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Revision 1.2 by elmex, Sun Apr 27 17:27:34 2008 UTC vs.
Revision 1.131 by root, Tue Jun 30 22:42:33 2009 UTC

1	package AnyEvent::Handle;	1	package AnyEvent::Handle;
2		2
3	use warnings;	3	no warnings;
4	use strict;	4	use strict qw(subs vars);
5		5
6	use AnyEvent;	6	use AnyEvent ();
7	use IO::Handle;	7	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		8	use Scalar::Util ();
		9	use Carp ();
		10	use Fcntl ();
8	use Errno qw/EAGAIN EINTR/;	11	use Errno qw(EAGAIN EINTR);
9		12
10	=head1 NAME	13	=head1 NAME
11		14
12	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
13		16
14	=head1 VERSION
15
16	Version 0.01
17
18	=cut	17	=cut
19		18
20	our $VERSION = '0.01';	19	our $VERSION = 4.45;
21		20
22	=head1 SYNOPSIS	21	=head1 SYNOPSIS
23		22
24	use AnyEvent;	23	use AnyEvent;
25	use AnyEvent::Handle;	24	use AnyEvent::Handle;
26		25
27	my $cv = AnyEvent->condvar;	26	my $cv = AnyEvent->condvar;
28		27
29	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	28	my $handle =
30
31	$ae_fh->on_eof (sub { $cv->broadcast });
32
33	$ae_fh->readlines (sub {
34	my ($ae_fh, @lines) = @_;
35	for (@lines) {
36	chomp;
37	print "Line: $_";
38	}
39	});
40
41	# or use the constructor to pass the callback:
42
43	my $ae_fh2 =
44	AnyEvent::Handle->new (	29	AnyEvent::Handle->new (
45	fh => \*STDIN,	30	fh => \*STDIN,
46	on_eof => sub {	31	on_eof => sub {
47	$cv->broadcast;	32	$cv->send;
48	},	33	},
		34	);
		35
		36	# send some request line
		37	$handle->push_write ("getinfo\015\012");
		38
		39	# read the response line
		40	$handle->push_read (line => sub {
		41	my ($handle, $line) = @_;
		42	warn "read line <$line>\n";
		43	$cv->send;
		44	});
		45
		46	$cv->recv;
		47
		48	=head1 DESCRIPTION
		49
		50	This module is a helper module to make it easier to do event-based I/O on
		51	filehandles. For utility functions for doing non-blocking connects and accepts
		52	on sockets see L<AnyEvent::Util>.
		53
		54	The L<AnyEvent::Intro> tutorial contains some well-documented
		55	AnyEvent::Handle examples.
		56
		57	In the following, when the documentation refers to of "bytes" then this
		58	means characters. As sysread and syswrite are used for all I/O, their
		59	treatment of characters applies to this module as well.
		60
		61	All callbacks will be invoked with the handle object as their first
		62	argument.
		63
		64	=head1 METHODS
		65
		66	=over 4
		67
		68	=item $handle = B<new> AnyEvent::TLS fh => $filehandle, key => value...
		69
		70	The constructor supports these arguments (all as C<< key => value >> pairs).
		71
		72	=over 4
		73
		74	=item fh => $filehandle [MANDATORY]
		75
		76	The filehandle this L<AnyEvent::Handle> object will operate on.
		77
		78	NOTE: The filehandle will be set to non-blocking mode (using
		79	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		80	that mode.
		81
		82	=item on_eof => $cb->($handle)
		83
		84	Set the callback to be called when an end-of-file condition is detected,
		85	i.e. in the case of a socket, when the other side has closed the
		86	connection cleanly.
		87
		88	For sockets, this just means that the other side has stopped sending data,
		89	you can still try to write data, and, in fact, one can return from the EOF
		90	callback and continue writing data, as only the read part has been shut
		91	down.
		92
		93	While not mandatory, it is I<highly> recommended to set an EOF callback,
		94	otherwise you might end up with a closed socket while you are still
		95	waiting for data.
		96
		97	If an EOF condition has been detected but no C<on_eof> callback has been
		98	set, then a fatal error will be raised with C<$!> set to <0>.
		99
		100	=item on_error => $cb->($handle, $fatal)
		101
		102	This is the error callback, which is called when, well, some error
		103	occured, such as not being able to resolve the hostname, failure to
		104	connect or a read error.
		105
		106	Some errors are fatal (which is indicated by C<$fatal> being true). On
		107	fatal errors the handle object will be shut down and will not be usable
		108	(but you are free to look at the current C<< ->rbuf >>). Examples of fatal
		109	errors are an EOF condition with active (but unsatisifable) read watchers
		110	(C<EPIPE>) or I/O errors.
		111
		112	Non-fatal errors can be retried by simply returning, but it is recommended
		113	to simply ignore this parameter and instead abondon the handle object
		114	when this callback is invoked. Examples of non-fatal errors are timeouts
		115	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		116
		117	On callback entrance, the value of C<$!> contains the operating system
		118	error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).
		119
		120	While not mandatory, it is I<highly> recommended to set this callback, as
		121	you will not be notified of errors otherwise. The default simply calls
		122	C<croak>.
		123
		124	=item on_read => $cb->($handle)
		125
		126	This sets the default read callback, which is called when data arrives
		127	and no read request is in the queue (unlike read queue callbacks, this
		128	callback will only be called when at least one octet of data is in the
		129	read buffer).
		130
		131	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
		132	method or access the C<$handle->{rbuf}> member directly. Note that you
		133	must not enlarge or modify the read buffer, you can only remove data at
		134	the beginning from it.
		135
		136	When an EOF condition is detected then AnyEvent::Handle will first try to
		137	feed all the remaining data to the queued callbacks and C<on_read> before
		138	calling the C<on_eof> callback. If no progress can be made, then a fatal
		139	error will be raised (with C<$!> set to C<EPIPE>).
		140
		141	=item on_drain => $cb->($handle)
		142
		143	This sets the callback that is called when the write buffer becomes empty
		144	(or when the callback is set and the buffer is empty already).
		145
		146	To append to the write buffer, use the C<< ->push_write >> method.
		147
		148	This callback is useful when you don't want to put all of your write data
		149	into the queue at once, for example, when you want to write the contents
		150	of some file to the socket you might not want to read the whole file into
		151	memory and push it into the queue, but instead only read more data from
		152	the file when the write queue becomes empty.
		153
		154	=item timeout => $fractional_seconds
		155
		156	If non-zero, then this enables an "inactivity" timeout: whenever this many
		157	seconds pass without a successful read or write on the underlying file
		158	handle, the C<on_timeout> callback will be invoked (and if that one is
		159	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		160
		161	Note that timeout processing is also active when you currently do not have
		162	any outstanding read or write requests: If you plan to keep the connection
		163	idle then you should disable the timout temporarily or ignore the timeout
		164	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		165	restart the timeout.
		166
		167	Zero (the default) disables this timeout.
		168
		169	=item on_timeout => $cb->($handle)
		170
		171	Called whenever the inactivity timeout passes. If you return from this
		172	callback, then the timeout will be reset as if some activity had happened,
		173	so this condition is not fatal in any way.
