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Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.6 by elmex, Mon Apr 28 09:27:47 2008 UTC vs.
Revision 1.161 by root, Sat Jul 25 06:16:45 2009 UTC

1	package AnyEvent::Handle;	1	package AnyEvent::Handle;
2		2
3	no 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 = 4.86;
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} if exists $self->{_tls_rbuf};
		1000
		1001	my $len = length $self->{rbuf};
		1002
		1003	if (my $cb = shift @{ $self->{_queue} }) {
		1004	unless ($cb->($self)) {
		1005	if ($self->{_eof}) {
		1006	# no progress can be made (not enough data and no data forthcoming)
		1007	$self->_error (Errno::EPIPE, 1), return;
54	}	1008	}
		1009
		1010	unshift @{ $self->{_queue} }, $cb;
		1011	last;
55	}	1012	}
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}) {	1013	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	1014	last unless $len;
122		1015
		1016	$self->{on_read}($self);
		1017
		1018	if (
		1019	$len == length $self->{rbuf} # if no data has been consumed
		1020	&& !@{ $self->{_queue} } # and the queue is still empty
		1021	&& $self->{on_read} # but we still have on_read
		1022	) {
		1023	# no further data will arrive
		1024	# so no progress can be made
		1025	$self->_error (Errno::EPIPE, 1), return
		1026	if $self->{_eof};
		1027
		1028	last; # more data might arrive
		1029	}
		1030	} else {
		1031	# read side becomes idle
		1032	delete $self->{_rw} unless $self->{tls};
		1033	last;
		1034	}
		1035	}
		1036
123	} elsif ($self->{on_eof}) {	1037	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});
125
126	} elsif ($self->{on_error}) {	1038	if ($self->{on_eof}) {
127	$self->on_eof ($self->{on_error});	1039	$self->{on_eof}($self)
		1040	} else {
		1041	$self->_error (0, 1, "Unexpected end-of-file");
		1042	}
128	}	1043	}
129		1044
130	return $self	1045	# may need to restart read watcher
		1046	unless ($self->{_rw}) {
		1047	$self->start_read
		1048	if $self->{on_read} || @{ $self->{_queue} };
		1049	}
131	}	1050	}
132		1051
133	=item B<fh>	1052	=item $handle->on_read ($cb)
134		1053
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	1054	This replaces the currently set C<on_read> callback, or clears it (when
136		1055	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	1056	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		1057
149	=cut	1058	=cut
150		1059
151	sub on_read {	1060	sub on_read {
152	my ($self, $cb) = @_;	1061	my ($self, $cb) = @_;
		1062
153	$self->{on_read} = $cb;	1063	$self->{on_read} = $cb;
		1064	$self->_drain_rbuf if $cb;
		1065	}
154		1066
155	unless (defined $self->{on_read}) {	1067	=item $handle->rbuf
156	delete $self->{on_read_w};	1068
		1069	Returns the read buffer (as a modifiable lvalue).
		1070
		1071	You can access the read buffer directly as the C<< ->{rbuf} >>
		1072	member, if you want. However, the only operation allowed on the
		1073	read buffer (apart from looking at it) is removing data from its
		1074	beginning. Otherwise modifying or appending to it is not allowed and will
		1075	lead to hard-to-track-down bugs.
		1076
		1077	NOTE: The read buffer should only be used or modified if the C<on_read>,
		1078	C<push_read> or C<unshift_read> methods are used. The other read methods
		1079	automatically manage the read buffer.
		1080
		1081	=cut
		1082
		1083	sub rbuf : lvalue {
		1084	$_[0]{rbuf}
		1085	}
		1086
		1087	=item $handle->push_read ($cb)
		1088
		1089	=item $handle->unshift_read ($cb)
		1090
		1091	Append the given callback to the end of the queue (C<push_read>) or
		1092	prepend it (C<unshift_read>).
		1093
		1094	The callback is called each time some additional read data arrives.
		1095
		1096	It must check whether enough data is in the read buffer already.
		1097
		1098	If not enough data is available, it must return the empty list or a false
		1099	value, in which case it will be called repeatedly until enough data is
		1100	available (or an error condition is detected).
		1101
		1102	If enough data was available, then the callback must remove all data it is
		1103	interested in (which can be none at all) and return a true value. After returning
		1104	true, it will be removed from the queue.
