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Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.2 by elmex, Sun Apr 27 17:27:34 2008 UTC vs.
Revision 1.113 by root, Wed Jan 21 06:02:21 2009 UTC

1	package AnyEvent::Handle;	1	package AnyEvent::Handle;
2		2
3	use warnings;	3	no warnings;
4	use strict;	4	use strict qw(subs vars);
5		5
6	use AnyEvent;	6	use AnyEvent ();
7	use IO::Handle;	7	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		8	use Scalar::Util ();
		9	use Carp ();
		10	use Fcntl ();
8	use Errno qw/EAGAIN EINTR/;	11	use Errno qw(EAGAIN EINTR);
9		12
10	=head1 NAME	13	=head1 NAME
11		14
12	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
13		16
14	=head1 VERSION
15
16	Version 0.01
17
18	=cut	17	=cut
19		18
20	our $VERSION = '0.01';	19	our $VERSION = 4.331;
21		20
22	=head1 SYNOPSIS	21	=head1 SYNOPSIS
23		22
24	use AnyEvent;	23	use AnyEvent;
25	use AnyEvent::Handle;	24	use AnyEvent::Handle;
26		25
27	my $cv = AnyEvent->condvar;	26	my $cv = AnyEvent->condvar;
28		27
29	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	28	my $handle =
30
31	$ae_fh->on_eof (sub { $cv->broadcast });
32
33	$ae_fh->readlines (sub {
34	my ($ae_fh, @lines) = @_;
35	for (@lines) {
36	chomp;
37	print "Line: $_";
38	}
39	});
40
41	# or use the constructor to pass the callback:
42
43	my $ae_fh2 =
44	AnyEvent::Handle->new (	29	AnyEvent::Handle->new (
45	fh => \*STDIN,	30	fh => \*STDIN,
46	on_eof => sub {	31	on_eof => sub {
47	$cv->broadcast;	32	$cv->send;
48	},	33	},
		34	);
		35
		36	# send some request line
		37	$handle->push_write ("getinfo\015\012");
		38
		39	# read the response line
		40	$handle->push_read (line => sub {
		41	my ($handle, $line) = @_;
		42	warn "read line <$line>\n";
		43	$cv->send;
		44	});
		45
		46	$cv->recv;
		47
		48	=head1 DESCRIPTION
		49
		50	This module is a helper module to make it easier to do event-based I/O on
		51	filehandles. For utility functions for doing non-blocking connects and accepts
		52	on sockets see L<AnyEvent::Util>.
		53
		54	The L<AnyEvent::Intro> tutorial contains some well-documented
		55	AnyEvent::Handle examples.
		56
		57	In the following, when the documentation refers to of "bytes" then this
		58	means characters. As sysread and syswrite are used for all I/O, their
		59	treatment of characters applies to this module as well.
		60
		61	All callbacks will be invoked with the handle object as their first
		62	argument.
		63
		64	=head1 METHODS
		65
		66	=over 4
		67
		68	=item B<new (%args)>
		69
		70	The constructor supports these arguments (all as key => value pairs).
		71
		72	=over 4
		73
		74	=item fh => $filehandle [MANDATORY]
		75
		76	The filehandle this L<AnyEvent::Handle> object will operate on.
		77
		78	NOTE: The filehandle will be set to non-blocking mode (using
		79	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		80	that mode.
		81
		82	=item on_eof => $cb->($handle)
		83
		84	Set the callback to be called when an end-of-file condition is detected,
		85	i.e. in the case of a socket, when the other side has closed the
		86	connection cleanly.
		87
		88	For sockets, this just means that the other side has stopped sending data,
		89	you can still try to write data, and, in fact, one can return from the EOF
		90	callback and continue writing data, as only the read part has been shut
		91	down.
		92
		93	While not mandatory, it is I<highly> recommended to set an EOF callback,
		94	otherwise you might end up with a closed socket while you are still
		95	waiting for data.
		96
		97	If an EOF condition has been detected but no C<on_eof> callback has been
		98	set, then a fatal error will be raised with C<$!> set to <0>.
		99
		100	=item on_error => $cb->($handle, $fatal)
		101
		102	This is the error callback, which is called when, well, some error
		103	occured, such as not being able to resolve the hostname, failure to
		104	connect or a read error.
		105
		106	Some errors are fatal (which is indicated by C<$fatal> being true). On
		107	fatal errors the handle object will be shut down and will not be usable
		108	(but you are free to look at the current C<< ->rbuf >>). Examples of fatal
		109	errors are an EOF condition with active (but unsatisifable) read watchers
		110	(C<EPIPE>) or I/O errors.
		111
		112	Non-fatal errors can be retried by simply returning, but it is recommended
		113	to simply ignore this parameter and instead abondon the handle object
		114	when this callback is invoked. Examples of non-fatal errors are timeouts
		115	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		116
		117	On callback entrance, the value of C<$!> contains the operating system
		118	error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).
		119
		120	While not mandatory, it is I<highly> recommended to set this callback, as
		121	you will not be notified of errors otherwise. The default simply calls
		122	C<croak>.
		123
		124	=item on_read => $cb->($handle)
		125
		126	This sets the default read callback, which is called when data arrives
		127	and no read request is in the queue (unlike read queue callbacks, this
		128	callback will only be called when at least one octet of data is in the
		129	read buffer).
		130
		131	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
		132	method or access the C<$handle->{rbuf}> member directly.
		133
		134	When an EOF condition is detected then AnyEvent::Handle will first try to
		135	feed all the remaining data to the queued callbacks and C<on_read> before
		136	calling the C<on_eof> callback. If no progress can be made, then a fatal
		137	error will be raised (with C<$!> 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	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		261	passing in the wrong integer will lead to certain crash. This most often
		262	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		263	segmentation fault.