		174
		175	=item rbuf_max => <bytes>
		176
		177	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		178	when the read buffer ever (strictly) exceeds this size. This is useful to
		179	avoid some forms of denial-of-service attacks.
		180
		181	For example, a server accepting connections from untrusted sources should
		182	be configured to accept only so-and-so much data that it cannot act on
		183	(for example, when expecting a line, an attacker could send an unlimited
		184	amount of data without a callback ever being called as long as the line
		185	isn't finished).
		186
		187	=item autocork => <boolean>
		188
		189	When disabled (the default), then C<push_write> will try to immediately
		190	write the data to the handle, if possible. This avoids having to register
		191	a write watcher and wait for the next event loop iteration, but can
		192	be inefficient if you write multiple small chunks (on the wire, this
		193	disadvantage is usually avoided by your kernel's nagle algorithm, see
		194	C<no_delay>, but this option can save costly syscalls).
		195
		196	When enabled, then writes will always be queued till the next event loop
		197	iteration. This is efficient when you do many small writes per iteration,
		198	but less efficient when you do a single write only per iteration (or when
		199	the write buffer often is full). It also increases write latency.
		200
		201	=item no_delay => <boolean>
		202
		203	When doing small writes on sockets, your operating system kernel might
		204	wait a bit for more data before actually sending it out. This is called
		205	the Nagle algorithm, and usually it is beneficial.
		206
		207	In some situations you want as low a delay as possible, which can be
		208	accomplishd by setting this option to a true value.
		209
		210	The default is your opertaing system's default behaviour (most likely
		211	enabled), this option explicitly enables or disables it, if possible.
		212
		213	=item read_size => <bytes>
		214
		215	The default read block size (the amount of bytes this module will
		216	try to read during each loop iteration, which affects memory
		217	requirements). Default: C<8192>.
		218
		219	=item low_water_mark => <bytes>
		220
		221	Sets the amount of bytes (default: C<0>) that make up an "empty" write
		222	buffer: If the write reaches this size or gets even samller it is
		223	considered empty.
		224
		225	Sometimes it can be beneficial (for performance reasons) to add data to
		226	the write buffer before it is fully drained, but this is a rare case, as
		227	the operating system kernel usually buffers data as well, so the default
		228	is good in almost all cases.
		229
		230	=item linger => <seconds>
		231
		232	If non-zero (default: C<3600>), then the destructor of the
		233	AnyEvent::Handle object will check whether there is still outstanding
		234	write data and will install a watcher that will write this data to the
		235	socket. No errors will be reported (this mostly matches how the operating
		236	system treats outstanding data at socket close time).
		237
		238	This will not work for partial TLS data that could not be encoded
		239	yet. This data will be lost. Calling the C<stoptls> method in time might
		240	help.
		241
		242	=item common_name => $string
		243
		244	The common name used by some verification methods (most notably SSL/TLS)
		245	associated with this connection. Usually this is the remote hostname used
		246	to connect, but can be almost anything.
		247
		248	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		249
		250	When this parameter is given, it enables TLS (SSL) mode, that means
		251	AnyEvent will start a TLS handshake as soon as the conenction has been
		252	established and will transparently encrypt/decrypt data afterwards.
		253
		254	TLS mode requires Net::SSLeay to be installed (it will be loaded
		255	automatically when you try to create a TLS handle): this module doesn't
		256	have a dependency on that module, so if your module requires it, you have
		257	to add the dependency yourself.
		258
		259	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		260	C<accept>, and for the TLS client side of a connection, use C<connect>
		261	mode.
		262
		263	You can also provide your own TLS connection object, but you have
		264	to make sure that you call either C<Net::SSLeay::set_connect_state>
		265	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		266	AnyEvent::Handle. Also, this module will take ownership of this connection
		267	object.
		268
		269	At some future point, AnyEvent::Handle might switch to another TLS
		270	implementation, then the option to use your own session object will go
		271	away.
		272
		273	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		274	passing in the wrong integer will lead to certain crash. This most often
		275	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		276	segmentation fault.
		277
		278	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		279
		280	=item tls_ctx => $anyevent_tls
		281
		282	Use the given C<AnyEvent::TLS> object to create the new TLS connection
		283	(unless a connection object was specified directly). If this parameter is
		284	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		285
		286	Instead of an object, you can also specify a hash reference with C<< key
		287	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		288	new TLS context object.
		289
		290	=item json => JSON or JSON::XS object
		291
		292	This is the json coder object used by the C<json> read and write types.
		293
		294	If you don't supply it, then AnyEvent::Handle will create and use a
		295	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		296	texts.
		297
		298	Note that you are responsible to depend on the JSON module if you want to
		299	use this functionality, as AnyEvent does not have a dependency itself.
		300
		301	=back
		302
		303	=cut
		304
		305	sub new {
		306	my $class = shift;
		307	my $self = bless { @_ }, $class;
		308
		309	$self->{fh} or Carp::croak "mandatory argument fh is missing";
		310
		311	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		312
		313	$self->{_activity} = AnyEvent->now;
		314	$self->_timeout;
		315
		316	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		317
		318	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		319	if $self->{tls};
		320
		321	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
		322
		323	$self->start_read
		324	if $self->{on_read};
		325
		326	$self->{fh} && $self
		327	}
		328
		329	sub _shutdown {
		330	my ($self) = @_;
		331
		332	delete @$self{qw(_tw _rw _ww fh rbuf wbuf on_read _queue)};
		333	$self->{_eof} = 1; # tell starttls et. al to stop trying
		334
		335	&_freetls;
		336	}
		337
		338	sub _error {
		339	my ($self, $errno, $fatal) = @_;
		340
		341	$self->_shutdown
		342	if $fatal;
		343
		344	$! = $errno;
		345
		346	if ($self->{on_error}) {
		347	$self->{on_error}($self, $fatal);
		348	} elsif ($self->{fh}) {
		349	Carp::croak "AnyEvent::Handle uncaught error: $!";
		350	}
		351	}
		352
		353	=item $fh = $handle->fh
		354
		355	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		356
		357	=cut
		358
		359	sub fh { $_[0]{fh} }
		360
		361	=item $handle->on_error ($cb)
		362
		363	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		364
		365	=cut
		366
		367	sub on_error {
		368	$_[0]{on_error} = $_[1];
		369	}
		370
		371	=item $handle->on_eof ($cb)
		372
		373	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		374
		375	=cut
		376
		377	sub on_eof {
		378	$_[0]{on_eof} = $_[1];
		379	}
		380
		381	=item $handle->on_timeout ($cb)
		382
		383	Replace the current C<on_timeout> callback, or disables the callback (but
		384	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		385	argument and method.
		386
		387	=cut
		388
		389	sub on_timeout {
		390	$_[0]{on_timeout} = $_[1];
		391	}
		392
		393	=item $handle->autocork ($boolean)
		394
		395	Enables or disables the current autocork behaviour (see C<autocork>
		396	constructor argument). Changes will only take effect on the next write.
		397
		398	=cut
		399
		400	sub autocork {
		401	$_[0]{autocork} = $_[1];
		402	}
		403
		404	=item $handle->no_delay ($boolean)
		405
		406	Enables or disables the C<no_delay> setting (see constructor argument of
		407	the same name for details).
