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Revision 1.4 by elmex, Sun Apr 27 20:20:20 2008 UTC vs.
Revision 1.95 by root, Thu Oct 2 06:42:39 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	$cv->recv;
		47
		48	=head1 DESCRIPTION
		49
		50	This module is a helper module to make it easier to do event-based I/O on
		51	filehandles. For utility functions for doing non-blocking connects and accepts
		52	on sockets see L<AnyEvent::Util>.
		53
		54	The L<AnyEvent::Intro> tutorial contains some well-documented
		55	AnyEvent::Handle examples.
		56
		57	In the following, when the documentation refers to of "bytes" then this
		58	means characters. As sysread and syswrite are used for all I/O, their
		59	treatment of characters applies to this module as well.
		60
		61	All callbacks will be invoked with the handle object as their first
		62	argument.
		63
		64	=head2 SIGPIPE is not handled by this module
		65
		66	SIGPIPE is not handled by this module, so one of the practical
		67	requirements of using it is to ignore SIGPIPE (C<$SIG{PIPE} =
		68	'IGNORE'>). At least, this is highly recommend in a networked program: If
		69	you use AnyEvent::Handle in a filter program (like sort), exiting on
		70	SIGPIPE is probably the right thing to do.
		71
		72	=head1 METHODS
		73
		74	=over 4
		75
		76	=item B<new (%args)>
		77
		78	The constructor supports these arguments (all as key => value pairs).
		79
		80	=over 4
		81
		82	=item fh => $filehandle [MANDATORY]
		83
		84	The filehandle this L<AnyEvent::Handle> object will operate on.
		85
		86	NOTE: The filehandle will be set to non-blocking mode (using
		87	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		88	that mode.
		89
		90	=item on_eof => $cb->($handle)
		91
		92	Set the callback to be called when an end-of-file condition is detected,
		93	i.e. in the case of a socket, when the other side has closed the
		94	connection cleanly.
		95
		96	For sockets, this just means that the other side has stopped sending data,
		97	you can still try to write data, and, in fact, one can return from the eof
		98	callback and continue writing data, as only the read part has been shut
		99	down.
		100
		101	While not mandatory, it is I<highly> recommended to set an eof callback,
		102	otherwise you might end up with a closed socket while you are still
		103	waiting for data.
		104
		105	If an EOF condition has been detected but no C<on_eof> callback has been
		106	set, then a fatal error will be raised with C<$!> set to <0>.
		107
		108	=item on_error => $cb->($handle, $fatal)
		109
		110	This is the error callback, which is called when, well, some error
		111	occured, such as not being able to resolve the hostname, failure to
		112	connect or a read error.
		113
		114	Some errors are fatal (which is indicated by C<$fatal> being true). On
		115	fatal errors the handle object will be shut down and will not be usable
		116	(but you are free to look at the current C<< ->rbuf >>). Examples of fatal
		117	errors are an EOF condition with active (but unsatisifable) read watchers
		118	(C<EPIPE>) or I/O errors.
		119
		120	Non-fatal errors can be retried by simply returning, but it is recommended
		121	to simply ignore this parameter and instead abondon the handle object
		122	when this callback is invoked. Examples of non-fatal errors are timeouts
		123	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		124
		125	On callback entrance, the value of C<$!> contains the operating system
		126	error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).
		127
		128	While not mandatory, it is I<highly> recommended to set this callback, as
		129	you will not be notified of errors otherwise. The default simply calls
		130	C<croak>.
		131
		132	=item on_read => $cb->($handle)
		133
		134	This sets the default read callback, which is called when data arrives
		135	and no read request is in the queue (unlike read queue callbacks, this
		136	callback will only be called when at least one octet of data is in the
		137	read buffer).
		138
		139	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
		140	method or access the C<$handle->{rbuf}> member directly.
		141
		142	When an EOF condition is detected then AnyEvent::Handle will first try to
		143	feed all the remaining data to the queued callbacks and C<on_read> before
		144	calling the C<on_eof> callback. If no progress can be made, then a fatal
		145	error will be raised (with C<$!> set to C<EPIPE>).
		146
		147	=item on_drain => $cb->($handle)
		148
		149	This sets the callback that is called when the write buffer becomes empty
		150	(or when the callback is set and the buffer is empty already).
		151
		152	To append to the write buffer, use the C<< ->push_write >> method.
		153
		154	This callback is useful when you don't want to put all of your write data
		155	into the queue at once, for example, when you want to write the contents
		156	of some file to the socket you might not want to read the whole file into
		157	memory and push it into the queue, but instead only read more data from
		158	the file when the write queue becomes empty.
		159
		160	=item timeout => $fractional_seconds
		161
		162	If non-zero, then this enables an "inactivity" timeout: whenever this many
		163	seconds pass without a successful read or write on the underlying file
		164	handle, the C<on_timeout> callback will be invoked (and if that one is
		165	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		166
		167	Note that timeout processing is also active when you currently do not have
		168	any outstanding read or write requests: If you plan to keep the connection
		169	idle then you should disable the timout temporarily or ignore the timeout
		170	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		171	restart the timeout.
		172
		173	Zero (the default) disables this timeout.
		174
		175	=item on_timeout => $cb->($handle)
		176
		177	Called whenever the inactivity timeout passes. If you return from this
		178	callback, then the timeout will be reset as if some activity had happened,
		179	so this condition is not fatal in any way.
		180
		181	=item rbuf_max => <bytes>
		182
		183	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		184	when the read buffer ever (strictly) exceeds this size. This is useful to
		185	avoid some forms of denial-of-service attacks.
		186
		187	For example, a server accepting connections from untrusted sources should
		188	be configured to accept only so-and-so much data that it cannot act on
		189	(for example, when expecting a line, an attacker could send an unlimited
		190	amount of data without a callback ever being called as long as the line
		191	isn't finished).
		192
		193	=item autocork => <boolean>
		194
		195	When disabled (the default), then C<push_write> will try to immediately
		196	write the data to the handle, if possible. This avoids having to register
		197	a write watcher and wait for the next event loop iteration, but can
		198	be inefficient if you write multiple small chunks (on the wire, this
		199	disadvantage is usually avoided by your kernel's nagle algorithm, see
		200	C<no_delay>, but this option can save costly syscalls).
		201
		202	When enabled, then writes will always be queued till the next event loop
		203	iteration. This is efficient when you do many small writes per iteration,
		204	but less efficient when you do a single write only per iteration (or when
		205	the write buffer often is full). It also increases write latency.