		1105
		1106	=cut
		1107
		1108	our %RH;
		1109
		1110	sub register_read_type($$) {
		1111	$RH{$_[0]} = $_[1];
		1112	}
		1113
		1114	sub push_read {
		1115	my $self = shift;
		1116	my $cb = pop;
		1117
		1118	if (@_) {
		1119	my $type = shift;
		1120
		1121	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		1122	->($self, $cb, @_);
		1123	}
		1124
		1125	push @{ $self->{_queue} }, $cb;
		1126	$self->_drain_rbuf;
		1127	}
		1128
		1129	sub unshift_read {
		1130	my $self = shift;
		1131	my $cb = pop;
		1132
		1133	if (@_) {
		1134	my $type = shift;
		1135
		1136	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		1137	->($self, $cb, @_);
		1138	}
		1139
		1140
		1141	unshift @{ $self->{_queue} }, $cb;
		1142	$self->_drain_rbuf;
		1143	}
		1144
		1145	=item $handle->push_read (type => @args, $cb)
		1146
		1147	=item $handle->unshift_read (type => @args, $cb)
		1148
		1149	Instead of providing a callback that parses the data itself you can chose
		1150	between a number of predefined parsing formats, for chunks of data, lines
		1151	etc.
		1152
		1153	Predefined types are (if you have ideas for additional types, feel free to
		1154	drop by and tell us):
		1155
		1156	=over 4
		1157
		1158	=item chunk => $octets, $cb->($handle, $data)
		1159
		1160	Invoke the callback only once C<$octets> bytes have been read. Pass the
		1161	data read to the callback. The callback will never be called with less
		1162	data.
		1163
		1164	Example: read 2 bytes.
		1165
		1166	$handle->push_read (chunk => 2, sub {
		1167	warn "yay ", unpack "H*", $_[1];
		1168	});
		1169
		1170	=cut
		1171
		1172	register_read_type chunk => sub {
		1173	my ($self, $cb, $len) = @_;
		1174
		1175	sub {
		1176	$len <= length $_[0]{rbuf} or return;
		1177	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		1178	1
		1179	}
		1180	};
		1181
		1182	=item line => [$eol, ]$cb->($handle, $line, $eol)
		1183
		1184	The callback will be called only once a full line (including the end of
		1185	line marker, C<$eol>) has been read. This line (excluding the end of line
		1186	marker) will be passed to the callback as second argument (C<$line>), and
		1187	the end of line marker as the third argument (C<$eol>).
		1188
		1189	The end of line marker, C<$eol>, can be either a string, in which case it
		1190	will be interpreted as a fixed record end marker, or it can be a regex
		1191	object (e.g. created by C<qr>), in which case it is interpreted as a
		1192	regular expression.
		1193
		1194	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		1195	undef), then C<qr|\015?\012|> is used (which is good for most internet
		1196	protocols).
		1197
		1198	Partial lines at the end of the stream will never be returned, as they are
		1199	not marked by the end of line marker.
		1200
		1201	=cut
		1202
		1203	register_read_type line => sub {
		1204	my ($self, $cb, $eol) = @_;
		1205
		1206	if (@_ < 3) {
		1207	# this is more than twice as fast as the generic code below
		1208	sub {
		1209	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1210
		1211	$cb->($_[0], $1, $2);
		1212	1
		1213	}
		1214	} else {
		1215	$eol = quotemeta $eol unless ref $eol;
		1216	$eol = qr|^(.*?)($eol)|s;
		1217
		1218	sub {
		1219	$_[0]{rbuf} =~ s/$eol// or return;
		1220
		1221	$cb->($_[0], $1, $2);
		1222	1
		1223	}
		1224	}
		1225	};
		1226
		1227	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1228
		1229	Makes a regex match against the regex object C<$accept> and returns
		1230	everything up to and including the match.
		1231
		1232	Example: read a single line terminated by '\n'.
		1233
		1234	$handle->push_read (regex => qr<\n>, sub { ... });
		1235
		1236	If C<$reject> is given and not undef, then it determines when the data is
		1237	to be rejected: it is matched against the data when the C<$accept> regex
		1238	does not match and generates an C<EBADMSG> error when it matches. This is
		1239	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1240	receive buffer overflow).
		1241
		1242	Example: expect a single decimal number followed by whitespace, reject
		1243	anything else (not the use of an anchor).
		1244
		1245	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1246
		1247	If C<$skip> is given and not C<undef>, then it will be matched against
		1248	the receive buffer when neither C<$accept> nor C<$reject> match,
		1249	and everything preceding and including the match will be accepted
		1250	unconditionally. This is useful to skip large amounts of data that you
		1251	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1252	have to start matching from the beginning. This is purely an optimisation
		1253	and is usually worth only when you expect more than a few kilobytes.
