwards. If only C<$callback> is provided it will be called when the
305	write buffer becomes empty the next time (or immediately if it already is empty).
306
307	=cut
308
309	sub write {
310	my ($self, $data, $cb) = @_;
311	if (ref $data) { $cb = $data; undef $data }
312	push @{$self->{write_bufs}}, [$data, $cb];
313	$self->_check_writer;
314	}
315
316	sub _check_writer {
317	my ($self) = @_;
318
319	if ($self->{write_w}) {
320	unless ($self->{write_cb}) {
321	while (@{$self->{write_bufs}} && not defined $self->{write_bufs}->[0]->[1]) {
322	my $wba = shift @{$self->{write_bufs}};
323	$self->{wbuf} .= $wba->[0];	1492	$self->{_eof} = 1;
324	}	1493	}
325	}	1494	}
326	return;	1495
		1496	$self->{_tls_rbuf} .= $tmp;
		1497	$self->_drain_rbuf unless $self->{_in_drain};
		1498	$self->{tls} or return; # tls session might have gone away in callback
		1499	}
		1500
		1501	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1502	return $self->_tls_error ($tmp)
		1503	if $tmp != $ERROR_WANT_READ
		1504	&& ($tmp != $ERROR_SYSCALL || $!);
		1505
		1506	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1507	$self->{wbuf} .= $tmp;
		1508	$self->_drain_wbuf;
		1509	}
		1510
		1511	$self->{_on_starttls}
		1512	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
		1513	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
		1514	}
		1515
		1516	=item $handle->starttls ($tls[, $tls_ctx])
		1517
		1518	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1519	object is created, you can also do that at a later time by calling
		1520	C<starttls>.
		1521
		1522	The first argument is the same as the C<tls> constructor argument (either
		1523	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1524
		1525	The second argument is the optional C<AnyEvent::TLS> object that is used
		1526	when AnyEvent::Handle has to create its own TLS connection object, or
		1527	a hash reference with C<< key => value >> pairs that will be used to
		1528	construct a new context.
		1529
		1530	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1531	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1532	changed to your liking. Note that the handshake might have already started
		1533	when this function returns.
		1534
		1535	If it an error to start a TLS handshake more than once per
		1536	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1537
		1538	=cut
		1539
		1540	our %TLS_CACHE; #TODO not yet documented, should we?
		1541
		1542	sub starttls {
		1543	my ($self, $ssl, $ctx) = @_;
		1544
		1545	require Net::SSLeay;
		1546
		1547	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
		1548	if $self->{tls};
		1549
		1550	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1551	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1552
		1553	$ctx ||= $self->{tls_ctx};
		1554
		1555	if ("HASH" eq ref $ctx) {
		1556	require AnyEvent::TLS;
		1557
		1558	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context
		1559
		1560	if ($ctx->{cache}) {
		1561	my $key = $ctx+0;
		1562	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1563	} else {
		1564	$ctx = new AnyEvent::TLS %$ctx;
		1565	}
		1566	}
327	}	1567
		1568	$self->{tls_ctx} = $ctx || TLS_CTX ();
		1569	$self->{tls} = $ssl = $self->{tls_ctx}->_get_session ($ssl, $self, $self->{peername});
328		1570
329	my $wba = shift @{$self->{write_bufs}}	1571	# basically, this is deep magic (because SSL_read should have the same issues)
330	or return;	1572	# but the openssl maintainers basically said: "trust us, it just works".
		1573	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1574	# and mismaintained ssleay-module doesn't even offer them).
		1575	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1576	#
		1577	# in short: this is a mess.
		1578	#
		1579	# note that we do not try to keep the length constant between writes as we are required to do.
		1580	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1581	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1582	# have identity issues in that area.
		1583	# Net::SSLeay::CTX_set_mode ($ssl,
		1584	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1585	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1586	Net::SSLeay::CTX_set_mode ($ssl, 1|2);
331		1587
332	unless (defined $wba->[0]) {	1588	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
333	$wba->[1]->($self) if $wba->[1];	1589	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
334	$self->_check_writer;	1590
335	return;	1591	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
		1592
		1593	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
		1594	if $self->{on_starttls};
		1595
		1596	&_dotls; # need to trigger the initial handshake
		1597	$self->start_read; # make sure we actually do read
		1598	}
		1599
		1600	=item $handle->stoptls
		1601
		1602	Shuts down the SSL connection - this makes a proper EOF handshake by
		1603	sending a close notify to the other side, but since OpenSSL doesn't
		1604	support non-blocking shut downs, it is not possible to re-use the stream
		1605	afterwards.