		408
		409	=cut
		410
		411	sub no_delay {
		412	$_[0]{no_delay} = $_[1];
		413
		414	eval {
		415	local $SIG{__DIE__};
		416	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		417	};
		418	}
		419
		420	#############################################################################
		421
		422	=item $handle->timeout ($seconds)
		423
		424	Configures (or disables) the inactivity timeout.
		425
		426	=cut
		427
		428	sub timeout {
		429	my ($self, $timeout) = @_;
		430
		431	$self->{timeout} = $timeout;
		432	$self->_timeout;
		433	}
		434
		435	# reset the timeout watcher, as neccessary
		436	# also check for time-outs
		437	sub _timeout {
		438	my ($self) = @_;
		439
		440	if ($self->{timeout}) {
		441	my $NOW = AnyEvent->now;
		442
		443	# when would the timeout trigger?
		444	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		445
		446	# now or in the past already?
		447	if ($after <= 0) {
		448	$self->{_activity} = $NOW;
		449
		450	if ($self->{on_timeout}) {
		451	$self->{on_timeout}($self);
		452	} else {
		453	$self->_error (&Errno::ETIMEDOUT);
		454	}
		455
		456	# callback could have changed timeout value, optimise
		457	return unless $self->{timeout};
		458
		459	# calculate new after
		460	$after = $self->{timeout};
		461	}
		462
		463	Scalar::Util::weaken $self;
		464	return unless $self; # ->error could have destroyed $self
		465
		466	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		467	delete $self->{_tw};
		468	$self->_timeout;
		469	});
		470	} else {
		471	delete $self->{_tw};
		472	}
		473	}
		474
		475	#############################################################################
		476
		477	=back
		478
		479	=head2 WRITE QUEUE
		480
		481	AnyEvent::Handle manages two queues per handle, one for writing and one
		482	for reading.
		483
		484	The write queue is very simple: you can add data to its end, and
		485	AnyEvent::Handle will automatically try to get rid of it for you.
		486
		487	When data could be written and the write buffer is shorter then the low
		488	water mark, the C<on_drain> callback will be invoked.
		489
		490	=over 4
		491
		492	=item $handle->on_drain ($cb)
		493
		494	Sets the C<on_drain> callback or clears it (see the description of
		495	C<on_drain> in the constructor).
		496
		497	=cut
		498
		499	sub on_drain {
		500	my ($self, $cb) = @_;
		501
		502	$self->{on_drain} = $cb;
		503
		504	$cb->($self)
		505	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		506	}
		507
		508	=item $handle->push_write ($data)
		509
		510	Queues the given scalar to be written. You can push as much data as you
		511	want (only limited by the available memory), as C<AnyEvent::Handle>
		512	buffers it independently of the kernel.
		513
		514	=cut
		515
		516	sub _drain_wbuf {
		517	my ($self) = @_;
		518
		519	if (!$self->{_ww} && length $self->{wbuf}) {
		520
		521	Scalar::Util::weaken $self;
		522
		523	my $cb = sub {
		524	my $len = syswrite $self->{fh}, $self->{wbuf};
		525
		526	if ($len >= 0) {
		527	substr $self->{wbuf}, 0, $len, "";
		528
		529	$self->{_activity} = AnyEvent->now;
		530
		531	$self->{on_drain}($self)
		532	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		533	&& $self->{on_drain};
		534
		535	delete $self->{_ww} unless length $self->{wbuf};
		536	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		537	$self->_error ($!, 1);
		538	}
		539	};
		540
		541	# try to write data immediately
		542	$cb->() unless $self->{autocork};
		543
		544	# if still data left in wbuf, we need to poll
		545	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
		546	if length $self->{wbuf};
		547	};
		548	}
		549
		550	our %WH;
		551
		552	sub register_write_type($$) {
		553	$WH{$_[0]} = $_[1];
		554	}
		555
		556	sub push_write {
		557	my $self = shift;
		558
		559	if (@_ > 1) {
		560	my $type = shift;
		561
		562	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		563	->($self, @_);
		564	}
		565
		566	if ($self->{tls}) {
		567	$self->{_tls_wbuf} .= $_[0];
		568
		569	&_dotls ($self);
		570	} else {
		571	$self->{wbuf} .= $_[0];
		572	$self->_drain_wbuf;
		573	}
		574	}
		575
		576	=item $handle->push_write (type => @args)
		577
		578	Instead of formatting your data yourself, you can also let this module do
		579	the job by specifying a type and type-specific arguments.
		580
		581	Predefined types are (if you have ideas for additional types, feel free to
		582	drop by and tell us):
		583
		584	=over 4
		585
		586	=item netstring => $string
		587
		588	Formats the given value as netstring
		589	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		590
		591	=cut
		592
		593	register_write_type netstring => sub {
		594	my ($self, $string) = @_;
		595
		596	(length $string) . ":$string,"
		597	};
		598
		599	=item packstring => $format, $data
		600
		601	An octet string prefixed with an encoded length. The encoding C<$format>
		602	uses the same format as a Perl C<pack> format, but must specify a single
		603	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		604	optional C<!>, C<< < >> or C<< > >> modifier).
		605
		606	=cut
		607
		608	register_write_type packstring => sub {
		609	my ($self, $format, $string) = @_;
		610
		611	pack "$format/a*", $string
		612	};
		613
		614	=item json => $array_or_hashref
		615
		616	Encodes the given hash or array reference into a JSON object. Unless you
		617	provide your own JSON object, this means it will be encoded to JSON text
		618	in UTF-8.
		619
		620	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		621	one end of a handle and read them at the other end without using any
		622	additional framing.
		623
		624	The generated JSON text is guaranteed not to contain any newlines: While
		625	this module doesn't need delimiters after or between JSON texts to be
		626	able to read them, many other languages depend on that.
		627
		628	A simple RPC protocol that interoperates easily with others is to send
		629	JSON arrays (or objects, although arrays are usually the better choice as
		630	they mimic how function argument passing works) and a newline after each
		631	JSON text:
		632
		633	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		634	$handle->push_write ("\012");
		635
		636	An AnyEvent::Handle receiver would simply use the C<json> read type and
		637	rely on the fact that the newline will be skipped as leading whitespace:
		638
		639	$handle->push_read (json => sub { my $array = $_[1]; ... });
		640
		641	Other languages could read single lines terminated by a newline and pass
		642	this line into their JSON decoder of choice.
		643
		644	=cut
		645
		646	register_write_type json => sub {
		647	my ($self, $ref) = @_;
		648
		649	require JSON;
		650
		651	$self->{json} ? $self->{json}->encode ($ref)
		652	: JSON::encode_json ($ref)
		653	};
		654
		655	=item storable => $reference
		656
		657	Freezes the given reference using L<Storable> and writes it to the
		658	handle. Uses the C<nfreeze> format.
		659
		660	=cut
		661
		662	register_write_type storable => sub {
		663	my ($self, $ref) = @_;
		664
		665	require Storable;
		666
		667	pack "w/a*", Storable::nfreeze ($ref)
		668	};
		669
		670	=back
		671
		672	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		673
		674	This function (not method) lets you add your own types to C<push_write>.
		675	Whenever the given C<type> is used, C<push_write> will invoke the code
		676	reference with the handle object and the remaining arguments.