		1254
		1255	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1256	expect the header to be very large (it isn't in practise, but...), we use
		1257	a skip regex to skip initial portions. The skip regex is tricky in that
		1258	it only accepts something not ending in either \015 or \012, as these are
		1259	required for the accept regex.
		1260
		1261	$handle->push_read (regex =>
		1262	qr<\015\012\015\012>,
		1263	undef, # no reject
		1264	qr<^.*[^\015\012]>,
		1265	sub { ... });
		1266
		1267	=cut
		1268
		1269	register_read_type regex => sub {
		1270	my ($self, $cb, $accept, $reject, $skip) = @_;
		1271
		1272	my $data;
		1273	my $rbuf = \$self->{rbuf};
		1274
		1275	sub {
		1276	# accept
		1277	if ($$rbuf =~ $accept) {
		1278	$data .= substr $$rbuf, 0, $+[0], "";
		1279	$cb->($self, $data);
157	return;	1280	return 1;
		1281	}
		1282
		1283	# reject
		1284	if ($reject && $$rbuf =~ $reject) {
		1285	$self->_error (Errno::EBADMSG);
		1286	}
		1287
		1288	# skip
		1289	if ($skip && $$rbuf =~ $skip) {
		1290	$data .= substr $$rbuf, 0, $+[0], "";
		1291	}
		1292
		1293	()
158	}	1294	}
159		1295	};
160	$self->{on_read_w} =	1296
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1297	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1298
163	my $rbuf_len = length $self->{rbuf};	1299	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1300
165	if (defined $self->{read_size}) {	1301	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1302
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1303	=cut
168	} else {	1304
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1305	register_read_type netstring => sub {
		1306	my ($self, $cb) = @_;
		1307
		1308	sub {
		1309	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1310	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1311	$self->_error (Errno::EBADMSG);
170	}	1312	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1313	return;
		1314	}
172		1315
173	if (not defined $l) {	1316	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1317
178	} elsif ($l == 0) {	1318	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1319	my $string = $_[1];
180	delete $self->{on_read_w};	1320	$_[0]->unshift_read (chunk => 1, sub {
181		1321	if ($_[1] eq ",") {
		1322	$cb->($_[0], $string);
182	} else {	1323	} else {
183	$self->{on_read}->($self);	1324	$self->_error (Errno::EBADMSG);
		1325	}
		1326	});
		1327	});
		1328
		1329	1
		1330	}
		1331	};
		1332
		1333	=item packstring => $format, $cb->($handle, $string)
		1334
		1335	An octet string prefixed with an encoded length. The encoding C<$format>
		1336	uses the same format as a Perl C<pack> format, but must specify a single
		1337	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1338	optional C<!>, C<< < >> or C<< > >> modifier).
		1339
		1340	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1341	EPP uses a prefix of C<N> (4 octtes).
		1342
		1343	Example: read a block of data prefixed by its length in BER-encoded
		1344	format (very efficient).
		1345
		1346	$handle->push_read (packstring => "w", sub {
		1347	my ($handle, $data) = @_;
		1348	});
		1349
		1350	=cut
		1351
		1352	register_read_type packstring => sub {
		1353	my ($self, $cb, $format) = @_;
		1354
		1355	sub {
		1356	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1357	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1358	or return;
		1359
		1360	$format = length pack $format, $len;
		1361
		1362	# bypass unshift if we already have the remaining chunk
		1363	if ($format + $len <= length $_[0]{rbuf}) {
		1364	my $data = substr $_[0]{rbuf}, $format, $len;
		1365	substr $_[0]{rbuf}, 0, $format + $len, "";
		1366	$cb->($_[0], $data);
		1367	} else {
		1368	# remove prefix
		1369	substr $_[0]{rbuf}, 0, $format, "";
		1370
		1371	# read remaining chunk
		1372	$_[0]->unshift_read (chunk => $len, $cb);
		1373	}
		1374
		1375	1
		1376	}
		1377	};
		1378
		1379	=item json => $cb->($handle, $hash_or_arrayref)
		1380
		1381	Reads a JSON object or array, decodes it and passes it to the
		1382	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1383
		1384	If a C<json> object was passed to the constructor, then that will be used
		1385	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1386
		1387	This read type uses the incremental parser available with JSON version
		1388	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1389	dependency on your own: this module will load the JSON module, but
		1390	AnyEvent does not depend on it itself.
		1391
		1392	Since JSON texts are fully self-delimiting, the C<json> read and write
		1393	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1394	the C<json> write type description, above, for an actual example.