		1606
		1607	=cut
		1608
		1609	sub stoptls {
		1610	my ($self) = @_;
		1611
		1612	if ($self->{tls}) {
		1613	Net::SSLeay::shutdown ($self->{tls});
		1614
		1615	&_dotls;
		1616
		1617	# # we don't give a shit. no, we do, but we can't. no...#d#
		1618	# # we, we... have to use openssl :/#d#
		1619	# &_freetls;#d#
		1620	}
		1621	}
		1622
		1623	sub _freetls {
		1624	my ($self) = @_;
		1625
		1626	return unless $self->{tls};
		1627
		1628	$self->{tls_ctx}->_put_session (delete $self->{tls});
336	}	1629
		1630	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		1631	}
337		1632
338	$self->{wbuf} = $wba->[0];	1633	sub DESTROY {
339	$self->{write_cb} = $wba->[1];	1634	my ($self) = @_;
340		1635
341	$self->{write_w} =	1636	&_freetls;
342	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1637
		1638	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1639
		1640	if ($linger && length $self->{wbuf}) {
		1641	my $fh = delete $self->{fh};
		1642	my $wbuf = delete $self->{wbuf};
		1643
		1644	my @linger;
		1645
		1646	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
343	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1647	my $len = syswrite $fh, $wbuf, length $wbuf;
344		1648
345	if (not defined $l) {	1649	if ($len > 0) {
346	return if $! == EAGAIN || $! == EINTR;	1650	substr $wbuf, 0, $len, "";
347	delete $self->{write_w};
348	$self->{on_error}->($self) if $self->{on_error};
349
350	} else {	1651	} else {
351	substr $self->{wbuf}, 0, $l, '';	1652	@linger = (); # end
352
353	if (length ($self->{wbuf}) == 0) {
354	$self->{write_cb}->($self) if $self->{write_cb};
355
356	delete $self->{write_w};
357	delete $self->{wbuf};
358	delete $self->{write_cb};
359
360	$self->_check_writer;
361	}
362	}	1653	}
363	});	1654	});
		1655	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1656	@linger = ();
		1657	});
		1658	}
		1659	}
		1660
		1661	=item $handle->destroy
		1662
		1663	Shuts down the handle object as much as possible - this call ensures that
		1664	no further callbacks will be invoked and as many resources as possible
		1665	will be freed. You must not call any methods on the object afterwards.
		1666
		1667	Normally, you can just "forget" any references to an AnyEvent::Handle
		1668	object and it will simply shut down. This works in fatal error and EOF
		1669	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1670	callback, so when you want to destroy the AnyEvent::Handle object from
		1671	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1672	that case.
		1673
		1674	The handle might still linger in the background and write out remaining
		1675	data, as specified by the C<linger> option, however.
		1676
		1677	=cut
		1678
		1679	sub destroy {
		1680	my ($self) = @_;
		1681
		1682	$self->DESTROY;
		1683	%$self = ();
		1684	}
		1685
		1686	=item AnyEvent::Handle::TLS_CTX
		1687
		1688	This function creates and returns the AnyEvent::TLS object used by default
		1689	for TLS mode.
		1690
		1691	The context is created by calling L<AnyEvent::TLS> without any arguments.
		1692
		1693	=cut
		1694
		1695	our $TLS_CTX;
		1696
		1697	sub TLS_CTX() {
		1698	$TLS_CTX ||= do {
		1699	require AnyEvent::TLS;
		1700
		1701	new AnyEvent::TLS
		1702	}
364	}	1703	}
365		1704
366	=back	1705	=back
367		1706
		1707
		1708	=head1 NONFREQUENTLY ASKED QUESTIONS
		1709
		1710	=over 4
		1711
		1712	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1713	still get further invocations!
		1714
		1715	That's because AnyEvent::Handle keeps a reference to itself when handling
		1716	read or write callbacks.
