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Revision 1.5 by elmex, Mon Apr 28 08:01:05 2008 UTC vs.
Revision 1.165 by root, Mon Jul 27 22:49:23 2009 UTC

1	package AnyEvent::Handle;	1	package AnyEvent::Handle;
2		2
3	use warnings;	3	use Scalar::Util ();
4	use strict;	4	use Carp ();
5
6	use AnyEvent;
7	use IO::Handle;
8	use Errno qw/EAGAIN EINTR/;	5	use Errno qw(EAGAIN EINTR);
		6
		7	use AnyEvent (); BEGIN { AnyEvent::common_sense }
		8	use AnyEvent::Util qw(WSAEWOULDBLOCK);
9		9
10	=head1 NAME	10	=head1 NAME
11		11
12	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	12	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
13		13
14	=head1 VERSION
15
16	Version 0.01
17
18	=cut	14	=cut
19		15
20	our $VERSION = '0.01';	16	our $VERSION = 4.87;
21		17
22	=head1 SYNOPSIS	18	=head1 SYNOPSIS
23		19
24	use AnyEvent;	20	use AnyEvent;
25	use AnyEvent::Handle;	21	use AnyEvent::Handle;
26		22
27	my $cv = AnyEvent->condvar;	23	my $cv = AnyEvent->condvar;
28		24
29	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	25	my $hdl; $hdl = new AnyEvent::Handle
		26	fh => \*STDIN,
		27	on_error => sub {
		28	my ($hdl, $fatal, $msg) = @_;
		29	warn "got error $msg\n";
		30	$hdl->destroy;
		31	$cv->send;
		32	);
30		33
31	$ae_fh->on_eof (sub { $cv->broadcast });	34	# send some request line
		35	$hdl->push_write ("getinfo\015\012");
32		36
33	$ae_fh->readlines (sub {	37	# read the response line
		38	$hdl->push_read (line => sub {
34	my ($ae_fh, @lines) = @_;	39	my ($hdl, $line) = @_;
35	for (@lines) {	40	warn "got line <$line>\n";
36	chomp;	41	$cv->send;
37	print "Line: $_";	42	});
		43
		44	$cv->recv;
		45
		46	=head1 DESCRIPTION
		47
		48	This module is a helper module to make it easier to do event-based I/O on
		49	filehandles.
		50
		51	The L<AnyEvent::Intro> tutorial contains some well-documented
		52	AnyEvent::Handle examples.
		53
		54	In the following, when the documentation refers to of "bytes" then this
		55	means characters. As sysread and syswrite are used for all I/O, their
		56	treatment of characters applies to this module as well.
		57
		58	At the very minimum, you should specify C<fh> or C<connect>, and the
		59	C<on_error> callback.
		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 => $filehandle [C<fh> or C<connect> MANDATORY]
		75
		76	The filehandle this L<AnyEvent::Handle> object will operate on.
		77	NOTE: The filehandle will be set to non-blocking mode (using
		78	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		79	that mode.
		80
		81	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
		82
		83	Try to connect to the specified host and service (port), using
		84	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		85	default C<peername>.
		86
		87	You have to specify either this parameter, or C<fh>, above.
		88
		89	It is possible to push requests on the read and write queues, and modify
		90	properties of the stream, even while AnyEvent::Handle is connecting.
		91
		92	When this parameter is specified, then the C<on_prepare>,
		93	C<on_connect_error> and C<on_connect> callbacks will be called under the
		94	appropriate circumstances:
		95
		96	=over 4
		97
		98	=item on_prepare => $cb->($handle)
		99
		100	This (rarely used) callback is called before a new connection is
		101	attempted, but after the file handle has been created. It could be used to
		102	prepare the file handle with parameters required for the actual connect
		103	(as opposed to settings that can be changed when the connection is already
		104	established).
		105
		106	The return value of this callback should be the connect timeout value in
		107	seconds (or C<0>, or C<undef>, or the empty list, to indicate the default
		108	timeout is to be used).
		109
		110	=item on_connect => $cb->($handle, $host, $port, $retry->())
		111
		112	This callback is called when a connection has been successfully established.
		113
		114	The actual numeric host and port (the socket peername) are passed as
		115	parameters, together with a retry callback.
		116
		117	When, for some reason, the handle is not acceptable, then calling
		118	C<$retry> will continue with the next conenction target (in case of
		119	multi-homed hosts or SRV records there can be multiple connection
		120	endpoints). When it is called then the read and write queues, eof status,
		121	tls status and similar properties of the handle are being reset.
		122
		123	In most cases, ignoring the C<$retry> parameter is the way to go.
		124
		125	=item on_connect_error => $cb->($handle, $message)
		126
		127	This callback is called when the conenction could not be
		128	established. C<$!> will contain the relevant error code, and C<$message> a
		129	message describing it (usually the same as C<"$!">).
		130
		131	If this callback isn't specified, then C<on_error> will be called with a
		132	fatal error instead.
		133
		134	=back
		135
		136	=item on_error => $cb->($handle, $fatal, $message)
		137
		138	This is the error callback, which is called when, well, some error
		139	occured, such as not being able to resolve the hostname, failure to
		140	connect or a read error.
		141
		142	Some errors are fatal (which is indicated by C<$fatal> being true). On
		143	fatal errors the handle object will be destroyed (by a call to C<< ->
		144	destroy >>) after invoking the error callback (which means you are free to
		145	examine the handle object). Examples of fatal errors are an EOF condition
		146	with active (but unsatisifable) read watchers (C<EPIPE>) or I/O errors. In
		147	cases where the other side can close the connection at their will it is
		148	often easiest to not report C<EPIPE> errors in this callback.
		149
		150	AnyEvent::Handle tries to find an appropriate error code for you to check
		151	against, but in some cases (TLS errors), this does not work well. It is
		152	recommended to always output the C<$message> argument in human-readable
		153	error messages (it's usually the same as C<"$!">).
		154
		155	Non-fatal errors can be retried by simply returning, but it is recommended
		156	to simply ignore this parameter and instead abondon the handle object
		157	when this callback is invoked. Examples of non-fatal errors are timeouts
		158	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		159
		160	On callback entrance, the value of C<$!> contains the operating system
		161	error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		162	C<EPROTO>).
		163
		164	While not mandatory, it is I<highly> recommended to set this callback, as
		165	you will not be notified of errors otherwise. The default simply calls
		166	C<croak>.
		167
		168	=item on_read => $cb->($handle)
		169
		170	This sets the default read callback, which is called when data arrives
		171	and no read request is in the queue (unlike read queue callbacks, this
		172	callback will only be called when at least one octet of data is in the
		173	read buffer).
		174
		175	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
		176	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		177	must not enlarge or modify the read buffer, you can only remove data at
		178	the beginning from it.
		179
		180	When an EOF condition is detected then AnyEvent::Handle will first try to
		181	feed all the remaining data to the queued callbacks and C<on_read> before
		182	calling the C<on_eof> callback. If no progress can be made, then a fatal
		183	error will be raised (with C<$!> set to C<EPIPE>).
		184
		185	Note that, unlike requests in the read queue, an C<on_read> callback
		186	doesn't mean you I<require> some data: if there is an EOF and there
		187	are outstanding read requests then an error will be flagged. With an
		188	C<on_read> callback, the C<on_eof> callback will be invoked.
		189
		190	=item on_eof => $cb->($handle)
		191
		192	Set the callback to be called when an end-of-file condition is detected,
		193	i.e. in the case of a socket, when the other side has closed the
		194	connection cleanly, and there are no outstanding read requests in the
		195	queue (if there are read requests, then an EOF counts as an unexpected
		196	connection close and will be flagged as an error).
		197
		198	For sockets, this just means that the other side has stopped sending data,
		199	you can still try to write data, and, in fact, one can return from the EOF
		200	callback and continue writing data, as only the read part has been shut
		201	down.
		202
		203	If an EOF condition has been detected but no C<on_eof> callback has been
		204	set, then a fatal error will be raised with C<$!> set to <0>.
		205
		206	=item on_drain => $cb->($handle)
		207
		208	This sets the callback that is called when the write buffer becomes empty
		209	(or when the callback is set and the buffer is empty already).
		210
		211	To append to the write buffer, use the C<< ->push_write >> method.
		212
		213	This callback is useful when you don't want to put all of your write data
		214	into the queue at once, for example, when you want to write the contents
		215	of some file to the socket you might not want to read the whole file into
		216	memory and push it into the queue, but instead only read more data from
		217	the file when the write queue becomes empty.