		1395
		1396	=cut
		1397
		1398	register_read_type json => sub {
		1399	my ($self, $cb) = @_;
		1400
		1401	my $json = $self->{json} ||=
		1402	eval { require JSON::XS; JSON::XS->new->utf8 }
		1403	|| do { require JSON; JSON->new->utf8 };
		1404
		1405	my $data;
		1406	my $rbuf = \$self->{rbuf};
		1407
		1408	sub {
		1409	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1410
		1411	if ($ref) {
		1412	$self->{rbuf} = $json->incr_text;
		1413	$json->incr_text = "";
		1414	$cb->($self, $ref);
		1415
		1416	1
		1417	} elsif ($@) {
		1418	# error case
		1419	$json->incr_skip;
		1420
		1421	$self->{rbuf} = $json->incr_text;
		1422	$json->incr_text = "";
		1423
		1424	$self->_error (Errno::EBADMSG);
		1425
		1426	()
		1427	} else {
		1428	$self->{rbuf} = "";
		1429
		1430	()
		1431	}
		1432	}
		1433	};
		1434
		1435	=item storable => $cb->($handle, $ref)
		1436
		1437	Deserialises a L<Storable> frozen representation as written by the
		1438	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1439	data).
		1440
		1441	Raises C<EBADMSG> error if the data could not be decoded.
		1442
		1443	=cut
		1444
		1445	register_read_type storable => sub {
		1446	my ($self, $cb) = @_;
		1447
		1448	require Storable;
		1449
		1450	sub {
		1451	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1452	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1453	or return;
		1454
		1455	my $format = length pack "w", $len;
		1456
		1457	# bypass unshift if we already have the remaining chunk
		1458	if ($format + $len <= length $_[0]{rbuf}) {
		1459	my $data = substr $_[0]{rbuf}, $format, $len;
		1460	substr $_[0]{rbuf}, 0, $format + $len, "";
		1461	$cb->($_[0], Storable::thaw ($data));
		1462	} else {
		1463	# remove prefix
		1464	substr $_[0]{rbuf}, 0, $format, "";
		1465
		1466	# read remaining chunk
		1467	$_[0]->unshift_read (chunk => $len, sub {
		1468	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1469	$cb->($_[0], $ref);
		1470	} else {
		1471	$self->_error (Errno::EBADMSG);
		1472	}
		1473	});
		1474	}
		1475
		1476	1
		1477	}
		1478	};
		1479
		1480	=back
		1481
		1482	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1483
		1484	This function (not method) lets you add your own types to C<push_read>.
		1485
		1486	Whenever the given C<type> is used, C<push_read> will invoke the code
		1487	reference with the handle object, the callback and the remaining
		1488	arguments.
		1489
		1490	The code reference is supposed to return a callback (usually a closure)
		1491	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1492
		1493	It should invoke the passed callback when it is done reading (remember to
		1494	pass C<$handle> as first argument as all other callbacks do that).
		1495
		1496	Note that this is a function, and all types registered this way will be
		1497	global, so try to use unique names.
		1498
		1499	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1500	search for C<register_read_type>)).
		1501
		1502	=item $handle->stop_read
		1503
		1504	=item $handle->start_read
		1505
		1506	In rare cases you actually do not want to read anything from the
		1507	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1508	any queued callbacks will be executed then. To start reading again, call
		1509	C<start_read>.
		1510
		1511	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1512	you change the C<on_read> callback or push/unshift a read callback, and it
		1513	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1514	there are any read requests in the queue.
		1515
		1516	These methods will have no effect when in TLS mode (as TLS doesn't support
		1517	half-duplex connections).
