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Revision 1.2 by elmex, Sun Apr 27 17:27:34 2008 UTC vs.
Revision 1.130 by root, Mon Jun 29 21:00:32 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 B<new (%args)>
		69
		70	The constructor supports these arguments (all as 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 tls => "accept" | "connect" | Net::SSLeay::SSL object
		243
		244	When this parameter is given, it enables TLS (SSL) mode, that means
		245	AnyEvent will start a TLS handshake as soon as the conenction has been
		246	established and will transparently encrypt/decrypt data afterwards.
		247
		248	TLS mode requires Net::SSLeay to be installed (it will be loaded
		249	automatically when you try to create a TLS handle): this module doesn't
		250	have a dependency on that module, so if your module requires it, you have
		251	to add the dependency yourself.
		252
		253	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		254	C<accept>, and for the TLS client side of a connection, use C<connect>
		255	mode.
		256
		257	You can also provide your own TLS connection object, but you have
		258	to make sure that you call either C<Net::SSLeay::set_connect_state>
		259	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		260	AnyEvent::Handle.
		261
		262	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		263	passing in the wrong integer will lead to certain crash. This most often
		264	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		265	segmentation fault.
		266
		267	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		268
		269	=item tls_ctx => $ssl_ctx
		270
		271	Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
		272	(unless a connection object was specified directly). If this parameter is
		273	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		274
		275	=item json => JSON or JSON::XS object
		276
		277	This is the json coder object used by the C<json> read and write types.
		278
		279	If you don't supply it, then AnyEvent::Handle will create and use a
		280	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		281	texts.
		282
		283	Note that you are responsible to depend on the JSON module if you want to
		284	use this functionality, as AnyEvent does not have a dependency itself.
		285
		286	=back
		287
		288	=cut
		289
		290	sub new {
		291	my $class = shift;
		292
		293	my $self = bless { @_ }, $class;
		294
		295	$self->{fh} or Carp::croak "mandatory argument fh is missing";
		296
		297	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		298
		299	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		300	if $self->{tls};
		301
		302	$self->{_activity} = AnyEvent->now;
		303	$self->_timeout;
		304
		305	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
		306	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		307
		308	$self->start_read
		309	if $self->{on_read};
		310
		311	$self
		312	}
		313
		314	sub _shutdown {
		315	my ($self) = @_;
		316
		317	delete @$self{qw(_tw _rw _ww fh rbuf wbuf on_read _queue)};
		318
		319	&_freetls;
		320	}
		321
		322	sub _error {
		323	my ($self, $errno, $fatal) = @_;
		324
		325	$self->_shutdown
		326	if $fatal;
		327
		328	$! = $errno;
		329
		330	if ($self->{on_error}) {
		331	$self->{on_error}($self, $fatal);
		332	} elsif ($self->{fh}) {
		333	Carp::croak "AnyEvent::Handle uncaught error: $!";
		334	}
		335	}
		336
		337	=item $fh = $handle->fh
		338
		339	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		340
		341	=cut
		342
		343	sub fh { $_[0]{fh} }
		344
		345	=item $handle->on_error ($cb)
		346
		347	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		348
		349	=cut
		350
		351	sub on_error {
		352	$_[0]{on_error} = $_[1];
		353	}
		354
		355	=item $handle->on_eof ($cb)
		356
		357	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		358
		359	=cut
		360
		361	sub on_eof {
		362	$_[0]{on_eof} = $_[1];
		363	}
		364
		365	=item $handle->on_timeout ($cb)
		366
		367	Replace the current C<on_timeout> callback, or disables the callback (but
		368	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		369	argument and method.
		370
		371	=cut
		372
		373	sub on_timeout {
		374	$_[0]{on_timeout} = $_[1];
		375	}
		376
		377	=item $handle->autocork ($boolean)
		378
		379	Enables or disables the current autocork behaviour (see C<autocork>
		380	constructor argument). Changes will only take effect on the next write.
		381
		382	=cut
		383
		384	sub autocork {
		385	$_[0]{autocork} = $_[1];
		386	}
		387
		388	=item $handle->no_delay ($boolean)
		389
		390	Enables or disables the C<no_delay> setting (see constructor argument of
		391	the same name for details).
		392
		393	=cut
		394
		395	sub no_delay {
		396	$_[0]{no_delay} = $_[1];
		397
		398	eval {
		399	local $SIG{__DIE__};
		400	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		401	};
		402	}
		403
		404	#############################################################################
		405
		406	=item $handle->timeout ($seconds)
		407
		408	Configures (or disables) the inactivity timeout.
		409
		410	=cut
		411
		412	sub timeout {
		413	my ($self, $timeout) = @_;
		414
		415	$self->{timeout} = $timeout;
		416	$self->_timeout;
		417	}
		418
		419	# reset the timeout watcher, as neccessary
		420	# also check for time-outs
		421	sub _timeout {
		422	my ($self) = @_;
		423
		424	if ($self->{timeout}) {
		425	my $NOW = AnyEvent->now;
		426
		427	# when would the timeout trigger?
		428	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		429
		430	# now or in the past already?
		431	if ($after <= 0) {
		432	$self->{_activity} = $NOW;
		433
		434	if ($self->{on_timeout}) {
		435	$self->{on_timeout}($self);
		436	} else {
		437	$self->_error (&Errno::ETIMEDOUT);
		438	}
		439
		440	# callback could have changed timeout value, optimise
		441	return unless $self->{timeout};
		442
		443	# calculate new after
		444	$after = $self->{timeout};
		445	}
		446
		447	Scalar::Util::weaken $self;
		448	return unless $self; # ->error could have destroyed $self
		449
		450	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		451	delete $self->{_tw};
		452	$self->_timeout;
		453	});
		454	} else {
		455	delete $self->{_tw};
		456	}
		457	}
		458
		459	#############################################################################
		460
		461	=back
		462
		463	=head2 WRITE QUEUE
		464
		465	AnyEvent::Handle manages two queues per handle, one for writing and one
		466	for reading.