		264
		265	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		266
		267	=item tls_ctx => $ssl_ctx
		268
		269	Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
		270	(unless a connection object was specified directly). If this parameter is
		271	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		272
		273	=item json => JSON or JSON::XS object
		274
		275	This is the json coder object used by the C<json> read and write types.
		276
		277	If you don't supply it, then AnyEvent::Handle will create and use a
		278	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		279	texts.
		280
		281	Note that you are responsible to depend on the JSON module if you want to
		282	use this functionality, as AnyEvent does not have a dependency itself.
		283
		284	=back
		285
		286	=cut
		287
		288	sub new {
		289	my $class = shift;
		290
		291	my $self = bless { @_ }, $class;
		292
		293	$self->{fh} or Carp::croak "mandatory argument fh is missing";
		294
		295	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		296
		297	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		298	if $self->{tls};
		299
		300	$self->{_activity} = AnyEvent->now;
		301	$self->_timeout;
		302
		303	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
		304	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		305
		306	$self->start_read
		307	if $self->{on_read};
		308
		309	$self
		310	}
		311
		312	sub _shutdown {
		313	my ($self) = @_;
		314
		315	delete $self->{_tw};
		316	delete $self->{_rw};
		317	delete $self->{_ww};
		318	delete $self->{fh};
		319
		320	&_freetls;
		321
		322	delete $self->{on_read};
		323	delete $self->{_queue};
		324	}
		325
		326	sub _error {
		327	my ($self, $errno, $fatal) = @_;
		328
		329	$self->_shutdown
		330	if $fatal;
		331
		332	$! = $errno;
		333
		334	if ($self->{on_error}) {
		335	$self->{on_error}($self, $fatal);
		336	} elsif ($self->{fh}) {
		337	Carp::croak "AnyEvent::Handle uncaught error: $!";
		338	}
		339	}
		340
		341	=item $fh = $handle->fh
		342
		343	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		344
		345	=cut
		346
		347	sub fh { $_[0]{fh} }
		348
		349	=item $handle->on_error ($cb)
		350
		351	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		352
		353	=cut
		354
		355	sub on_error {
		356	$_[0]{on_error} = $_[1];
		357	}
		358
		359	=item $handle->on_eof ($cb)
		360
		361	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		362
		363	=cut
		364
		365	sub on_eof {
		366	$_[0]{on_eof} = $_[1];
		367	}
		368
		369	=item $handle->on_timeout ($cb)
		370
		371	Replace the current C<on_timeout> callback, or disables the callback (but
		372	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		373	argument and method.
		374
		375	=cut
		376
		377	sub on_timeout {
		378	$_[0]{on_timeout} = $_[1];
		379	}
		380
		381	=item $handle->autocork ($boolean)
		382
		383	Enables or disables the current autocork behaviour (see C<autocork>
		384	constructor argument). Changes will only take effect on the next write.
		385
		386	=cut
		387
		388	sub autocork {
		389	$_[0]{autocork} = $_[1];
		390	}
		391
		392	=item $handle->no_delay ($boolean)
		393
		394	Enables or disables the C<no_delay> setting (see constructor argument of
		395	the same name for details).
		396
		397	=cut
		398
		399	sub no_delay {
		400	$_[0]{no_delay} = $_[1];
		401
		402	eval {
		403	local $SIG{__DIE__};
		404	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		405	};
		406	}
		407
		408	#############################################################################
		409
		410	=item $handle->timeout ($seconds)
		411
		412	Configures (or disables) the inactivity timeout.
		413
		414	=cut
		415
		416	sub timeout {
		417	my ($self, $timeout) = @_;
		418
		419	$self->{timeout} = $timeout;
		420	$self->_timeout;
		421	}
		422
		423	# reset the timeout watcher, as neccessary
		424	# also check for time-outs
		425	sub _timeout {
		426	my ($self) = @_;
		427
		428	if ($self->{timeout}) {
		429	my $NOW = AnyEvent->now;
		430
		431	# when would the timeout trigger?
		432	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		433
		434	# now or in the past already?
		435	if ($after <= 0) {
		436	$self->{_activity} = $NOW;
		437
		438	if ($self->{on_timeout}) {
		439	$self->{on_timeout}($self);
		440	} else {
		441	$self->_error (&Errno::ETIMEDOUT);
		442	}
		443
		444	# callback could have changed timeout value, optimise
		445	return unless $self->{timeout};
		446
		447	# calculate new after
		448	$after = $self->{timeout};
		449	}
		450
		451	Scalar::Util::weaken $self;
		452	return unless $self; # ->error could have destroyed $self
		453
		454	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		455	delete $self->{_tw};
		456	$self->_timeout;
		457	});
		458	} else {
		459	delete $self->{_tw};
		460	}
		461	}
		462
		463	#############################################################################
		464
		465	=back
		466
		467	=head2 WRITE QUEUE
		468
		469	AnyEvent::Handle manages two queues per handle, one for writing and one
		470	for reading.
		471
		472	The write queue is very simple: you can add data to its end, and
		473	AnyEvent::Handle will automatically try to get rid of it for you.
		474
		475	When data could be written and the write buffer is shorter then the low
		476	water mark, the C<on_drain> callback will be invoked.
		477
		478	=over 4
		479
		480	=item $handle->on_drain ($cb)
		481
		482	Sets the C<on_drain> callback or clears it (see the description of
		483	C<on_drain> in the constructor).
		484
		485	=cut
		486
		487	sub on_drain {
		488	my ($self, $cb) = @_;
		489
		490	$self->{on_drain} = $cb;
		491
		492	$cb->($self)
		493	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		494	}
		495
		496	=item $handle->push_write ($data)
		497
		498	Queues the given scalar to be written. You can push as much data as you
		499	want (only limited by the available memory), as C<AnyEvent::Handle>
		500	buffers it independently of the kernel.