		677
		678	The code reference is supposed to return a single octet string that will
		679	be appended to the write buffer.
		680
		681	Note that this is a function, and all types registered this way will be
		682	global, so try to use unique names.
		683
		684	=cut
		685
		686	#############################################################################
		687
		688	=back
		689
		690	=head2 READ QUEUE
		691
		692	AnyEvent::Handle manages two queues per handle, one for writing and one
		693	for reading.
		694
		695	The read queue is more complex than the write queue. It can be used in two
		696	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		697	a queue.
		698
		699	In the simple case, you just install an C<on_read> callback and whenever
		700	new data arrives, it will be called. You can then remove some data (if
		701	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
		702	leave the data there if you want to accumulate more (e.g. when only a
		703	partial message has been received so far).
		704
		705	In the more complex case, you want to queue multiple callbacks. In this
		706	case, AnyEvent::Handle will call the first queued callback each time new
		707	data arrives (also the first time it is queued) and removes it when it has
		708	done its job (see C<push_read>, below).
		709
		710	This way you can, for example, push three line-reads, followed by reading
		711	a chunk of data, and AnyEvent::Handle will execute them in order.
		712
		713	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		714	the specified number of bytes which give an XML datagram.
		715
		716	# in the default state, expect some header bytes
		717	$handle->on_read (sub {
		718	# some data is here, now queue the length-header-read (4 octets)
		719	shift->unshift_read (chunk => 4, sub {
		720	# header arrived, decode
		721	my $len = unpack "N", $_[1];
		722
		723	# now read the payload
		724	shift->unshift_read (chunk => $len, sub {
		725	my $xml = $_[1];
		726	# handle xml
		727	});
		728	});
		729	});
		730
		731	Example 2: Implement a client for a protocol that replies either with "OK"
		732	and another line or "ERROR" for the first request that is sent, and 64
		733	bytes for the second request. Due to the availability of a queue, we can
		734	just pipeline sending both requests and manipulate the queue as necessary
		735	in the callbacks.
		736
		737	When the first callback is called and sees an "OK" response, it will
		738	C<unshift> another line-read. This line-read will be queued I<before> the
		739	64-byte chunk callback.
		740
		741	# request one, returns either "OK + extra line" or "ERROR"
		742	$handle->push_write ("request 1\015\012");
		743
		744	# we expect "ERROR" or "OK" as response, so push a line read
		745	$handle->push_read (line => sub {
		746	# if we got an "OK", we have to _prepend_ another line,
		747	# so it will be read before the second request reads its 64 bytes
		748	# which are already in the queue when this callback is called
		749	# we don't do this in case we got an error
		750	if ($_[1] eq "OK") {
49	on_readline => sub {	751	$_[0]->unshift_read (line => sub {
50	my ($ae_fh, @lines) = @_;	752	my $response = $_[1];
51	for (@lines) {	753	...
52	chomp;	754	});
53	print "Line: $_";	755	}
		756	});
		757
		758	# request two, simply returns 64 octets
		759	$handle->push_write ("request 2\015\012");
		760
		761	# simply read 64 bytes, always
		762	$handle->push_read (chunk => 64, sub {
		763	my $response = $_[1];
		764	...
		765	});
		766
		767	=over 4
		768
		769	=cut
		770
		771	sub _drain_rbuf {
		772	my ($self) = @_;
		773
		774	local $self->{_in_drain} = 1;
		775
		776	if (
		777	defined $self->{rbuf_max}
		778	&& $self->{rbuf_max} < length $self->{rbuf}
		779	) {
		780	$self->_error (&Errno::ENOSPC, 1), return;
		781	}
		782
		783	while () {
		784	# we need to use a separate tls read buffer, as we must not receive data while
		785	# we are draining the buffer, and this can only happen with TLS.
		786	$self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
		787
		788	my $len = length $self->{rbuf};
		789
		790	if (my $cb = shift @{ $self->{_queue} }) {
		791	unless ($cb->($self)) {
		792	if ($self->{_eof}) {
		793	# no progress can be made (not enough data and no data forthcoming)
		794	$self->_error (&Errno::EPIPE, 1), return;
54	}	795	}
		796
		797	unshift @{ $self->{_queue} }, $cb;
		798	last;
55	}	799	}
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}) {	800	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	801	last unless $len;
122		802
		803	$self->{on_read}($self);
		804
		805	if (
		806	$len == length $self->{rbuf} # if no data has been consumed
		807	&& !@{ $self->{_queue} } # and the queue is still empty
		808	&& $self->{on_read} # but we still have on_read
		809	) {
		810	# no further data will arrive
		811	# so no progress can be made
		812	$self->_error (&Errno::EPIPE, 1), return
		813	if $self->{_eof};
		814
		815	last; # more data might arrive
		816	}
		817	} else {
		818	# read side becomes idle
		819	delete $self->{_rw} unless $self->{tls};
		820	last;
		821	}
		822	}
		823
123	} elsif ($self->{on_eof}) {	824	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});
125
126	} elsif ($self->{on_error}) {	825	if ($self->{on_eof}) {
127	$self->on_eof ($self->{on_error});	826	$self->{on_eof}($self)
		827	} else {
		828	$self->_error (0, 1);
		829	}
128	}	830	}
129		831
130	return $self	832	# may need to restart read watcher
		833	unless ($self->{_rw}) {
		834	$self->start_read
		835	if $self->{on_read} || @{ $self->{_queue} };
		836	}
131	}	837	}
132		838
133	=item B<fh>	839	=item $handle->on_read ($cb)
134		840
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	841	This replaces the currently set C<on_read> callback, or clears it (when
136		842	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	843	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		844
149	=cut	845	=cut
150		846
151	sub on_read {	847	sub on_read {
152	my ($self, $cb) = @_;	848	my ($self, $cb) = @_;
		849
153	$self->{on_read} = $cb;	850	$self->{on_read} = $cb;
		851	$self->_drain_rbuf if $cb && !$self->{_in_drain};
		852	}
154		853
155	unless (defined $self->{on_read}) {	854	=item $handle->rbuf
156	delete $self->{on_read_w};	855
		856	Returns the read buffer (as a modifiable lvalue).
		857
		858	You can access the read buffer directly as the C<< ->{rbuf} >>
		859	member, if you want. However, the only operation allowed on the
		860	read buffer (apart from looking at it) is removing data from its
		861	beginning. Otherwise modifying or appending to it is not allowed and will
		862	lead to hard-to-track-down bugs.
		863
		864	NOTE: The read buffer should only be used or modified if the C<on_read>,
		865	C<push_read> or C<unshift_read> methods are used. The other read methods
		866	automatically manage the read buffer.
		867
		868	=cut
		869
		870	sub rbuf : lvalue {
		871	$_[0]{rbuf}
		872	}
		873
		874	=item $handle->push_read ($cb)
		875
		876	=item $handle->unshift_read ($cb)
		877
		878	Append the given callback to the end of the queue (C<push_read>) or
		879	prepend it (C<unshift_read>).
		880
		881	The callback is called each time some additional read data arrives.
		882
		883	It must check whether enough data is in the read buffer already.
		884
		885	If not enough data is available, it must return the empty list or a false
		886	value, in which case it will be called repeatedly until enough data is
		887	available (or an error condition is detected).