		467
		468	The write queue is very simple: you can add data to its end, and
		469	AnyEvent::Handle will automatically try to get rid of it for you.
		470
		471	When data could be written and the write buffer is shorter then the low
		472	water mark, the C<on_drain> callback will be invoked.
		473
		474	=over 4
		475
		476	=item $handle->on_drain ($cb)
		477
		478	Sets the C<on_drain> callback or clears it (see the description of
		479	C<on_drain> in the constructor).
		480
		481	=cut
		482
		483	sub on_drain {
		484	my ($self, $cb) = @_;
		485
		486	$self->{on_drain} = $cb;
		487
		488	$cb->($self)
		489	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		490	}
		491
		492	=item $handle->push_write ($data)
		493
		494	Queues the given scalar to be written. You can push as much data as you
		495	want (only limited by the available memory), as C<AnyEvent::Handle>
		496	buffers it independently of the kernel.
		497
		498	=cut
		499
		500	sub _drain_wbuf {
		501	my ($self) = @_;
		502
		503	if (!$self->{_ww} && length $self->{wbuf}) {
		504
		505	Scalar::Util::weaken $self;
		506
		507	my $cb = sub {
		508	my $len = syswrite $self->{fh}, $self->{wbuf};
		509
		510	if ($len >= 0) {
		511	substr $self->{wbuf}, 0, $len, "";
		512
		513	$self->{_activity} = AnyEvent->now;
		514
		515	$self->{on_drain}($self)
		516	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		517	&& $self->{on_drain};
		518
		519	delete $self->{_ww} unless length $self->{wbuf};
		520	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		521	$self->_error ($!, 1);
		522	}
		523	};
		524
		525	# try to write data immediately
		526	$cb->() unless $self->{autocork};
		527
		528	# if still data left in wbuf, we need to poll
		529	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
		530	if length $self->{wbuf};
		531	};
		532	}
		533
		534	our %WH;
		535
		536	sub register_write_type($$) {
		537	$WH{$_[0]} = $_[1];
		538	}
		539
		540	sub push_write {
		541	my $self = shift;
		542
		543	if (@_ > 1) {
		544	my $type = shift;
		545
		546	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		547	->($self, @_);
		548	}
		549
		550	if ($self->{tls}) {
		551	$self->{_tls_wbuf} .= $_[0];
		552
		553	&_dotls ($self);
		554	} else {
		555	$self->{wbuf} .= $_[0];
		556	$self->_drain_wbuf;
		557	}
		558	}
		559
		560	=item $handle->push_write (type => @args)
		561
		562	Instead of formatting your data yourself, you can also let this module do
		563	the job by specifying a type and type-specific arguments.
		564
		565	Predefined types are (if you have ideas for additional types, feel free to
		566	drop by and tell us):
		567
		568	=over 4
		569
		570	=item netstring => $string
		571
		572	Formats the given value as netstring
		573	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		574
		575	=cut
		576
		577	register_write_type netstring => sub {
		578	my ($self, $string) = @_;
		579
		580	(length $string) . ":$string,"
		581	};
		582
		583	=item packstring => $format, $data
		584
		585	An octet string prefixed with an encoded length. The encoding C<$format>
		586	uses the same format as a Perl C<pack> format, but must specify a single
		587	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		588	optional C<!>, C<< < >> or C<< > >> modifier).
		589
		590	=cut
		591
		592	register_write_type packstring => sub {
		593	my ($self, $format, $string) = @_;
		594
		595	pack "$format/a*", $string
		596	};
		597
		598	=item json => $array_or_hashref
		599
		600	Encodes the given hash or array reference into a JSON object. Unless you
		601	provide your own JSON object, this means it will be encoded to JSON text
		602	in UTF-8.
		603
		604	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		605	one end of a handle and read them at the other end without using any
		606	additional framing.
		607
		608	The generated JSON text is guaranteed not to contain any newlines: While
		609	this module doesn't need delimiters after or between JSON texts to be
		610	able to read them, many other languages depend on that.
		611
		612	A simple RPC protocol that interoperates easily with others is to send
		613	JSON arrays (or objects, although arrays are usually the better choice as
		614	they mimic how function argument passing works) and a newline after each
		615	JSON text:
		616
		617	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		618	$handle->push_write ("\012");
		619
		620	An AnyEvent::Handle receiver would simply use the C<json> read type and
		621	rely on the fact that the newline will be skipped as leading whitespace:
		622
		623	$handle->push_read (json => sub { my $array = $_[1]; ... });
		624
		625	Other languages could read single lines terminated by a newline and pass
		626	this line into their JSON decoder of choice.
		627
		628	=cut
		629
		630	register_write_type json => sub {
		631	my ($self, $ref) = @_;
		632
		633	require JSON;
		634
		635	$self->{json} ? $self->{json}->encode ($ref)
		636	: JSON::encode_json ($ref)
		637	};
		638
		639	=item storable => $reference
		640
		641	Freezes the given reference using L<Storable> and writes it to the
		642	handle. Uses the C<nfreeze> format.
		643
		644	=cut
		645
		646	register_write_type storable => sub {
		647	my ($self, $ref) = @_;
		648
		649	require Storable;
		650
		651	pack "w/a*", Storable::nfreeze ($ref)
		652	};
		653
		654	=back
		655
		656	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		657
		658	This function (not method) lets you add your own types to C<push_write>.
		659	Whenever the given C<type> is used, C<push_write> will invoke the code
		660	reference with the handle object and the remaining arguments.