		501
		502	=cut
		503
		504	sub _drain_wbuf {
		505	my ($self) = @_;
		506
		507	if (!$self->{_ww} && length $self->{wbuf}) {
		508
		509	Scalar::Util::weaken $self;
		510
		511	my $cb = sub {
		512	my $len = syswrite $self->{fh}, $self->{wbuf};
		513
		514	if ($len >= 0) {
		515	substr $self->{wbuf}, 0, $len, "";
		516
		517	$self->{_activity} = AnyEvent->now;
		518
		519	$self->{on_drain}($self)
		520	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		521	&& $self->{on_drain};
		522
		523	delete $self->{_ww} unless length $self->{wbuf};
		524	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		525	$self->_error ($!, 1);
		526	}
		527	};
		528
		529	# try to write data immediately
		530	$cb->() unless $self->{autocork};
		531
		532	# if still data left in wbuf, we need to poll
		533	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
		534	if length $self->{wbuf};
		535	};
		536	}
		537
		538	our %WH;
		539
		540	sub register_write_type($$) {
		541	$WH{$_[0]} = $_[1];
		542	}
		543
		544	sub push_write {
		545	my $self = shift;
		546
		547	if (@_ > 1) {
		548	my $type = shift;
		549
		550	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		551	->($self, @_);
		552	}
		553
		554	if ($self->{tls}) {
		555	$self->{_tls_wbuf} .= $_[0];
		556
		557	&_dotls ($self);
		558	} else {
		559	$self->{wbuf} .= $_[0];
		560	$self->_drain_wbuf;
		561	}
		562	}
		563
		564	=item $handle->push_write (type => @args)
		565
		566	Instead of formatting your data yourself, you can also let this module do
		567	the job by specifying a type and type-specific arguments.
		568
		569	Predefined types are (if you have ideas for additional types, feel free to
		570	drop by and tell us):
		571
		572	=over 4
		573
		574	=item netstring => $string
		575
		576	Formats the given value as netstring
		577	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		578
		579	=cut
		580
		581	register_write_type netstring => sub {
		582	my ($self, $string) = @_;
		583
		584	(length $string) . ":$string,"
		585	};
		586
		587	=item packstring => $format, $data
		588
		589	An octet string prefixed with an encoded length. The encoding C<$format>
		590	uses the same format as a Perl C<pack> format, but must specify a single
		591	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		592	optional C<!>, C<< < >> or C<< > >> modifier).
		593
		594	=cut
		595
		596	register_write_type packstring => sub {
		597	my ($self, $format, $string) = @_;
		598
		599	pack "$format/a*", $string
		600	};
		601
		602	=item json => $array_or_hashref
		603
		604	Encodes the given hash or array reference into a JSON object. Unless you
		605	provide your own JSON object, this means it will be encoded to JSON text
		606	in UTF-8.
		607
		608	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		609	one end of a handle and read them at the other end without using any
		610	additional framing.
		611
		612	The generated JSON text is guaranteed not to contain any newlines: While
		613	this module doesn't need delimiters after or between JSON texts to be
		614	able to read them, many other languages depend on that.
		615
		616	A simple RPC protocol that interoperates easily with others is to send
		617	JSON arrays (or objects, although arrays are usually the better choice as
		618	they mimic how function argument passing works) and a newline after each
		619	JSON text:
		620
		621	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		622	$handle->push_write ("\012");
		623
		624	An AnyEvent::Handle receiver would simply use the C<json> read type and
		625	rely on the fact that the newline will be skipped as leading whitespace:
		626
		627	$handle->push_read (json => sub { my $array = $_[1]; ... });
		628
		629	Other languages could read single lines terminated by a newline and pass
		630	this line into their JSON decoder of choice.
		631
		632	=cut
		633
		634	register_write_type json => sub {
		635	my ($self, $ref) = @_;
		636
		637	require JSON;
		638
		639	$self->{json} ? $self->{json}->encode ($ref)
		640	: JSON::encode_json ($ref)
		641	};
		642
		643	=item storable => $reference
		644
		645	Freezes the given reference using L<Storable> and writes it to the
		646	handle. Uses the C<nfreeze> format.
		647
		648	=cut
		649
		650	register_write_type storable => sub {
		651	my ($self, $ref) = @_;
		652
		653	require Storable;
		654
		655	pack "w/a*", Storable::nfreeze ($ref)
		656	};
		657
		658	=back
		659
		660	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		661
		662	This function (not method) lets you add your own types to C<push_write>.
		663	Whenever the given C<type> is used, C<push_write> will invoke the code
		664	reference with the handle object and the remaining arguments.
		665
		666	The code reference is supposed to return a single octet string that will
		667	be appended to the write buffer.
		668
		669	Note that this is a function, and all types registered this way will be
		670	global, so try to use unique names.
		671
		672	=cut
		673
		674	#############################################################################
		675
		676	=back
		677
		678	=head2 READ QUEUE
		679
		680	AnyEvent::Handle manages two queues per handle, one for writing and one
		681	for reading.
		682
		683	The read queue is more complex than the write queue. It can be used in two
		684	ways, the "simple" way, using only C<on_read> and the "complex" way, using
		685	a queue.
		686
		687	In the simple case, you just install an C<on_read> callback and whenever
		688	new data arrives, it will be called. You can then remove some data (if
		689	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
		690	leave the data there if you want to accumulate more (e.g. when only a
		691	partial message has been received so far).
		692
		693	In the more complex case, you want to queue multiple callbacks. In this
		694	case, AnyEvent::Handle will call the first queued callback each time new
		695	data arrives (also the first time it is queued) and removes it when it has
		696	done its job (see C<push_read>, below).
		697
		698	This way you can, for example, push three line-reads, followed by reading
		699	a chunk of data, and AnyEvent::Handle will execute them in order.
		700
		701	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
		702	the specified number of bytes which give an XML datagram.