		218
		219	=item timeout => $fractional_seconds
		220
		221	If non-zero, then this enables an "inactivity" timeout: whenever this many
		222	seconds pass without a successful read or write on the underlying file
		223	handle, the C<on_timeout> callback will be invoked (and if that one is
		224	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		225
		226	Note that timeout processing is also active when you currently do not have
		227	any outstanding read or write requests: If you plan to keep the connection
		228	idle then you should disable the timout temporarily or ignore the timeout
		229	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		230	restart the timeout.
		231
		232	Zero (the default) disables this timeout.
		233
		234	=item on_timeout => $cb->($handle)
		235
		236	Called whenever the inactivity timeout passes. If you return from this
		237	callback, then the timeout will be reset as if some activity had happened,
		238	so this condition is not fatal in any way.
		239
		240	=item rbuf_max => <bytes>
		241
		242	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		243	when the read buffer ever (strictly) exceeds this size. This is useful to
		244	avoid some forms of denial-of-service attacks.
		245
		246	For example, a server accepting connections from untrusted sources should
		247	be configured to accept only so-and-so much data that it cannot act on
		248	(for example, when expecting a line, an attacker could send an unlimited
		249	amount of data without a callback ever being called as long as the line
		250	isn't finished).
		251
		252	=item autocork => <boolean>
		253
		254	When disabled (the default), then C<push_write> will try to immediately
		255	write the data to the handle, if possible. This avoids having to register
		256	a write watcher and wait for the next event loop iteration, but can
		257	be inefficient if you write multiple small chunks (on the wire, this
		258	disadvantage is usually avoided by your kernel's nagle algorithm, see
		259	C<no_delay>, but this option can save costly syscalls).
		260
		261	When enabled, then writes will always be queued till the next event loop
		262	iteration. This is efficient when you do many small writes per iteration,
		263	but less efficient when you do a single write only per iteration (or when
		264	the write buffer often is full). It also increases write latency.
		265
		266	=item no_delay => <boolean>
		267
		268	When doing small writes on sockets, your operating system kernel might
		269	wait a bit for more data before actually sending it out. This is called
		270	the Nagle algorithm, and usually it is beneficial.
		271
		272	In some situations you want as low a delay as possible, which can be
		273	accomplishd by setting this option to a true value.
		274
		275	The default is your opertaing system's default behaviour (most likely
		276	enabled), this option explicitly enables or disables it, if possible.
		277
		278	=item read_size => <bytes>
		279
		280	The default read block size (the amount of bytes this module will
		281	try to read during each loop iteration, which affects memory
		282	requirements). Default: C<8192>.
		283
		284	=item low_water_mark => <bytes>
		285
		286	Sets the amount of bytes (default: C<0>) that make up an "empty" write
		287	buffer: If the write reaches this size or gets even samller it is
		288	considered empty.
		289
		290	Sometimes it can be beneficial (for performance reasons) to add data to
		291	the write buffer before it is fully drained, but this is a rare case, as
		292	the operating system kernel usually buffers data as well, so the default
		293	is good in almost all cases.
		294
		295	=item linger => <seconds>
		296
		297	If non-zero (default: C<3600>), then the destructor of the
		298	AnyEvent::Handle object will check whether there is still outstanding
		299	write data and will install a watcher that will write this data to the
		300	socket. No errors will be reported (this mostly matches how the operating
		301	system treats outstanding data at socket close time).
		302
		303	This will not work for partial TLS data that could not be encoded
		304	yet. This data will be lost. Calling the C<stoptls> method in time might
		305	help.
		306
		307	=item peername => $string
		308
		309	A string used to identify the remote site - usually the DNS hostname
		310	(I<not> IDN!) used to create the connection, rarely the IP address.
		311
		312	Apart from being useful in error messages, this string is also used in TLS
		313	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		314	verification will be skipped when C<peername> is not specified or
		315	C<undef>.
		316
		317	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		318
		319	When this parameter is given, it enables TLS (SSL) mode, that means
		320	AnyEvent will start a TLS handshake as soon as the conenction has been
		321	established and will transparently encrypt/decrypt data afterwards.
		322
		323	All TLS protocol errors will be signalled as C<EPROTO>, with an
		324	appropriate error message.
		325
		326	TLS mode requires Net::SSLeay to be installed (it will be loaded
		327	automatically when you try to create a TLS handle): this module doesn't
		328	have a dependency on that module, so if your module requires it, you have
		329	to add the dependency yourself.
		330
		331	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		332	C<accept>, and for the TLS client side of a connection, use C<connect>
		333	mode.
		334
		335	You can also provide your own TLS connection object, but you have
		336	to make sure that you call either C<Net::SSLeay::set_connect_state>
		337	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		338	AnyEvent::Handle. Also, this module will take ownership of this connection
		339	object.
		340
		341	At some future point, AnyEvent::Handle might switch to another TLS
		342	implementation, then the option to use your own session object will go
		343	away.
		344
		345	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		346	passing in the wrong integer will lead to certain crash. This most often
		347	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		348	segmentation fault.
		349
		350	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		351
		352	=item tls_ctx => $anyevent_tls
		353
		354	Use the given C<AnyEvent::TLS> object to create the new TLS connection
		355	(unless a connection object was specified directly). If this parameter is
		356	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		357
		358	Instead of an object, you can also specify a hash reference with C<< key
		359	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		360	new TLS context object.
		361
		362	=item on_starttls => $cb->($handle, $success[, $error_message])
		363
		364	This callback will be invoked when the TLS/SSL handshake has finished. If
		365	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		366	(C<on_stoptls> will not be called in this case).
		367
		368	The session in C<< $handle->{tls} >> can still be examined in this
		369	callback, even when the handshake was not successful.
		370
		371	TLS handshake failures will not cause C<on_error> to be invoked when this
		372	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		373
		374	Without this callback, handshake failures lead to C<on_error> being
		375	called, as normal.
		376
		377	Note that you cannot call C<starttls> right again in this callback. If you
		378	need to do that, start an zero-second timer instead whose callback can
		379	then call C<< ->starttls >> again.
		380
		381	=item on_stoptls => $cb->($handle)
		382
		383	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		384	set, then it will be invoked after freeing the TLS session. If it is not,
		385	then a TLS shutdown condition will be treated like a normal EOF condition
		386	on the handle.
		387
		388	The session in C<< $handle->{tls} >> can still be examined in this
		389	callback.
		390
		391	This callback will only be called on TLS shutdowns, not when the
		392	underlying handle signals EOF.
		393
		394	=item json => JSON or JSON::XS object
		395
		396	This is the json coder object used by the C<json> read and write types.
		397
		398	If you don't supply it, then AnyEvent::Handle will create and use a
		399	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		400	texts.
		401
		402	Note that you are responsible to depend on the JSON module if you want to
		403	use this functionality, as AnyEvent does not have a dependency itself.