		206
		207	=item no_delay => <boolean>
		208
		209	When doing small writes on sockets, your operating system kernel might
		210	wait a bit for more data before actually sending it out. This is called
		211	the Nagle algorithm, and usually it is beneficial.
		212
		213	In some situations you want as low a delay as possible, which can be
		214	accomplishd by setting this option to a true value.
		215
		216	The default is your opertaing system's default behaviour (most likely
		217	enabled), this option explicitly enables or disables it, if possible.
		218
		219	=item read_size => <bytes>
		220
		221	The default read block size (the amount of bytes this module will
		222	try to read during each loop iteration, which affects memory
		223	requirements). Default: C<8192>.
		224
		225	=item low_water_mark => <bytes>
		226
		227	Sets the amount of bytes (default: C<0>) that make up an "empty" write
		228	buffer: If the write reaches this size or gets even samller it is
		229	considered empty.
		230
		231	Sometimes it can be beneficial (for performance reasons) to add data to
		232	the write buffer before it is fully drained, but this is a rare case, as
		233	the operating system kernel usually buffers data as well, so the default
		234	is good in almost all cases.
		235
		236	=item linger => <seconds>
		237
		238	If non-zero (default: C<3600>), then the destructor of the
		239	AnyEvent::Handle object will check whether there is still outstanding
		240	write data and will install a watcher that will write this data to the
		241	socket. No errors will be reported (this mostly matches how the operating
		242	system treats outstanding data at socket close time).
		243
		244	This will not work for partial TLS data that could not be encoded
		245	yet. This data will be lost. Calling the C<stoptls> method in time might
		246	help.
		247
		248	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		249
		250	When this parameter is given, it enables TLS (SSL) mode, that means
		251	AnyEvent will start a TLS handshake as soon as the conenction has been
		252	established and will transparently encrypt/decrypt data afterwards.
		253
		254	TLS mode requires Net::SSLeay to be installed (it will be loaded
		255	automatically when you try to create a TLS handle): this module doesn't
		256	have a dependency on that module, so if your module requires it, you have
		257	to add the dependency yourself.
		258
		259	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		260	C<accept>, and for the TLS client side of a connection, use C<connect>
		261	mode.
		262
		263	You can also provide your own TLS connection object, but you have
		264	to make sure that you call either C<Net::SSLeay::set_connect_state>
		265	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		266	AnyEvent::Handle.
		267
		268	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		269
		270	=item tls_ctx => $ssl_ctx
		271
		272	Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
		273	(unless a connection object was specified directly). If this parameter is
		274	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		275
		276	=item json => JSON or JSON::XS object
		277
		278	This is the json coder object used by the C<json> read and write types.
		279
		280	If you don't supply it, then AnyEvent::Handle will create and use a
		281	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		282	texts.
		283
		284	Note that you are responsible to depend on the JSON module if you want to
		285	use this functionality, as AnyEvent does not have a dependency itself.
		286
		287	=back
		288
		289	=cut
		290
		291	sub new {
		292	my $class = shift;
		293
		294	my $self = bless { @_ }, $class;
		295
		296	$self->{fh} or Carp::croak "mandatory argument fh is missing";
		297
		298	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		299
		300	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		301	if $self->{tls};
		302
		303	$self->{_activity} = AnyEvent->now;
		304	$self->_timeout;
		305
		306	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
		307	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		308
		309	$self->start_read
		310	if $self->{on_read};
		311
		312	$self
		313	}
		314
		315	sub _shutdown {
		316	my ($self) = @_;
		317
		318	delete $self->{_tw};
		319	delete $self->{_rw};
		320	delete $self->{_ww};
		321	delete $self->{fh};
		322
		323	&_freetls;
		324
		325	delete $self->{on_read};
		326	delete $self->{_queue};
		327	}
		328
		329	sub _error {
		330	my ($self, $errno, $fatal) = @_;
		331
		332	$self->_shutdown
		333	if $fatal;
		334
		335	$! = $errno;
		336
		337	if ($self->{on_error}) {
		338	$self->{on_error}($self, $fatal);
		339	} else {
		340	Carp::croak "AnyEvent::Handle uncaught error: $!";
		341	}
		342	}
		343
		344	=item $fh = $handle->fh
		345
		346	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		347
		348	=cut
		349
		350	sub fh { $_[0]{fh} }
		351
		352	=item $handle->on_error ($cb)
		353
		354	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		355
		356	=cut
		357
		358	sub on_error {
		359	$_[0]{on_error} = $_[1];
		360	}
		361
		362	=item $handle->on_eof ($cb)
		363
		364	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		365
		366	=cut
		367
		368	sub on_eof {
		369	$_[0]{on_eof} = $_[1];
		370	}
		371
		372	=item $handle->on_timeout ($cb)
		373
		374	Replace the current C<on_timeout> callback, or disables the callback (but
		375	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		376	argument and method.
		377
		378	=cut
		379
		380	sub on_timeout {
		381	$_[0]{on_timeout} = $_[1];
		382	}
		383
		384	=item $handle->autocork ($boolean)
		385
		386	Enables or disables the current autocork behaviour (see C<autocork>
		387	constructor argument).
		388
		389	=cut
		390
		391	=item $handle->no_delay ($boolean)
		392
		393	Enables or disables the C<no_delay> setting (see constructor argument of
		394	the same name for details).
		395
		396	=cut
		397
		398	sub no_delay {
		399	$_[0]{no_delay} = $_[1];
		400
		401	eval {
		402	local $SIG{__DIE__};
		403	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		404	};
		405	}
		406
		407	#############################################################################
		408
		409	=item $handle->timeout ($seconds)
		410
		411	Configures (or disables) the inactivity timeout.
		412
		413	=cut
		414
		415	sub timeout {
		416	my ($self, $timeout) = @_;
		417
		418	$self->{timeout} = $timeout;
		419	$self->_timeout;
		420	}
		421
		422	# reset the timeout watcher, as neccessary
		423	# also check for time-outs
		424	sub _timeout {
		425	my ($self) = @_;
		426
		427	if ($self->{timeout}) {
		428	my $NOW = AnyEvent->now;
		429
		430	# when would the timeout trigger?
		431	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		432
		433	# now or in the past already?
		434	if ($after <= 0) {
		435	$self->{_activity} = $NOW;
		436
		437	if ($self->{on_timeout}) {
		438	$self->{on_timeout}($self);
		439	} else {
		440	$self->_error (&Errno::ETIMEDOUT);
		441	}
		442
		443	# callback could have changed timeout value, optimise
		444	return unless $self->{timeout};
		445
		446	# calculate new after
		447	$after = $self->{timeout};
		448	}
		449
		450	Scalar::Util::weaken $self;
		451	return unless $self; # ->error could have destroyed $self
		452
		453	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		454	delete $self->{_tw};
		455	$self->_timeout;
		456	});
		457	} else {
		458	delete $self->{_tw};
		459	}
		460	}
		461
		462	#############################################################################
		463
		464	=back
		465
		466	=head2 WRITE QUEUE
		467
		468	AnyEvent::Handle manages two queues per handle, one for writing and one
		469	for reading.
		470
		471	The write queue is very simple: you can add data to its end, and
		472	AnyEvent::Handle will automatically try to get rid of it for you.
		473
		474	When data could be written and the write buffer is shorter then the low
		475	water mark, the C<on_drain> callback will be invoked.
		476
		477	=over 4
		478
		479	=item $handle->on_drain ($cb)
		480
		481	Sets the C<on_drain> callback or clears it (see the description of
		482	C<on_drain> in the constructor).
		483
		484	=cut
		485
		486	sub on_drain {
		487	my ($self, $cb) = @_;
		488
		489	$self->{on_drain} = $cb;
		490
		491	$cb->($self)
		492	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		493	}
		494
		495	=item $handle->push_write ($data)
		496
		497	Queues the given scalar to be written. You can push as much data as you
		498	want (only limited by the available memory), as C<AnyEvent::Handle>
		499	buffers it independently of the kernel.
		500
		501	=cut
		502
		503	sub _drain_wbuf {
		504	my ($self) = @_;
		505
		506	if (!$self->{_ww} && length $self->{wbuf}) {
		507
		508	Scalar::Util::weaken $self;
		509
		510	my $cb = sub {
		511	my $len = syswrite $self->{fh}, $self->{wbuf};
		512
		513	if ($len >= 0) {
		514	substr $self->{wbuf}, 0, $len, "";
		515
		516	$self->{_activity} = AnyEvent->now;
		517
		518	$self->{on_drain}($self)
		519	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		520	&& $self->{on_drain};
		521
		522	delete $self->{_ww} unless length $self->{wbuf};
		523	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		524	$self->_error ($!, 1);
		525	}
		526	};
		527
		528	# try to write data immediately
		529	$cb->() unless $self->{autocork};
		530
		531	# if still data left in wbuf, we need to poll
		532	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
		533	if length $self->{wbuf};
		534	};
		535	}
		536
		537	our %WH;
		538
		539	sub register_write_type($$) {
		540	$WH{$_[0]} = $_[1];
		541	}
		542
		543	sub push_write {
		544	my $self = shift;
		545
		546	if (@_ > 1) {
		547	my $type = shift;
		548
		549	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		550	->($self, @_);
		551	}
		552
		553	if ($self->{tls}) {
		554	$self->{_tls_wbuf} .= $_[0];
		555	&_dotls ($self);
		556	} else {
		557	$self->{wbuf} .= $_[0];
		558	$self->_drain_wbuf;
		559	}
		560	}
		561
		562	=item $handle->push_write (type => @args)
		563
		564	Instead of formatting your data yourself, you can also let this module do
		565	the job by specifying a type and type-specific arguments.
		566
		567	Predefined types are (if you have ideas for additional types, feel free to
		568	drop by and tell us):
		569
		570	=over 4
		571
		572	=item netstring => $string
		573
		574	Formats the given value as netstring
		575	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		576
		577	=cut
		578
		579	register_write_type netstring => sub {
		580	my ($self, $string) = @_;
		581
		582	sprintf "%d:%s,", (length $string), $string
		583	};
		584
		585	=item packstring => $format, $data
		586
		587	An octet string prefixed with an encoded length. The encoding C<$format>
		588	uses the same format as a Perl C<pack> format, but must specify a single
		589	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		590	optional C<!>, C<< < >> or C<< > >> modifier).
		591
		592	=cut
		593
		594	register_write_type packstring => sub {
		595	my ($self, $format, $string) = @_;
		596
		597	pack "$format/a*", $string
		598	};
		599
		600	=item json => $array_or_hashref
		601
		602	Encodes the given hash or array reference into a JSON object. Unless you
		603	provide your own JSON object, this means it will be encoded to JSON text
		604	in UTF-8.
		605
		606	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		607	one end of a handle and read them at the other end without using any
		608	additional framing.
		609
		610	The generated JSON text is guaranteed not to contain any newlines: While
		611	this module doesn't need delimiters after or between JSON texts to be
		612	able to read them, many other languages depend on that.
		613
		614	A simple RPC protocol that interoperates easily with others is to send
		615	JSON arrays (or objects, although arrays are usually the better choice as
		616	they mimic how function argument passing works) and a newline after each
		617	JSON text:
		618
		619	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		620	$handle->push_write ("\012");
		621
		622	An AnyEvent::Handle receiver would simply use the C<json> read type and
		623	rely on the fact that the newline will be skipped as leading whitespace:
		624
		625	$handle->push_read (json => sub { my $array = $_[1]; ... });
		626
		627	Other languages could read single lines terminated by a newline and pass
		628	this line into their JSON decoder of choice.
		629
		630	=cut
		631
		632	register_write_type json => sub {
		633	my ($self, $ref) = @_;
		634
		635	require JSON;
		636
		637	$self->{json} ? $self->{json}->encode ($ref)
		638	: JSON::encode_json ($ref)
		639	};
		640
		641	=item storable => $reference
		642
		643	Freezes the given reference using L<Storable> and writes it to the
		644	handle. Uses the C<nfreeze> format.
		645
		646	=cut
		647
		648	register_write_type storable => sub {
		649	my ($self, $ref) = @_;
		650
		651	require Storable;
		652
		653	pack "w/a*", Storable::nfreeze ($ref)
		654	};
		655
		656	=back
		657
		658	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		659
		660	This function (not method) lets you add your own types to C<push_write>.
		661	Whenever the given C<type> is used, C<push_write> will invoke the code
		662	reference with the handle object and the remaining arguments.
		663
		664	The code reference is supposed to return a single octet string that will
		665	be appended to the write buffer.
		666
		667	Note that this is a function, and all types registered this way will be
		668	global, so try to use unique names.