		703
		704	# in the default state, expect some header bytes
		705	$handle->on_read (sub {
		706	# some data is here, now queue the length-header-read (4 octets)
		707	shift->unshift_read (chunk => 4, sub {
		708	# header arrived, decode
		709	my $len = unpack "N", $_[1];
		710
		711	# now read the payload
		712	shift->unshift_read (chunk => $len, sub {
		713	my $xml = $_[1];
		714	# handle xml
		715	});
		716	});
		717	});
		718
		719	Example 2: Implement a client for a protocol that replies either with "OK"
		720	and another line or "ERROR" for the first request that is sent, and 64
		721	bytes for the second request. Due to the availability of a queue, we can
		722	just pipeline sending both requests and manipulate the queue as necessary
		723	in the callbacks.
		724
		725	When the first callback is called and sees an "OK" response, it will
		726	C<unshift> another line-read. This line-read will be queued I<before> the
		727	64-byte chunk callback.
		728
		729	# request one, returns either "OK + extra line" or "ERROR"
		730	$handle->push_write ("request 1\015\012");
		731
		732	# we expect "ERROR" or "OK" as response, so push a line read
		733	$handle->push_read (line => sub {
		734	# if we got an "OK", we have to _prepend_ another line,
		735	# so it will be read before the second request reads its 64 bytes
		736	# which are already in the queue when this callback is called
		737	# we don't do this in case we got an error
		738	if ($_[1] eq "OK") {
49	on_readline => sub {	739	$_[0]->unshift_read (line => sub {
50	my ($ae_fh, @lines) = @_;	740	my $response = $_[1];
51	for (@lines) {	741	...
52	chomp;	742	});
53	print "Line: $_";	743	}
		744	});
		745
		746	# request two, simply returns 64 octets
		747	$handle->push_write ("request 2\015\012");
		748
		749	# simply read 64 bytes, always
		750	$handle->push_read (chunk => 64, sub {
		751	my $response = $_[1];
		752	...
		753	});
		754
		755	=over 4
		756
		757	=cut
		758
		759	sub _drain_rbuf {
		760	my ($self) = @_;
		761
		762	local $self->{_in_drain} = 1;
		763
		764	if (
		765	defined $self->{rbuf_max}
		766	&& $self->{rbuf_max} < length $self->{rbuf}
		767	) {
		768	$self->_error (&Errno::ENOSPC, 1), return;
		769	}
		770
		771	while () {
		772	my $len = length $self->{rbuf};
		773
		774	if (my $cb = shift @{ $self->{_queue} }) {
		775	unless ($cb->($self)) {
		776	if ($self->{_eof}) {
		777	# no progress can be made (not enough data and no data forthcoming)
		778	$self->_error (&Errno::EPIPE, 1), return;
54	}	779	}
		780
		781	unshift @{ $self->{_queue} }, $cb;
		782	last;
55	}	783	}
56	);
57
58	$cv->wait;
59
60	=head1 DESCRIPTION
61
62	This module is a helper module to make it easier to do non-blocking I/O
63	on filehandles (and sockets, see L<AnyEvent::Socket>).
64
65	The event loop is provided by L<AnyEvent>.
66
67	=head1 METHODS
68
69	=over 4
70
71	=item B<new (%args)>
72
73	The constructor has these arguments:
74
75	=over 4
76
77	=item fh => $filehandle
78
79	The filehandle this L<AnyEvent::Handle> object will operate on.
80
81	NOTE: The filehandle will be set to non-blocking.
82
83	=item read_block_size => $size
84
85	The default read block size use for reads via the C<on_read>
86	method.
87
88	=item on_read => $cb
89
90	=item on_eof => $cb
91
92	=item on_error => $cb
93
94	These are shortcuts, that will call the corresponding method and set the callback to C<$cb>.
95
96	=item on_readline => $cb
97
98	The C<readlines> method is called with the default seperator and C<$cb> as callback
99	for you.
100
101	=back
102
103	=cut
104
105	sub new {
106	my $this = shift;
107	my $class = ref($this) || $this;
108	my $self = {
109	read_block_size => 4096,
110	rbuf => '',
111	@_
112	};
113	bless $self, $class;
114
115	$self->{fh}->blocking (0) if $self->{fh};
116
117	if ($self->{on_read}) {
118	$self->on_read ($self->{on_read});
119
120	} elsif ($self->{on_readline}) {	784	} elsif ($self->{on_read}) {
121	$self->readlines ($self->{on_readline});	785	last unless $len;
122		786
		787	$self->{on_read}($self);
		788
		789	if (
		790	$len == length $self->{rbuf} # if no data has been consumed
		791	&& !@{ $self->{_queue} } # and the queue is still empty
		792	&& $self->{on_read} # but we still have on_read
		793	) {
		794	# no further data will arrive
		795	# so no progress can be made
		796	$self->_error (&Errno::EPIPE, 1), return
		797	if $self->{_eof};
		798
		799	last; # more data might arrive
		800	}
		801	} else {
		802	# read side becomes idle
		803	delete $self->{_rw} unless $self->{tls};
		804	last;
		805	}
		806	}
		807
123	} elsif ($self->{on_eof}) {	808	if ($self->{_eof}) {
124	$self->on_eof ($self->{on_eof});
125
126	} elsif ($self->{on_error}) {	809	if ($self->{on_eof}) {
127	$self->on_eof ($self->{on_error});	810	$self->{on_eof}($self)
		811	} else {
		812	$self->_error (0, 1);
		813	}
128	}	814	}
129		815
130	return $self	816	# may need to restart read watcher
		817	unless ($self->{_rw}) {
		818	$self->start_read
		819	if $self->{on_read} || @{ $self->{_queue} };
		820	}
131	}	821	}
132		822
133	=item B<fh>	823	=item $handle->on_read ($cb)
134		824
135	This method returns the filehandle of the L<AnyEvent::Handle> object.	825	This replaces the currently set C<on_read> callback, or clears it (when
136		826	the new callback is C<undef>). See the description of C<on_read> in the
137	=cut	827	constructor.
138
139	sub fh { $_[0]->{fh} }
140
141	=item B<on_read ($callback)>
142
143	This method installs a C<$callback> that will be called
144	when new data arrived. You can access the read buffer via the C<rbuf>
145	method (see below).