		1717
		1718	It is only safe to "forget" the reference inside EOF or error callbacks,
		1719	from within all other callbacks, you need to explicitly call the C<<
		1720	->destroy >> method.
		1721
		1722	=item I get different callback invocations in TLS mode/Why can't I pause
		1723	reading?
		1724
		1725	Unlike, say, TCP, TLS connections do not consist of two independent
		1726	communication channels, one for each direction. Or put differently. The
		1727	read and write directions are not independent of each other: you cannot
		1728	write data unless you are also prepared to read, and vice versa.
		1729
		1730	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1731	callback invocations when you are not expecting any read data - the reason
		1732	is that AnyEvent::Handle always reads in TLS mode.
		1733
		1734	During the connection, you have to make sure that you always have a
		1735	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1736	connection (or when you no longer want to use it) you can call the
		1737	C<destroy> method.
		1738
		1739	=item How do I read data until the other side closes the connection?
		1740
		1741	If you just want to read your data into a perl scalar, the easiest way
		1742	to achieve this is by setting an C<on_read> callback that does nothing,
		1743	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1744	will be in C<$_[0]{rbuf}>:
		1745
		1746	$handle->on_read (sub { });
		1747	$handle->on_eof (undef);
		1748	$handle->on_error (sub {
		1749	my $data = delete $_[0]{rbuf};
		1750	undef $handle;
		1751	});
		1752
		1753	The reason to use C<on_error> is that TCP connections, due to latencies
		1754	and packets loss, might get closed quite violently with an error, when in
		1755	fact, all data has been received.
		1756
		1757	It is usually better to use acknowledgements when transferring data,
		1758	to make sure the other side hasn't just died and you got the data
		1759	intact. This is also one reason why so many internet protocols have an
		1760	explicit QUIT command.
		1761
		1762	=item I don't want to destroy the handle too early - how do I wait until
		1763	all data has been written?
		1764
		1765	After writing your last bits of data, set the C<on_drain> callback
		1766	and destroy the handle in there - with the default setting of
		1767	C<low_water_mark> this will be called precisely when all data has been
		1768	written to the socket:
		1769
		1770	$handle->push_write (...);
		1771	$handle->on_drain (sub {
		1772	warn "all data submitted to the kernel\n";
		1773	undef $handle;
		1774	});
		1775
		1776	If you just want to queue some data and then signal EOF to the other side,
		1777	consider using C<< ->push_shutdown >> instead.
		1778
		1779	=item I want to contact a TLS/SSL server, I don't care about security.
		1780
		1781	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		1782	simply connect to it and then create the AnyEvent::Handle with the C<tls>
		1783	parameter:
		1784
		1785	my $handle = new AnyEvent::Handle
		1786	fh => $fh,
		1787	tls => "connect",
		1788	on_error => sub { ... };
		1789
		1790	$handle->push_write (...);
		1791
		1792	=item I want to contact a TLS/SSL server, I do care about security.
		1793
		1794	Then you #x##TODO#
		1795
		1796
		1797
		1798	=back
		1799
		1800
		1801	=head1 SUBCLASSING AnyEvent::Handle
		1802
		1803	In many cases, you might want to subclass AnyEvent::Handle.
		1804
		1805	To make this easier, a given version of AnyEvent::Handle uses these
		1806	conventions:
		1807
		1808	=over 4
		1809
		1810	=item * all constructor arguments become object members.
		1811
		1812	At least initially, when you pass a C<tls>-argument to the constructor it
		1813	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1814	mutated later on (for example C<tls> will hold the TLS connection object).
		1815
		1816	=item * other object member names are prefixed with an C<_>.
		1817
		1818	All object members not explicitly documented (internal use) are prefixed
		1819	with an underscore character, so the remaining non-C<_>-namespace is free
		1820	for use for subclasses.
		1821
		1822	=item * all members not documented here and not prefixed with an underscore
		1823	are free to use in subclasses.
		1824
		1825	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1826	member variables, but thats just life, at least it is documented.
		1827
		1828	=back
		1829
368	=head1 AUTHOR	1830	=head1 AUTHOR
369		1831
370	Robin Redeker, C<< <elmex at ta-sa.org> >>	1832	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
371		1833
372	=cut	1834	=cut
373		1835
374	1; # End of AnyEvent::Handle	1836	1; # End of AnyEvent::Handle

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines