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Revision 1.4 by elmex, Sun Apr 27 20:20:20 2008 UTC vs.
Revision 1.98 by root, Thu Oct 2 15:11:01 2008 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 = 4.3;
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->broadcast;
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<$handle->{rbuf}> member directly.
		133
		134	When an EOF condition is detected then AnyEvent::Handle will first try to
		135	feed all the remaining data to the queued callbacks and C<on_read> before
		136	calling the C<on_eof> callback. If no progress can be made, then a fatal
		137	error will be raised (with C<$!> set to C<EPIPE>).
		138
		139	=item on_drain => $cb->($handle)
		140
		141	This sets the callback that is called when the write buffer becomes empty
		142	(or when the callback is set and the buffer is empty already).
		143
		144	To append to the write buffer, use the C<< ->push_write >> method.
		145
		146	This callback is useful when you don't want to put all of your write data
		147	into the queue at once, for example, when you want to write the contents
		148	of some file to the socket you might not want to read the whole file into
		149	memory and push it into the queue, but instead only read more data from
		150	the file when the write queue becomes empty.
		151
		152	=item timeout => $fractional_seconds
		153
		154	If non-zero, then this enables an "inactivity" timeout: whenever this many
		155	seconds pass without a successful read or write on the underlying file
		156	handle, the C<on_timeout> callback will be invoked (and if that one is
		157	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		158
		159	Note that timeout processing is also active when you currently do not have
		160	any outstanding read or write requests: If you plan to keep the connection
		161	idle then you should disable the timout temporarily or ignore the timeout
		162	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		163	restart the timeout.
		164
		165	Zero (the default) disables this timeout.
		166
		167	=item on_timeout => $cb->($handle)
		168
		169	Called whenever the inactivity timeout passes. If you return from this
		170	callback, then the timeout will be reset as if some activity had happened,
		171	so this condition is not fatal in any way.
		172
		173	=item rbuf_max => <bytes>
		174
		175	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		176	when the read buffer ever (strictly) exceeds this size. This is useful to
		177	avoid some forms of denial-of-service attacks.
		178
		179	For example, a server accepting connections from untrusted sources should
		180	be configured to accept only so-and-so much data that it cannot act on
		181	(for example, when expecting a line, an attacker could send an unlimited
		182	amount of data without a callback ever being called as long as the line
		183	isn't finished).
		184
		185	=item autocork => <boolean>
		186
		187	When disabled (the default), then C<push_write> will try to immediately
		188	write the data to the handle, if possible. This avoids having to register
		189	a write watcher and wait for the next event loop iteration, but can
		190	be inefficient if you write multiple small chunks (on the wire, this
		191	disadvantage is usually avoided by your kernel's nagle algorithm, see
		192	C<no_delay>, but this option can save costly syscalls).
		193
		194	When enabled, then writes will always be queued till the next event loop
		195	iteration. This is efficient when you do many small writes per iteration,
		196	but less efficient when you do a single write only per iteration (or when
		197	the write buffer often is full). It also increases write latency.
		198
		199	=item no_delay => <boolean>
		200
		201	When doing small writes on sockets, your operating system kernel might
		202	wait a bit for more data before actually sending it out. This is called
		203	the Nagle algorithm, and usually it is beneficial.
		204
		205	In some situations you want as low a delay as possible, which can be
		206	accomplishd by setting this option to a true value.
		207
		208	The default is your opertaing system's default behaviour (most likely
		209	enabled), this option explicitly enables or disables it, if possible.
		210
		211	=item read_size => <bytes>
		212
		213	The default read block size (the amount of bytes this module will
		214	try to read during each loop iteration, which affects memory
		215	requirements). Default: C<8192>.
		216
		217	=item low_water_mark => <bytes>
		218
		219	Sets the amount of bytes (default: C<0>) that make up an "empty" write
		220	buffer: If the write reaches this size or gets even samller it is
		221	considered empty.
		222
		223	Sometimes it can be beneficial (for performance reasons) to add data to
		224	the write buffer before it is fully drained, but this is a rare case, as
		225	the operating system kernel usually buffers data as well, so the default
		226	is good in almost all cases.
		227
		228	=item linger => <seconds>
		229
		230	If non-zero (default: C<3600>), then the destructor of the
		231	AnyEvent::Handle object will check whether there is still outstanding
		232	write data and will install a watcher that will write this data to the
		233	socket. No errors will be reported (this mostly matches how the operating
		234	system treats outstanding data at socket close time).
		235
		236	This will not work for partial TLS data that could not be encoded
		237	yet. This data will be lost. Calling the C<stoptls> method in time might
		238	help.
		239
		240	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		241
		242	When this parameter is given, it enables TLS (SSL) mode, that means
		243	AnyEvent will start a TLS handshake as soon as the conenction has been
		244	established and will transparently encrypt/decrypt data afterwards.
		245
		246	TLS mode requires Net::SSLeay to be installed (it will be loaded
		247	automatically when you try to create a TLS handle): this module doesn't
		248	have a dependency on that module, so if your module requires it, you have
		249	to add the dependency yourself.
		250
		251	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		252	C<accept>, and for the TLS client side of a connection, use C<connect>
		253	mode.
		254
		255	You can also provide your own TLS connection object, but you have
		256	to make sure that you call either C<Net::SSLeay::set_connect_state>
		257	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		258	AnyEvent::Handle.
		259
		260	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		261
		262	=item tls_ctx => $ssl_ctx
		263
		264	Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
		265	(unless a connection object was specified directly). If this parameter is
		266	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		267
		268	=item json => JSON or JSON::XS object
		269
		270	This is the json coder object used by the C<json> read and write types.
		271
		272	If you don't supply it, then AnyEvent::Handle will create and use a
		273	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		274	texts.
		275
		276	Note that you are responsible to depend on the JSON module if you want to
		277	use this functionality, as AnyEvent does not have a dependency itself.
		278
		279	=back
		280
		281	=cut
		282
		283	sub new {
		284	my $class = shift;
		285
		286	my $self = bless { @_ }, $class;
		287
		288	$self->{fh} or Carp::croak "mandatory argument fh is missing";
		289
		290	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		291
		292	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		293	if $self->{tls};
		294
		295	$self->{_activity} = AnyEvent->now;
		296	$self->_timeout;
		297
		298	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
		299	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		300
		301	$self->start_read
		302	if $self->{on_read};
		303
		304	$self
		305	}
		306
		307	sub _shutdown {
		308	my ($self) = @_;
		309
		310	delete $self->{_tw};
		311	delete $self->{_rw};
		312	delete $self->{_ww};
		313	delete $self->{fh};
		314
		315	&_freetls;
		316
		317	delete $self->{on_read};
		318	delete $self->{_queue};
		319	}
		320
		321	sub _error {
		322	my ($self, $errno, $fatal) = @_;
		323
		324	$self->_shutdown
		325	if $fatal;
		326
		327	$! = $errno;
		328
		329	if ($self->{on_error}) {
		330	$self->{on_error}($self, $fatal);
		331	} else {
		332	Carp::croak "AnyEvent::Handle uncaught error: $!";
		333	}
		334	}
		335
		336	=item $fh = $handle->fh
		337
		338	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		339
		340	=cut
		341
		342	sub fh { $_[0]{fh} }
		343
		344	=item $handle->on_error ($cb)
		345
		346	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		347
		348	=cut
		349
		350	sub on_error {
		351	$_[0]{on_error} = $_[1];
		352	}
		353
		354	=item $handle->on_eof ($cb)
		355
		356	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		357
		358	=cut
		359
		360	sub on_eof {
		361	$_[0]{on_eof} = $_[1];
		362	}
		363
		364	=item $handle->on_timeout ($cb)
		365
		366	Replace the current C<on_timeout> callback, or disables the callback (but
		367	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		368	argument and method.
		369
		370	=cut
		371
		372	sub on_timeout {
		373	$_[0]{on_timeout} = $_[1];
		374	}
		375
		376	=item $handle->autocork ($boolean)
		377
		378	Enables or disables the current autocork behaviour (see C<autocork>
		379	constructor argument).
		380
		381	=cut
		382
		383	=item $handle->no_delay ($boolean)
		384
		385	Enables or disables the C<no_delay> setting (see constructor argument of
		386	the same name for details).
		387
		388	=cut
		389
		390	sub no_delay {
		391	$_[0]{no_delay} = $_[1];
		392
		393	eval {
		394	local $SIG{__DIE__};
		395	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		396	};
		397	}
		398
		399	#############################################################################
		400
		401	=item $handle->timeout ($seconds)
		402
		403	Configures (or disables) the inactivity timeout.
		404
		405	=cut
		406
		407	sub timeout {
		408	my ($self, $timeout) = @_;
		409
		410	$self->{timeout} = $timeout;
		411	$self->_timeout;
		412	}
		413
		414	# reset the timeout watcher, as neccessary
		415	# also check for time-outs
		416	sub _timeout {
		417	my ($self) = @_;
		418
		419	if ($self->{timeout}) {
		420	my $NOW = AnyEvent->now;
		421
		422	# when would the timeout trigger?
		423	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		424
		425	# now or in the past already?
		426	if ($after <= 0) {
		427	$self->{_activity} = $NOW;
		428
		429	if ($self->{on_timeout}) {
		430	$self->{on_timeout}($self);
		431	} else {
		432	$self->_error (&Errno::ETIMEDOUT);
		433	}
		434
		435	# callback could have changed timeout value, optimise
		436	return unless $self->{timeout};
		437
		438	# calculate new after
		439	$after = $self->{timeout};
		440	}
		441
		442	Scalar::Util::weaken $self;
		443	return unless $self; # ->error could have destroyed $self
		444
		445	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		446	delete $self->{_tw};
		447	$self->_timeout;
		448	});
		449	} else {
		450	delete $self->{_tw};
		451	}
		452	}
		453
		454	#############################################################################
		455
		456	=back
		457
		458	=head2 WRITE QUEUE
		459
		460	AnyEvent::Handle manages two queues per handle, one for writing and one
		461	for reading.
		462
		463	The write queue is very simple: you can add data to its end, and
		464	AnyEvent::Handle will automatically try to get rid of it for you.
		465
		466	When data could be written and the write buffer is shorter then the low
		467	water mark, the C<on_drain> callback will be invoked.
		468
		469	=over 4
		470
		471	=item $handle->on_drain ($cb)
		472
		473	Sets the C<on_drain> callback or clears it (see the description of
		474	C<on_drain> in the constructor).
		475
		476	=cut
		477
		478	sub on_drain {
		479	my ($self, $cb) = @_;
		480
		481	$self->{on_drain} = $cb;
		482
		483	$cb->($self)
		484	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		485	}
		486
		487	=item $handle->push_write ($data)
		488
		489	Queues the given scalar to be written. You can push as much data as you
		490	want (only limited by the available memory), as C<AnyEvent::Handle>
		491	buffers it independently of the kernel.
		492
		493	=cut
		494
		495	sub _drain_wbuf {
		496	my ($self) = @_;
		497
		498	if (!$self->{_ww} && length $self->{wbuf}) {
		499
		500	Scalar::Util::weaken $self;
		501
		502	my $cb = sub {
		503	my $len = syswrite $self->{fh}, $self->{wbuf};
		504
		505	if ($len >= 0) {
		506	substr $self->{wbuf}, 0, $len, "";
		507
		508	$self->{_activity} = AnyEvent->now;
		509
		510	$self->{on_drain}($self)
		511	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		512	&& $self->{on_drain};
		513
		514	delete $self->{_ww} unless length $self->{wbuf};
		515	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		516	$self->_error ($!, 1);
		517	}
		518	};
		519
		520	# try to write data immediately
		521	$cb->() unless $self->{autocork};
		522
		523	# if still data left in wbuf, we need to poll
		524	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
		525	if length $self->{wbuf};
		526	};
		527	}
		528
		529	our %WH;
		530
		531	sub register_write_type($$) {
		532	$WH{$_[0]} = $_[1];
		533	}
		534
		535	sub push_write {
		536	my $self = shift;
		537
		538	if (@_ > 1) {
		539	my $type = shift;
		540
		541	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		542	->($self, @_);
		543	}
		544
		545	if ($self->{tls}) {
		546	$self->{_tls_wbuf} .= $_[0];
		547
		548	&_dotls ($self);
		549	} else {
		550	$self->{wbuf} .= $_[0];
		551	$self->_drain_wbuf;
		552	}
		553	}
		554
		555	=item $handle->push_write (type => @args)
		556
		557	Instead of formatting your data yourself, you can also let this module do
		558	the job by specifying a type and type-specific arguments.
		559
		560	Predefined types are (if you have ideas for additional types, feel free to
		561	drop by and tell us):
		562
		563	=over 4
		564
		565	=item netstring => $string
		566
		567	Formats the given value as netstring
		568	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		569
		570	=cut
		571
		572	register_write_type netstring => sub {
		573	my ($self, $string) = @_;
		574
		575	(length $string) . ":$string,"
		576	};
		577
		578	=item packstring => $format, $data
		579
		580	An octet string prefixed with an encoded length. The encoding C<$format>
		581	uses the same format as a Perl C<pack> format, but must specify a single
		582	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		583	optional C<!>, C<< < >> or C<< > >> modifier).
		584
		585	=cut
		586
		587	register_write_type packstring => sub {
		588	my ($self, $format, $string) = @_;
		589
		590	pack "$format/a*", $string
		591	};
		592
		593	=item json => $array_or_hashref
		594
		595	Encodes the given hash or array reference into a JSON object. Unless you
		596	provide your own JSON object, this means it will be encoded to JSON text
		597	in UTF-8.
		598
		599	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		600	one end of a handle and read them at the other end without using any
		601	additional framing.
		602
		603	The generated JSON text is guaranteed not to contain any newlines: While
		604	this module doesn't need delimiters after or between JSON texts to be
		605	able to read them, many other languages depend on that.
		606
		607	A simple RPC protocol that interoperates easily with others is to send
		608	JSON arrays (or objects, although arrays are usually the better choice as
		609	they mimic how function argument passing works) and a newline after each
		610	JSON text:
		611
		612	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		613	$handle->push_write ("\012");
		614
		615	An AnyEvent::Handle receiver would simply use the C<json> read type and
		616	rely on the fact that the newline will be skipped as leading whitespace:
		617
		618	$handle->push_read (json => sub { my $array = $_[1]; ... });
		619
		620	Other languages could read single lines terminated by a newline and pass
		621	this line into their JSON decoder of choice.
		622
		623	=cut
		624
		625	register_write_type json => sub {
		626	my ($self, $ref) = @_;
		627
		628	require JSON;
		629
		630	$self->{json} ? $self->{json}->encode ($ref)
		631	: JSON::encode_json ($ref)
		632	};
		633
		634	=item storable => $reference
		635
		636	Freezes the given reference using L<Storable> and writes it to the
		637	handle. Uses the C<nfreeze> format.
		638
		639	=cut
		640
		641	register_write_type storable => sub {
		642	my ($self, $ref) = @_;
		643
		644	require Storable;
		645
		646	pack "w/a*", Storable::nfreeze ($ref)
		647	};
		648
		649	=back
		650
		651	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		652
		653	This function (not method) lets you add your own types to C<push_write>.
		654	Whenever the given C<type> is used, C<push_write> will invoke the code
		655	reference with the handle object and the remaining arguments.
		656
		657	The code reference is supposed to return a single octet string that will
		658	be appended to the write buffer.
		659
		660	Note that this is a function, and all types registered this way will be
		661	global, so try to use unique names.
		662
		663	=cut
		664
		665	#############################################################################
		666
		667	=back
		668
		669	=head2 READ QUEUE
		670
		671	AnyEvent::Handle manages two queues per handle, one for writing and one
		672	for reading.
		673
		674	The read queue is more complex than the write queue. It can be used in two
		675	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		676	a queue.
		677
		678	In the simple case, you just install an C<on_read> callback and whenever
		679	new data arrives, it will be called. You can then remove some data (if
		680	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
		681	leave the data there if you want to accumulate more (e.g. when only a
		682	partial message has been received so far).
		683
		684	In the more complex case, you want to queue multiple callbacks. In this
		685	case, AnyEvent::Handle will call the first queued callback each time new
		686	data arrives (also the first time it is queued) and removes it when it has
		687	done its job (see C<push_read>, below).
		688
		689	This way you can, for example, push three line-reads, followed by reading
		690	a chunk of data, and AnyEvent::Handle will execute them in order.
		691
		692	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		693	the specified number of bytes which give an XML datagram.
		694
		695	# in the default state, expect some header bytes
		696	$handle->on_read (sub {
		697	# some data is here, now queue the length-header-read (4 octets)
		698	shift->unshift_read (chunk => 4, sub {
		699	# header arrived, decode
		700	my $len = unpack "N", $_[1];
		701
		702	# now read the payload
		703	shift->unshift_read (chunk => $len, sub {
		704	my $xml = $_[1];
		705	# handle xml
		706	});
		707	});
		708	});
		709
		710	Example 2: Implement a client for a protocol that replies either with "OK"
		711	and another line or "ERROR" for the first request that is sent, and 64
		712	bytes for the second request. Due to the availability of a queue, we can
		713	just pipeline sending both requests and manipulate the queue as necessary
		714	in the callbacks.
		715
		716	When the first callback is called and sees an "OK" response, it will
		717	C<unshift> another line-read. This line-read will be queued I<before> the
		718	64-byte chunk callback.
		719
		720	# request one, returns either "OK + extra line" or "ERROR"
		721	$handle->push_write ("request 1\015\012");
		722
		723	# we expect "ERROR" or "OK" as response, so push a line read
		724	$handle->push_read (line => sub {
		725	# if we got an "OK", we have to _prepend_ another line,
		726	# so it will be read before the second request reads its 64 bytes
		727	# which are already in the queue when this callback is called
		728	# we don't do this in case we got an error
		729	if ($_[1] eq "OK") {
49	on_readline => sub {	730	$_[0]->unshift_read (line => sub {
50	my ($ae_fh, @lines) = @_;	731	my $response = $_[1];
51	for (@lines) {	732	...
52	chomp;	733	});
53	print "Line: $_";	734	}
		735	});
		736
		737	# request two, simply returns 64 octets
		738	$handle->push_write ("request 2\015\012");
		739
		740	# simply read 64 bytes, always
		741	$handle->push_read (chunk => 64, sub {
		742	my $response = $_[1];
		743	...
		744	});
		745
		746	=over 4
		747
		748	=cut
		749
		750	sub _drain_rbuf {
		751	my ($self) = @_;
		752
		753	local $self->{_in_drain} = 1;
		754
		755	if (
		756	defined $self->{rbuf_max}
		757	&& $self->{rbuf_max} < length $self->{rbuf}
		758	) {
		759	$self->_error (&Errno::ENOSPC, 1), return;
		760	}
		761
		762	while () {
		763	my $len = length $self->{rbuf};
		764
		765	if (my $cb = shift @{ $self->{_queue} }) {
		766	unless ($cb->($self)) {
		767	if ($self->{_eof}) {
		768	# no progress can be made (not enough data and no data forthcoming)
		769	$self->_error (&Errno::EPIPE, 1), return;
54	}	770	}
		771
		772	unshift @{ $self->{_queue} }, $cb;
		773	last;
55	}	774	}
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}) {	775	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	776	last unless $len;
122		777
		778	$self->{on_read}($self);
		779
		780	if (
		781	$len == length $self->{rbuf} # if no data has been consumed
		782	&& !@{ $self->{_queue} } # and the queue is still empty
		783	&& $self->{on_read} # but we still have on_read
		784	) {
		785	# no further data will arrive
		786	# so no progress can be made
		787	$self->_error (&Errno::EPIPE, 1), return
		788	if $self->{_eof};
		789
		790	last; # more data might arrive
		791	}
		792	} else {
		793	# read side becomes idle
		794	delete $self->{_rw} unless $self->{tls};
		795	last;
		796	}
		797	}
		798
123	} elsif ($self->{on_eof}) {	799	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});
125
126	} elsif ($self->{on_error}) {	800	if ($self->{on_eof}) {
127	$self->on_eof ($self->{on_error});	801	$self->{on_eof}($self)
		802	} else {
		803	$self->_error (0, 1);
		804	}
128	}	805	}
129		806
130	return $self	807	# may need to restart read watcher
		808	unless ($self->{_rw}) {
		809	$self->start_read
		810	if $self->{on_read} || @{ $self->{_queue} };
		811	}
131	}	812	}
132		813
133	=item B<fh>	814	=item $handle->on_read ($cb)
134		815
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	816	This replaces the currently set C<on_read> callback, or clears it (when
136		817	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	818	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		819
149	=cut	820	=cut
150		821
151	sub on_read {	822	sub on_read {
152	my ($self, $cb) = @_;	823	my ($self, $cb) = @_;
		824
153	$self->{on_read} = $cb;	825	$self->{on_read} = $cb;
		826	$self->_drain_rbuf if $cb && !$self->{_in_drain};
		827	}
154		828
155	unless (defined $self->{on_read}) {	829	=item $handle->rbuf
156	delete $self->{on_read_w};	830
		831	Returns the read buffer (as a modifiable lvalue).
		832
		833	You can access the read buffer directly as the C<< ->{rbuf} >> member, if
		834	you want.
		835
		836	NOTE: The read buffer should only be used or modified if the C<on_read>,
		837	C<push_read> or C<unshift_read> methods are used. The other read methods
		838	automatically manage the read buffer.
		839
		840	=cut
		841
		842	sub rbuf : lvalue {
		843	$_[0]{rbuf}
		844	}
		845
		846	=item $handle->push_read ($cb)
		847
		848	=item $handle->unshift_read ($cb)
		849
		850	Append the given callback to the end of the queue (C<push_read>) or
		851	prepend it (C<unshift_read>).
		852
		853	The callback is called each time some additional read data arrives.
		854
		855	It must check whether enough data is in the read buffer already.
		856
		857	If not enough data is available, it must return the empty list or a false
		858	value, in which case it will be called repeatedly until enough data is
		859	available (or an error condition is detected).
		860
		861	If enough data was available, then the callback must remove all data it is
		862	interested in (which can be none at all) and return a true value. After returning
		863	true, it will be removed from the queue.
		864
		865	=cut
		866
		867	our %RH;
		868
		869	sub register_read_type($$) {
		870	$RH{$_[0]} = $_[1];
		871	}
		872
		873	sub push_read {
		874	my $self = shift;
		875	my $cb = pop;
		876
		877	if (@_) {
		878	my $type = shift;
		879
		880	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		881	->($self, $cb, @_);
		882	}
		883
		884	push @{ $self->{_queue} }, $cb;
		885	$self->_drain_rbuf unless $self->{_in_drain};
		886	}
		887
		888	sub unshift_read {
		889	my $self = shift;
		890	my $cb = pop;
		891
		892	if (@_) {
		893	my $type = shift;
		894
		895	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		896	->($self, $cb, @_);
		897	}
		898
		899
		900	unshift @{ $self->{_queue} }, $cb;
		901	$self->_drain_rbuf unless $self->{_in_drain};
		902	}
		903
		904	=item $handle->push_read (type => @args, $cb)
		905
		906	=item $handle->unshift_read (type => @args, $cb)
		907
		908	Instead of providing a callback that parses the data itself you can chose
		909	between a number of predefined parsing formats, for chunks of data, lines
		910	etc.
		911
		912	Predefined types are (if you have ideas for additional types, feel free to
		913	drop by and tell us):
		914
		915	=over 4
		916
		917	=item chunk => $octets, $cb->($handle, $data)
		918
		919	Invoke the callback only once C<$octets> bytes have been read. Pass the
		920	data read to the callback. The callback will never be called with less
		921	data.
		922
		923	Example: read 2 bytes.
		924
		925	$handle->push_read (chunk => 2, sub {
		926	warn "yay ", unpack "H*", $_[1];
		927	});
		928
		929	=cut
		930
		931	register_read_type chunk => sub {
		932	my ($self, $cb, $len) = @_;
		933
		934	sub {
		935	$len <= length $_[0]{rbuf} or return;
		936	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		937	1
		938	}
		939	};
		940
		941	=item line => [$eol, ]$cb->($handle, $line, $eol)
		942
		943	The callback will be called only once a full line (including the end of
		944	line marker, C<$eol>) has been read. This line (excluding the end of line
		945	marker) will be passed to the callback as second argument (C<$line>), and
		946	the end of line marker as the third argument (C<$eol>).
		947
		948	The end of line marker, C<$eol>, can be either a string, in which case it
		949	will be interpreted as a fixed record end marker, or it can be a regex
		950	object (e.g. created by C<qr>), in which case it is interpreted as a
		951	regular expression.
		952
		953	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		954	undef), then C<qr|\015?\012|> is used (which is good for most internet
		955	protocols).
		956
		957	Partial lines at the end of the stream will never be returned, as they are
		958	not marked by the end of line marker.
		959
		960	=cut
		961
		962	register_read_type line => sub {
		963	my ($self, $cb, $eol) = @_;
		964
		965	if (@_ < 3) {
		966	# this is more than twice as fast as the generic code below
		967	sub {
		968	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		969
		970	$cb->($_[0], $1, $2);
		971	1
		972	}
		973	} else {
		974	$eol = quotemeta $eol unless ref $eol;
		975	$eol = qr|^(.*?)($eol)|s;
		976
		977	sub {
		978	$_[0]{rbuf} =~ s/$eol// or return;
		979
		980	$cb->($_[0], $1, $2);
		981	1
		982	}
		983	}
		984	};
		985
		986	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		987
		988	Makes a regex match against the regex object C<$accept> and returns
		989	everything up to and including the match.
		990
		991	Example: read a single line terminated by '\n'.
		992
		993	$handle->push_read (regex => qr<\n>, sub { ... });
		994
		995	If C<$reject> is given and not undef, then it determines when the data is
		996	to be rejected: it is matched against the data when the C<$accept> regex
		997	does not match and generates an C<EBADMSG> error when it matches. This is
		998	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		999	receive buffer overflow).
		1000
		1001	Example: expect a single decimal number followed by whitespace, reject
		1002	anything else (not the use of an anchor).
		1003
		1004	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1005
		1006	If C<$skip> is given and not C<undef>, then it will be matched against
		1007	the receive buffer when neither C<$accept> nor C<$reject> match,
		1008	and everything preceding and including the match will be accepted
		1009	unconditionally. This is useful to skip large amounts of data that you
		1010	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1011	have to start matching from the beginning. This is purely an optimisation
		1012	and is usually worth only when you expect more than a few kilobytes.
		1013
		1014	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1015	expect the header to be very large (it isn't in practise, but...), we use
		1016	a skip regex to skip initial portions. The skip regex is tricky in that
		1017	it only accepts something not ending in either \015 or \012, as these are
		1018	required for the accept regex.
		1019
		1020	$handle->push_read (regex =>
		1021	qr<\015\012\015\012>,
		1022	undef, # no reject
		1023	qr<^.*[^\015\012]>,
		1024	sub { ... });
		1025
		1026	=cut
		1027
		1028	register_read_type regex => sub {
		1029	my ($self, $cb, $accept, $reject, $skip) = @_;
		1030
		1031	my $data;
		1032	my $rbuf = \$self->{rbuf};
		1033
		1034	sub {
		1035	# accept
		1036	if ($$rbuf =~ $accept) {
		1037	$data .= substr $$rbuf, 0, $+[0], "";
		1038	$cb->($self, $data);
157	return;	1039	return 1;
		1040	}
		1041
		1042	# reject
		1043	if ($reject && $$rbuf =~ $reject) {
		1044	$self->_error (&Errno::EBADMSG);
		1045	}
		1046
		1047	# skip
		1048	if ($skip && $$rbuf =~ $skip) {
		1049	$data .= substr $$rbuf, 0, $+[0], "";
		1050	}
		1051
		1052	()
158	}	1053	}
159		1054	};
160	$self->{on_read_w} =	1055
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1056	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1057
163	my $rbuf_len = length $self->{rbuf};	1058	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1059
165	if (defined $self->{read_size}) {	1060	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1061
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1062	=cut
168	} else {	1063
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1064	register_read_type netstring => sub {
		1065	my ($self, $cb) = @_;
		1066
		1067	sub {
		1068	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1069	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1070	$self->_error (&Errno::EBADMSG);
170	}	1071	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1072	return;
		1073	}
172		1074
173	if (not defined $l) {	1075	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1076
178	} elsif ($l == 0) {	1077	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1078	my $string = $_[1];
180	delete $self->{on_read_w};	1079	$_[0]->unshift_read (chunk => 1, sub {
181		1080	if ($_[1] eq ",") {
		1081	$cb->($_[0], $string);
182	} else {	1082	} else {
183	$self->{on_read}->($self);	1083	$self->_error (&Errno::EBADMSG);
		1084	}
		1085	});
		1086	});
		1087
		1088	1
		1089	}
		1090	};
		1091
		1092	=item packstring => $format, $cb->($handle, $string)
		1093
		1094	An octet string prefixed with an encoded length. The encoding C<$format>
		1095	uses the same format as a Perl C<pack> format, but must specify a single
		1096	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1097	optional C<!>, C<< < >> or C<< > >> modifier).