		661
		662	The code reference is supposed to return a single octet string that will
		663	be appended to the write buffer.
		664
		665	Note that this is a function, and all types registered this way will be
		666	global, so try to use unique names.
		667
		668	=cut
		669
		670	#############################################################################
		671
		672	=back
		673
		674	=head2 READ QUEUE
		675
		676	AnyEvent::Handle manages two queues per handle, one for writing and one
		677	for reading.
		678
		679	The read queue is more complex than the write queue. It can be used in two
		680	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		681	a queue.
		682
		683	In the simple case, you just install an C<on_read> callback and whenever
		684	new data arrives, it will be called. You can then remove some data (if
		685	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
		686	leave the data there if you want to accumulate more (e.g. when only a
		687	partial message has been received so far).
		688
		689	In the more complex case, you want to queue multiple callbacks. In this
		690	case, AnyEvent::Handle will call the first queued callback each time new
		691	data arrives (also the first time it is queued) and removes it when it has
		692	done its job (see C<push_read>, below).
		693
		694	This way you can, for example, push three line-reads, followed by reading
		695	a chunk of data, and AnyEvent::Handle will execute them in order.
		696
		697	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		698	the specified number of bytes which give an XML datagram.
		699
		700	# in the default state, expect some header bytes
		701	$handle->on_read (sub {
		702	# some data is here, now queue the length-header-read (4 octets)
		703	shift->unshift_read (chunk => 4, sub {
		704	# header arrived, decode
		705	my $len = unpack "N", $_[1];
		706
		707	# now read the payload
		708	shift->unshift_read (chunk => $len, sub {
		709	my $xml = $_[1];
		710	# handle xml
		711	});
		712	});
		713	});
		714
		715	Example 2: Implement a client for a protocol that replies either with "OK"
		716	and another line or "ERROR" for the first request that is sent, and 64
		717	bytes for the second request. Due to the availability of a queue, we can
		718	just pipeline sending both requests and manipulate the queue as necessary
		719	in the callbacks.
		720
		721	When the first callback is called and sees an "OK" response, it will
		722	C<unshift> another line-read. This line-read will be queued I<before> the
		723	64-byte chunk callback.
		724
		725	# request one, returns either "OK + extra line" or "ERROR"
		726	$handle->push_write ("request 1\015\012");
		727
		728	# we expect "ERROR" or "OK" as response, so push a line read
		729	$handle->push_read (line => sub {
		730	# if we got an "OK", we have to _prepend_ another line,
		731	# so it will be read before the second request reads its 64 bytes
		732	# which are already in the queue when this callback is called
		733	# we don't do this in case we got an error
		734	if ($_[1] eq "OK") {
49	on_readline => sub {	735	$_[0]->unshift_read (line => sub {
50	my ($ae_fh, @lines) = @_;	736	my $response = $_[1];
51	for (@lines) {	737	...
52	chomp;	738	});
53	print "Line: $_";	739	}
		740	});
		741
		742	# request two, simply returns 64 octets
		743	$handle->push_write ("request 2\015\012");
		744
		745	# simply read 64 bytes, always
		746	$handle->push_read (chunk => 64, sub {
		747	my $response = $_[1];
		748	...
		749	});
		750
		751	=over 4
		752
		753	=cut
		754
		755	sub _drain_rbuf {
		756	my ($self) = @_;
		757
		758	local $self->{_in_drain} = 1;
		759
		760	if (
		761	defined $self->{rbuf_max}
		762	&& $self->{rbuf_max} < length $self->{rbuf}
		763	) {
		764	$self->_error (&Errno::ENOSPC, 1), return;
		765	}
		766
		767	while () {
		768	# we need to use a separate tls read buffer, as we must not receive data while
		769	# we are draining the buffer, and this can only happen with TLS.
		770	$self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
		771
		772	my $len = length $self->{rbuf};
		773
		774	if (my $cb = shift @{ $self->{_queue} }) {
		775	unless ($cb->($self)) {
		776	if ($self->{_eof}) {
		777	# no progress can be made (not enough data and no data forthcoming)
		778	$self->_error (&Errno::EPIPE, 1), return;
54	}	779	}
		780
		781	unshift @{ $self->{_queue} }, $cb;
		782	last;
55	}	783	}
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}) {	784	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	785	last unless $len;
122		786
		787	$self->{on_read}($self);
		788
		789	if (
		790	$len == length $self->{rbuf} # if no data has been consumed
		791	&& !@{ $self->{_queue} } # and the queue is still empty
		792	&& $self->{on_read} # but we still have on_read
		793	) {
		794	# no further data will arrive
		795	# so no progress can be made
		796	$self->_error (&Errno::EPIPE, 1), return
		797	if $self->{_eof};
		798
		799	last; # more data might arrive
		800	}
		801	} else {
		802	# read side becomes idle
		803	delete $self->{_rw} unless $self->{tls};
		804	last;
		805	}
		806	}
		807
123	} elsif ($self->{on_eof}) {	808	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});
125
126	} elsif ($self->{on_error}) {	809	if ($self->{on_eof}) {
127	$self->on_eof ($self->{on_error});	810	$self->{on_eof}($self)
		811	} else {
		812	$self->_error (0, 1);
		813	}
128	}	814	}
129		815
130	return $self	816	# may need to restart read watcher
		817	unless ($self->{_rw}) {
		818	$self->start_read
		819	if $self->{on_read} || @{ $self->{_queue} };
		820	}
131	}	821	}
132		822
133	=item B<fh>	823	=item $handle->on_read ($cb)
134		824
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	825	This replaces the currently set C<on_read> callback, or clears it (when
136		826	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	827	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		828
149	=cut	829	=cut
150		830
151	sub on_read {	831	sub on_read {
152	my ($self, $cb) = @_;	832	my ($self, $cb) = @_;
		833
153	$self->{on_read} = $cb;	834	$self->{on_read} = $cb;
		835	$self->_drain_rbuf if $cb && !$self->{_in_drain};
		836	}
154		837
155	unless (defined $self->{on_read}) {	838	=item $handle->rbuf
156	delete $self->{on_read_w};	839
		840	Returns the read buffer (as a modifiable lvalue).
		841
		842	You can access the read buffer directly as the C<< ->{rbuf} >>
		843	member, if you want. However, the only operation allowed on the
		844	read buffer (apart from looking at it) is removing data from its
		845	beginning. Otherwise modifying or appending to it is not allowed and will
		846	lead to hard-to-track-down bugs.