		1518
		1519	=cut
		1520
		1521	sub stop_read {
		1522	my ($self) = @_;
		1523
		1524	delete $self->{_rw} unless $self->{tls};
		1525	}
		1526
		1527	sub start_read {
		1528	my ($self) = @_;
		1529
		1530	unless ($self->{_rw} || $self->{_eof}) {
		1531	Scalar::Util::weaken $self;
		1532
		1533	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1534	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1535	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1536
		1537	if ($len > 0) {
		1538	$self->{_activity} = AnyEvent->now;
		1539
		1540	if ($self->{tls}) {
		1541	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1542
		1543	&_dotls ($self);
		1544	} else {
		1545	$self->_drain_rbuf;
		1546	}
		1547
		1548	} elsif (defined $len) {
		1549	delete $self->{_rw};
		1550	$self->{_eof} = 1;
		1551	$self->_drain_rbuf;
		1552
		1553	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1554	return $self->_error ($!, 1);
184	}	1555	}
185	});	1556	});
		1557	}
186	}	1558	}
187		1559
188	=item B<on_error ($callback)>	1560	our $ERROR_SYSCALL;
		1561	our $ERROR_WANT_READ;
189		1562
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 {	1563	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) = @_;	1564	my ($self, $err) = @_;
240		1565
241	$self->{read_cb} = $cb;	1566	return $self->_error ($!, 1)
242	my $old_blk_size = $self->{read_block_size};	1567	if $err == Net::SSLeay::ERROR_SYSCALL ();
243	$self->{read_block_size} = $len;
244		1568
245	$self->on_read (sub {	1569	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";
247		1570
248	if ($len == length $_[0]->{rbuf}) {	1571	# reduce error string to look less scary
249	$_[0]->{read_block_size} = $old_blk_size;	1572	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
250	$_[0]->on_read (undef);	1573
251	$_[0]->{read_cb}->($_[0], (substr $self->{rbuf}, 0, $len, ''));	1574	if ($self->{_on_starttls}) {
		1575	(delete $self->{_on_starttls})->($self, undef, $err);
		1576	&_freetls;
		1577	} else {
		1578	&_freetls;
		1579	$self->_error (Errno::EPROTO, 1, $err);
		1580	}
		1581	}
		1582
		1583	# poll the write BIO and send the data if applicable
		1584	# also decode read data if possible
		1585	# this is basiclaly our TLS state machine
		1586	# more efficient implementations are possible with openssl,
		1587	# but not with the buggy and incomplete Net::SSLeay.
		1588	sub _dotls {
		1589	my ($self) = @_;
		1590
		1591	my $tmp;
		1592
		1593	if (length $self->{_tls_wbuf}) {
		1594	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
		1595	substr $self->{_tls_wbuf}, 0, $tmp, "";
252	}	1596	}
		1597
		1598	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1599	return $self->_tls_error ($tmp)
		1600	if $tmp != $ERROR_WANT_READ
		1601	&& ($tmp != $ERROR_SYSCALL || $!);
253	});	1602	}
254	}
255		1603
256	=item B<readlines ($callback)>	1604	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1605	unless (length $tmp) {
		1606	$self->{_on_starttls}
		1607	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1608	&_freetls;
257		1609
258	=item B<readlines ($sep, $callback)>	1610	if ($self->{on_stoptls}) {
259		1611	$self->{on_stoptls}($self);
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1612	return;
261	if C<$sep> is not provided. C<$sep> will be used as "line" seperator.	1613	} else {
262		1614	# let's treat SSL-eof as we treat normal EOF
263	The C<$callback> will be called when at least one	1615	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];	1616	$self->{_eof} = 1;
324	}	1617	}
325	}	1618	}
326	return;	1619
		1620	$self->{_tls_rbuf} .= $tmp;
		1621	$self->_drain_rbuf;
		1622	$self->{tls} or return; # tls session might have gone away in callback
		1623	}
		1624
		1625	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1626	return $self->_tls_error ($tmp)
		1627	if $tmp != $ERROR_WANT_READ
		1628	&& ($tmp != $ERROR_SYSCALL || $!);
		1629
		1630	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1631	$self->{wbuf} .= $tmp;
		1632	$self->_drain_wbuf;
		1633	}
		1634
		1635	$self->{_on_starttls}
		1636	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
		1637	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
		1638	}
		1639
		1640	=item $handle->starttls ($tls[, $tls_ctx])
		1641
		1642	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1643	object is created, you can also do that at a later time by calling
		1644	C<starttls>.
		1645
		1646	Starting TLS is currently an asynchronous operation - when you push some
		1647	write data and then call C<< ->starttls >> then TLS negotiation will start
		1648	immediately, after which the queued write data is then sent.
		1649
		1650	The first argument is the same as the C<tls> constructor argument (either
		1651	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1652
		1653	The second argument is the optional C<AnyEvent::TLS> object that is used
		1654	when AnyEvent::Handle has to create its own TLS connection object, or
		1655	a hash reference with C<< key => value >> pairs that will be used to
		1656	construct a new context.