		404
		405	=back
		406
		407	=cut
		408
		409	sub new {
		410	my $class = shift;
		411	my $self = bless { @_ }, $class;
		412
		413	if ($self->{fh}) {
		414	$self->_start;
		415	return unless $self->{fh}; # could be gone by now
		416
		417	} elsif ($self->{connect}) {
		418	require AnyEvent::Socket;
		419
		420	$self->{peername} = $self->{connect}[0]
		421	unless exists $self->{peername};
		422
		423	$self->{_skip_drain_rbuf} = 1;
		424
		425	{
		426	Scalar::Util::weaken (my $self = $self);
		427
		428	$self->{_connect} =
		429	AnyEvent::Socket::tcp_connect (
		430	$self->{connect}[0],
		431	$self->{connect}[1],
		432	sub {
		433	my ($fh, $host, $port, $retry) = @_;
		434
		435	if ($fh) {
		436	$self->{fh} = $fh;
		437
		438	delete $self->{_skip_drain_rbuf};
		439	$self->_start;
		440
		441	$self->{on_connect}
		442	and $self->{on_connect}($self, $host, $port, sub {
		443	delete @$self{qw(fh _tw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		444	$self->{_skip_drain_rbuf} = 1;
		445	&$retry;
		446	});
		447
		448	} else {
		449	if ($self->{on_connect_error}) {
		450	$self->{on_connect_error}($self, "$!");
		451	$self->destroy;
		452	} else {
		453	$self->_error ($!, 1);
		454	}
		455	}
		456	},
		457	sub {
		458	local $self->{fh} = $_[0];
		459
		460	$self->{on_prepare}
		461	? $self->{on_prepare}->($self)
		462	: ()
		463	}
		464	);
		465	}
		466
		467	} else {
		468	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		469	}
		470
		471	$self
		472	}
		473
		474	sub _start {
		475	my ($self) = @_;
		476
		477	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		478
		479	$self->{_activity} = AnyEvent->now;
		480	$self->_timeout;
		481
		482	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		483
		484	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		485	if $self->{tls};
		486
		487	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};
		488
		489	$self->start_read
		490	if $self->{on_read} || @{ $self->{_queue} };
		491
		492	$self->_drain_wbuf;
		493	}
		494
		495	#sub _shutdown {
		496	# my ($self) = @_;
		497	#
		498	# delete @$self{qw(_tw _rw _ww fh wbuf on_read _queue)};
		499	# $self->{_eof} = 1; # tell starttls et. al to stop trying
		500	#
		501	# &_freetls;
		502	#}
		503
		504	sub _error {
		505	my ($self, $errno, $fatal, $message) = @_;
		506
		507	$! = $errno;
		508	$message ||= "$!";
		509
		510	if ($self->{on_error}) {
		511	$self->{on_error}($self, $fatal, $message);
		512	$self->destroy if $fatal;
		513	} elsif ($self->{fh}) {
		514	$self->destroy;
		515	Carp::croak "AnyEvent::Handle uncaught error: $message";
		516	}
		517	}
		518
		519	=item $fh = $handle->fh
		520
		521	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		522
		523	=cut
		524
		525	sub fh { $_[0]{fh} }
		526
		527	=item $handle->on_error ($cb)
		528
		529	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		530
		531	=cut
		532
		533	sub on_error {
		534	$_[0]{on_error} = $_[1];
		535	}
		536
		537	=item $handle->on_eof ($cb)
		538
		539	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		540
		541	=cut
		542
		543	sub on_eof {
		544	$_[0]{on_eof} = $_[1];
		545	}
		546
		547	=item $handle->on_timeout ($cb)
		548
		549	Replace the current C<on_timeout> callback, or disables the callback (but
		550	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		551	argument and method.
		552
		553	=cut
		554
		555	sub on_timeout {
		556	$_[0]{on_timeout} = $_[1];
		557	}
		558
		559	=item $handle->autocork ($boolean)
		560
		561	Enables or disables the current autocork behaviour (see C<autocork>
		562	constructor argument). Changes will only take effect on the next write.
		563
		564	=cut
		565
		566	sub autocork {
		567	$_[0]{autocork} = $_[1];
		568	}
		569
		570	=item $handle->no_delay ($boolean)
		571
		572	Enables or disables the C<no_delay> setting (see constructor argument of
		573	the same name for details).
		574
		575	=cut
		576
		577	sub no_delay {
		578	$_[0]{no_delay} = $_[1];
		579
		580	eval {
		581	local $SIG{__DIE__};
		582	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1]
		583	if $_[0]{fh};
		584	};
		585	}
		586
		587	=item $handle->on_starttls ($cb)
		588
		589	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		590
		591	=cut
		592
		593	sub on_starttls {
		594	$_[0]{on_starttls} = $_[1];
		595	}
		596
		597	=item $handle->on_stoptls ($cb)
		598
		599	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		600
		601	=cut
		602
		603	sub on_starttls {
		604	$_[0]{on_stoptls} = $_[1];
		605	}
		606
		607	#############################################################################
		608
		609	=item $handle->timeout ($seconds)
		610
		611	Configures (or disables) the inactivity timeout.
		612
		613	=cut
		614
		615	sub timeout {
		616	my ($self, $timeout) = @_;
		617
		618	$self->{timeout} = $timeout;
		619	$self->_timeout;
		620	}
		621
		622	# reset the timeout watcher, as neccessary
		623	# also check for time-outs
		624	sub _timeout {
		625	my ($self) = @_;
		626
		627	if ($self->{timeout} && $self->{fh}) {
		628	my $NOW = AnyEvent->now;
		629
		630	# when would the timeout trigger?
		631	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		632
		633	# now or in the past already?
		634	if ($after <= 0) {
		635	$self->{_activity} = $NOW;
		636
		637	if ($self->{on_timeout}) {
		638	$self->{on_timeout}($self);
		639	} else {
		640	$self->_error (Errno::ETIMEDOUT);
		641	}
		642
		643	# callback could have changed timeout value, optimise
		644	return unless $self->{timeout};
		645
		646	# calculate new after
		647	$after = $self->{timeout};
		648	}
		649
		650	Scalar::Util::weaken $self;
		651	return unless $self; # ->error could have destroyed $self
		652
		653	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		654	delete $self->{_tw};
		655	$self->_timeout;
		656	});
		657	} else {
		658	delete $self->{_tw};
		659	}
		660	}
		661
		662	#############################################################################
		663
		664	=back
		665
		666	=head2 WRITE QUEUE
		667
		668	AnyEvent::Handle manages two queues per handle, one for writing and one
		669	for reading.
		670
		671	The write queue is very simple: you can add data to its end, and
		672	AnyEvent::Handle will automatically try to get rid of it for you.
		673
		674	When data could be written and the write buffer is shorter then the low
		675	water mark, the C<on_drain> callback will be invoked.
		676
		677	=over 4
		678
		679	=item $handle->on_drain ($cb)
		680
		681	Sets the C<on_drain> callback or clears it (see the description of
		682	C<on_drain> in the constructor).
		683
		684	=cut
		685
		686	sub on_drain {
		687	my ($self, $cb) = @_;
		688
		689	$self->{on_drain} = $cb;
		690
		691	$cb->($self)
		692	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		693	}
		694
		695	=item $handle->push_write ($data)
		696
		697	Queues the given scalar to be written. You can push as much data as you
		698	want (only limited by the available memory), as C<AnyEvent::Handle>
		699	buffers it independently of the kernel.
		700
		701	=cut
		702
		703	sub _drain_wbuf {
		704	my ($self) = @_;
		705
		706	if (!$self->{_ww} && length $self->{wbuf}) {
		707
		708	Scalar::Util::weaken $self;
		709
		710	my $cb = sub {
		711	my $len = syswrite $self->{fh}, $self->{wbuf};
		712
		713	if (defined $len) {
		714	substr $self->{wbuf}, 0, $len, "";
		715
		716	$self->{_activity} = AnyEvent->now;
		717
		718	$self->{on_drain}($self)
		719	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		720	&& $self->{on_drain};
		721
		722	delete $self->{_ww} unless length $self->{wbuf};
		723	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		724	$self->_error ($!, 1);
		725	}
		726	};
		727
		728	# try to write data immediately
		729	$cb->() unless $self->{autocork};
		730
		731	# if still data left in wbuf, we need to poll
		732	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
		733	if length $self->{wbuf};
		734	};
		735	}
		736
		737	our %WH;
		738
		739	sub register_write_type($$) {
		740	$WH{$_[0]} = $_[1];
		741	}
		742
		743	sub push_write {
		744	my $self = shift;
		745
		746	if (@_ > 1) {
		747	my $type = shift;
		748
		749	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		750	->($self, @_);
		751	}
		752
		753	if ($self->{tls}) {
		754	$self->{_tls_wbuf} .= $_[0];
		755	&_dotls ($self) if $self->{fh};
		756	} else {
		757	$self->{wbuf} .= $_[0];
		758	$self->_drain_wbuf if $self->{fh};
		759	}
		760	}
		761
		762	=item $handle->push_write (type => @args)
		763
		764	Instead of formatting your data yourself, you can also let this module do
		765	the job by specifying a type and type-specific arguments.
		766
		767	Predefined types are (if you have ideas for additional types, feel free to
		768	drop by and tell us):
		769
		770	=over 4
		771
		772	=item netstring => $string
		773
		774	Formats the given value as netstring
		775	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		776
		777	=cut
		778
		779	register_write_type netstring => sub {
		780	my ($self, $string) = @_;
		781
		782	(length $string) . ":$string,"
		783	};
		784
		785	=item packstring => $format, $data
		786
		787	An octet string prefixed with an encoded length. The encoding C<$format>
		788	uses the same format as a Perl C<pack> format, but must specify a single
		789	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		790	optional C<!>, C<< < >> or C<< > >> modifier).