		847
		848	NOTE: The read buffer should only be used or modified if the C<on_read>,
		849	C<push_read> or C<unshift_read> methods are used. The other read methods
		850	automatically manage the read buffer.
		851
		852	=cut
		853
		854	sub rbuf : lvalue {
		855	$_[0]{rbuf}
		856	}
		857
		858	=item $handle->push_read ($cb)
		859
		860	=item $handle->unshift_read ($cb)
		861
		862	Append the given callback to the end of the queue (C<push_read>) or
		863	prepend it (C<unshift_read>).
		864
		865	The callback is called each time some additional read data arrives.
		866
		867	It must check whether enough data is in the read buffer already.
		868
		869	If not enough data is available, it must return the empty list or a false
		870	value, in which case it will be called repeatedly until enough data is
		871	available (or an error condition is detected).
		872
		873	If enough data was available, then the callback must remove all data it is
		874	interested in (which can be none at all) and return a true value. After returning
		875	true, it will be removed from the queue.
		876
		877	=cut
		878
		879	our %RH;
		880
		881	sub register_read_type($$) {
		882	$RH{$_[0]} = $_[1];
		883	}
		884
		885	sub push_read {
		886	my $self = shift;
		887	my $cb = pop;
		888
		889	if (@_) {
		890	my $type = shift;
		891
		892	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		893	->($self, $cb, @_);
		894	}
		895
		896	push @{ $self->{_queue} }, $cb;
		897	$self->_drain_rbuf unless $self->{_in_drain};
		898	}
		899
		900	sub unshift_read {
		901	my $self = shift;
		902	my $cb = pop;
		903
		904	if (@_) {
		905	my $type = shift;
		906
		907	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		908	->($self, $cb, @_);
		909	}
		910
		911
		912	unshift @{ $self->{_queue} }, $cb;
		913	$self->_drain_rbuf unless $self->{_in_drain};
		914	}
		915
		916	=item $handle->push_read (type => @args, $cb)
		917
		918	=item $handle->unshift_read (type => @args, $cb)
		919
		920	Instead of providing a callback that parses the data itself you can chose
		921	between a number of predefined parsing formats, for chunks of data, lines
		922	etc.
		923
		924	Predefined types are (if you have ideas for additional types, feel free to
		925	drop by and tell us):
		926
		927	=over 4
		928
		929	=item chunk => $octets, $cb->($handle, $data)
		930
		931	Invoke the callback only once C<$octets> bytes have been read. Pass the
		932	data read to the callback. The callback will never be called with less
		933	data.
		934
		935	Example: read 2 bytes.
		936
		937	$handle->push_read (chunk => 2, sub {
		938	warn "yay ", unpack "H*", $_[1];
		939	});
		940
		941	=cut
		942
		943	register_read_type chunk => sub {
		944	my ($self, $cb, $len) = @_;
		945
		946	sub {
		947	$len <= length $_[0]{rbuf} or return;
		948	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		949	1
		950	}
		951	};
		952
		953	=item line => [$eol, ]$cb->($handle, $line, $eol)
		954
		955	The callback will be called only once a full line (including the end of
		956	line marker, C<$eol>) has been read. This line (excluding the end of line
		957	marker) will be passed to the callback as second argument (C<$line>), and
		958	the end of line marker as the third argument (C<$eol>).
		959
		960	The end of line marker, C<$eol>, can be either a string, in which case it
		961	will be interpreted as a fixed record end marker, or it can be a regex
		962	object (e.g. created by C<qr>), in which case it is interpreted as a
		963	regular expression.
		964
		965	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		966	undef), then C<qr|\015?\012|> is used (which is good for most internet
		967	protocols).
		968
		969	Partial lines at the end of the stream will never be returned, as they are
		970	not marked by the end of line marker.
		971
		972	=cut
		973
		974	register_read_type line => sub {
		975	my ($self, $cb, $eol) = @_;
		976
		977	if (@_ < 3) {
		978	# this is more than twice as fast as the generic code below
		979	sub {
		980	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		981
		982	$cb->($_[0], $1, $2);
		983	1
		984	}
		985	} else {
		986	$eol = quotemeta $eol unless ref $eol;
		987	$eol = qr|^(.*?)($eol)|s;
		988
		989	sub {
		990	$_[0]{rbuf} =~ s/$eol// or return;
		991
		992	$cb->($_[0], $1, $2);
		993	1
		994	}
		995	}
		996	};
		997
		998	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		999
		1000	Makes a regex match against the regex object C<$accept> and returns
		1001	everything up to and including the match.
		1002
		1003	Example: read a single line terminated by '\n'.
		1004
		1005	$handle->push_read (regex => qr<\n>, sub { ... });
		1006
		1007	If C<$reject> is given and not undef, then it determines when the data is
		1008	to be rejected: it is matched against the data when the C<$accept> regex
		1009	does not match and generates an C<EBADMSG> error when it matches. This is
		1010	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1011	receive buffer overflow).
		1012
		1013	Example: expect a single decimal number followed by whitespace, reject
		1014	anything else (not the use of an anchor).