146
147	The first argument of the C<$callback> will be the L<AnyEvent::Handle> object.
148		828
149	=cut	829	=cut
150		830
151	sub on_read {	831	sub on_read {
152	my ($self, $cb) = @_;	832	my ($self, $cb) = @_;
		833
153	$self->{on_read} = $cb;	834	$self->{on_read} = $cb;
		835	$self->_drain_rbuf if $cb && !$self->{_in_drain};
		836	}
154		837
155	unless (defined $self->{on_read}) {	838	=item $handle->rbuf
156	delete $self->{on_read_w};	839
		840	Returns the read buffer (as a modifiable lvalue).
		841
		842	You can access the read buffer directly as the C<< ->{rbuf} >> member, if
		843	you want.
		844
		845	NOTE: The read buffer should only be used or modified if the C<on_read>,
		846	C<push_read> or C<unshift_read> methods are used. The other read methods
		847	automatically manage the read buffer.
		848
		849	=cut
		850
		851	sub rbuf : lvalue {
		852	$_[0]{rbuf}
		853	}
		854
		855	=item $handle->push_read ($cb)
		856
		857	=item $handle->unshift_read ($cb)
		858
		859	Append the given callback to the end of the queue (C<push_read>) or
		860	prepend it (C<unshift_read>).
		861
		862	The callback is called each time some additional read data arrives.
		863
		864	It must check whether enough data is in the read buffer already.
		865
		866	If not enough data is available, it must return the empty list or a false
		867	value, in which case it will be called repeatedly until enough data is
		868	available (or an error condition is detected).
		869
		870	If enough data was available, then the callback must remove all data it is
		871	interested in (which can be none at all) and return a true value. After returning
		872	true, it will be removed from the queue.
		873
		874	=cut
		875
		876	our %RH;
		877
		878	sub register_read_type($$) {
		879	$RH{$_[0]} = $_[1];
		880	}
		881
		882	sub push_read {
		883	my $self = shift;
		884	my $cb = pop;
		885
		886	if (@_) {
		887	my $type = shift;
		888
		889	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		890	->($self, $cb, @_);
		891	}
		892
		893	push @{ $self->{_queue} }, $cb;
		894	$self->_drain_rbuf unless $self->{_in_drain};
		895	}
		896
		897	sub unshift_read {
		898	my $self = shift;
		899	my $cb = pop;
		900
		901	if (@_) {
		902	my $type = shift;
		903
		904	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		905	->($self, $cb, @_);
		906	}
		907
		908
		909	unshift @{ $self->{_queue} }, $cb;
		910	$self->_drain_rbuf unless $self->{_in_drain};
		911	}
		912
		913	=item $handle->push_read (type => @args, $cb)
		914
		915	=item $handle->unshift_read (type => @args, $cb)
		916
		917	Instead of providing a callback that parses the data itself you can chose
		918	between a number of predefined parsing formats, for chunks of data, lines
		919	etc.
		920
		921	Predefined types are (if you have ideas for additional types, feel free to
		922	drop by and tell us):
		923
		924	=over 4
		925
		926	=item chunk => $octets, $cb->($handle, $data)
		927
		928	Invoke the callback only once C<$octets> bytes have been read. Pass the
		929	data read to the callback. The callback will never be called with less
		930	data.
		931
		932	Example: read 2 bytes.
		933
		934	$handle->push_read (chunk => 2, sub {
		935	warn "yay ", unpack "H*", $_[1];
		936	});
		937
		938	=cut
		939
		940	register_read_type chunk => sub {
		941	my ($self, $cb, $len) = @_;
		942
		943	sub {
		944	$len <= length $_[0]{rbuf} or return;
		945	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
		946	1
		947	}
		948	};
		949
		950	=item line => [$eol, ]$cb->($handle, $line, $eol)
		951
		952	The callback will be called only once a full line (including the end of
		953	line marker, C<$eol>) has been read. This line (excluding the end of line
		954	marker) will be passed to the callback as second argument (C<$line>), and
		955	the end of line marker as the third argument (C<$eol>).
		956
		957	The end of line marker, C<$eol>, can be either a string, in which case it
		958	will be interpreted as a fixed record end marker, or it can be a regex
		959	object (e.g. created by C<qr>), in which case it is interpreted as a
		960	regular expression.
		961
		962	The end of line marker argument C<$eol> is optional, if it is missing (NOT
		963	undef), then C<qr|\015?\012|> is used (which is good for most internet
		964	protocols).
		965
		966	Partial lines at the end of the stream will never be returned, as they are
		967	not marked by the end of line marker.
		968
		969	=cut
		970
		971	register_read_type line => sub {
		972	my ($self, $cb, $eol) = @_;
		973
		974	if (@_ < 3) {
		975	# this is more than twice as fast as the generic code below
		976	sub {
		977	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		978
		979	$cb->($_[0], $1, $2);
		980	1
		981	}
		982	} else {
		983	$eol = quotemeta $eol unless ref $eol;
		984	$eol = qr|^(.*?)($eol)|s;
		985
		986	sub {
		987	$_[0]{rbuf} =~ s/$eol// or return;
		988
		989	$cb->($_[0], $1, $2);
		990	1
		991	}
		992	}
		993	};
		994
		995	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		996
		997	Makes a regex match against the regex object C<$accept> and returns
		998	everything up to and including the match.
		999
		1000	Example: read a single line terminated by '\n'.
		1001
		1002	$handle->push_read (regex => qr<\n>, sub { ... });
		1003
		1004	If C<$reject> is given and not undef, then it determines when the data is
		1005	to be rejected: it is matched against the data when the C<$accept> regex
		1006	does not match and generates an C<EBADMSG> error when it matches. This is
		1007	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1008	receive buffer overflow).
		1009
		1010	Example: expect a single decimal number followed by whitespace, reject
		1011	anything else (not the use of an anchor).