		1657
		1658	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1659	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1660	changed to your liking. Note that the handshake might have already started
		1661	when this function returns.
		1662
		1663	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1664	handshakes on the same stream. Best do not attempt to use the stream after
		1665	stopping TLS.
		1666
		1667	=cut
		1668
		1669	our %TLS_CACHE; #TODO not yet documented, should we?
		1670
		1671	sub starttls {
		1672	my ($self, $tls, $ctx) = @_;
		1673
		1674	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1675	if $self->{tls};
		1676
		1677	$self->{tls} = $tls;
		1678	$self->{tls_ctx} = $ctx if @_ > 2;
		1679
		1680	return unless $self->{fh};
		1681
		1682	require Net::SSLeay;
		1683
		1684	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1685	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1686
		1687	$tls = $self->{tls};
		1688	$ctx = $self->{tls_ctx};
		1689
		1690	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1691
		1692	if ("HASH" eq ref $ctx) {
		1693	require AnyEvent::TLS;
		1694
		1695	if ($ctx->{cache}) {
		1696	my $key = $ctx+0;
		1697	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1698	} else {
		1699	$ctx = new AnyEvent::TLS %$ctx;
		1700	}
		1701	}
327	}	1702
		1703	$self->{tls_ctx} = $ctx || TLS_CTX ();
		1704	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
328		1705
329	my $wba = shift @{$self->{write_bufs}}	1706	# basically, this is deep magic (because SSL_read should have the same issues)
330	or return;	1707	# but the openssl maintainers basically said: "trust us, it just works".
		1708	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1709	# and mismaintained ssleay-module doesn't even offer them).
		1710	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1711	#
		1712	# in short: this is a mess.
		1713	#
		1714	# note that we do not try to keep the length constant between writes as we are required to do.
		1715	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1716	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1717	# have identity issues in that area.
		1718	# Net::SSLeay::CTX_set_mode ($ssl,
		1719	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1720	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1721	Net::SSLeay::CTX_set_mode ($tls, 1|2);
331		1722
332	unless (defined $wba->[0]) {	1723	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
333	$wba->[1]->($self) if $wba->[1];	1724	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
334	$self->_check_writer;	1725
335	return;	1726	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
		1727
		1728	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
		1729	if $self->{on_starttls};
		1730
		1731	&_dotls; # need to trigger the initial handshake
		1732	$self->start_read; # make sure we actually do read
		1733	}
		1734
		1735	=item $handle->stoptls
		1736
		1737	Shuts down the SSL connection - this makes a proper EOF handshake by
		1738	sending a close notify to the other side, but since OpenSSL doesn't
		1739	support non-blocking shut downs, it is not guarenteed that you can re-use
		1740	the stream afterwards.
		1741
		1742	=cut
		1743
		1744	sub stoptls {
		1745	my ($self) = @_;
		1746
		1747	if ($self->{tls}) {
		1748	Net::SSLeay::shutdown ($self->{tls});
		1749
		1750	&_dotls;
		1751
		1752	# # we don't give a shit. no, we do, but we can't. no...#d#
		1753	# # we, we... have to use openssl :/#d#
		1754	# &_freetls;#d#
		1755	}
		1756	}
		1757
		1758	sub _freetls {
		1759	my ($self) = @_;
		1760
		1761	return unless $self->{tls};
		1762
		1763	$self->{tls_ctx}->_put_session (delete $self->{tls})
		1764	if ref $self->{tls};
336	}	1765
		1766	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		1767	}
337		1768
338	$self->{wbuf} = $wba->[0];	1769	sub DESTROY {
339	$self->{write_cb} = $wba->[1];	1770	my ($self) = @_;
340		1771
341	$self->{write_w} =	1772	&_freetls;
342	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1773
		1774	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1775
		1776	if ($linger && length $self->{wbuf} && $self->{fh}) {
		1777	my $fh = delete $self->{fh};
		1778	my $wbuf = delete $self->{wbuf};
		1779
		1780	my @linger;
		1781
		1782	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
343	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1783	my $len = syswrite $fh, $wbuf, length $wbuf;
344		1784
345	if (not defined $l) {	1785	if ($len > 0) {
346	return if $! == EAGAIN || $! == EINTR;	1786	substr $wbuf, 0, $len, "";
347	delete $self->{write_w};
348	$self->{on_error}->($self) if $self->{on_error};
349
350	} else {	1787	} else {
351	substr $self->{wbuf}, 0, $l, '';	1788	@linger = (); # end
352
353	if (length ($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	}	1789	}
363	});	1790	});
		1791	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1792	@linger = ();
		1793	});
		1794	}
		1795	}
		1796
		1797	=item $handle->destroy
		1798
		1799	Shuts down the handle object as much as possible - this call ensures that
		1800	no further callbacks will be invoked and as many resources as possible
		1801	will be freed. You must not call any methods on the object afterwards.