		1098
		1099	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1100	EPP uses a prefix of C<N> (4 octtes).
		1101
		1102	Example: read a block of data prefixed by its length in BER-encoded
		1103	format (very efficient).
		1104
		1105	$handle->push_read (packstring => "w", sub {
		1106	my ($handle, $data) = @_;
		1107	});
		1108
		1109	=cut
		1110
		1111	register_read_type packstring => sub {
		1112	my ($self, $cb, $format) = @_;
		1113
		1114	sub {
		1115	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1116	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1117	or return;
		1118
		1119	$format = length pack $format, $len;
		1120
		1121	# bypass unshift if we already have the remaining chunk
		1122	if ($format + $len <= length $_[0]{rbuf}) {
		1123	my $data = substr $_[0]{rbuf}, $format, $len;
		1124	substr $_[0]{rbuf}, 0, $format + $len, "";
		1125	$cb->($_[0], $data);
		1126	} else {
		1127	# remove prefix
		1128	substr $_[0]{rbuf}, 0, $format, "";
		1129
		1130	# read remaining chunk
		1131	$_[0]->unshift_read (chunk => $len, $cb);
		1132	}
		1133
		1134	1
		1135	}
		1136	};
		1137
		1138	=item json => $cb->($handle, $hash_or_arrayref)
		1139
		1140	Reads a JSON object or array, decodes it and passes it to the callback.
		1141
		1142	If a C<json> object was passed to the constructor, then that will be used
		1143	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1144
		1145	This read type uses the incremental parser available with JSON version
		1146	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1147	dependency on your own: this module will load the JSON module, but
		1148	AnyEvent does not depend on it itself.
		1149
		1150	Since JSON texts are fully self-delimiting, the C<json> read and write
		1151	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1152	the C<json> write type description, above, for an actual example.
		1153
		1154	=cut
		1155
		1156	register_read_type json => sub {
		1157	my ($self, $cb) = @_;
		1158
		1159	require JSON;
		1160
		1161	my $data;
		1162	my $rbuf = \$self->{rbuf};
		1163
		1164	my $json = $self->{json} ||= JSON->new->utf8;
		1165
		1166	sub {
		1167	my $ref = $json->incr_parse ($self->{rbuf});
		1168
		1169	if ($ref) {
		1170	$self->{rbuf} = $json->incr_text;
		1171	$json->incr_text = "";
		1172	$cb->($self, $ref);
		1173
		1174	1
		1175	} else {
		1176	$self->{rbuf} = "";
		1177	()
		1178	}
		1179	}
		1180	};
		1181
		1182	=item storable => $cb->($handle, $ref)
		1183
		1184	Deserialises a L<Storable> frozen representation as written by the
		1185	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1186	data).
		1187
		1188	Raises C<EBADMSG> error if the data could not be decoded.
		1189
		1190	=cut
		1191
		1192	register_read_type storable => sub {
		1193	my ($self, $cb) = @_;
		1194
		1195	require Storable;
		1196
		1197	sub {
		1198	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1199	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1200	or return;
		1201
		1202	my $format = length pack "w", $len;
		1203
		1204	# bypass unshift if we already have the remaining chunk
		1205	if ($format + $len <= length $_[0]{rbuf}) {
		1206	my $data = substr $_[0]{rbuf}, $format, $len;
		1207	substr $_[0]{rbuf}, 0, $format + $len, "";
		1208	$cb->($_[0], Storable::thaw ($data));
		1209	} else {
		1210	# remove prefix
		1211	substr $_[0]{rbuf}, 0, $format, "";
		1212
		1213	# read remaining chunk
		1214	$_[0]->unshift_read (chunk => $len, sub {
		1215	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1216	$cb->($_[0], $ref);
		1217	} else {
		1218	$self->_error (&Errno::EBADMSG);
		1219	}
		1220	});
		1221	}
		1222
		1223	1
		1224	}
		1225	};
		1226
		1227	=back
		1228
		1229	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1230
		1231	This function (not method) lets you add your own types to C<push_read>.
		1232
		1233	Whenever the given C<type> is used, C<push_read> will invoke the code
		1234	reference with the handle object, the callback and the remaining
		1235	arguments.
		1236
		1237	The code reference is supposed to return a callback (usually a closure)
		1238	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1239
		1240	It should invoke the passed callback when it is done reading (remember to
		1241	pass C<$handle> as first argument as all other callbacks do that).
		1242
		1243	Note that this is a function, and all types registered this way will be
		1244	global, so try to use unique names.
		1245
		1246	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1247	search for C<register_read_type>)).
		1248
		1249	=item $handle->stop_read
		1250
		1251	=item $handle->start_read
		1252
		1253	In rare cases you actually do not want to read anything from the
		1254	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1255	any queued callbacks will be executed then. To start reading again, call
		1256	C<start_read>.
		1257
		1258	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1259	you change the C<on_read> callback or push/unshift a read callback, and it
		1260	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1261	there are any read requests in the queue.
		1262
		1263	These methods will have no effect when in TLS mode (as TLS doesn't support
		1264	half-duplex connections).