		791
		792	=cut
		793
		794	register_write_type packstring => sub {
		795	my ($self, $format, $string) = @_;
		796
		797	pack "$format/a*", $string
		798	};
		799
		800	=item json => $array_or_hashref
		801
		802	Encodes the given hash or array reference into a JSON object. Unless you
		803	provide your own JSON object, this means it will be encoded to JSON text
		804	in UTF-8.
		805
		806	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		807	one end of a handle and read them at the other end without using any
		808	additional framing.
		809
		810	The generated JSON text is guaranteed not to contain any newlines: While
		811	this module doesn't need delimiters after or between JSON texts to be
		812	able to read them, many other languages depend on that.
		813
		814	A simple RPC protocol that interoperates easily with others is to send
		815	JSON arrays (or objects, although arrays are usually the better choice as
		816	they mimic how function argument passing works) and a newline after each
		817	JSON text:
		818
		819	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		820	$handle->push_write ("\012");
		821
		822	An AnyEvent::Handle receiver would simply use the C<json> read type and
		823	rely on the fact that the newline will be skipped as leading whitespace:
		824
		825	$handle->push_read (json => sub { my $array = $_[1]; ... });
		826
		827	Other languages could read single lines terminated by a newline and pass
		828	this line into their JSON decoder of choice.
		829
		830	=cut
		831
		832	register_write_type json => sub {
		833	my ($self, $ref) = @_;
		834
		835	require JSON;
		836
		837	$self->{json} ? $self->{json}->encode ($ref)
		838	: JSON::encode_json ($ref)
		839	};
		840
		841	=item storable => $reference
		842
		843	Freezes the given reference using L<Storable> and writes it to the
		844	handle. Uses the C<nfreeze> format.
		845
		846	=cut
		847
		848	register_write_type storable => sub {
		849	my ($self, $ref) = @_;
		850
		851	require Storable;
		852
		853	pack "w/a*", Storable::nfreeze ($ref)
		854	};
		855
		856	=back
		857
		858	=item $handle->push_shutdown
		859
		860	Sometimes you know you want to close the socket after writing your data
		861	before it was actually written. One way to do that is to replace your
		862	C<on_drain> handler by a callback that shuts down the socket (and set
		863	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		864	replaces the C<on_drain> callback with:
		865
		866	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		867
		868	This simply shuts down the write side and signals an EOF condition to the
		869	the peer.
		870
		871	You can rely on the normal read queue and C<on_eof> handling
		872	afterwards. This is the cleanest way to close a connection.
		873
		874	=cut
		875
		876	sub push_shutdown {
		877	my ($self) = @_;
		878
		879	delete $self->{low_water_mark};
		880	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		881	}
		882
		883	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		884
		885	This function (not method) lets you add your own types to C<push_write>.
		886	Whenever the given C<type> is used, C<push_write> will invoke the code
		887	reference with the handle object and the remaining arguments.
		888
		889	The code reference is supposed to return a single octet string that will
		890	be appended to the write buffer.
		891
		892	Note that this is a function, and all types registered this way will be
		893	global, so try to use unique names.
		894
		895	=cut
		896
		897	#############################################################################
		898
		899	=back
		900
		901	=head2 READ QUEUE
		902
		903	AnyEvent::Handle manages two queues per handle, one for writing and one
		904	for reading.
		905
		906	The read queue is more complex than the write queue. It can be used in two
		907	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		908	a queue.
		909
		910	In the simple case, you just install an C<on_read> callback and whenever
		911	new data arrives, it will be called. You can then remove some data (if
		912	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
		913	leave the data there if you want to accumulate more (e.g. when only a
		914	partial message has been received so far).
		915
		916	In the more complex case, you want to queue multiple callbacks. In this
		917	case, AnyEvent::Handle will call the first queued callback each time new
		918	data arrives (also the first time it is queued) and removes it when it has
		919	done its job (see C<push_read>, below).
		920
		921	This way you can, for example, push three line-reads, followed by reading
		922	a chunk of data, and AnyEvent::Handle will execute them in order.
		923
		924	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		925	the specified number of bytes which give an XML datagram.
		926
		927	# in the default state, expect some header bytes
		928	$handle->on_read (sub {
		929	# some data is here, now queue the length-header-read (4 octets)
		930	shift->unshift_read (chunk => 4, sub {
		931	# header arrived, decode
		932	my $len = unpack "N", $_[1];
		933
		934	# now read the payload
		935	shift->unshift_read (chunk => $len, sub {
		936	my $xml = $_[1];
		937	# handle xml
		938	});
		939	});
		940	});
		941
		942	Example 2: Implement a client for a protocol that replies either with "OK"
		943	and another line or "ERROR" for the first request that is sent, and 64
		944	bytes for the second request. Due to the availability of a queue, we can
		945	just pipeline sending both requests and manipulate the queue as necessary
		946	in the callbacks.
		947
		948	When the first callback is called and sees an "OK" response, it will
		949	C<unshift> another line-read. This line-read will be queued I<before> the
		950	64-byte chunk callback.
		951
		952	# request one, returns either "OK + extra line" or "ERROR"
		953	$handle->push_write ("request 1\015\012");
		954
		955	# we expect "ERROR" or "OK" as response, so push a line read
		956	$handle->push_read (line => sub {
		957	# if we got an "OK", we have to _prepend_ another line,
		958	# so it will be read before the second request reads its 64 bytes
		959	# which are already in the queue when this callback is called
		960	# we don't do this in case we got an error
		961	if ($_[1] eq "OK") {
		962	$_[0]->unshift_read (line => sub {
		963	my $response = $_[1];
		964	...
		965	});
38	}	966	}
39	});	967	});
40		968
41	# or use the constructor to pass the callback:	969	# request two, simply returns 64 octets
		970	$handle->push_write ("request 2\015\012");
42		971
43	my $ae_fh2 =	972	# simply read 64 bytes, always
44	AnyEvent::Handle->new (	973	$handle->push_read (chunk => 64, sub {
45	fh => \*STDIN,	974	my $response = $_[1];
46	on_eof => sub {	975	...
47	$cv->broadcast;	976	});
48	},	977
49	on_readline => sub {	978	=over 4
50	my ($ae_fh, @lines) = @_;	979
51	for (@lines) {	980	=cut
52	chomp;	981
53	print "Line: $_";	982	sub _drain_rbuf {
		983	my ($self) = @_;
		984
		985	# avoid recursion
		986	return if exists $self->{_skip_drain_rbuf};
		987	local $self->{_skip_drain_rbuf} = 1;
		988
		989	if (
		990	defined $self->{rbuf_max}
		991	&& $self->{rbuf_max} < length $self->{rbuf}
		992	) {
		993	$self->_error (Errno::ENOSPC, 1), return;
		994	}
		995
		996	while () {
		997	# we need to use a separate tls read buffer, as we must not receive data while
		998	# we are draining the buffer, and this can only happen with TLS.
		999	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1000	if exists $self->{_tls_rbuf};
		1001
		1002	my $len = length $self->{rbuf};
		1003
		1004	if (my $cb = shift @{ $self->{_queue} }) {
		1005	unless ($cb->($self)) {
		1006	# no progress can be made
		1007	# (not enough data and no data forthcoming)
		1008	$self->_error (Errno::EPIPE, 1), return
		1009	if $self->{_eof};
		1010
		1011	unshift @{ $self->{_queue} }, $cb;
54	}	1012	last;
55	}	1013	}
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}) {	1014	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	1015	last unless $len;
122		1016
		1017	$self->{on_read}($self);
		1018
		1019	if (
		1020	$len == length $self->{rbuf} # if no data has been consumed
		1021	&& !@{ $self->{_queue} } # and the queue is still empty
		1022	&& $self->{on_read} # but we still have on_read
		1023	) {
		1024	# no further data will arrive
		1025	# so no progress can be made
		1026	$self->_error (Errno::EPIPE, 1), return
		1027	if $self->{_eof};
		1028
		1029	last; # more data might arrive
		1030	}
		1031	} else {
		1032	# read side becomes idle
		1033	delete $self->{_rw} unless $self->{tls};
		1034	last;
		1035	}
		1036	}
		1037
123	} elsif ($self->{on_eof}) {	1038	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});	1039	$self->{on_eof}
		1040	? $self->{on_eof}($self)
		1041	: $self->_error (0, 1, "Unexpected end-of-file");
125		1042
126	} elsif ($self->{on_error}) {	1043	return;
127	$self->on_eof ($self->{on_error});
128	}	1044	}
129		1045
130	return $self	1046	# may need to restart read watcher
		1047	unless ($self->{_rw}) {
		1048	$self->start_read
		1049	if $self->{on_read} || @{ $self->{_queue} };
		1050	}
131	}	1051	}
132		1052
133	=item B<fh>	1053	=item $handle->on_read ($cb)
134		1054
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	1055	This replaces the currently set C<on_read> callback, or clears it (when
136		1056	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	1057	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		1058
149	=cut	1059	=cut
150		1060
151	sub on_read {	1061	sub on_read {
152	my ($self, $cb) = @_;	1062	my ($self, $cb) = @_;
		1063
153	$self->{on_read} = $cb;	1064	$self->{on_read} = $cb;
		1065	$self->_drain_rbuf if $cb;