		1802
		1803	Normally, you can just "forget" any references to an AnyEvent::Handle
		1804	object and it will simply shut down. This works in fatal error and EOF
		1805	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1806	callback, so when you want to destroy the AnyEvent::Handle object from
		1807	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1808	that case.
		1809
		1810	Destroying the handle object in this way has the advantage that callbacks
		1811	will be removed as well, so if those are the only reference holders (as
		1812	is common), then one doesn't need to do anything special to break any
		1813	reference cycles.
		1814
		1815	The handle might still linger in the background and write out remaining
		1816	data, as specified by the C<linger> option, however.
		1817
		1818	=cut
		1819
		1820	sub destroy {
		1821	my ($self) = @_;
		1822
		1823	$self->DESTROY;
		1824	%$self = ();
		1825	}
		1826
		1827	=item AnyEvent::Handle::TLS_CTX
		1828
		1829	This function creates and returns the AnyEvent::TLS object used by default
		1830	for TLS mode.
		1831
		1832	The context is created by calling L<AnyEvent::TLS> without any arguments.
		1833
		1834	=cut
		1835
		1836	our $TLS_CTX;
		1837
		1838	sub TLS_CTX() {
		1839	$TLS_CTX ||= do {
		1840	require AnyEvent::TLS;
		1841
		1842	new AnyEvent::TLS
		1843	}
364	}	1844	}
365		1845
366	=back	1846	=back
367		1847
		1848
		1849	=head1 NONFREQUENTLY ASKED QUESTIONS
		1850
		1851	=over 4
		1852
		1853	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1854	still get further invocations!
		1855
		1856	That's because AnyEvent::Handle keeps a reference to itself when handling
		1857	read or write callbacks.
		1858
		1859	It is only safe to "forget" the reference inside EOF or error callbacks,
		1860	from within all other callbacks, you need to explicitly call the C<<
		1861	->destroy >> method.
		1862
		1863	=item I get different callback invocations in TLS mode/Why can't I pause
		1864	reading?
		1865
		1866	Unlike, say, TCP, TLS connections do not consist of two independent
		1867	communication channels, one for each direction. Or put differently. The
		1868	read and write directions are not independent of each other: you cannot
		1869	write data unless you are also prepared to read, and vice versa.
		1870
		1871	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1872	callback invocations when you are not expecting any read data - the reason
		1873	is that AnyEvent::Handle always reads in TLS mode.
		1874
		1875	During the connection, you have to make sure that you always have a
		1876	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1877	connection (or when you no longer want to use it) you can call the
		1878	C<destroy> method.
		1879
		1880	=item How do I read data until the other side closes the connection?
		1881
		1882	If you just want to read your data into a perl scalar, the easiest way
		1883	to achieve this is by setting an C<on_read> callback that does nothing,
		1884	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1885	will be in C<$_[0]{rbuf}>:
		1886
		1887	$handle->on_read (sub { });
		1888	$handle->on_eof (undef);
		1889	$handle->on_error (sub {
		1890	my $data = delete $_[0]{rbuf};
		1891	});
		1892
		1893	The reason to use C<on_error> is that TCP connections, due to latencies
		1894	and packets loss, might get closed quite violently with an error, when in
		1895	fact, all data has been received.
		1896
		1897	It is usually better to use acknowledgements when transferring data,
		1898	to make sure the other side hasn't just died and you got the data
		1899	intact. This is also one reason why so many internet protocols have an
		1900	explicit QUIT command.
		1901
		1902	=item I don't want to destroy the handle too early - how do I wait until
		1903	all data has been written?
		1904
		1905	After writing your last bits of data, set the C<on_drain> callback
		1906	and destroy the handle in there - with the default setting of
		1907	C<low_water_mark> this will be called precisely when all data has been
		1908	written to the socket:
		1909
		1910	$handle->push_write (...);
		1911	$handle->on_drain (sub {
		1912	warn "all data submitted to the kernel\n";
		1913	undef $handle;
		1914	});
		1915
		1916	If you just want to queue some data and then signal EOF to the other side,
		1917	consider using C<< ->push_shutdown >> instead.