		669
		670	=cut
		671
		672	#############################################################################
		673
		674	=back
		675
		676	=head2 READ QUEUE
		677
		678	AnyEvent::Handle manages two queues per handle, one for writing and one
		679	for reading.
		680
		681	The read queue is more complex than the write queue. It can be used in two
		682	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		683	a queue.
		684
		685	In the simple case, you just install an C<on_read> callback and whenever
		686	new data arrives, it will be called. You can then remove some data (if
		687	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
		688	leave the data there if you want to accumulate more (e.g. when only a
		689	partial message has been received so far).
		690
		691	In the more complex case, you want to queue multiple callbacks. In this
		692	case, AnyEvent::Handle will call the first queued callback each time new
		693	data arrives (also the first time it is queued) and removes it when it has
		694	done its job (see C<push_read>, below).
		695
		696	This way you can, for example, push three line-reads, followed by reading
		697	a chunk of data, and AnyEvent::Handle will execute them in order.
		698
		699	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		700	the specified number of bytes which give an XML datagram.
		701
		702	# in the default state, expect some header bytes
		703	$handle->on_read (sub {
		704	# some data is here, now queue the length-header-read (4 octets)
		705	shift->unshift_read (chunk => 4, sub {
		706	# header arrived, decode
		707	my $len = unpack "N", $_[1];
		708
		709	# now read the payload
		710	shift->unshift_read (chunk => $len, sub {
		711	my $xml = $_[1];
		712	# handle xml
		713	});
		714	});
		715	});
		716
		717	Example 2: Implement a client for a protocol that replies either with "OK"
		718	and another line or "ERROR" for the first request that is sent, and 64
		719	bytes for the second request. Due to the availability of a queue, we can
		720	just pipeline sending both requests and manipulate the queue as necessary
		721	in the callbacks.
		722
		723	When the first callback is called and sees an "OK" response, it will
		724	C<unshift> another line-read. This line-read will be queued I<before> the
		725	64-byte chunk callback.
		726
		727	# request one, returns either "OK + extra line" or "ERROR"
		728	$handle->push_write ("request 1\015\012");
		729
		730	# we expect "ERROR" or "OK" as response, so push a line read
		731	$handle->push_read (line => sub {
		732	# if we got an "OK", we have to _prepend_ another line,
		733	# so it will be read before the second request reads its 64 bytes
		734	# which are already in the queue when this callback is called
		735	# we don't do this in case we got an error
		736	if ($_[1] eq "OK") {
49	on_readline => sub {	737	$_[0]->unshift_read (line => sub {
50	my ($ae_fh, @lines) = @_;	738	my $response = $_[1];
51	for (@lines) {	739	...
52	chomp;	740	});
53	print "Line: $_";	741	}
		742	});
		743
		744	# request two, simply returns 64 octets
		745	$handle->push_write ("request 2\015\012");
		746
		747	# simply read 64 bytes, always
		748	$handle->push_read (chunk => 64, sub {
		749	my $response = $_[1];
		750	...
		751	});
		752
		753	=over 4
		754
		755	=cut
		756
		757	sub _drain_rbuf {
		758	my ($self) = @_;
		759
		760	local $self->{_in_drain} = 1;
		761
		762	if (
		763	defined $self->{rbuf_max}
		764	&& $self->{rbuf_max} < length $self->{rbuf}
		765	) {
		766	$self->_error (&Errno::ENOSPC, 1), return;
		767	}
		768
		769	while () {
		770	my $len = length $self->{rbuf};
		771
		772	if (my $cb = shift @{ $self->{_queue} }) {
		773	unless ($cb->($self)) {
		774	if ($self->{_eof}) {
		775	# no progress can be made (not enough data and no data forthcoming)
		776	$self->_error (&Errno::EPIPE, 1), return;
54	}	777	}
		778
		779	unshift @{ $self->{_queue} }, $cb;
		780	last;
55	}	781	}
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}) {	782	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	783	last unless $len;
122		784
		785	$self->{on_read}($self);
		786
		787	if (
		788	$len == length $self->{rbuf} # if no data has been consumed
		789	&& !@{ $self->{_queue} } # and the queue is still empty
		790	&& $self->{on_read} # but we still have on_read
		791	) {
		792	# no further data will arrive
		793	# so no progress can be made
		794	$self->_error (&Errno::EPIPE, 1), return
		795	if $self->{_eof};
		796
		797	last; # more data might arrive
		798	}
		799	} else {
		800	# read side becomes idle
		801	delete $self->{_rw} unless $self->{tls};
		802	last;
		803	}
		804	}
		805
123	} elsif ($self->{on_eof}) {	806	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});
125
126	} elsif ($self->{on_error}) {	807	if ($self->{on_eof}) {
127	$self->on_eof ($self->{on_error});	808	$self->{on_eof}($self)
		809	} else {
		810	$self->_error (0, 1);
		811	}
128	}	812	}
129		813
130	return $self	814	# may need to restart read watcher
		815	unless ($self->{_rw}) {
		816	$self->start_read
		817	if $self->{on_read} || @{ $self->{_queue} };
		818	}
131	}	819	}
132		820
133	=item B<fh>	821	=item $handle->on_read ($cb)
134		822
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	823	This replaces the currently set C<on_read> callback, or clears it (when
136		824	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	825	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		826
149	=cut	827	=cut
150		828
151	sub on_read {	829	sub on_read {
152	my ($self, $cb) = @_;	830	my ($self, $cb) = @_;
		831
153	$self->{on_read} = $cb;	832	$self->{on_read} = $cb;
		833	$self->_drain_rbuf if $cb && !$self->{_in_drain};
		834	}
154		835
155	unless (defined $self->{on_read}) {	836	=item $handle->rbuf
156	delete $self->{on_read_w};	837
		838	Returns the read buffer (as a modifiable lvalue).
		839
		840	You can access the read buffer directly as the C<< ->{rbuf} >> member, if
		841	you want.
		842
		843	NOTE: The read buffer should only be used or modified if the C<on_read>,
		844	C<push_read> or C<unshift_read> methods are used. The other read methods
		845	automatically manage the read buffer.
		846
		847	=cut
		848
		849	sub rbuf : lvalue {
		850	$_[0]{rbuf}
		851	}
		852
		853	=item $handle->push_read ($cb)
		854
		855	=item $handle->unshift_read ($cb)
		856
		857	Append the given callback to the end of the queue (C<push_read>) or
		858	prepend it (C<unshift_read>).