		1066	}
154		1067
155	unless (defined $self->{on_read}) {	1068	=item $handle->rbuf
156	delete $self->{on_read_w};	1069
		1070	Returns the read buffer (as a modifiable lvalue).
		1071
		1072	You can access the read buffer directly as the C<< ->{rbuf} >>
		1073	member, if you want. However, the only operation allowed on the
		1074	read buffer (apart from looking at it) is removing data from its
		1075	beginning. Otherwise modifying or appending to it is not allowed and will
		1076	lead to hard-to-track-down bugs.
		1077
		1078	NOTE: The read buffer should only be used or modified if the C<on_read>,
		1079	C<push_read> or C<unshift_read> methods are used. The other read methods
		1080	automatically manage the read buffer.
		1081
		1082	=cut
		1083
		1084	sub rbuf : lvalue {
		1085	$_[0]{rbuf}
		1086	}
		1087
		1088	=item $handle->push_read ($cb)
		1089
		1090	=item $handle->unshift_read ($cb)
		1091
		1092	Append the given callback to the end of the queue (C<push_read>) or
		1093	prepend it (C<unshift_read>).
		1094
		1095	The callback is called each time some additional read data arrives.
		1096
		1097	It must check whether enough data is in the read buffer already.
		1098
		1099	If not enough data is available, it must return the empty list or a false
		1100	value, in which case it will be called repeatedly until enough data is
		1101	available (or an error condition is detected).
		1102
		1103	If enough data was available, then the callback must remove all data it is
		1104	interested in (which can be none at all) and return a true value. After returning
		1105	true, it will be removed from the queue.
		1106
		1107	=cut
		1108
		1109	our %RH;
		1110
		1111	sub register_read_type($$) {
		1112	$RH{$_[0]} = $_[1];
		1113	}
		1114
		1115	sub push_read {
		1116	my $self = shift;
		1117	my $cb = pop;
		1118
		1119	if (@_) {
		1120	my $type = shift;
		1121
		1122	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		1123	->($self, $cb, @_);
		1124	}
		1125
		1126	push @{ $self->{_queue} }, $cb;
		1127	$self->_drain_rbuf;
		1128	}
		1129
		1130	sub unshift_read {
		1131	my $self = shift;
		1132	my $cb = pop;
		1133
		1134	if (@_) {
		1135	my $type = shift;
		1136
		1137	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		1138	->($self, $cb, @_);
		1139	}
		1140
		1141
		1142	unshift @{ $self->{_queue} }, $cb;
		1143	$self->_drain_rbuf;
		1144	}
		1145
		1146	=item $handle->push_read (type => @args, $cb)
		1147
		1148	=item $handle->unshift_read (type => @args, $cb)
		1149
		1150	Instead of providing a callback that parses the data itself you can chose
		1151	between a number of predefined parsing formats, for chunks of data, lines
		1152	etc.
		1153
		1154	Predefined types are (if you have ideas for additional types, feel free to
		1155	drop by and tell us):
		1156
		1157	=over 4
		1158
		1159	=item chunk => $octets, $cb->($handle, $data)
		1160
		1161	Invoke the callback only once C<$octets> bytes have been read. Pass the
		1162	data read to the callback. The callback will never be called with less
		1163	data.
		1164
		1165	Example: read 2 bytes.
		1166
		1167	$handle->push_read (chunk => 2, sub {
		1168	warn "yay ", unpack "H*", $_[1];
		1169	});
		1170
		1171	=cut
		1172
		1173	register_read_type chunk => sub {
		1174	my ($self, $cb, $len) = @_;
		1175
		1176	sub {
		1177	$len <= length $_[0]{rbuf} or return;
		1178	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		1179	1
		1180	}
		1181	};
		1182
		1183	=item line => [$eol, ]$cb->($handle, $line, $eol)
		1184
		1185	The callback will be called only once a full line (including the end of
		1186	line marker, C<$eol>) has been read. This line (excluding the end of line
		1187	marker) will be passed to the callback as second argument (C<$line>), and
		1188	the end of line marker as the third argument (C<$eol>).
		1189
		1190	The end of line marker, C<$eol>, can be either a string, in which case it
		1191	will be interpreted as a fixed record end marker, or it can be a regex
		1192	object (e.g. created by C<qr>), in which case it is interpreted as a
		1193	regular expression.
		1194
		1195	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		1196	undef), then C<qr|\015?\012|> is used (which is good for most internet
		1197	protocols).
		1198
		1199	Partial lines at the end of the stream will never be returned, as they are
		1200	not marked by the end of line marker.
		1201
		1202	=cut
		1203
		1204	register_read_type line => sub {
		1205	my ($self, $cb, $eol) = @_;
		1206
		1207	if (@_ < 3) {
		1208	# this is more than twice as fast as the generic code below
		1209	sub {
		1210	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1211
		1212	$cb->($_[0], $1, $2);
		1213	1
		1214	}
		1215	} else {
		1216	$eol = quotemeta $eol unless ref $eol;
		1217	$eol = qr|^(.*?)($eol)|s;
		1218
		1219	sub {
		1220	$_[0]{rbuf} =~ s/$eol// or return;
		1221
		1222	$cb->($_[0], $1, $2);
		1223	1
		1224	}
		1225	}
		1226	};
		1227
		1228	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1229
		1230	Makes a regex match against the regex object C<$accept> and returns
		1231	everything up to and including the match.
		1232
		1233	Example: read a single line terminated by '\n'.
		1234
		1235	$handle->push_read (regex => qr<\n>, sub { ... });
		1236
		1237	If C<$reject> is given and not undef, then it determines when the data is
		1238	to be rejected: it is matched against the data when the C<$accept> regex
		1239	does not match and generates an C<EBADMSG> error when it matches. This is
		1240	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1241	receive buffer overflow).
		1242
		1243	Example: expect a single decimal number followed by whitespace, reject
		1244	anything else (not the use of an anchor).
		1245
		1246	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1247
		1248	If C<$skip> is given and not C<undef>, then it will be matched against
		1249	the receive buffer when neither C<$accept> nor C<$reject> match,
		1250	and everything preceding and including the match will be accepted
		1251	unconditionally. This is useful to skip large amounts of data that you
		1252	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1253	have to start matching from the beginning. This is purely an optimisation
		1254	and is usually worth only when you expect more than a few kilobytes.
		1255
		1256	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1257	expect the header to be very large (it isn't in practise, but...), we use
		1258	a skip regex to skip initial portions. The skip regex is tricky in that
		1259	it only accepts something not ending in either \015 or \012, as these are
		1260	required for the accept regex.