		1918
		1919	=item I want to contact a TLS/SSL server, I don't care about security.
		1920
		1921	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		1922	simply connect to it and then create the AnyEvent::Handle with the C<tls>
		1923	parameter:
		1924
		1925	tcp_connect $host, $port, sub {
		1926	my ($fh) = @_;
		1927
		1928	my $handle = new AnyEvent::Handle
		1929	fh => $fh,
		1930	tls => "connect",
		1931	on_error => sub { ... };
		1932
		1933	$handle->push_write (...);
		1934	};
		1935
		1936	=item I want to contact a TLS/SSL server, I do care about security.
		1937
		1938	Then you should additionally enable certificate verification, including
		1939	peername verification, if the protocol you use supports it (see
		1940	L<AnyEvent::TLS>, C<verify_peername>).
		1941
		1942	E.g. for HTTPS:
		1943
		1944	tcp_connect $host, $port, sub {
		1945	my ($fh) = @_;
		1946
		1947	my $handle = new AnyEvent::Handle
		1948	fh => $fh,
		1949	peername => $host,
		1950	tls => "connect",
		1951	tls_ctx => { verify => 1, verify_peername => "https" },
		1952	...
		1953
		1954	Note that you must specify the hostname you connected to (or whatever
		1955	"peername" the protocol needs) as the C<peername> argument, otherwise no
		1956	peername verification will be done.
		1957
		1958	The above will use the system-dependent default set of trusted CA
		1959	certificates. If you want to check against a specific CA, add the
		1960	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		1961
		1962	tls_ctx => {
		1963	verify => 1,
		1964	verify_peername => "https",
		1965	ca_file => "my-ca-cert.pem",
		1966	},
		1967
		1968	=item I want to create a TLS/SSL server, how do I do that?
		1969
		1970	Well, you first need to get a server certificate and key. You have
		1971	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		1972	self-signed certificate (cheap. check the search engine of your choice,
		1973	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		1974	nice program for that purpose).
		1975
		1976	Then create a file with your private key (in PEM format, see
		1977	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		1978	file should then look like this:
		1979
		1980	-----BEGIN RSA PRIVATE KEY-----
		1981	...header data
		1982	... lots of base64'y-stuff
		1983	-----END RSA PRIVATE KEY-----
		1984
		1985	-----BEGIN CERTIFICATE-----
		1986	... lots of base64'y-stuff
		1987	-----END CERTIFICATE-----
		1988
		1989	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		1990	specify this file as C<cert_file>:
		1991
		1992	tcp_server undef, $port, sub {
		1993	my ($fh) = @_;
		1994
		1995	my $handle = new AnyEvent::Handle
		1996	fh => $fh,
		1997	tls => "accept",
		1998	tls_ctx => { cert_file => "my-server-keycert.pem" },
		1999	...
		2000
		2001	When you have intermediate CA certificates that your clients might not
		2002	know about, just append them to the C<cert_file>.
		2003
		2004	=back
		2005
		2006
		2007	=head1 SUBCLASSING AnyEvent::Handle
		2008
		2009	In many cases, you might want to subclass AnyEvent::Handle.
		2010
		2011	To make this easier, a given version of AnyEvent::Handle uses these
		2012	conventions:
		2013
		2014	=over 4
		2015
		2016	=item * all constructor arguments become object members.
		2017
		2018	At least initially, when you pass a C<tls>-argument to the constructor it
		2019	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2020	mutated later on (for example C<tls> will hold the TLS connection object).
		2021
		2022	=item * other object member names are prefixed with an C<_>.
		2023
		2024	All object members not explicitly documented (internal use) are prefixed
		2025	with an underscore character, so the remaining non-C<_>-namespace is free
		2026	for use for subclasses.
		2027
		2028	=item * all members not documented here and not prefixed with an underscore
		2029	are free to use in subclasses.
		2030
		2031	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2032	member variables, but thats just life, at least it is documented.
		2033
		2034	=back
		2035
368	=head1 AUTHOR	2036	=head1 AUTHOR
369		2037
370	Robin Redeker, C<< <elmex at ta-sa.org> >>	2038	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
371		2039
372	=cut	2040	=cut
373		2041
374	1; # End of AnyEvent::Handle	2042	1; # End of AnyEvent::Handle

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