		1012
		1013	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1014
		1015	If C<$skip> is given and not C<undef>, then it will be matched against
		1016	the receive buffer when neither C<$accept> nor C<$reject> match,
		1017	and everything preceding and including the match will be accepted
		1018	unconditionally. This is useful to skip large amounts of data that you
		1019	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1020	have to start matching from the beginning. This is purely an optimisation
		1021	and is usually worth only when you expect more than a few kilobytes.
		1022
		1023	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1024	expect the header to be very large (it isn't in practise, but...), we use
		1025	a skip regex to skip initial portions. The skip regex is tricky in that
		1026	it only accepts something not ending in either \015 or \012, as these are
		1027	required for the accept regex.
		1028
		1029	$handle->push_read (regex =>
		1030	qr<\015\012\015\012>,
		1031	undef, # no reject
		1032	qr<^.*[^\015\012]>,
		1033	sub { ... });
		1034
		1035	=cut
		1036
		1037	register_read_type regex => sub {
		1038	my ($self, $cb, $accept, $reject, $skip) = @_;
		1039
		1040	my $data;
		1041	my $rbuf = \$self->{rbuf};
		1042
		1043	sub {
		1044	# accept
		1045	if ($$rbuf =~ $accept) {
		1046	$data .= substr $$rbuf, 0, $+[0], "";
		1047	$cb->($self, $data);
157	return;	1048	return 1;
		1049	}
		1050
		1051	# reject
		1052	if ($reject && $$rbuf =~ $reject) {
		1053	$self->_error (&Errno::EBADMSG);
		1054	}
		1055
		1056	# skip
		1057	if ($skip && $$rbuf =~ $skip) {
		1058	$data .= substr $$rbuf, 0, $+[0], "";
		1059	}
		1060
		1061	()
158	}	1062	}
159		1063	};
160	$self->{on_read_w} =	1064
161	AnyEvent->io (poll => 'r', fh => $self->{fh}, cb => sub {	1065	=item netstring => $cb->($handle, $string)
162	#d# warn "READ:[$self->{read_size}] $self->{read_block_size} : ".length ($self->{rbuf})."\n";	1066
163	my $rbuf_len = length $self->{rbuf};	1067	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
164	my $l;	1068
165	if (defined $self->{read_size}) {	1069	Throws an error with C<$!> set to EBADMSG on format violations.
166	$l = sysread $self->{fh}, $self->{rbuf},	1070
167	($self->{read_size} - $rbuf_len), $rbuf_len;	1071	=cut
168	} else {	1072
169	$l = sysread $self->{fh}, $self->{rbuf}, $self->{read_block_size}, $rbuf_len;	1073	register_read_type netstring => sub {
		1074	my ($self, $cb) = @_;
		1075
		1076	sub {
		1077	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1078	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1079	$self->_error (&Errno::EBADMSG);
170	}	1080	}
171	#d# warn "READL $l [$self->{rbuf}]\n";	1081	return;
		1082	}
172		1083
173	if (not defined $l) {	1084	my $len = $1;
174	return if $! == EAGAIN || $! == EINTR;
175	$self->{on_error}->($self) if $self->{on_error};
176	delete $self->{on_read_w};
177		1085
178	} elsif ($l == 0) {	1086	$self->unshift_read (chunk => $len, sub {
179	$self->{on_eof}->($self) if $self->{on_eof};	1087	my $string = $_[1];
180	delete $self->{on_read_w};	1088	$_[0]->unshift_read (chunk => 1, sub {
181		1089	if ($_[1] eq ",") {
		1090	$cb->($_[0], $string);
182	} else {	1091	} else {
183	$self->{on_read}->($self);	1092	$self->_error (&Errno::EBADMSG);
		1093	}
		1094	});
		1095	});
		1096
		1097	1
		1098	}
		1099	};
		1100
		1101	=item packstring => $format, $cb->($handle, $string)
		1102
		1103	An octet string prefixed with an encoded length. The encoding C<$format>
		1104	uses the same format as a Perl C<pack> format, but must specify a single
		1105	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1106	optional C<!>, C<< < >> or C<< > >> modifier).
		1107
		1108	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1109	EPP uses a prefix of C<N> (4 octtes).
		1110
		1111	Example: read a block of data prefixed by its length in BER-encoded
		1112	format (very efficient).
		1113
		1114	$handle->push_read (packstring => "w", sub {
		1115	my ($handle, $data) = @_;
		1116	});
		1117
		1118	=cut
		1119
		1120	register_read_type packstring => sub {
		1121	my ($self, $cb, $format) = @_;
		1122
		1123	sub {
		1124	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1125	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1126	or return;
		1127
		1128	$format = length pack $format, $len;
		1129
		1130	# bypass unshift if we already have the remaining chunk
		1131	if ($format + $len <= length $_[0]{rbuf}) {
		1132	my $data = substr $_[0]{rbuf}, $format, $len;
		1133	substr $_[0]{rbuf}, 0, $format + $len, "";
		1134	$cb->($_[0], $data);
		1135	} else {
		1136	# remove prefix
		1137	substr $_[0]{rbuf}, 0, $format, "";
		1138
		1139	# read remaining chunk
		1140	$_[0]->unshift_read (chunk => $len, $cb);
		1141	}
		1142
		1143	1
		1144	}
		1145	};
		1146
		1147	=item json => $cb->($handle, $hash_or_arrayref)
		1148
		1149	Reads a JSON object or array, decodes it and passes it to the
		1150	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1151
		1152	If a C<json> object was passed to the constructor, then that will be used
		1153	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1154
		1155	This read type uses the incremental parser available with JSON version
		1156	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1157	dependency on your own: this module will load the JSON module, but
		1158	AnyEvent does not depend on it itself.
		1159
		1160	Since JSON texts are fully self-delimiting, the C<json> read and write
		1161	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1162	the C<json> write type description, above, for an actual example.