		888
		889	If enough data was available, then the callback must remove all data it is
		890	interested in (which can be none at all) and return a true value. After returning
		891	true, it will be removed from the queue.
		892
		893	=cut
		894
		895	our %RH;
		896
		897	sub register_read_type($$) {
		898	$RH{$_[0]} = $_[1];
		899	}
		900
		901	sub push_read {
		902	my $self = shift;
		903	my $cb = pop;
		904
		905	if (@_) {
		906	my $type = shift;
		907
		908	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		909	->($self, $cb, @_);
		910	}
		911
		912	push @{ $self->{_queue} }, $cb;
		913	$self->_drain_rbuf unless $self->{_in_drain};
		914	}
		915
		916	sub unshift_read {
		917	my $self = shift;
		918	my $cb = pop;
		919
		920	if (@_) {
		921	my $type = shift;
		922
		923	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		924	->($self, $cb, @_);
		925	}
		926
		927
		928	unshift @{ $self->{_queue} }, $cb;
		929	$self->_drain_rbuf unless $self->{_in_drain};
		930	}
		931
		932	=item $handle->push_read (type => @args, $cb)
		933
		934	=item $handle->unshift_read (type => @args, $cb)
		935
		936	Instead of providing a callback that parses the data itself you can chose
		937	between a number of predefined parsing formats, for chunks of data, lines
		938	etc.
		939
		940	Predefined types are (if you have ideas for additional types, feel free to
		941	drop by and tell us):
		942
		943	=over 4
		944
		945	=item chunk => $octets, $cb->($handle, $data)
		946
		947	Invoke the callback only once C<$octets> bytes have been read. Pass the
		948	data read to the callback. The callback will never be called with less
		949	data.
		950
		951	Example: read 2 bytes.
		952
		953	$handle->push_read (chunk => 2, sub {
		954	warn "yay ", unpack "H*", $_[1];
		955	});
		956
		957	=cut
		958
		959	register_read_type chunk => sub {
		960	my ($self, $cb, $len) = @_;
		961
		962	sub {
		963	$len <= length $_[0]{rbuf} or return;
		964	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		965	1
		966	}
		967	};
		968
		969	=item line => [$eol, ]$cb->($handle, $line, $eol)
		970
		971	The callback will be called only once a full line (including the end of
		972	line marker, C<$eol>) has been read. This line (excluding the end of line
		973	marker) will be passed to the callback as second argument (C<$line>), and
		974	the end of line marker as the third argument (C<$eol>).
		975
		976	The end of line marker, C<$eol>, can be either a string, in which case it
		977	will be interpreted as a fixed record end marker, or it can be a regex
		978	object (e.g. created by C<qr>), in which case it is interpreted as a
		979	regular expression.
		980
		981	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		982	undef), then C<qr|\015?\012|> is used (which is good for most internet
		983	protocols).
		984
		985	Partial lines at the end of the stream will never be returned, as they are
		986	not marked by the end of line marker.
		987
		988	=cut
		989
		990	register_read_type line => sub {
		991	my ($self, $cb, $eol) = @_;
		992
		993	if (@_ < 3) {
		994	# this is more than twice as fast as the generic code below
		995	sub {
		996	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		997
		998	$cb->($_[0], $1, $2);
		999	1
		1000	}
		1001	} else {
		1002	$eol = quotemeta $eol unless ref $eol;
		1003	$eol = qr|^(.*?)($eol)|s;
		1004
		1005	sub {
		1006	$_[0]{rbuf} =~ s/$eol// or return;
		1007
		1008	$cb->($_[0], $1, $2);
		1009	1
		1010	}
		1011	}
		1012	};
		1013
		1014	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1015
		1016	Makes a regex match against the regex object C<$accept> and returns
		1017	everything up to and including the match.
		1018
		1019	Example: read a single line terminated by '\n'.
		1020
		1021	$handle->push_read (regex => qr<\n>, sub { ... });
		1022
		1023	If C<$reject> is given and not undef, then it determines when the data is
		1024	to be rejected: it is matched against the data when the C<$accept> regex
		1025	does not match and generates an C<EBADMSG> error when it matches. This is
		1026	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1027	receive buffer overflow).
		1028
		1029	Example: expect a single decimal number followed by whitespace, reject
		1030	anything else (not the use of an anchor).
		1031
		1032	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1033
		1034	If C<$skip> is given and not C<undef>, then it will be matched against
		1035	the receive buffer when neither C<$accept> nor C<$reject> match,
		1036	and everything preceding and including the match will be accepted
		1037	unconditionally. This is useful to skip large amounts of data that you
		1038	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1039	have to start matching from the beginning. This is purely an optimisation
		1040	and is usually worth only when you expect more than a few kilobytes.
		1041
		1042	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1043	expect the header to be very large (it isn't in practise, but...), we use
		1044	a skip regex to skip initial portions. The skip regex is tricky in that
		1045	it only accepts something not ending in either \015 or \012, as these are
		1046	required for the accept regex.
		1047
		1048	$handle->push_read (regex =>
		1049	qr<\015\012\015\012>,
		1050	undef, # no reject
		1051	qr<^.*[^\015\012]>,
		1052	sub { ... });
		1053
		1054	=cut
		1055
		1056	register_read_type regex => sub {
		1057	my ($self, $cb, $accept, $reject, $skip) = @_;
		1058
		1059	my $data;
		1060	my $rbuf = \$self->{rbuf};
		1061
		1062	sub {
		1063	# accept
		1064	if ($$rbuf =~ $accept) {
		1065	$data .= substr $$rbuf, 0, $+[0], "";
		1066	$cb->($self, $data);
157	return;	1067	return 1;
		1068	}
		1069
		1070	# reject
		1071	if ($reject && $$rbuf =~ $reject) {
		1072	$self->_error (&Errno::EBADMSG);
		1073	}
		1074
		1075	# skip
		1076	if ($skip && $$rbuf =~ $skip) {
		1077	$data .= substr $$rbuf, 0, $+[0], "";
		1078	}
		1079
		1080	()
158	}	1081	}
159		1082	};
160	$self->{on_read_w} =	1083
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1084	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1085
163	my $rbuf_len = length $self->{rbuf};	1086	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1087
165	if (defined $self->{read_size}) {	1088	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1089
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1090	=cut
168	} else {	1091
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1092	register_read_type netstring => sub {
		1093	my ($self, $cb) = @_;
		1094
		1095	sub {
		1096	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1097	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1098	$self->_error (&Errno::EBADMSG);
170	}	1099	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1100	return;
		1101	}
172		1102
173	if (not defined $l) {	1103	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1104
178	} elsif ($l == 0) {	1105	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1106	my $string = $_[1];
180	delete $self->{on_read_w};	1107	$_[0]->unshift_read (chunk => 1, sub {
181		1108	if ($_[1] eq ",") {
		1109	$cb->($_[0], $string);
182	} else {	1110	} else {
183	$self->{on_read}->($self);	1111	$self->_error (&Errno::EBADMSG);
		1112	}
		1113	});
		1114	});
		1115
		1116	1
		1117	}
		1118	};
		1119
		1120	=item packstring => $format, $cb->($handle, $string)
		1121
		1122	An octet string prefixed with an encoded length. The encoding C<$format>
		1123	uses the same format as a Perl C<pack> format, but must specify a single
		1124	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1125	optional C<!>, C<< < >> or C<< > >> modifier).