		1265
		1266	=cut
		1267
		1268	sub stop_read {
		1269	my ($self) = @_;
		1270
		1271	delete $self->{_rw} unless $self->{tls};
		1272	}
		1273
		1274	sub start_read {
		1275	my ($self) = @_;
		1276
		1277	unless ($self->{_rw} || $self->{_eof}) {
		1278	Scalar::Util::weaken $self;
		1279
		1280	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1281	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1282	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1283
		1284	if ($len > 0) {
		1285	$self->{_activity} = AnyEvent->now;
		1286
		1287	if ($self->{tls}) {
		1288	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1289
		1290	&_dotls ($self);
		1291	} else {
		1292	$self->_drain_rbuf unless $self->{_in_drain};
		1293	}
		1294
		1295	} elsif (defined $len) {
		1296	delete $self->{_rw};
		1297	$self->{_eof} = 1;
		1298	$self->_drain_rbuf unless $self->{_in_drain};
		1299
		1300	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1301	return $self->_error ($!, 1);
184	}	1302	}
185	});	1303	});
		1304	}
186	}	1305	}
187		1306
188	=item B<on_error ($callback)>	1307	# poll the write BIO and send the data if applicable
189		1308	sub _dotls {
190	Whenever a read or write operation resulted in an error the C<$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, $cb) = @_;	1309	my ($self) = @_;
240		1310
241	$self->{read_cb} = $cb;	1311	my $tmp;
242	my $old_blk_size = $self->{read_block_size};
243	$self->{read_block_size} = $len;
244		1312
245	$self->on_read (sub {	1313	if (length $self->{_tls_wbuf}) {
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";	1314	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
247		1315	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, $len, ''));
252	}	1316	}
253	});	1317	}
254	}
255		1318
256	=item B<readlines ($callback)>	1319	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1320	unless (length $tmp) {
		1321	# let's treat SSL-eof as we treat normal EOF
		1322	delete $self->{_rw};
		1323	$self->{_eof} = 1;
		1324	&_freetls;
		1325	}
257		1326
258	=item B<readlines ($sep, $callback)>	1327	$self->{rbuf} .= $tmp;
		1328	$self->_drain_rbuf unless $self->{_in_drain};
		1329	$self->{tls} or return; # tls session might have gone away in callback
		1330	}
259		1331
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1332	$tmp = Net::SSLeay::get_error ($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		1333
264	The C<$callback> will be called when at least one	1334	if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
265	line could be read. The first argument to the C<$callback> will be the L<AnyEvent::Handle>	1335	if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
266	object itself and the rest of the arguments will be the read lines.	1336	return $self->_error ($!, 1);
		1337	} elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
		1338	return $self->_error (&Errno::EIO, 1);
		1339	}
267		1340
268	NOTE: This method will override any callbacks installed via the C<on_read> method.	1341	# all other errors are fine for our purposes
		1342	}
269		1343
270	=cut	1344	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1345	$self->{wbuf} .= $tmp;
		1346	$self->_drain_wbuf;
		1347	}
		1348	}
271		1349
272	sub readlines {	1350	=item $handle->starttls ($tls[, $tls_ctx])
		1351
		1352	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1353	object is created, you can also do that at a later time by calling
		1354	C<starttls>.
		1355
		1356	The first argument is the same as the C<tls> constructor argument (either
		1357	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1358
		1359	The second argument is the optional C<Net::SSLeay::CTX> object that is
		1360	used when AnyEvent::Handle has to create its own TLS connection object.
		1361
		1362	The TLS connection object will end up in C<< $handle->{tls} >> after this
		1363	call and can be used or changed to your liking. Note that the handshake
		1364	might have already started when this function returns.
		1365
		1366	If it an error to start a TLS handshake more than once per
		1367	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1368
		1369	=cut
		1370
		1371	sub starttls {
273	my ($self, $NL, $cb) = @_;	1372	my ($self, $ssl, $ctx) = @_;
274		1373
275	if (ref $NL) {	1374	require Net::SSLeay;
276	$cb = $NL;	1375
277	$NL = "\n";	1376	Carp::croak "it is an error to call starttls more than once on an Anyevent::Handle object"
		1377	if $self->{tls};
278	}	1378
279		1379	if ($ssl eq "accept") {
280	$self->{on_readline} = $cb;	1380	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
281		1381	Net::SSLeay::set_accept_state ($ssl);
282	$self->on_read (sub {	1382	} elsif ($ssl eq "connect") {
283	my @lines;	1383	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
284	push @lines, $1 while $_[0]->{rbuf} =~ s/(.*)$NL//;	1384	Net::SSLeay::set_connect_state ($ssl);
285	$self->{on_readline}->($_[0], @lines);
286	});	1385	}
287	}
288		1386
289	=item B<write ($data)>	1387	$self->{tls} = $ssl;
290		1388
291	=item B<write ($callback)>	1389	# basically, this is deep magic (because SSL_read should have the same issues)
		1390	# but the openssl maintainers basically said: "trust us, it just works".
		1391	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1392	# and mismaintained ssleay-module doesn't even offer them).
		1393	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1394	#
		1395	# in short: this is a mess.
		1396	#
		1397	# note that we do not try to keep the length constant between writes as we are required to do.
		1398	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1399	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1400	# have identity issues in that area.
		1401	Net::SSLeay::CTX_set_mode ($self->{tls},
		1402	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1403	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
292		1404
293	=item B<write ($data, $callback)>	1405	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1406	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
294		1407
295	This method will write C<$data> to the filehandle and call the C<$callback>	1408	Net::SSLeay::set_bio ($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		1409
299	=cut	1410	&_dotls; # need to trigger the initial handshake
300		1411	$self->start_read; # make sure we actually do read
301	sub write {
302	my ($self, $data, $cb) = @_;
303	if (ref $data) { $cb = $data; undef $data }
304	push @{$self->{write_bufs}}, [$data, $cb];
305	$self->_check_writer;
306	}	1412	}
307		1413
308	sub _check_writer {	1414	=item $handle->stoptls
		1415
		1416	Shuts down the SSL connection - this makes a proper EOF handshake by
		1417	sending a close notify to the other side, but since OpenSSL doesn't
		1418	support non-blocking shut downs, it is not possible to re-use the stream
		1419	afterwards.
		1420
		1421	=cut
		1422
		1423	sub stoptls {
309	my ($self) = @_;	1424	my ($self) = @_;
310		1425
311	if ($self->{write_w}) {	1426	if ($self->{tls}) {
312	unless ($self->{write_cb}) {	1427	Net::SSLeay::shutdown ($self->{tls});
313	while (@{$self->{write_bufs}} && not defined $self->{write_bufs}->[0]->[1]) {	1428
314	my $wba = shift @{$self->{write_bufs}};	1429	&_dotls;
315	$self->{wbuf} .= $wba->[0];	1430
316	}	1431	# we don't give a shit. no, we do, but we can't. no...