		1015
		1016	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1017
		1018	If C<$skip> is given and not C<undef>, then it will be matched against
		1019	the receive buffer when neither C<$accept> nor C<$reject> match,
		1020	and everything preceding and including the match will be accepted
		1021	unconditionally. This is useful to skip large amounts of data that you
		1022	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1023	have to start matching from the beginning. This is purely an optimisation
		1024	and is usually worth only when you expect more than a few kilobytes.
		1025
		1026	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1027	expect the header to be very large (it isn't in practise, but...), we use
		1028	a skip regex to skip initial portions. The skip regex is tricky in that
		1029	it only accepts something not ending in either \015 or \012, as these are
		1030	required for the accept regex.
		1031
		1032	$handle->push_read (regex =>
		1033	qr<\015\012\015\012>,
		1034	undef, # no reject
		1035	qr<^.*[^\015\012]>,
		1036	sub { ... });
		1037
		1038	=cut
		1039
		1040	register_read_type regex => sub {
		1041	my ($self, $cb, $accept, $reject, $skip) = @_;
		1042
		1043	my $data;
		1044	my $rbuf = \$self->{rbuf};
		1045
		1046	sub {
		1047	# accept
		1048	if ($$rbuf =~ $accept) {
		1049	$data .= substr $$rbuf, 0, $+[0], "";
		1050	$cb->($self, $data);
157	return;	1051	return 1;
		1052	}
		1053
		1054	# reject
		1055	if ($reject && $$rbuf =~ $reject) {
		1056	$self->_error (&Errno::EBADMSG);
		1057	}
		1058
		1059	# skip
		1060	if ($skip && $$rbuf =~ $skip) {
		1061	$data .= substr $$rbuf, 0, $+[0], "";
		1062	}
		1063
		1064	()
158	}	1065	}
159		1066	};
160	$self->{on_read_w} =	1067
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1068	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1069
163	my $rbuf_len = length $self->{rbuf};	1070	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1071
165	if (defined $self->{read_size}) {	1072	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1073
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1074	=cut
168	} else {	1075
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1076	register_read_type netstring => sub {
		1077	my ($self, $cb) = @_;
		1078
		1079	sub {
		1080	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1081	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1082	$self->_error (&Errno::EBADMSG);
170	}	1083	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1084	return;
		1085	}
172		1086
173	if (not defined $l) {	1087	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1088
178	} elsif ($l == 0) {	1089	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1090	my $string = $_[1];
180	delete $self->{on_read_w};	1091	$_[0]->unshift_read (chunk => 1, sub {
181		1092	if ($_[1] eq ",") {
		1093	$cb->($_[0], $string);
182	} else {	1094	} else {
183	$self->{on_read}->($self);	1095	$self->_error (&Errno::EBADMSG);
		1096	}
		1097	});
		1098	});
		1099
		1100	1
		1101	}
		1102	};
		1103
		1104	=item packstring => $format, $cb->($handle, $string)
		1105
		1106	An octet string prefixed with an encoded length. The encoding C<$format>
		1107	uses the same format as a Perl C<pack> format, but must specify a single
		1108	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1109	optional C<!>, C<< < >> or C<< > >> modifier).
		1110
		1111	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1112	EPP uses a prefix of C<N> (4 octtes).
		1113
		1114	Example: read a block of data prefixed by its length in BER-encoded
		1115	format (very efficient).
		1116
		1117	$handle->push_read (packstring => "w", sub {
		1118	my ($handle, $data) = @_;
		1119	});
		1120
		1121	=cut
		1122
		1123	register_read_type packstring => sub {
		1124	my ($self, $cb, $format) = @_;
		1125
		1126	sub {
		1127	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1128	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1129	or return;
		1130
		1131	$format = length pack $format, $len;
		1132
		1133	# bypass unshift if we already have the remaining chunk
		1134	if ($format + $len <= length $_[0]{rbuf}) {
		1135	my $data = substr $_[0]{rbuf}, $format, $len;
		1136	substr $_[0]{rbuf}, 0, $format + $len, "";
		1137	$cb->($_[0], $data);
		1138	} else {
		1139	# remove prefix
		1140	substr $_[0]{rbuf}, 0, $format, "";
		1141
		1142	# read remaining chunk
		1143	$_[0]->unshift_read (chunk => $len, $cb);
		1144	}
		1145
		1146	1
		1147	}
		1148	};
		1149
		1150	=item json => $cb->($handle, $hash_or_arrayref)
		1151
		1152	Reads a JSON object or array, decodes it and passes it to the
		1153	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1154
		1155	If a C<json> object was passed to the constructor, then that will be used
		1156	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1157
		1158	This read type uses the incremental parser available with JSON version
		1159	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1160	dependency on your own: this module will load the JSON module, but
		1161	AnyEvent does not depend on it itself.
		1162
		1163	Since JSON texts are fully self-delimiting, the C<json> read and write
		1164	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1165	the C<json> write type description, above, for an actual example.
		1166
		1167	=cut
		1168
		1169	register_read_type json => sub {
		1170	my ($self, $cb) = @_;
		1171
		1172	require JSON;
		1173
		1174	my $data;
		1175	my $rbuf = \$self->{rbuf};
		1176
		1177	my $json = $self->{json} ||= JSON->new->utf8;
		1178
		1179	sub {
		1180	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1181
		1182	if ($ref) {
		1183	$self->{rbuf} = $json->incr_text;
		1184	$json->incr_text = "";
		1185	$cb->($self, $ref);
		1186
		1187	1
		1188	} elsif ($@) {
		1189	# error case
		1190	$json->incr_skip;
		1191
		1192	$self->{rbuf} = $json->incr_text;
		1193	$json->incr_text = "";
		1194
		1195	$self->_error (&Errno::EBADMSG);
		1196
		1197	()
		1198	} else {
		1199	$self->{rbuf} = "";
		1200
		1201	()
		1202	}
		1203	}
		1204	};
		1205
		1206	=item storable => $cb->($handle, $ref)
		1207
		1208	Deserialises a L<Storable> frozen representation as written by the
		1209	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1210	data).