		1126
		1127	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1128	EPP uses a prefix of C<N> (4 octtes).
		1129
		1130	Example: read a block of data prefixed by its length in BER-encoded
		1131	format (very efficient).
		1132
		1133	$handle->push_read (packstring => "w", sub {
		1134	my ($handle, $data) = @_;
		1135	});
		1136
		1137	=cut
		1138
		1139	register_read_type packstring => sub {
		1140	my ($self, $cb, $format) = @_;
		1141
		1142	sub {
		1143	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1144	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1145	or return;
		1146
		1147	$format = length pack $format, $len;
		1148
		1149	# bypass unshift if we already have the remaining chunk
		1150	if ($format + $len <= length $_[0]{rbuf}) {
		1151	my $data = substr $_[0]{rbuf}, $format, $len;
		1152	substr $_[0]{rbuf}, 0, $format + $len, "";
		1153	$cb->($_[0], $data);
		1154	} else {
		1155	# remove prefix
		1156	substr $_[0]{rbuf}, 0, $format, "";
		1157
		1158	# read remaining chunk
		1159	$_[0]->unshift_read (chunk => $len, $cb);
		1160	}
		1161
		1162	1
		1163	}
		1164	};
		1165
		1166	=item json => $cb->($handle, $hash_or_arrayref)
		1167
		1168	Reads a JSON object or array, decodes it and passes it to the
		1169	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1170
		1171	If a C<json> object was passed to the constructor, then that will be used
		1172	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1173
		1174	This read type uses the incremental parser available with JSON version
		1175	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1176	dependency on your own: this module will load the JSON module, but
		1177	AnyEvent does not depend on it itself.
		1178
		1179	Since JSON texts are fully self-delimiting, the C<json> read and write
		1180	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1181	the C<json> write type description, above, for an actual example.
		1182
		1183	=cut
		1184
		1185	register_read_type json => sub {
		1186	my ($self, $cb) = @_;
		1187
		1188	require JSON;
		1189
		1190	my $data;
		1191	my $rbuf = \$self->{rbuf};
		1192
		1193	my $json = $self->{json} ||= JSON->new->utf8;
		1194
		1195	sub {
		1196	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1197
		1198	if ($ref) {
		1199	$self->{rbuf} = $json->incr_text;
		1200	$json->incr_text = "";
		1201	$cb->($self, $ref);
		1202
		1203	1
		1204	} elsif ($@) {
		1205	# error case
		1206	$json->incr_skip;
		1207
		1208	$self->{rbuf} = $json->incr_text;
		1209	$json->incr_text = "";
		1210
		1211	$self->_error (&Errno::EBADMSG);
		1212
		1213	()
		1214	} else {
		1215	$self->{rbuf} = "";
		1216
		1217	()
		1218	}
		1219	}
		1220	};
		1221
		1222	=item storable => $cb->($handle, $ref)
		1223
		1224	Deserialises a L<Storable> frozen representation as written by the
		1225	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1226	data).
		1227
		1228	Raises C<EBADMSG> error if the data could not be decoded.
		1229
		1230	=cut
		1231
		1232	register_read_type storable => sub {
		1233	my ($self, $cb) = @_;
		1234
		1235	require Storable;
		1236
		1237	sub {
		1238	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1239	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1240	or return;
		1241
		1242	my $format = length pack "w", $len;
		1243
		1244	# bypass unshift if we already have the remaining chunk
		1245	if ($format + $len <= length $_[0]{rbuf}) {
		1246	my $data = substr $_[0]{rbuf}, $format, $len;
		1247	substr $_[0]{rbuf}, 0, $format + $len, "";
		1248	$cb->($_[0], Storable::thaw ($data));
		1249	} else {
		1250	# remove prefix
		1251	substr $_[0]{rbuf}, 0, $format, "";
		1252
		1253	# read remaining chunk
		1254	$_[0]->unshift_read (chunk => $len, sub {
		1255	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1256	$cb->($_[0], $ref);
		1257	} else {
		1258	$self->_error (&Errno::EBADMSG);
		1259	}
		1260	});
		1261	}
		1262
		1263	1
		1264	}
		1265	};
		1266
		1267	=back
		1268
		1269	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1270
		1271	This function (not method) lets you add your own types to C<push_read>.
		1272
		1273	Whenever the given C<type> is used, C<push_read> will invoke the code
		1274	reference with the handle object, the callback and the remaining
		1275	arguments.
		1276
		1277	The code reference is supposed to return a callback (usually a closure)
		1278	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1279
		1280	It should invoke the passed callback when it is done reading (remember to
		1281	pass C<$handle> as first argument as all other callbacks do that).
		1282
		1283	Note that this is a function, and all types registered this way will be
		1284	global, so try to use unique names.
		1285
		1286	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1287	search for C<register_read_type>)).
		1288
		1289	=item $handle->stop_read
		1290
		1291	=item $handle->start_read
		1292
		1293	In rare cases you actually do not want to read anything from the
		1294	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1295	any queued callbacks will be executed then. To start reading again, call
		1296	C<start_read>.
		1297
		1298	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1299	you change the C<on_read> callback or push/unshift a read callback, and it
		1300	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1301	there are any read requests in the queue.
		1302
		1303	These methods will have no effect when in TLS mode (as TLS doesn't support
		1304	half-duplex connections).
		1305
		1306	=cut
		1307
		1308	sub stop_read {
		1309	my ($self) = @_;
		1310
		1311	delete $self->{_rw} unless $self->{tls};
		1312	}
		1313
		1314	sub start_read {
		1315	my ($self) = @_;
		1316
		1317	unless ($self->{_rw} || $self->{_eof}) {
		1318	Scalar::Util::weaken $self;
		1319
		1320	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1321	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1322	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1323
		1324	if ($len > 0) {
		1325	$self->{_activity} = AnyEvent->now;
		1326
		1327	if ($self->{tls}) {
		1328	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1329
		1330	&_dotls ($self);
		1331	} else {
		1332	$self->_drain_rbuf unless $self->{_in_drain};
		1333	}
		1334
		1335	} elsif (defined $len) {
		1336	delete $self->{_rw};
		1337	$self->{_eof} = 1;
		1338	$self->_drain_rbuf unless $self->{_in_drain};
		1339
		1340	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1341	return $self->_error ($!, 1);
184	}	1342	}
185	});	1343	});
		1344	}
186	}	1345	}
187		1346
188	=item B<on_error ($callback)>	1347	# poll the write BIO and send the data if applicable
189		1348	sub _dotls {
190	Whenever a read or write operation resulted in an error the C<$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 {
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, $cb) = @_;	1349	my ($self) = @_;
240		1350
241	$self->{read_cb} = $cb;	1351	my $tmp;
242	my $old_blk_size = $self->{read_block_size};
243	$self->{read_block_size} = $len;
244		1352
245	$self->on_read (sub {	1353	if (length $self->{_tls_wbuf}) {
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";	1354	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
247		1355	substr $self->{_tls_wbuf}, 0, $tmp, "";
248	if ($len == length $_[0]->{rbuf}) {
249	$_[0]->{read_block_size} = $old_blk_size;
250	$_[0]->on_read (undef);
251	$_[0]->{read_cb}->($_[0], (substr $self->{rbuf}, 0, $len, ''));
252	}	1356	}
253	});	1357	}
254	}
255		1358
256	=item B<readlines ($callback)>	1359	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1360	unless (length $tmp) {
		1361	# let's treat SSL-eof as we treat normal EOF
		1362	delete $self->{_rw};
		1363	$self->{_eof} = 1;
		1364	&_freetls;
		1365	}
257		1366
258	=item B<readlines ($sep, $callback)>	1367	$self->{_tls_rbuf} .= $tmp;
		1368	$self->_drain_rbuf unless $self->{_in_drain};
		1369	$self->{tls} or return; # tls session might have gone away in callback
		1370	}
259		1371
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1372	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
261	if C<$sep> is not provided. C<$sep> will be used as part of a regex, so it can be
262	a regex itself and won't be quoted!