317	}	1432	# we, we... have to use openssl :/
318	return;	1433	&_freetls;
		1434	}
		1435	}
		1436
		1437	sub _freetls {
		1438	my ($self) = @_;
		1439
		1440	return unless $self->{tls};
		1441
		1442	Net::SSLeay::free (delete $self->{tls});
319	}	1443
		1444	delete @$self{qw(_rbio _wbio _tls_wbuf)};
		1445	}
320		1446
321	my $wba = shift @{$self->{write_bufs}}	1447	sub DESTROY {
322	or return;	1448	my $self = shift;
323		1449
324	unless (defined $wba->[0]) {	1450	&_freetls;
325	$wba->[1]->($self) if $wba->[1];
326	$self->_check_writer;
327	return;
328	}
329		1451
330	$self->{wbuf} = $wba->[0];	1452	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
331	$self->{write_cb} = $wba->[1];
332		1453
333	$self->{write_w} =	1454	if ($linger && length $self->{wbuf}) {
334	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1455	my $fh = delete $self->{fh};
		1456	my $wbuf = delete $self->{wbuf};
		1457
		1458	my @linger;
		1459
		1460	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
335	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1461	my $len = syswrite $fh, $wbuf, length $wbuf;
336		1462
337	if (not defined $l) {	1463	if ($len > 0) {
338	return if $! == EAGAIN || $! == EINTR;	1464	substr $wbuf, 0, $len, "";
339	delete $self->{write_w};
340	$self->{on_error}->($self) if $self->{on_error};
341
342	} else {	1465	} else {
343	substr $self->{wbuf}, 0, $l, '';	1466	@linger = (); # end
344
345	if (length ($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	}	1467	}
355	});	1468	});
		1469	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1470	@linger = ();
		1471	});
		1472	}
		1473	}
		1474
		1475	=item AnyEvent::Handle::TLS_CTX
		1476
		1477	This function creates and returns the Net::SSLeay::CTX object used by
		1478	default for TLS mode.
		1479
		1480	The context is created like this:
		1481
		1482	Net::SSLeay::load_error_strings;
		1483	Net::SSLeay::SSLeay_add_ssl_algorithms;
		1484	Net::SSLeay::randomize;
		1485
		1486	my $CTX = Net::SSLeay::CTX_new;
		1487
		1488	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
		1489
		1490	=cut
		1491
		1492	our $TLS_CTX;
		1493
		1494	sub TLS_CTX() {
		1495	$TLS_CTX || do {
		1496	require Net::SSLeay;
		1497
		1498	Net::SSLeay::load_error_strings ();
		1499	Net::SSLeay::SSLeay_add_ssl_algorithms ();
		1500	Net::SSLeay::randomize ();
		1501
		1502	$TLS_CTX = Net::SSLeay::CTX_new ();
		1503
		1504	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
		1505
		1506	$TLS_CTX
		1507	}
356	}	1508	}
357		1509
358	=back	1510	=back
359		1511
		1512
		1513	=head1 NONFREQUENTLY ASKED QUESTIONS
		1514
		1515	=over 4
		1516
		1517	=item How do I read data until the other side closes the connection?
		1518
		1519	If you just want to read your data into a perl scalar, the easiest way
		1520	to achieve this is by setting an C<on_read> callback that does nothing,
		1521	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1522	will be in C<$_[0]{rbuf}>:
		1523
		1524	$handle->on_read (sub { });
		1525	$handle->on_eof (undef);
		1526	$handle->on_error (sub {
		1527	my $data = delete $_[0]{rbuf};
		1528	undef $handle;
		1529	});
		1530
		1531	The reason to use C<on_error> is that TCP connections, due to latencies
		1532	and packets loss, might get closed quite violently with an error, when in
		1533	fact, all data has been received.
		1534
		1535	It is usually better to use acknowledgements when transfering data,
		1536	to make sure the other side hasn't just died and you got the data
		1537	intact. This is also one reason why so many internet protocols have an
		1538	explicit QUIT command.
		1539
		1540
		1541	=item I don't want to destroy the handle too early - how do I wait until
		1542	all data has been written?
		1543
		1544	After writing your last bits of data, set the C<on_drain> callback
		1545	and destroy the handle in there - with the default setting of
		1546	C<low_water_mark> this will be called precisely when all data has been
		1547	written to the socket:
		1548
		1549	$handle->push_write (...);
		1550	$handle->on_drain (sub {
		1551	warn "all data submitted to the kernel\n";
		1552	undef $handle;
		1553	});
		1554
		1555	=back
		1556
		1557
		1558	=head1 SUBCLASSING AnyEvent::Handle
		1559
		1560	In many cases, you might want to subclass AnyEvent::Handle.
		1561
		1562	To make this easier, a given version of AnyEvent::Handle uses these
		1563	conventions:
		1564
		1565	=over 4
		1566
		1567	=item * all constructor arguments become object members.
		1568
		1569	At least initially, when you pass a C<tls>-argument to the constructor it
		1570	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1571	mutated later on (for example C<tls> will hold the TLS connection object).
		1572
		1573	=item * other object member names are prefixed with an C<_>.
		1574
		1575	All object members not explicitly documented (internal use) are prefixed
		1576	with an underscore character, so the remaining non-C<_>-namespace is free
		1577	for use for subclasses.
		1578
		1579	=item * all members not documented here and not prefixed with an underscore
		1580	are free to use in subclasses.
		1581
		1582	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1583	member variables, but thats just life, at least it is documented.
		1584
		1585	=back
		1586
360	=head1 AUTHOR	1587	=head1 AUTHOR
361		1588
362	Robin Redeker, C<< <elmex at ta-sa.org> >>	1589	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
363		1590
364	=cut	1591	=cut
365		1592
366	1; # End of AnyEvent::Handle	1593	1; # End of AnyEvent::Handle

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