		1211
		1212	Raises C<EBADMSG> error if the data could not be decoded.
		1213
		1214	=cut
		1215
		1216	register_read_type storable => sub {
		1217	my ($self, $cb) = @_;
		1218
		1219	require Storable;
		1220
		1221	sub {
		1222	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1223	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1224	or return;
		1225
		1226	my $format = length pack "w", $len;
		1227
		1228	# bypass unshift if we already have the remaining chunk
		1229	if ($format + $len <= length $_[0]{rbuf}) {
		1230	my $data = substr $_[0]{rbuf}, $format, $len;
		1231	substr $_[0]{rbuf}, 0, $format + $len, "";
		1232	$cb->($_[0], Storable::thaw ($data));
		1233	} else {
		1234	# remove prefix
		1235	substr $_[0]{rbuf}, 0, $format, "";
		1236
		1237	# read remaining chunk
		1238	$_[0]->unshift_read (chunk => $len, sub {
		1239	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1240	$cb->($_[0], $ref);
		1241	} else {
		1242	$self->_error (&Errno::EBADMSG);
		1243	}
		1244	});
		1245	}
		1246
		1247	1
		1248	}
		1249	};
		1250
		1251	=back
		1252
		1253	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1254
		1255	This function (not method) lets you add your own types to C<push_read>.
		1256
		1257	Whenever the given C<type> is used, C<push_read> will invoke the code
		1258	reference with the handle object, the callback and the remaining
		1259	arguments.
		1260
		1261	The code reference is supposed to return a callback (usually a closure)
		1262	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1263
		1264	It should invoke the passed callback when it is done reading (remember to
		1265	pass C<$handle> as first argument as all other callbacks do that).
		1266
		1267	Note that this is a function, and all types registered this way will be
		1268	global, so try to use unique names.
		1269
		1270	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1271	search for C<register_read_type>)).
		1272
		1273	=item $handle->stop_read
		1274
		1275	=item $handle->start_read
		1276
		1277	In rare cases you actually do not want to read anything from the
		1278	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1279	any queued callbacks will be executed then. To start reading again, call
		1280	C<start_read>.
		1281
		1282	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1283	you change the C<on_read> callback or push/unshift a read callback, and it
		1284	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1285	there are any read requests in the queue.
		1286
		1287	These methods will have no effect when in TLS mode (as TLS doesn't support
		1288	half-duplex connections).
		1289
		1290	=cut
		1291
		1292	sub stop_read {
		1293	my ($self) = @_;
		1294
		1295	delete $self->{_rw} unless $self->{tls};
		1296	}
		1297
		1298	sub start_read {
		1299	my ($self) = @_;
		1300
		1301	unless ($self->{_rw} || $self->{_eof}) {
		1302	Scalar::Util::weaken $self;
		1303
		1304	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1305	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1306	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1307
		1308	if ($len > 0) {
		1309	$self->{_activity} = AnyEvent->now;
		1310
		1311	if ($self->{tls}) {
		1312	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1313
		1314	&_dotls ($self);
		1315	} else {
		1316	$self->_drain_rbuf unless $self->{_in_drain};
		1317	}
		1318
		1319	} elsif (defined $len) {
		1320	delete $self->{_rw};
		1321	$self->{_eof} = 1;
		1322	$self->_drain_rbuf unless $self->{_in_drain};
		1323
		1324	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1325	return $self->_error ($!, 1);
184	}	1326	}
185	});	1327	});
		1328	}
186	}	1329	}
187		1330
188	=item B<on_error ($callback)>	1331	# poll the write BIO and send the data if applicable
189		1332	sub _dotls {
190	Whenever a read or write operation resulted in an error the C<$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, $cb) = @_;	1333	my ($self) = @_;
240		1334
241	$self->{read_cb} = $cb;	1335	my $tmp;
242	my $old_blk_size = $self->{read_block_size};
243	$self->{read_block_size} = $len;
244		1336
245	$self->on_read (sub {	1337	if (length $self->{_tls_wbuf}) {
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";	1338	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
247		1339	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, $len, ''));
252	}	1340	}
253	});	1341	}
254	}
255		1342
256	=item B<readlines ($callback)>	1343	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1344	unless (length $tmp) {
		1345	# let's treat SSL-eof as we treat normal EOF
		1346	delete $self->{_rw};
		1347	$self->{_eof} = 1;
		1348	&_freetls;
		1349	}
257		1350
258	=item B<readlines ($sep, $callback)>	1351	$self->{_tls_rbuf} .= $tmp;
		1352	$self->_drain_rbuf unless $self->{_in_drain};
		1353	$self->{tls} or return; # tls session might have gone away in callback
		1354	}
259		1355
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1356	$tmp = Net::SSLeay::get_error ($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		1357
264	The C<$callback> will be called when at least one	1358	if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
265	line could be read. The first argument to the C<$callback> will be the L<AnyEvent::Handle>	1359	if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
266	object itself and the rest of the arguments will be the read lines.	1360	return $self->_error ($!, 1);
		1361	} elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
		1362	return $self->_error (&Errno::EIO, 1);
		1363	}
267		1364
268	NOTE: This method will override any callbacks installed via the C<on_read> method.	1365	# all other errors are fine for our purposes
		1366	}
269		1367
270	=cut	1368	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1369	$self->{wbuf} .= $tmp;
		1370	$self->_drain_wbuf;
		1371	}
		1372	}
271		1373
272	sub readlines {	1374	=item $handle->starttls ($tls[, $tls_ctx])
		1375
		1376	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1377	object is created, you can also do that at a later time by calling
		1378	C<starttls>.
		1379
		1380	The first argument is the same as the C<tls> constructor argument (either
		1381	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1382
		1383	The second argument is the optional C<Net::SSLeay::CTX> object that is
		1384	used when AnyEvent::Handle has to create its own TLS connection object.