263		1373
264	The C<$callback> will be called when at least one	1374	if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
265	line could be read. The first argument to the C<$callback> will be the L<AnyEvent::Handle>	1375	if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
266	object itself and the rest of the arguments will be the read lines.	1376	return $self->_error ($!, 1);
		1377	} elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
		1378	return $self->_error (&Errno::EIO, 1);
		1379	}
267		1380
268	NOTE: This method will override any callbacks installed via the C<on_read> method.	1381	# all other errors are fine for our purposes
		1382	}
269		1383
270	=cut	1384	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1385	$self->{wbuf} .= $tmp;
		1386	$self->_drain_wbuf;
		1387	}
		1388	}
271		1389
272	sub readlines {	1390	=item $handle->starttls ($tls[, $tls_ctx])
		1391
		1392	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1393	object is created, you can also do that at a later time by calling
		1394	C<starttls>.
		1395
		1396	The first argument is the same as the C<tls> constructor argument (either
		1397	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1398
		1399	The second argument is the optional C<AnyEvent::TLS> object that is used
		1400	when AnyEvent::Handle has to create its own TLS connection object, or
		1401	a hash reference with C<< key => value >> pairs that will be used to
		1402	construct a new context.
		1403
		1404	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1405	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1406	changed to your liking. Note that the handshake might have already started
		1407	when this function returns.
		1408
		1409	If it an error to start a TLS handshake more than once per
		1410	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1411
		1412	=cut
		1413
		1414	sub starttls {
273	my ($self, $NL, $cb) = @_;	1415	my ($self, $ssl, $ctx) = @_;
274		1416
275	if (ref $NL) {	1417	require Net::SSLeay;
276	$cb = $NL;	1418
277	$NL = "\n";	1419	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
		1420	if $self->{tls};
		1421
		1422	$ctx ||= $self->{tls_ctx};
		1423
		1424	if ("HASH" eq ref $ctx) {
		1425	require AnyEvent::TLS;
		1426
		1427	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context
		1428	$ctx = new AnyEvent::TLS %$ctx;
		1429	}
278	}	1430
		1431	$self->{tls_ctx} = $ctx || TLS_CTX ();
		1432	$self->{tls} = $ssl = $self->{tls_ctx}->_get_session ($ssl, $self);
279		1433
280	$self->{on_readline} = $cb;	1434	# basically, this is deep magic (because SSL_read should have the same issues)
		1435	# but the openssl maintainers basically said: "trust us, it just works".
		1436	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1437	# and mismaintained ssleay-module doesn't even offer them).
		1438	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1439	#
		1440	# in short: this is a mess.
		1441	#
		1442	# note that we do not try to keep the length constant between writes as we are required to do.
		1443	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1444	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1445	# have identity issues in that area.
		1446	# Net::SSLeay::CTX_set_mode ($ssl,
		1447	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1448	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1449	Net::SSLeay::CTX_set_mode ($ssl, 1|2);
281		1450
282	$self->on_read (sub {	1451	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
283	my @lines;	1452	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
284	push @lines, $1 while $_[0]->{rbuf} =~ s/(.*)$NL//;
285	$self->{on_readline}->($_[0], @lines);
286	});
287	}
288		1453
289	=item B<write ($data)>	1454	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
290		1455
291	=item B<write ($callback)>	1456	&_dotls; # need to trigger the initial handshake
292		1457	$self->start_read; # make sure we actually do read
293	=item B<write ($data, $callback)>
294
295	This method will write C<$data> to the filehandle and call the C<$callback>
296	afterwards. If only C<$callback> is provided it will be called when the
297	write buffer becomes empty the next time (or immediately if it already is empty).
298
299	=cut
300
301	sub write {
302	my ($self, $data, $cb) = @_;
303	if (ref $data) { $cb = $data; undef $data }
304	push @{$self->{write_bufs}}, [$data, $cb];
305	$self->_check_writer;
306	}	1458	}
307		1459
308	sub _check_writer {	1460	=item $handle->stoptls
		1461
		1462	Shuts down the SSL connection - this makes a proper EOF handshake by
		1463	sending a close notify to the other side, but since OpenSSL doesn't
		1464	support non-blocking shut downs, it is not possible to re-use the stream
		1465	afterwards.
		1466
		1467	=cut
		1468
		1469	sub stoptls {
309	my ($self) = @_;	1470	my ($self) = @_;
310		1471
311	if ($self->{write_w}) {	1472	if ($self->{tls}) {
312	unless ($self->{write_cb}) {	1473	Net::SSLeay::shutdown ($self->{tls});
313	while (@{$self->{write_bufs}} && not defined $self->{write_bufs}->[0]->[1]) {	1474
314	my $wba = shift @{$self->{write_bufs}};	1475	&_dotls;
315	$self->{wbuf} .= $wba->[0];	1476
316	}	1477	# we don't give a shit. no, we do, but we can't. no...
317	}	1478	# we, we... have to use openssl :/
318	return;	1479	&_freetls;
		1480	}
		1481	}
		1482
		1483	sub _freetls {
		1484	my ($self) = @_;
		1485
		1486	return unless $self->{tls};
		1487
		1488	$self->{tls_ctx}->_put_session (delete $self->{tls});
319	}	1489
		1490	delete @$self{qw(_rbio _wbio _tls_wbuf)};
		1491	}
320		1492
321	my $wba = shift @{$self->{write_bufs}}	1493	sub DESTROY {
322	or return;	1494	my ($self) = @_;
323		1495
324	unless (defined $wba->[0]) {	1496	&_freetls;
325	$wba->[1]->($self) if $wba->[1];
326	$self->_check_writer;
327	return;
328	}
329		1497
330	$self->{wbuf} = $wba->[0];	1498	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
331	$self->{write_cb} = $wba->[1];
332		1499
333	$self->{write_w} =	1500	if ($linger && length $self->{wbuf}) {
334	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1501	my $fh = delete $self->{fh};
		1502	my $wbuf = delete $self->{wbuf};
		1503
		1504	my @linger;
		1505
		1506	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
335	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1507	my $len = syswrite $fh, $wbuf, length $wbuf;
336		1508
337	if (not defined $l) {	1509	if ($len > 0) {
338	return if $! == EAGAIN || $! == EINTR;	1510	substr $wbuf, 0, $len, "";
339	delete $self->{write_w};
340	$self->{on_error}->($self) if $self->{on_error};
341
342	} else {	1511	} else {
343	substr $self->{wbuf}, 0, $l, '';	1512	@linger = (); # end
344
345	if (length ($self->{wbuf}) == 0) {
346	$self->{write_cb}->($self) if $self->{write_cb};
347
348	delete $self->{write_w};
349	delete $self->{wbuf};
350	delete $self->{write_cb};
351
352	$self->_check_writer;
353	}
354	}	1513	}
355	});	1514	});
		1515	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1516	@linger = ();
		1517	});
		1518	}
		1519	}
		1520
		1521	=item $handle->destroy
		1522
		1523	Shuts down the handle object as much as possible - this call ensures that
		1524	no further callbacks will be invoked and resources will be freed as much
		1525	as possible. You must not call any methods on the object afterwards.