		1261
		1262	$handle->push_read (regex =>
		1263	qr<\015\012\015\012>,
		1264	undef, # no reject
		1265	qr<^.*[^\015\012]>,
		1266	sub { ... });
		1267
		1268	=cut
		1269
		1270	register_read_type regex => sub {
		1271	my ($self, $cb, $accept, $reject, $skip) = @_;
		1272
		1273	my $data;
		1274	my $rbuf = \$self->{rbuf};
		1275
		1276	sub {
		1277	# accept
		1278	if ($$rbuf =~ $accept) {
		1279	$data .= substr $$rbuf, 0, $+[0], "";
		1280	$cb->($self, $data);
157	return;	1281	return 1;
		1282	}
		1283
		1284	# reject
		1285	if ($reject && $$rbuf =~ $reject) {
		1286	$self->_error (Errno::EBADMSG);
		1287	}
		1288
		1289	# skip
		1290	if ($skip && $$rbuf =~ $skip) {
		1291	$data .= substr $$rbuf, 0, $+[0], "";
		1292	}
		1293
		1294	()
158	}	1295	}
159		1296	};
160	$self->{on_read_w} =	1297
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1298	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1299
163	my $rbuf_len = length $self->{rbuf};	1300	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1301
165	if (defined $self->{read_size}) {	1302	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1303
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1304	=cut
168	} else {	1305
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1306	register_read_type netstring => sub {
		1307	my ($self, $cb) = @_;
		1308
		1309	sub {
		1310	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1311	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1312	$self->_error (Errno::EBADMSG);
170	}	1313	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1314	return;
		1315	}
172		1316
173	if (not defined $l) {	1317	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1318
178	} elsif ($l == 0) {	1319	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1320	my $string = $_[1];
180	delete $self->{on_read_w};	1321	$_[0]->unshift_read (chunk => 1, sub {
181		1322	if ($_[1] eq ",") {
		1323	$cb->($_[0], $string);
182	} else {	1324	} else {
183	$self->{on_read}->($self);	1325	$self->_error (Errno::EBADMSG);
		1326	}
		1327	});
		1328	});
		1329
		1330	1
		1331	}
		1332	};
		1333
		1334	=item packstring => $format, $cb->($handle, $string)
		1335
		1336	An octet string prefixed with an encoded length. The encoding C<$format>
		1337	uses the same format as a Perl C<pack> format, but must specify a single
		1338	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1339	optional C<!>, C<< < >> or C<< > >> modifier).
		1340
		1341	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1342	EPP uses a prefix of C<N> (4 octtes).
		1343
		1344	Example: read a block of data prefixed by its length in BER-encoded
		1345	format (very efficient).
		1346
		1347	$handle->push_read (packstring => "w", sub {
		1348	my ($handle, $data) = @_;
		1349	});
		1350
		1351	=cut
		1352
		1353	register_read_type packstring => sub {
		1354	my ($self, $cb, $format) = @_;
		1355
		1356	sub {
		1357	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1358	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1359	or return;
		1360
		1361	$format = length pack $format, $len;
		1362
		1363	# bypass unshift if we already have the remaining chunk
		1364	if ($format + $len <= length $_[0]{rbuf}) {
		1365	my $data = substr $_[0]{rbuf}, $format, $len;
		1366	substr $_[0]{rbuf}, 0, $format + $len, "";
		1367	$cb->($_[0], $data);
		1368	} else {
		1369	# remove prefix
		1370	substr $_[0]{rbuf}, 0, $format, "";
		1371
		1372	# read remaining chunk
		1373	$_[0]->unshift_read (chunk => $len, $cb);
		1374	}
		1375
		1376	1
		1377	}
		1378	};
		1379
		1380	=item json => $cb->($handle, $hash_or_arrayref)
		1381
		1382	Reads a JSON object or array, decodes it and passes it to the
		1383	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1384
		1385	If a C<json> object was passed to the constructor, then that will be used
		1386	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1387
		1388	This read type uses the incremental parser available with JSON version
		1389	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1390	dependency on your own: this module will load the JSON module, but
		1391	AnyEvent does not depend on it itself.
		1392
		1393	Since JSON texts are fully self-delimiting, the C<json> read and write
		1394	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1395	the C<json> write type description, above, for an actual example.
		1396
		1397	=cut
		1398
		1399	register_read_type json => sub {
		1400	my ($self, $cb) = @_;
		1401
		1402	my $json = $self->{json} ||=
		1403	eval { require JSON::XS; JSON::XS->new->utf8 }
		1404	|| do { require JSON; JSON->new->utf8 };
		1405
		1406	my $data;
		1407	my $rbuf = \$self->{rbuf};
		1408
		1409	sub {
		1410	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1411
		1412	if ($ref) {
		1413	$self->{rbuf} = $json->incr_text;
		1414	$json->incr_text = "";
		1415	$cb->($self, $ref);
		1416
		1417	1
		1418	} elsif ($@) {
		1419	# error case
		1420	$json->incr_skip;
		1421
		1422	$self->{rbuf} = $json->incr_text;
		1423	$json->incr_text = "";
		1424
		1425	$self->_error (Errno::EBADMSG);
		1426
		1427	()
		1428	} else {
		1429	$self->{rbuf} = "";
		1430
		1431	()
		1432	}
		1433	}
		1434	};
		1435
		1436	=item storable => $cb->($handle, $ref)
		1437
		1438	Deserialises a L<Storable> frozen representation as written by the
		1439	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1440	data).
		1441
		1442	Raises C<EBADMSG> error if the data could not be decoded.
		1443
		1444	=cut
		1445
		1446	register_read_type storable => sub {
		1447	my ($self, $cb) = @_;
		1448
		1449	require Storable;
		1450
		1451	sub {
		1452	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1453	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1454	or return;
		1455
		1456	my $format = length pack "w", $len;
		1457
		1458	# bypass unshift if we already have the remaining chunk
		1459	if ($format + $len <= length $_[0]{rbuf}) {
		1460	my $data = substr $_[0]{rbuf}, $format, $len;
		1461	substr $_[0]{rbuf}, 0, $format + $len, "";
		1462	$cb->($_[0], Storable::thaw ($data));
		1463	} else {
		1464	# remove prefix
		1465	substr $_[0]{rbuf}, 0, $format, "";
		1466
		1467	# read remaining chunk
		1468	$_[0]->unshift_read (chunk => $len, sub {
		1469	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1470	$cb->($_[0], $ref);
		1471	} else {
		1472	$self->_error (Errno::EBADMSG);
		1473	}
		1474	});
		1475	}
		1476
		1477	1
		1478	}
		1479	};
		1480
		1481	=back
		1482
		1483	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1484
		1485	This function (not method) lets you add your own types to C<push_read>.
		1486
		1487	Whenever the given C<type> is used, C<push_read> will invoke the code
		1488	reference with the handle object, the callback and the remaining
		1489	arguments.
		1490
		1491	The code reference is supposed to return a callback (usually a closure)
		1492	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1493
		1494	It should invoke the passed callback when it is done reading (remember to
		1495	pass C<$handle> as first argument as all other callbacks do that).
		1496
		1497	Note that this is a function, and all types registered this way will be
		1498	global, so try to use unique names.
		1499
		1500	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1501	search for C<register_read_type>)).
		1502
		1503	=item $handle->stop_read
		1504
		1505	=item $handle->start_read
		1506
		1507	In rare cases you actually do not want to read anything from the
		1508	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1509	any queued callbacks will be executed then. To start reading again, call
		1510	C<start_read>.
		1511
		1512	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1513	you change the C<on_read> callback or push/unshift a read callback, and it
		1514	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1515	there are any read requests in the queue.
		1516
		1517	These methods will have no effect when in TLS mode (as TLS doesn't support
		1518	half-duplex connections).
		1519
		1520	=cut
		1521
		1522	sub stop_read {
		1523	my ($self) = @_;
		1524
		1525	delete $self->{_rw} unless $self->{tls};
		1526	}
		1527
		1528	sub start_read {
		1529	my ($self) = @_;
		1530
		1531	unless ($self->{_rw} || $self->{_eof}) {
		1532	Scalar::Util::weaken $self;
		1533
		1534	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1535	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1536	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1537
		1538	if ($len > 0) {
		1539	$self->{_activity} = AnyEvent->now;
		1540
		1541	if ($self->{tls}) {
		1542	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1543
		1544	&_dotls ($self);
		1545	} else {
		1546	$self->_drain_rbuf;
		1547	}
		1548
		1549	} elsif (defined $len) {
		1550	delete $self->{_rw};
		1551	$self->{_eof} = 1;
		1552	$self->_drain_rbuf;
		1553
		1554	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1555	return $self->_error ($!, 1);
184	}	1556	}
185	});	1557	});
		1558	}
186	}	1559	}
187		1560
188	=item B<on_error ($callback)>	1561	our $ERROR_SYSCALL;
		1562	our $ERROR_WANT_READ;
189		1563
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 {	1564	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) = @_;	1565	my ($self, $err) = @_;
240		1566
241	$self->{read_cb} = $cb;	1567	return $self->_error ($!, 1)
242	my $old_blk_size = $self->{read_block_size};	1568	if $err == Net::SSLeay::ERROR_SYSCALL ();
243	$self->{read_block_size} = $len;
244		1569
245	$self->on_read (sub {	1570	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";
247		1571
248	if ($len == length $_[0]->{rbuf}) {	1572	# reduce error string to look less scary
249	$_[0]->{read_block_size} = $old_blk_size;	1573	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
250	$_[0]->on_read (undef);	1574
251	$_[0]->{read_cb}->($_[0], (substr $self->{rbuf}, 0, $len, ''));	1575	if ($self->{_on_starttls}) {
		1576	(delete $self->{_on_starttls})->($self, undef, $err);
		1577	&_freetls;
		1578	} else {
		1579	&_freetls;
		1580	$self->_error (Errno::EPROTO, 1, $err);
		1581	}
		1582	}
		1583
		1584	# poll the write BIO and send the data if applicable
		1585	# also decode read data if possible
		1586	# this is basiclaly our TLS state machine
		1587	# more efficient implementations are possible with openssl,
		1588	# but not with the buggy and incomplete Net::SSLeay.