		1385
		1386	The TLS connection object will end up in C<< $handle->{tls} >> after this
		1387	call and can be used or changed to your liking. Note that the handshake
		1388	might have already started when this function returns.
		1389
		1390	If it an error to start a TLS handshake more than once per
		1391	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1392
		1393	=cut
		1394
		1395	sub starttls {
273	my ($self, $NL, $cb) = @_;	1396	my ($self, $ssl, $ctx) = @_;
274		1397
275	if (ref $NL) {	1398	require Net::SSLeay;
276	$cb = $NL;	1399
277	$NL = "\n";	1400	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
		1401	if $self->{tls};
278	}	1402
279		1403	if ($ssl eq "accept") {
280	$self->{on_readline} = $cb;	1404	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
281		1405	Net::SSLeay::set_accept_state ($ssl);
282	$self->on_read (sub {	1406	} elsif ($ssl eq "connect") {
283	my @lines;	1407	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
284	push @lines, $1 while $_[0]->{rbuf} =~ s/(.*)$NL//;	1408	Net::SSLeay::set_connect_state ($ssl);
285	$self->{on_readline}->($_[0], @lines);
286	});	1409	}
287	}
288		1410
289	=item B<write ($data)>	1411	$self->{tls} = $ssl;
290		1412
291	=item B<write ($callback)>	1413	# basically, this is deep magic (because SSL_read should have the same issues)
		1414	# but the openssl maintainers basically said: "trust us, it just works".
		1415	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1416	# and mismaintained ssleay-module doesn't even offer them).
		1417	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1418	#
		1419	# in short: this is a mess.
		1420	#
		1421	# note that we do not try to keep the length constant between writes as we are required to do.
		1422	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1423	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1424	# have identity issues in that area.
		1425	Net::SSLeay::CTX_set_mode ($self->{tls},
		1426	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1427	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
292		1428
293	=item B<write ($data, $callback)>	1429	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1430	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
294		1431
295	This method will write C<$data> to the filehandle and call the C<$callback>	1432	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
296	afterwards. If only C<$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		1433
299	=cut	1434	&_dotls; # need to trigger the initial handshake
300		1435	$self->start_read; # make sure we actually do read
301	sub write {
302	my ($self, $data, $cb) = @_;
303	if (ref $data) { $cb = $data; undef $data }
304	push @{$self->{write_bufs}}, [$data, $cb];
305	$self->_check_writer;
306	}	1436	}
307		1437
308	sub _check_writer {	1438	=item $handle->stoptls
		1439
		1440	Shuts down the SSL connection - this makes a proper EOF handshake by
		1441	sending a close notify to the other side, but since OpenSSL doesn't
		1442	support non-blocking shut downs, it is not possible to re-use the stream
		1443	afterwards.
		1444
		1445	=cut
		1446
		1447	sub stoptls {
309	my ($self) = @_;	1448	my ($self) = @_;
310		1449
311	if ($self->{write_w}) {	1450	if ($self->{tls}) {
312	unless ($self->{write_cb}) {	1451	Net::SSLeay::shutdown ($self->{tls});
313	while (@{$self->{write_bufs}} && not defined $self->{write_bufs}->[0]->[1]) {	1452
314	my $wba = shift @{$self->{write_bufs}};	1453	&_dotls;
315	$self->{wbuf} .= $wba->[0];	1454
316	}	1455	# we don't give a shit. no, we do, but we can't. no...
317	}	1456	# we, we... have to use openssl :/
318	return;	1457	&_freetls;
		1458	}
		1459	}
		1460
		1461	sub _freetls {
		1462	my ($self) = @_;
		1463
		1464	return unless $self->{tls};
		1465
		1466	Net::SSLeay::free (delete $self->{tls});
319	}	1467
		1468	delete @$self{qw(_rbio _wbio _tls_wbuf)};
		1469	}
320		1470
321	my $wba = shift @{$self->{write_bufs}}	1471	sub DESTROY {
322	or return;	1472	my ($self) = @_;
323		1473
324	unless (defined $wba->[0]) {	1474	&_freetls;
325	$wba->[1]->($self) if $wba->[1];
326	$self->_check_writer;
327	return;
328	}
329		1475
330	$self->{wbuf} = $wba->[0];	1476	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
331	$self->{write_cb} = $wba->[1];
332		1477
333	$self->{write_w} =	1478	if ($linger && length $self->{wbuf}) {
334	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1479	my $fh = delete $self->{fh};
		1480	my $wbuf = delete $self->{wbuf};
		1481
		1482	my @linger;
		1483
		1484	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
335	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1485	my $len = syswrite $fh, $wbuf, length $wbuf;
336		1486
337	if (not defined $l) {	1487	if ($len > 0) {
338	return if $! == EAGAIN || $! == EINTR;	1488	substr $wbuf, 0, $len, "";
339	delete $self->{write_w};
340	$self->{on_error}->($self) if $self->{on_error};
341
342	} else {	1489	} else {
343	substr $self->{wbuf}, 0, $l, '';	1490	@linger = (); # end
344
345	if (length ($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	}	1491	}
355	});	1492	});
		1493	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1494	@linger = ();
		1495	});
		1496	}
		1497	}
		1498
		1499	=item $handle->destroy
		1500
		1501	Shuts down the handle object as much as possible - this call ensures that
		1502	no further callbacks will be invoked and resources will be freed as much
		1503	as possible. You must not call any methods on the object afterwards.