		1526
		1527	Normally, you can just "forget" any references to an AnyEvent::Handle
		1528	object and it will simply shut down. This works in fatal error and EOF
		1529	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1530	callback, so when you want to destroy the AnyEvent::Handle object from
		1531	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1532	that case.
		1533
		1534	The handle might still linger in the background and write out remaining
		1535	data, as specified by the C<linger> option, however.
		1536
		1537	=cut
		1538
		1539	sub destroy {
		1540	my ($self) = @_;
		1541
		1542	$self->DESTROY;
		1543	%$self = ();
		1544	}
		1545
		1546	=item AnyEvent::Handle::TLS_CTX
		1547
		1548	This function creates and returns the AnyEvent::TLS object used by default
		1549	for TLS mode.
		1550
		1551	The context is created by calling L<AnyEvent::TLS> without any arguments.
		1552
		1553	=cut
		1554
		1555	our $TLS_CTX;
		1556
		1557	sub TLS_CTX() {
		1558	$TLS_CTX ||= do {
		1559	require AnyEvent::TLS;
		1560
		1561	new AnyEvent::TLS
		1562	}
356	}	1563	}
357		1564
358	=back	1565	=back
359		1566
		1567
		1568	=head1 NONFREQUENTLY ASKED QUESTIONS
		1569
		1570	=over 4
		1571
		1572	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1573	still get further invocations!
		1574
		1575	That's because AnyEvent::Handle keeps a reference to itself when handling
		1576	read or write callbacks.
		1577
		1578	It is only safe to "forget" the reference inside EOF or error callbacks,
		1579	from within all other callbacks, you need to explicitly call the C<<
		1580	->destroy >> method.
		1581
		1582	=item I get different callback invocations in TLS mode/Why can't I pause
		1583	reading?
		1584
		1585	Unlike, say, TCP, TLS connections do not consist of two independent
		1586	communication channels, one for each direction. Or put differently. The
		1587	read and write directions are not independent of each other: you cannot
		1588	write data unless you are also prepared to read, and vice versa.
		1589
		1590	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1591	callback invocations when you are not expecting any read data - the reason
		1592	is that AnyEvent::Handle always reads in TLS mode.
		1593
		1594	During the connection, you have to make sure that you always have a
		1595	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1596	connection (or when you no longer want to use it) you can call the
		1597	C<destroy> method.
		1598
		1599	=item How do I read data until the other side closes the connection?
		1600
		1601	If you just want to read your data into a perl scalar, the easiest way
		1602	to achieve this is by setting an C<on_read> callback that does nothing,
		1603	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1604	will be in C<$_[0]{rbuf}>:
		1605
		1606	$handle->on_read (sub { });
		1607	$handle->on_eof (undef);
		1608	$handle->on_error (sub {
		1609	my $data = delete $_[0]{rbuf};
		1610	undef $handle;
		1611	});
		1612
		1613	The reason to use C<on_error> is that TCP connections, due to latencies
		1614	and packets loss, might get closed quite violently with an error, when in
		1615	fact, all data has been received.
		1616
		1617	It is usually better to use acknowledgements when transferring data,
		1618	to make sure the other side hasn't just died and you got the data
		1619	intact. This is also one reason why so many internet protocols have an
		1620	explicit QUIT command.
		1621
		1622	=item I don't want to destroy the handle too early - how do I wait until
		1623	all data has been written?
		1624
		1625	After writing your last bits of data, set the C<on_drain> callback
		1626	and destroy the handle in there - with the default setting of
		1627	C<low_water_mark> this will be called precisely when all data has been
		1628	written to the socket:
		1629
		1630	$handle->push_write (...);
		1631	$handle->on_drain (sub {
		1632	warn "all data submitted to the kernel\n";
		1633	undef $handle;
		1634	});
		1635
		1636	=back
		1637
		1638
		1639	=head1 SUBCLASSING AnyEvent::Handle
		1640
		1641	In many cases, you might want to subclass AnyEvent::Handle.
		1642
		1643	To make this easier, a given version of AnyEvent::Handle uses these
		1644	conventions:
		1645
		1646	=over 4
		1647
		1648	=item * all constructor arguments become object members.
		1649
		1650	At least initially, when you pass a C<tls>-argument to the constructor it
		1651	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1652	mutated later on (for example C<tls> will hold the TLS connection object).
		1653
		1654	=item * other object member names are prefixed with an C<_>.
		1655
		1656	All object members not explicitly documented (internal use) are prefixed
		1657	with an underscore character, so the remaining non-C<_>-namespace is free
		1658	for use for subclasses.
		1659
		1660	=item * all members not documented here and not prefixed with an underscore
		1661	are free to use in subclasses.
		1662
		1663	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1664	member variables, but thats just life, at least it is documented.
		1665
		1666	=back
		1667
360	=head1 AUTHOR	1668	=head1 AUTHOR
361		1669
362	Robin Redeker, C<< <elmex at ta-sa.org> >>	1670	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
363
364	=head1 BUGS
365
366	Please report any bugs or feature requests to
367	C<bug-io-anyevent at rt.cpan.org>, or through the web interface at
368	L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=IO-AnyEvent>.
369	I will be notified, and then you'll automatically be notified of progress on
370	your bug as I make changes.
371
372	=head1 SUPPORT
373
374	You can find documentation for this module with the perldoc command.
375
376	perldoc AnyEvent::Handle
377
378	You can also look for information at:
379
380	=over 4
381
382	=item * AnnoCPAN: Annotated CPAN documentation
383
384	L<http://annocpan.org/dist/IO-AnyEvent>
385
386	=item * CPAN Ratings
387
388	L<http://cpanratings.perl.org/d/IO-AnyEvent>
389
390	=item * RT: CPAN's request tracker
391
392	L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=IO-AnyEvent>
393
394	=item * Search CPAN
395
396	L<http://search.cpan.org/dist/IO-AnyEvent>
397
398	=back
399
400	=head1 ACKNOWLEDGEMENTS
401
402	=head1 COPYRIGHT & LICENSE
403
404	Copyright 2008 Robin Redeker, all rights reserved.
405
406	This program is free software; you can redistribute it and/or modify it
407	under the same terms as Perl itself.
408		1671
409	=cut	1672	=cut
410		1673
411	1; # End of AnyEvent::Handle	1674	1; # End of AnyEvent::Handle

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