		859
		860	The callback is called each time some additional read data arrives.
		861
		862	It must check whether enough data is in the read buffer already.
		863
		864	If not enough data is available, it must return the empty list or a false
		865	value, in which case it will be called repeatedly until enough data is
		866	available (or an error condition is detected).
		867
		868	If enough data was available, then the callback must remove all data it is
		869	interested in (which can be none at all) and return a true value. After returning
		870	true, it will be removed from the queue.
		871
		872	=cut
		873
		874	our %RH;
		875
		876	sub register_read_type($$) {
		877	$RH{$_[0]} = $_[1];
		878	}
		879
		880	sub push_read {
		881	my $self = shift;
		882	my $cb = pop;
		883
		884	if (@_) {
		885	my $type = shift;
		886
		887	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		888	->($self, $cb, @_);
		889	}
		890
		891	push @{ $self->{_queue} }, $cb;
		892	$self->_drain_rbuf unless $self->{_in_drain};
		893	}
		894
		895	sub unshift_read {
		896	my $self = shift;
		897	my $cb = pop;
		898
		899	if (@_) {
		900	my $type = shift;
		901
		902	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		903	->($self, $cb, @_);
		904	}
		905
		906
		907	unshift @{ $self->{_queue} }, $cb;
		908	$self->_drain_rbuf unless $self->{_in_drain};
		909	}
		910
		911	=item $handle->push_read (type => @args, $cb)
		912
		913	=item $handle->unshift_read (type => @args, $cb)
		914
		915	Instead of providing a callback that parses the data itself you can chose
		916	between a number of predefined parsing formats, for chunks of data, lines
		917	etc.
		918
		919	Predefined types are (if you have ideas for additional types, feel free to
		920	drop by and tell us):
		921
		922	=over 4
		923
		924	=item chunk => $octets, $cb->($handle, $data)
		925
		926	Invoke the callback only once C<$octets> bytes have been read. Pass the
		927	data read to the callback. The callback will never be called with less
		928	data.
		929
		930	Example: read 2 bytes.
		931
		932	$handle->push_read (chunk => 2, sub {
		933	warn "yay ", unpack "H*", $_[1];
		934	});
		935
		936	=cut
		937
		938	register_read_type chunk => sub {
		939	my ($self, $cb, $len) = @_;
		940
		941	sub {
		942	$len <= length $_[0]{rbuf} or return;
		943	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		944	1
		945	}
		946	};
		947
		948	=item line => [$eol, ]$cb->($handle, $line, $eol)
		949
		950	The callback will be called only once a full line (including the end of
		951	line marker, C<$eol>) has been read. This line (excluding the end of line
		952	marker) will be passed to the callback as second argument (C<$line>), and
		953	the end of line marker as the third argument (C<$eol>).
		954
		955	The end of line marker, C<$eol>, can be either a string, in which case it
		956	will be interpreted as a fixed record end marker, or it can be a regex
		957	object (e.g. created by C<qr>), in which case it is interpreted as a
		958	regular expression.
		959
		960	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		961	undef), then C<qr|\015?\012|> is used (which is good for most internet
		962	protocols).
		963
		964	Partial lines at the end of the stream will never be returned, as they are
		965	not marked by the end of line marker.
		966
		967	=cut
		968
		969	register_read_type line => sub {
		970	my ($self, $cb, $eol) = @_;
		971
		972	if (@_ < 3) {
		973	# this is more than twice as fast as the generic code below
		974	sub {
		975	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		976
		977	$cb->($_[0], $1, $2);
		978	1
		979	}
		980	} else {
		981	$eol = quotemeta $eol unless ref $eol;
		982	$eol = qr|^(.*?)($eol)|s;
		983
		984	sub {
		985	$_[0]{rbuf} =~ s/$eol// or return;
		986
		987	$cb->($_[0], $1, $2);
		988	1
		989	}
		990	}
		991	};
		992
		993	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		994
		995	Makes a regex match against the regex object C<$accept> and returns
		996	everything up to and including the match.
		997
		998	Example: read a single line terminated by '\n'.
		999
		1000	$handle->push_read (regex => qr<\n>, sub { ... });
		1001
		1002	If C<$reject> is given and not undef, then it determines when the data is
		1003	to be rejected: it is matched against the data when the C<$accept> regex
		1004	does not match and generates an C<EBADMSG> error when it matches. This is
		1005	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1006	receive buffer overflow).
		1007
		1008	Example: expect a single decimal number followed by whitespace, reject
		1009	anything else (not the use of an anchor).
		1010
		1011	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1012
		1013	If C<$skip> is given and not C<undef>, then it will be matched against
		1014	the receive buffer when neither C<$accept> nor C<$reject> match,
		1015	and everything preceding and including the match will be accepted
		1016	unconditionally. This is useful to skip large amounts of data that you
		1017	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1018	have to start matching from the beginning. This is purely an optimisation
		1019	and is usually worth only when you expect more than a few kilobytes.
		1020
		1021	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1022	expect the header to be very large (it isn't in practise, but...), we use
		1023	a skip regex to skip initial portions. The skip regex is tricky in that
		1024	it only accepts something not ending in either \015 or \012, as these are
		1025	required for the accept regex.