		1589	sub _dotls {
		1590	my ($self) = @_;
		1591
		1592	my $tmp;
		1593
		1594	if (length $self->{_tls_wbuf}) {
		1595	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
		1596	substr $self->{_tls_wbuf}, 0, $tmp, "";
252	}	1597	}
		1598
		1599	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1600	return $self->_tls_error ($tmp)
		1601	if $tmp != $ERROR_WANT_READ
		1602	&& ($tmp != $ERROR_SYSCALL || $!);
253	});	1603	}
254	}
255		1604
256	=item B<readlines ($callback)>	1605	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1606	unless (length $tmp) {
		1607	$self->{_on_starttls}
		1608	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1609	&_freetls;
257		1610
258	=item B<readlines ($sep, $callback)>	1611	if ($self->{on_stoptls}) {
259		1612	$self->{on_stoptls}($self);
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1613	return;
261	if C<$sep> is not provided. C<$sep> will be used as "line" seperator.	1614	} else {
262		1615	# let's treat SSL-eof as we treat normal EOF
263	The C<$callback> will be called when at least one	1616	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];	1617	$self->{_eof} = 1;
324	}	1618	}
325	}	1619	}
326	return;	1620
		1621	$self->{_tls_rbuf} .= $tmp;
		1622	$self->_drain_rbuf;
		1623	$self->{tls} or return; # tls session might have gone away in callback
		1624	}
		1625
		1626	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1627	return $self->_tls_error ($tmp)
		1628	if $tmp != $ERROR_WANT_READ
		1629	&& ($tmp != $ERROR_SYSCALL || $!);
		1630
		1631	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1632	$self->{wbuf} .= $tmp;
		1633	$self->_drain_wbuf;
		1634	}
		1635
		1636	$self->{_on_starttls}
		1637	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
		1638	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
		1639	}
		1640
		1641	=item $handle->starttls ($tls[, $tls_ctx])
		1642
		1643	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1644	object is created, you can also do that at a later time by calling
		1645	C<starttls>.
		1646
		1647	Starting TLS is currently an asynchronous operation - when you push some
		1648	write data and then call C<< ->starttls >> then TLS negotiation will start
		1649	immediately, after which the queued write data is then sent.
		1650
		1651	The first argument is the same as the C<tls> constructor argument (either
		1652	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1653
		1654	The second argument is the optional C<AnyEvent::TLS> object that is used
		1655	when AnyEvent::Handle has to create its own TLS connection object, or
		1656	a hash reference with C<< key => value >> pairs that will be used to
		1657	construct a new context.
		1658
		1659	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1660	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1661	changed to your liking. Note that the handshake might have already started
		1662	when this function returns.
		1663
		1664	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1665	handshakes on the same stream. Best do not attempt to use the stream after
		1666	stopping TLS.
		1667
		1668	=cut
		1669
		1670	our %TLS_CACHE; #TODO not yet documented, should we?
		1671
		1672	sub starttls {
		1673	my ($self, $tls, $ctx) = @_;
		1674
		1675	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1676	if $self->{tls};
		1677
		1678	$self->{tls} = $tls;
		1679	$self->{tls_ctx} = $ctx if @_ > 2;
		1680
		1681	return unless $self->{fh};
		1682
		1683	require Net::SSLeay;
		1684
		1685	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1686	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1687
		1688	$tls = $self->{tls};
		1689	$ctx = $self->{tls_ctx};
		1690
		1691	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1692
		1693	if ("HASH" eq ref $ctx) {
		1694	require AnyEvent::TLS;
		1695
		1696	if ($ctx->{cache}) {
		1697	my $key = $ctx+0;
		1698	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1699	} else {
		1700	$ctx = new AnyEvent::TLS %$ctx;
		1701	}
		1702	}
327	}	1703
		1704	$self->{tls_ctx} = $ctx || TLS_CTX ();
		1705	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
328		1706
329	my $wba = shift @{$self->{write_bufs}}	1707	# basically, this is deep magic (because SSL_read should have the same issues)
330	or return;	1708	# but the openssl maintainers basically said: "trust us, it just works".
		1709	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1710	# and mismaintained ssleay-module doesn't even offer them).
		1711	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1712	#
		1713	# in short: this is a mess.
		1714	#
		1715	# note that we do not try to keep the length constant between writes as we are required to do.
		1716	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1717	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1718	# have identity issues in that area.
		1719	# Net::SSLeay::CTX_set_mode ($ssl,
		1720	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1721	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1722	Net::SSLeay::CTX_set_mode ($tls, 1|2);
331		1723
332	unless (defined $wba->[0]) {	1724	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
333	$wba->[1]->($self) if $wba->[1];	1725	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
334	$self->_check_writer;	1726
335	return;	1727	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
		1728
		1729	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
		1730	if $self->{on_starttls};
		1731
		1732	&_dotls; # need to trigger the initial handshake
		1733	$self->start_read; # make sure we actually do read
		1734	}
		1735
		1736	=item $handle->stoptls
		1737
		1738	Shuts down the SSL connection - this makes a proper EOF handshake by
		1739	sending a close notify to the other side, but since OpenSSL doesn't
		1740	support non-blocking shut downs, it is not guarenteed that you can re-use
		1741	the stream afterwards.
		1742
		1743	=cut
		1744
		1745	sub stoptls {
		1746	my ($self) = @_;
		1747
		1748	if ($self->{tls}) {
		1749	Net::SSLeay::shutdown ($self->{tls});
		1750
		1751	&_dotls;
		1752
		1753	# # we don't give a shit. no, we do, but we can't. no...#d#
		1754	# # we, we... have to use openssl :/#d#
		1755	# &_freetls;#d#
		1756	}
		1757	}
		1758
		1759	sub _freetls {
		1760	my ($self) = @_;
		1761
		1762	return unless $self->{tls};
		1763
		1764	$self->{tls_ctx}->_put_session (delete $self->{tls})
		1765	if ref $self->{tls};
336	}	1766
		1767	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		1768	}
337		1769
338	$self->{wbuf} = $wba->[0];	1770	sub DESTROY {
339	$self->{write_cb} = $wba->[1];	1771	my ($self) = @_;
340		1772
341	$self->{write_w} =	1773	&_freetls;
342	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1774
		1775	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1776
		1777	if ($linger && length $self->{wbuf} && $self->{fh}) {
		1778	my $fh = delete $self->{fh};
		1779	my $wbuf = delete $self->{wbuf};
		1780
		1781	my @linger;
		1782
		1783	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
343	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1784	my $len = syswrite $fh, $wbuf, length $wbuf;
344		1785
345	if (not defined $l) {	1786	if ($len > 0) {
346	return if $! == EAGAIN || $! == EINTR;	1787	substr $wbuf, 0, $len, "";
347	delete $self->{write_w};
348	$self->{on_error}->($self) if $self->{on_error};
349
350	} else {	1788	} else {
351	substr $self->{wbuf}, 0, $l, '';	1789	@linger = (); # end
352
353	if (length ($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	}	1790	}
363	});	1791	});
		1792	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1793	@linger = ();
		1794	});
		1795	}
		1796	}
		1797
		1798	=item $handle->destroy
		1799
		1800	Shuts down the handle object as much as possible - this call ensures that
		1801	no further callbacks will be invoked and as many resources as possible
		1802	will be freed. Any method you will call on the handle object after
		1803	destroying it in this way will be silently ignored (and it will return the
		1804	empty list).