		1163
		1164	=cut
		1165
		1166	register_read_type json => sub {
		1167	my ($self, $cb) = @_;
		1168
		1169	require JSON;
		1170
		1171	my $data;
		1172	my $rbuf = \$self->{rbuf};
		1173
		1174	my $json = $self->{json} ||= JSON->new->utf8;
		1175
		1176	sub {
		1177	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1178
		1179	if ($ref) {
		1180	$self->{rbuf} = $json->incr_text;
		1181	$json->incr_text = "";
		1182	$cb->($self, $ref);
		1183
		1184	1
		1185	} elsif ($@) {
		1186	# error case
		1187	$json->incr_skip;
		1188
		1189	$self->{rbuf} = $json->incr_text;
		1190	$json->incr_text = "";
		1191
		1192	$self->_error (&Errno::EBADMSG);
		1193	()
		1194
		1195	} else {
		1196	$self->{rbuf} = "";
		1197	()
		1198	}
		1199	}
		1200	};
		1201
		1202	=item storable => $cb->($handle, $ref)
		1203
		1204	Deserialises a L<Storable> frozen representation as written by the
		1205	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1206	data).
		1207
		1208	Raises C<EBADMSG> error if the data could not be decoded.
		1209
		1210	=cut
		1211
		1212	register_read_type storable => sub {
		1213	my ($self, $cb) = @_;
		1214
		1215	require Storable;
		1216
		1217	sub {
		1218	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1219	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1220	or return;
		1221
		1222	my $format = length pack "w", $len;
		1223
		1224	# bypass unshift if we already have the remaining chunk
		1225	if ($format + $len <= length $_[0]{rbuf}) {
		1226	my $data = substr $_[0]{rbuf}, $format, $len;
		1227	substr $_[0]{rbuf}, 0, $format + $len, "";
		1228	$cb->($_[0], Storable::thaw ($data));
		1229	} else {
		1230	# remove prefix
		1231	substr $_[0]{rbuf}, 0, $format, "";
		1232
		1233	# read remaining chunk
		1234	$_[0]->unshift_read (chunk => $len, sub {
		1235	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1236	$cb->($_[0], $ref);
		1237	} else {
		1238	$self->_error (&Errno::EBADMSG);
		1239	}
		1240	});
		1241	}
		1242
		1243	1
		1244	}
		1245	};
		1246
		1247	=back
		1248
		1249	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1250
		1251	This function (not method) lets you add your own types to C<push_read>.
		1252
		1253	Whenever the given C<type> is used, C<push_read> will invoke the code
		1254	reference with the handle object, the callback and the remaining
		1255	arguments.
		1256
		1257	The code reference is supposed to return a callback (usually a closure)
		1258	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1259
		1260	It should invoke the passed callback when it is done reading (remember to
		1261	pass C<$handle> as first argument as all other callbacks do that).
		1262
		1263	Note that this is a function, and all types registered this way will be
		1264	global, so try to use unique names.
		1265
		1266	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1267	search for C<register_read_type>)).
		1268
		1269	=item $handle->stop_read
		1270
		1271	=item $handle->start_read
		1272
		1273	In rare cases you actually do not want to read anything from the
		1274	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1275	any queued callbacks will be executed then. To start reading again, call
		1276	C<start_read>.
		1277
		1278	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1279	you change the C<on_read> callback or push/unshift a read callback, and it
		1280	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1281	there are any read requests in the queue.
		1282
		1283	These methods will have no effect when in TLS mode (as TLS doesn't support
		1284	half-duplex connections).
		1285
		1286	=cut
		1287
		1288	sub stop_read {
		1289	my ($self) = @_;
		1290
		1291	delete $self->{_rw} unless $self->{tls};
		1292	}
		1293
		1294	sub start_read {
		1295	my ($self) = @_;
		1296
		1297	unless ($self->{_rw} || $self->{_eof}) {
		1298	Scalar::Util::weaken $self;
		1299
		1300	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1301	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1302	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1303
		1304	if ($len > 0) {
		1305	$self->{_activity} = AnyEvent->now;
		1306
		1307	if ($self->{tls}) {
		1308	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1309
		1310	&_dotls ($self);
		1311	} else {
		1312	$self->_drain_rbuf unless $self->{_in_drain};
		1313	}
		1314
		1315	} elsif (defined $len) {
		1316	delete $self->{_rw};
		1317	$self->{_eof} = 1;
		1318	$self->_drain_rbuf unless $self->{_in_drain};
		1319
		1320	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1321	return $self->_error ($!, 1);
184	}	1322	}
185	});	1323	});
		1324	}
186	}	1325	}
187		1326
188	=item B<on_error ($callback)>	1327	# poll the write BIO and send the data if applicable
189		1328	sub _dotls {
190	Whenever a read or write operation resulted in an error the C<$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, $cb) = @_;	1329	my ($self) = @_;
240		1330
241	$self->{read_cb} = $cb;	1331	my $tmp;
242	my $old_blk_size = $self->{read_block_size};
243	$self->{read_block_size} = $len;
244		1332
245	$self->on_read (sub {	1333	if (length $self->{_tls_wbuf}) {
246	#d# warn "OFOFO $len || ".length($_[0]->{rbuf})."||\n";	1334	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
247		1335	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, $len, ''));
252	}	1336	}
253	});	1337	}
254	}
255		1338
256	=item B<readlines ($callback)>	1339	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1340	unless (length $tmp) {
		1341	# let's treat SSL-eof as we treat normal EOF
		1342	delete $self->{_rw};
		1343	$self->{_eof} = 1;
		1344	&_freetls;
		1345	}
257		1346
258	=item B<readlines ($sep, $callback)>	1347	$self->{rbuf} .= $tmp;
		1348	$self->_drain_rbuf unless $self->{_in_drain};
		1349	$self->{tls} or return; # tls session might have gone away in callback
		1350	}
259		1351
260	This method will read lines from the filehandle, seperated by C<$sep> or C<"\n">	1352	$tmp = Net::SSLeay::get_error ($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		1353
264	The C<$callback> will be called when at least one	1354	if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
265	line could be read. The first argument to the C<$callback> will be the L<AnyEvent::Handle>	1355	if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
266	object itself and the rest of the arguments will be the read lines.	1356	return $self->_error ($!, 1);
		1357	} elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
		1358	return $self->_error (&Errno::EIO, 1);
		1359	}
267		1360
268	NOTE: This method will override any callbacks installed via the C<on_read> method.	1361	# all other errors are fine for our purposes
		1362	}
269		1363
270	=cut	1364	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1365	$self->{wbuf} .= $tmp;
		1366	$self->_drain_wbuf;
		1367	}
		1368	}
271		1369
272	sub readlines {	1370	=item $handle->starttls ($tls[, $tls_ctx])
		1371
		1372	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1373	object is created, you can also do that at a later time by calling