		1026
		1027	$handle->push_read (regex =>
		1028	qr<\015\012\015\012>,
		1029	undef, # no reject
		1030	qr<^.*[^\015\012]>,
		1031	sub { ... });
		1032
		1033	=cut
		1034
		1035	register_read_type regex => sub {
		1036	my ($self, $cb, $accept, $reject, $skip) = @_;
		1037
		1038	my $data;
		1039	my $rbuf = \$self->{rbuf};
		1040
		1041	sub {
		1042	# accept
		1043	if ($$rbuf =~ $accept) {
		1044	$data .= substr $$rbuf, 0, $+[0], "";
		1045	$cb->($self, $data);
157	return;	1046	return 1;
		1047	}
		1048
		1049	# reject
		1050	if ($reject && $$rbuf =~ $reject) {
		1051	$self->_error (&Errno::EBADMSG);
		1052	}
		1053
		1054	# skip
		1055	if ($skip && $$rbuf =~ $skip) {
		1056	$data .= substr $$rbuf, 0, $+[0], "";
		1057	}
		1058
		1059	()
158	}	1060	}
159		1061	};
160	$self->{on_read_w} =	1062
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1063	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1064
163	my $rbuf_len = length $self->{rbuf};	1065	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1066
165	if (defined $self->{read_size}) {	1067	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1068
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1069	=cut
168	} else {	1070
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1071	register_read_type netstring => sub {
		1072	my ($self, $cb) = @_;
		1073
		1074	sub {
		1075	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1076	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1077	$self->_error (&Errno::EBADMSG);
170	}	1078	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1079	return;
		1080	}
172		1081
173	if (not defined $l) {	1082	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1083
178	} elsif ($l == 0) {	1084	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1085	my $string = $_[1];
180	delete $self->{on_read_w};	1086	$_[0]->unshift_read (chunk => 1, sub {
181		1087	if ($_[1] eq ",") {
		1088	$cb->($_[0], $string);
182	} else {	1089	} else {
183	$self->{on_read}->($self);	1090	$self->_error (&Errno::EBADMSG);
		1091	}
		1092	});
		1093	});
		1094
		1095	1
		1096	}
		1097	};
		1098
		1099	=item packstring => $format, $cb->($handle, $string)
		1100
		1101	An octet string prefixed with an encoded length. The encoding C<$format>
		1102	uses the same format as a Perl C<pack> format, but must specify a single
		1103	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1104	optional C<!>, C<< < >> or C<< > >> modifier).
		1105
		1106	DNS over TCP uses a prefix of C<n>, EPP uses a prefix of C<N>.
		1107
		1108	Example: read a block of data prefixed by its length in BER-encoded
		1109	format (very efficient).
		1110
		1111	$handle->push_read (packstring => "w", sub {
		1112	my ($handle, $data) = @_;
		1113	});
		1114
		1115	=cut
		1116
		1117	register_read_type packstring => sub {
		1118	my ($self, $cb, $format) = @_;
		1119
		1120	sub {
		1121	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1122	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1123	or return;
		1124
		1125	$format = length pack $format, $len;
		1126
		1127	# bypass unshift if we already have the remaining chunk
		1128	if ($format + $len <= length $_[0]{rbuf}) {
		1129	my $data = substr $_[0]{rbuf}, $format, $len;
		1130	substr $_[0]{rbuf}, 0, $format + $len, "";
		1131	$cb->($_[0], $data);
		1132	} else {
		1133	# remove prefix
		1134	substr $_[0]{rbuf}, 0, $format, "";
		1135
		1136	# read remaining chunk
		1137	$_[0]->unshift_read (chunk => $len, $cb);
		1138	}
		1139
		1140	1
		1141	}
		1142	};
		1143
		1144	=item json => $cb->($handle, $hash_or_arrayref)
		1145
		1146	Reads a JSON object or array, decodes it and passes it to the callback.
		1147
		1148	If a C<json> object was passed to the constructor, then that will be used
		1149	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1150
		1151	This read type uses the incremental parser available with JSON version
		1152	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1153	dependency on your own: this module will load the JSON module, but
		1154	AnyEvent does not depend on it itself.
		1155
		1156	Since JSON texts are fully self-delimiting, the C<json> read and write
		1157	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1158	the C<json> write type description, above, for an actual example.
		1159
		1160	=cut
		1161
		1162	register_read_type json => sub {
		1163	my ($self, $cb) = @_;
		1164
		1165	require JSON;
		1166
		1167	my $data;
		1168	my $rbuf = \$self->{rbuf};
		1169
		1170	my $json = $self->{json} ||= JSON->new->utf8;
		1171
		1172	sub {
		1173	my $ref = $json->incr_parse ($self->{rbuf});
		1174
		1175	if ($ref) {
		1176	$self->{rbuf} = $json->incr_text;
		1177	$json->incr_text = "";
		1178	$cb->($self, $ref);
		1179
		1180	1
		1181	} else {
		1182	$self->{rbuf} = "";
		1183	()
		1184	}
		1185	}
		1186	};
		1187
		1188	=item storable => $cb->($handle, $ref)
		1189
		1190	Deserialises a L<Storable> frozen representation as written by the
		1191	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1192	data).
		1193
		1194	Raises C<EBADMSG> error if the data could not be decoded.
		1195
		1196	=cut
		1197
		1198	register_read_type storable => sub {
		1199	my ($self, $cb) = @_;
		1200
		1201	require Storable;
		1202
		1203	sub {
		1204	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1205	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1206	or return;
		1207
		1208	my $format = length pack "w", $len;
		1209
		1210	# bypass unshift if we already have the remaining chunk
		1211	if ($format + $len <= length $_[0]{rbuf}) {
		1212	my $data = substr $_[0]{rbuf}, $format, $len;
		1213	substr $_[0]{rbuf}, 0, $format + $len, "";
		1214	$cb->($_[0], Storable::thaw ($data));
		1215	} else {
		1216	# remove prefix
		1217	substr $_[0]{rbuf}, 0, $format, "";
		1218
		1219	# read remaining chunk
		1220	$_[0]->unshift_read (chunk => $len, sub {
		1221	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1222	$cb->($_[0], $ref);
		1223	} else {
		1224	$self->_error (&Errno::EBADMSG);
		1225	}
		1226	});
		1227	}
		1228
		1229	1
		1230	}
		1231	};
		1232
		1233	=back
		1234
		1235	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1236
		1237	This function (not method) lets you add your own types to C<push_read>.
		1238
		1239	Whenever the given C<type> is used, C<push_read> will invoke the code
		1240	reference with the handle object, the callback and the remaining
		1241	arguments.
		1242
		1243	The code reference is supposed to return a callback (usually a closure)
		1244	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1245
		1246	It should invoke the passed callback when it is done reading (remember to
		1247	pass C<$handle> as first argument as all other callbacks do that).
		1248
		1249	Note that this is a function, and all types registered this way will be
		1250	global, so try to use unique names.
		1251
		1252	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1253	search for C<register_read_type>)).
		1254
		1255	=item $handle->stop_read
		1256
		1257	=item $handle->start_read
		1258
		1259	In rare cases you actually do not want to read anything from the
		1260	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1261	any queued callbacks will be executed then. To start reading again, call
		1262	C<start_read>.
		1263
		1264	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1265	you change the C<on_read> callback or push/unshift a read callback, and it
		1266	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1267	there are any read requests in the queue.
		1268
		1269	These methods will have no effect when in TLS mode (as TLS doesn't support
		1270	half-duplex connections).