		1805
		1806	Normally, you can just "forget" any references to an AnyEvent::Handle
		1807	object and it will simply shut down. This works in fatal error and EOF
		1808	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1809	callback, so when you want to destroy the AnyEvent::Handle object from
		1810	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1811	that case.
		1812
		1813	Destroying the handle object in this way has the advantage that callbacks
		1814	will be removed as well, so if those are the only reference holders (as
		1815	is common), then one doesn't need to do anything special to break any
		1816	reference cycles.
		1817
		1818	The handle might still linger in the background and write out remaining
		1819	data, as specified by the C<linger> option, however.
		1820
		1821	=cut
		1822
		1823	sub destroy {
		1824	my ($self) = @_;
		1825
		1826	$self->DESTROY;
		1827	%$self = ();
		1828	bless $self, "AnyEvent::Handle::destroyed";
		1829	}
		1830
		1831	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		1832	#nop
		1833	}
		1834
		1835	=item AnyEvent::Handle::TLS_CTX
		1836
		1837	This function creates and returns the AnyEvent::TLS object used by default
		1838	for TLS mode.
		1839
		1840	The context is created by calling L<AnyEvent::TLS> without any arguments.
		1841
		1842	=cut
		1843
		1844	our $TLS_CTX;
		1845
		1846	sub TLS_CTX() {
		1847	$TLS_CTX ||= do {
		1848	require AnyEvent::TLS;
		1849
		1850	new AnyEvent::TLS
		1851	}
364	}	1852	}
365		1853
366	=back	1854	=back
367		1855
		1856
		1857	=head1 NONFREQUENTLY ASKED QUESTIONS
		1858
		1859	=over 4
		1860
		1861	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1862	still get further invocations!
		1863
		1864	That's because AnyEvent::Handle keeps a reference to itself when handling
		1865	read or write callbacks.
		1866
		1867	It is only safe to "forget" the reference inside EOF or error callbacks,
		1868	from within all other callbacks, you need to explicitly call the C<<
		1869	->destroy >> method.
		1870
		1871	=item I get different callback invocations in TLS mode/Why can't I pause
		1872	reading?
		1873
		1874	Unlike, say, TCP, TLS connections do not consist of two independent
		1875	communication channels, one for each direction. Or put differently. The
		1876	read and write directions are not independent of each other: you cannot
		1877	write data unless you are also prepared to read, and vice versa.
		1878
		1879	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1880	callback invocations when you are not expecting any read data - the reason
		1881	is that AnyEvent::Handle always reads in TLS mode.
		1882
		1883	During the connection, you have to make sure that you always have a
		1884	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1885	connection (or when you no longer want to use it) you can call the
		1886	C<destroy> method.
		1887
		1888	=item How do I read data until the other side closes the connection?
		1889
		1890	If you just want to read your data into a perl scalar, the easiest way
		1891	to achieve this is by setting an C<on_read> callback that does nothing,
		1892	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1893	will be in C<$_[0]{rbuf}>:
		1894
		1895	$handle->on_read (sub { });
		1896	$handle->on_eof (undef);
		1897	$handle->on_error (sub {
		1898	my $data = delete $_[0]{rbuf};
		1899	});
		1900
		1901	The reason to use C<on_error> is that TCP connections, due to latencies
		1902	and packets loss, might get closed quite violently with an error, when in
		1903	fact, all data has been received.
		1904
		1905	It is usually better to use acknowledgements when transferring data,
		1906	to make sure the other side hasn't just died and you got the data
		1907	intact. This is also one reason why so many internet protocols have an
		1908	explicit QUIT command.
		1909
		1910	=item I don't want to destroy the handle too early - how do I wait until
		1911	all data has been written?
		1912
		1913	After writing your last bits of data, set the C<on_drain> callback
		1914	and destroy the handle in there - with the default setting of
		1915	C<low_water_mark> this will be called precisely when all data has been
		1916	written to the socket:
		1917
		1918	$handle->push_write (...);
		1919	$handle->on_drain (sub {
		1920	warn "all data submitted to the kernel\n";
		1921	undef $handle;
		1922	});
		1923
		1924	If you just want to queue some data and then signal EOF to the other side,
		1925	consider using C<< ->push_shutdown >> instead.
		1926
		1927	=item I want to contact a TLS/SSL server, I don't care about security.
		1928
		1929	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		1930	simply connect to it and then create the AnyEvent::Handle with the C<tls>
		1931	parameter:
		1932
		1933	tcp_connect $host, $port, sub {
		1934	my ($fh) = @_;
		1935
		1936	my $handle = new AnyEvent::Handle
		1937	fh => $fh,
		1938	tls => "connect",
		1939	on_error => sub { ... };
		1940
		1941	$handle->push_write (...);
		1942	};
		1943
		1944	=item I want to contact a TLS/SSL server, I do care about security.
		1945
		1946	Then you should additionally enable certificate verification, including
		1947	peername verification, if the protocol you use supports it (see
		1948	L<AnyEvent::TLS>, C<verify_peername>).
		1949
		1950	E.g. for HTTPS:
		1951
		1952	tcp_connect $host, $port, sub {
		1953	my ($fh) = @_;
		1954
		1955	my $handle = new AnyEvent::Handle
		1956	fh => $fh,
		1957	peername => $host,
		1958	tls => "connect",
		1959	tls_ctx => { verify => 1, verify_peername => "https" },
		1960	...
		1961
		1962	Note that you must specify the hostname you connected to (or whatever
		1963	"peername" the protocol needs) as the C<peername> argument, otherwise no
		1964	peername verification will be done.
		1965
		1966	The above will use the system-dependent default set of trusted CA
		1967	certificates. If you want to check against a specific CA, add the
		1968	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		1969
		1970	tls_ctx => {
		1971	verify => 1,
		1972	verify_peername => "https",
		1973	ca_file => "my-ca-cert.pem",
		1974	},
		1975
		1976	=item I want to create a TLS/SSL server, how do I do that?
		1977
		1978	Well, you first need to get a server certificate and key. You have
		1979	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		1980	self-signed certificate (cheap. check the search engine of your choice,
		1981	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		1982	nice program for that purpose).
		1983
		1984	Then create a file with your private key (in PEM format, see
		1985	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		1986	file should then look like this:
		1987
		1988	-----BEGIN RSA PRIVATE KEY-----
		1989	...header data
		1990	... lots of base64'y-stuff
		1991	-----END RSA PRIVATE KEY-----
		1992
		1993	-----BEGIN CERTIFICATE-----
		1994	... lots of base64'y-stuff
		1995	-----END CERTIFICATE-----
		1996
		1997	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		1998	specify this file as C<cert_file>:
		1999
		2000	tcp_server undef, $port, sub {
		2001	my ($fh) = @_;
		2002
		2003	my $handle = new AnyEvent::Handle
		2004	fh => $fh,
		2005	tls => "accept",
		2006	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2007	...
		2008
		2009	When you have intermediate CA certificates that your clients might not
		2010	know about, just append them to the C<cert_file>.
		2011
		2012	=back
		2013
		2014
		2015	=head1 SUBCLASSING AnyEvent::Handle
		2016
		2017	In many cases, you might want to subclass AnyEvent::Handle.
		2018
		2019	To make this easier, a given version of AnyEvent::Handle uses these
		2020	conventions:
		2021
		2022	=over 4
		2023
		2024	=item * all constructor arguments become object members.
		2025
		2026	At least initially, when you pass a C<tls>-argument to the constructor it
		2027	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2028	mutated later on (for example C<tls> will hold the TLS connection object).
		2029
		2030	=item * other object member names are prefixed with an C<_>.
		2031
		2032	All object members not explicitly documented (internal use) are prefixed
		2033	with an underscore character, so the remaining non-C<_>-namespace is free
		2034	for use for subclasses.
		2035
		2036	=item * all members not documented here and not prefixed with an underscore
		2037	are free to use in subclasses.
		2038
		2039	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2040	member variables, but thats just life, at least it is documented.
		2041
		2042	=back
		2043
368	=head1 AUTHOR	2044	=head1 AUTHOR
369		2045
370	Robin Redeker, C<< <elmex at ta-sa.org> >>	2046	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
371		2047
372	=cut	2048	=cut
373		2049
374	1; # End of AnyEvent::Handle	2050	1; # End of AnyEvent::Handle

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