		1504
		1505	Normally, you can just "forget" any references to an AnyEvent::Handle
		1506	object and it will simply shut down. This works in fatal error and EOF
		1507	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1508	callback, so when you want to destroy the AnyEvent::Handle object from
		1509	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1510	that case.
		1511
		1512	The handle might still linger in the background and write out remaining
		1513	data, as specified by the C<linger> option, however.
		1514
		1515	=cut
		1516
		1517	sub destroy {
		1518	my ($self) = @_;
		1519
		1520	$self->DESTROY;
		1521	%$self = ();
		1522	}
		1523
		1524	=item AnyEvent::Handle::TLS_CTX
		1525
		1526	This function creates and returns the Net::SSLeay::CTX object used by
		1527	default for TLS mode.
		1528
		1529	The context is created like this:
		1530
		1531	Net::SSLeay::load_error_strings;
		1532	Net::SSLeay::SSLeay_add_ssl_algorithms;
		1533	Net::SSLeay::randomize;
		1534
		1535	my $CTX = Net::SSLeay::CTX_new;
		1536
		1537	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
		1538
		1539	=cut
		1540
		1541	our $TLS_CTX;
		1542
		1543	sub TLS_CTX() {
		1544	$TLS_CTX || do {
		1545	require Net::SSLeay;
		1546
		1547	Net::SSLeay::load_error_strings ();
		1548	Net::SSLeay::SSLeay_add_ssl_algorithms ();
		1549	Net::SSLeay::randomize ();
		1550
		1551	$TLS_CTX = Net::SSLeay::CTX_new ();
		1552
		1553	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
		1554
		1555	$TLS_CTX
		1556	}
356	}	1557	}
357		1558
358	=back	1559	=back
359		1560
		1561
		1562	=head1 NONFREQUENTLY ASKED QUESTIONS
		1563
		1564	=over 4
		1565
		1566	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1567	still get further invocations!
		1568
		1569	That's because AnyEvent::Handle keeps a reference to itself when handling
		1570	read or write callbacks.
		1571
		1572	It is only safe to "forget" the reference inside EOF or error callbacks,
		1573	from within all other callbacks, you need to explicitly call the C<<
		1574	->destroy >> method.
		1575
		1576	=item I get different callback invocations in TLS mode/Why can't I pause
		1577	reading?
		1578
		1579	Unlike, say, TCP, TLS connections do not consist of two independent
		1580	communication channels, one for each direction. Or put differently. The
		1581	read and write directions are not independent of each other: you cannot
		1582	write data unless you are also prepared to read, and vice versa.
		1583
		1584	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1585	callback invocations when you are not expecting any read data - the reason
		1586	is that AnyEvent::Handle always reads in TLS mode.
		1587
		1588	During the connection, you have to make sure that you always have a
		1589	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1590	connection (or when you no longer want to use it) you can call the
		1591	C<destroy> method.
		1592
		1593	=item How do I read data until the other side closes the connection?
		1594
		1595	If you just want to read your data into a perl scalar, the easiest way
		1596	to achieve this is by setting an C<on_read> callback that does nothing,
		1597	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1598	will be in C<$_[0]{rbuf}>:
		1599
		1600	$handle->on_read (sub { });
		1601	$handle->on_eof (undef);
		1602	$handle->on_error (sub {
		1603	my $data = delete $_[0]{rbuf};
		1604	undef $handle;
		1605	});
		1606
		1607	The reason to use C<on_error> is that TCP connections, due to latencies
		1608	and packets loss, might get closed quite violently with an error, when in
		1609	fact, all data has been received.
		1610
		1611	It is usually better to use acknowledgements when transferring data,
		1612	to make sure the other side hasn't just died and you got the data
		1613	intact. This is also one reason why so many internet protocols have an
		1614	explicit QUIT command.
		1615
		1616	=item I don't want to destroy the handle too early - how do I wait until
		1617	all data has been written?
		1618
		1619	After writing your last bits of data, set the C<on_drain> callback
		1620	and destroy the handle in there - with the default setting of
		1621	C<low_water_mark> this will be called precisely when all data has been
		1622	written to the socket:
		1623
		1624	$handle->push_write (...);
		1625	$handle->on_drain (sub {
		1626	warn "all data submitted to the kernel\n";
		1627	undef $handle;
		1628	});
		1629
		1630	=back
		1631
		1632
		1633	=head1 SUBCLASSING AnyEvent::Handle
		1634
		1635	In many cases, you might want to subclass AnyEvent::Handle.
		1636
		1637	To make this easier, a given version of AnyEvent::Handle uses these
		1638	conventions:
		1639
		1640	=over 4
		1641
		1642	=item * all constructor arguments become object members.
		1643
		1644	At least initially, when you pass a C<tls>-argument to the constructor it
		1645	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1646	mutated later on (for example C<tls> will hold the TLS connection object).
		1647
		1648	=item * other object member names are prefixed with an C<_>.
		1649
		1650	All object members not explicitly documented (internal use) are prefixed
		1651	with an underscore character, so the remaining non-C<_>-namespace is free
		1652	for use for subclasses.
		1653
		1654	=item * all members not documented here and not prefixed with an underscore
		1655	are free to use in subclasses.
		1656
		1657	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1658	member variables, but thats just life, at least it is documented.
		1659
		1660	=back
		1661
360	=head1 AUTHOR	1662	=head1 AUTHOR
361		1663
362	Robin Redeker, C<< <elmex at ta-sa.org> >>	1664	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		1665
409	=cut	1666	=cut
410		1667
411	1; # End of AnyEvent::Handle	1668	1; # End of AnyEvent::Handle

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