		1271
		1272	=cut
		1273
		1274	sub stop_read {
		1275	my ($self) = @_;
		1276
		1277	delete $self->{_rw} unless $self->{tls};
		1278	}
		1279
		1280	sub start_read {
		1281	my ($self) = @_;
		1282
		1283	unless ($self->{_rw} || $self->{_eof}) {
		1284	Scalar::Util::weaken $self;
		1285
		1286	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1287	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1288	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1289
		1290	if ($len > 0) {
		1291	$self->{_activity} = AnyEvent->now;
		1292
		1293	if ($self->{tls}) {
		1294	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1295	&_dotls ($self);
		1296	} else {
		1297	$self->_drain_rbuf unless $self->{_in_drain};
		1298	}
		1299
		1300	} elsif (defined $len) {
		1301	delete $self->{_rw};
		1302	$self->{_eof} = 1;
		1303	$self->_drain_rbuf unless $self->{_in_drain};
		1304
		1305	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1306	return $self->_error ($!, 1);
184	}	1307	}
185	});	1308	});
		1309	}
186	}	1310	}
187		1311
188	=item B<on_error ($callback)>	1312	sub _dotls {
189
190	Whenever a read or write operation resulted in an error the C<$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, $cb) = @_;	1313	my ($self) = @_;
240		1314
241	$self->{read_cb} = $cb;	1315	my $buf;
242	my $old_blk_size = $self->{read_block_size};
243	$self->{read_block_size} = $len;
244		1316
245	$self->on_read (sub {	1317	if (length $self->{_tls_wbuf}) {
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";	1318	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
247		1319	substr $self->{_tls_wbuf}, 0, $len, "";
248	if ($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, $len, ''));
252	}	1320	}
253	});	1321	}
254	}
255		1322
256	=item B<readlines ($callback)>	1323	while (defined ($buf = Net::SSLeay::read ($self->{tls}))) {
		1324	unless (length $buf) {
		1325	# let's treat SSL-eof as we treat normal EOF
		1326	delete $self->{_rw};
		1327	$self->{_eof} = 1;
		1328	&_freetls;
		1329	}
257		1330
258	=item B<readlines ($sep, $callback)>	1331	$self->{rbuf} .= $buf;
		1332	$self->_drain_rbuf unless $self->{_in_drain};
		1333	$self->{tls} or return; # tls session might have gone away in callback
		1334	}
259		1335
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1336	my $err = Net::SSLeay::get_error ($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		1337
264	The C<$callback> will be called when at least one	1338	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
265	line could be read. The first argument to the C<$callback> will be the L<AnyEvent::Handle>	1339	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
266	object itself and the rest of the arguments will be the read lines.	1340	return $self->_error ($!, 1);
		1341	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
		1342	return $self->_error (&Errno::EIO, 1);
		1343	}
267		1344
268	NOTE: This method will override any callbacks installed via the C<on_read> method.	1345	# all others are fine for our purposes
		1346	}
269		1347
270	=cut	1348	if (length ($buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1349	$self->{wbuf} .= $buf;
		1350	$self->_drain_wbuf;
		1351	}
		1352	}
271		1353
272	sub readlines {	1354	=item $handle->starttls ($tls[, $tls_ctx])
		1355
		1356	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1357	object is created, you can also do that at a later time by calling
		1358	C<starttls>.
		1359
		1360	The first argument is the same as the C<tls> constructor argument (either
		1361	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1362
		1363	The second argument is the optional C<Net::SSLeay::CTX> object that is
		1364	used when AnyEvent::Handle has to create its own TLS connection object.
		1365
		1366	The TLS connection object will end up in C<< $handle->{tls} >> after this
		1367	call and can be used or changed to your liking. Note that the handshake
		1368	might have already started when this function returns.
		1369
		1370	If it an error to start a TLS handshake more than once per
		1371	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1372
		1373	=cut
		1374
		1375	sub starttls {
273	my ($self, $NL, $cb) = @_;	1376	my ($self, $ssl, $ctx) = @_;
274		1377
275	if (ref $NL) {	1378	require Net::SSLeay;
276	$cb = $NL;	1379
277	$NL = "\n";	1380	Carp::croak "it is an error to call starttls more than once on an Anyevent::Handle object"
		1381	if $self->{tls};
278	}	1382
279		1383	if ($ssl eq "accept") {
280	$self->{on_readline} = $cb;	1384	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
281		1385	Net::SSLeay::set_accept_state ($ssl);
282	$self->on_read (sub {	1386	} elsif ($ssl eq "connect") {
283	my @lines;	1387	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
284	push @lines, $1 while $_[0]->{rbuf} =~ s/(.*)$NL//;	1388	Net::SSLeay::set_connect_state ($ssl);
285	$self->{on_readline}->($_[0], @lines);
286	});	1389	}
287	}
288		1390
289	=item B<write ($data)>	1391	$self->{tls} = $ssl;
290		1392
291	=item B<write ($callback)>	1393	# basically, this is deep magic (because SSL_read should have the same issues)
		1394	# but the openssl maintainers basically said: "trust us, it just works".
		1395	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1396	# and mismaintained ssleay-module doesn't even offer them).
		1397	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1398	#
		1399	# in short: this is a mess.
		1400	#
		1401	# note that we do not try to keep the length constant between writes as we are required to do.
		1402	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1403	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1404	# have identity issues in that area.
		1405	Net::SSLeay::CTX_set_mode ($self->{tls},
		1406	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1407	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
292		1408
293	=item B<write ($data, $callback)>	1409	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1410	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
294		1411
295	This method will write C<$data> to the filehandle and call the C<$callback>	1412	Net::SSLeay::set_bio ($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		1413
299	=cut	1414	&_dotls; # need to trigger the initial handshake
300		1415	$self->start_read; # make sure we actually do read
301	sub write {
302	my ($self, $data, $cb) = @_;
303	if (ref $data) { $cb = $data; undef $data }
304	push @{$self->{write_bufs}}, [$data, $cb];
305	$self->_check_writer;
306	}	1416	}
307		1417
308	sub _check_writer {	1418	=item $handle->stoptls
		1419
		1420	Shuts down the SSL connection - this makes a proper EOF handshake by
		1421	sending a close notify to the other side, but since OpenSSL doesn't
		1422	support non-blocking shut downs, it is not possible to re-use the stream
		1423	afterwards.
		1424
		1425	=cut
		1426
		1427	sub stoptls {
309	my ($self) = @_;	1428	my ($self) = @_;
310		1429
311	if ($self->{write_w}) {	1430	if ($self->{tls}) {
312	unless ($self->{write_cb}) {	1431	Net::SSLeay::shutdown ($self->{tls});
313	while (@{$self->{write_bufs}} && not defined $self->{write_bufs}->[0]->[1]) {	1432
314	my $wba = shift @{$self->{write_bufs}};	1433	&_dotls;
315	$self->{wbuf} .= $wba->[0];	1434
316	}	1435	# we don't give a shit. no, we do, but we can't. no...
317	}	1436	# we, we... have to use openssl :/
318	return;	1437	&_freetls;
		1438	}
		1439	}
		1440
		1441	sub _freetls {
		1442	my ($self) = @_;
		1443
		1444	return unless $self->{tls};
		1445
		1446	Net::SSLeay::free (delete $self->{tls});
319	}	1447
		1448	delete @$self{qw(_rbio _wbio _tls_wbuf)};
		1449	}
320		1450
321	my $wba = shift @{$self->{write_bufs}}	1451	sub DESTROY {
322	or return;	1452	my $self = shift;
323		1453
324	unless (defined $wba->[0]) {	1454	&_freetls;
325	$wba->[1]->($self) if $wba->[1];
326	$self->_check_writer;
327	return;
328	}
329		1455
330	$self->{wbuf} = $wba->[0];	1456	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
331	$self->{write_cb} = $wba->[1];
332		1457
333	$self->{write_w} =	1458	if ($linger && length $self->{wbuf}) {
334	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1459	my $fh = delete $self->{fh};
		1460	my $wbuf = delete $self->{wbuf};
		1461
		1462	my @linger;
		1463
		1464	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
335	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1465	my $len = syswrite $fh, $wbuf, length $wbuf;
336		1466
337	if (not defined $l) {	1467	if ($len > 0) {
338	return if $! == EAGAIN || $! == EINTR;	1468	substr $wbuf, 0, $len, "";
339	delete $self->{write_w};
340	$self->{on_error}->($self) if $self->{on_error};
341
342	} else {	1469	} else {
343	substr $self->{wbuf}, 0, $l, '';	1470	@linger = (); # end
344
345	if (length ($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	}	1471	}
355	});	1472	});
		1473	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1474	@linger = ();
		1475	});
		1476	}
		1477	}
		1478
		1479	=item AnyEvent::Handle::TLS_CTX
		1480
		1481	This function creates and returns the Net::SSLeay::CTX object used by
		1482	default for TLS mode.
		1483
		1484	The context is created like this:
		1485
		1486	Net::SSLeay::load_error_strings;
		1487	Net::SSLeay::SSLeay_add_ssl_algorithms;
		1488	Net::SSLeay::randomize;
		1489
		1490	my $CTX = Net::SSLeay::CTX_new;
		1491
		1492	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
		1493
		1494	=cut
		1495
		1496	our $TLS_CTX;
		1497
		1498	sub TLS_CTX() {
		1499	$TLS_CTX || do {
		1500	require Net::SSLeay;
		1501
		1502	Net::SSLeay::load_error_strings ();
		1503	Net::SSLeay::SSLeay_add_ssl_algorithms ();
		1504	Net::SSLeay::randomize ();
		1505
		1506	$TLS_CTX = Net::SSLeay::CTX_new ();
		1507
		1508	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
		1509
		1510	$TLS_CTX
		1511	}
356	}	1512	}
357		1513
358	=back	1514	=back
359		1515
		1516
		1517	=head1 NONFREQUENTLY ASKED QUESTIONS
		1518
		1519	=over 4
		1520
		1521	=item How do I read data until the other side closes the connection?
		1522
		1523	If you just want to read your data into a perl scalar, the easiest way to achieve this is
		1524	by setting an C<on_read> callback that does nothing, clearing the C<on_eof> callback
		1525	and in the C<on_error> callback, the data will be in C<$_[0]{rbuf}>:
		1526
		1527	$handle->on_read (sub { });
		1528	$handle->on_eof (undef);
		1529	$handle->on_error (sub {
		1530	my $data = delete $_[0]{rbuf};
		1531	undef $handle;
		1532	});
		1533
		1534	The reason to use C<on_error> is that TCP connections, due to latencies
		1535	and packets loss, might get closed quite violently with an error, when in
		1536	fact, all data has been received.
		1537
		1538	It is usually better to use acknowledgements when transfering data,
		1539	to make sure the other side hasn't just died and you got the data
		1540	intact. This is also one reason why so many internet protocols have an
		1541	explicit QUIT command.
		1542
		1543
		1544	=item I don't want to destroy the handle too early - how do I wait until all data has been sent?
		1545
		1546	After writing your last bits of data, set the C<on_drain> callback
		1547	and destroy the handle in there - with the default setting of
		1548	C<low_water_mark> this will be called precisely when all data has been
		1549	written to the socket:
		1550
		1551	$handle->push_write (...);
		1552	$handle->on_drain (sub {
		1553	warn "all data submitted to the kernel\n";
		1554	undef $handle;
		1555	});
		1556
		1557	=back
		1558
		1559
		1560	=head1 SUBCLASSING AnyEvent::Handle
		1561
		1562	In many cases, you might want to subclass AnyEvent::Handle.
		1563
		1564	To make this easier, a given version of AnyEvent::Handle uses these
		1565	conventions:
		1566
		1567	=over 4
		1568
		1569	=item * all constructor arguments become object members.
		1570
		1571	At least initially, when you pass a C<tls>-argument to the constructor it
		1572	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1573	mutated later on (for example C<tls> will hold the TLS connection object).
		1574
		1575	=item * other object member names are prefixed with an C<_>.
		1576
		1577	All object members not explicitly documented (internal use) are prefixed
		1578	with an underscore character, so the remaining non-C<_>-namespace is free
		1579	for use for subclasses.
		1580
		1581	=item * all members not documented here and not prefixed with an underscore
		1582	are free to use in subclasses.
		1583
		1584	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1585	member variables, but thats just life, at least it is documented.
		1586
		1587	=back
		1588
360	=head1 AUTHOR	1589	=head1 AUTHOR
361		1590
362	Robin Redeker, C<< <elmex at ta-sa.org> >>	1591	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
363		1592
364	=cut	1593	=cut
365		1594
366	1; # End of AnyEvent::Handle	1595	1; # End of AnyEvent::Handle

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