		1374	C<starttls>.
		1375
		1376	The first argument is the same as the C<tls> constructor argument (either
		1377	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1378
		1379	The second argument is the optional C<Net::SSLeay::CTX> object that is
		1380	used when AnyEvent::Handle has to create its own TLS connection object.
		1381
		1382	The TLS connection object will end up in C<< $handle->{tls} >> after this
		1383	call and can be used or changed to your liking. Note that the handshake
		1384	might have already started when this function returns.
		1385
		1386	If it an error to start a TLS handshake more than once per
		1387	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1388
		1389	=cut
		1390
		1391	sub starttls {
273	my ($self, $NL, $cb) = @_;	1392	my ($self, $ssl, $ctx) = @_;
274		1393
275	if (ref $NL) {	1394	require Net::SSLeay;
276	$cb = $NL;	1395
277	$NL = "\n";	1396	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
		1397	if $self->{tls};
278	}	1398
279		1399	if ($ssl eq "accept") {
280	$self->{on_readline} = $cb;	1400	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
281		1401	Net::SSLeay::set_accept_state ($ssl);
282	$self->on_read (sub {	1402	} elsif ($ssl eq "connect") {
283	my @lines;	1403	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
284	push @lines, $1 while $_[0]->{rbuf} =~ s/(.*)$NL//;	1404	Net::SSLeay::set_connect_state ($ssl);
285	$self->{on_readline}->($_[0], @lines);
286	});	1405	}
287	}
288		1406
289	=item B<write ($data)>	1407	$self->{tls} = $ssl;
290		1408
291	=item B<write ($callback)>	1409	# basically, this is deep magic (because SSL_read should have the same issues)
		1410	# but the openssl maintainers basically said: "trust us, it just works".
		1411	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1412	# and mismaintained ssleay-module doesn't even offer them).
		1413	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1414	#
		1415	# in short: this is a mess.
		1416	#
		1417	# note that we do not try to keep the length constant between writes as we are required to do.
		1418	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1419	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1420	# have identity issues in that area.
		1421	Net::SSLeay::CTX_set_mode ($self->{tls},
		1422	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1423	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
292		1424
293	=item B<write ($data, $callback)>	1425	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1426	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
294		1427
295	This method will write C<$data> to the filehandle and call the C<$callback>	1428	Net::SSLeay::set_bio ($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		1429
299	=cut	1430	&_dotls; # need to trigger the initial handshake
300		1431	$self->start_read; # make sure we actually do read
301	sub write {
302	my ($self, $data, $cb) = @_;
303	if (ref $data) { $cb = $data; undef $data }
304	push @{$self->{write_bufs}}, [$data, $cb];
305	$self->_check_writer;
306	}	1432	}
307		1433
308	sub _check_writer {	1434	=item $handle->stoptls
		1435
		1436	Shuts down the SSL connection - this makes a proper EOF handshake by
		1437	sending a close notify to the other side, but since OpenSSL doesn't
		1438	support non-blocking shut downs, it is not possible to re-use the stream
		1439	afterwards.
		1440
		1441	=cut
		1442
		1443	sub stoptls {
309	my ($self) = @_;	1444	my ($self) = @_;
310		1445
311	if ($self->{write_w}) {	1446	if ($self->{tls}) {
312	unless ($self->{write_cb}) {	1447	Net::SSLeay::shutdown ($self->{tls});
313	while (@{$self->{write_bufs}} && not defined $self->{write_bufs}->[0]->[1]) {	1448
314	my $wba = shift @{$self->{write_bufs}};	1449	&_dotls;
315	$self->{wbuf} .= $wba->[0];	1450
316	}	1451	# we don't give a shit. no, we do, but we can't. no...
317	}	1452	# we, we... have to use openssl :/
318	return;	1453	&_freetls;
		1454	}
		1455	}
		1456
		1457	sub _freetls {
		1458	my ($self) = @_;
		1459
		1460	return unless $self->{tls};
		1461
		1462	Net::SSLeay::free (delete $self->{tls});
319	}	1463
		1464	delete @$self{qw(_rbio _wbio _tls_wbuf)};
		1465	}
320		1466
321	my $wba = shift @{$self->{write_bufs}}	1467	sub DESTROY {
322	or return;	1468	my $self = shift;
323		1469
324	unless (defined $wba->[0]) {	1470	&_freetls;
325	$wba->[1]->($self) if $wba->[1];
326	$self->_check_writer;
327	return;
328	}
329		1471
330	$self->{wbuf} = $wba->[0];	1472	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
331	$self->{write_cb} = $wba->[1];
332		1473
333	$self->{write_w} =	1474	if ($linger && length $self->{wbuf}) {
334	AnyEvent->io (poll => 'w', fh => $self->{fh}, cb => sub {	1475	my $fh = delete $self->{fh};
		1476	my $wbuf = delete $self->{wbuf};
		1477
		1478	my @linger;
		1479
		1480	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
335	my $l = syswrite $self->{fh}, $self->{wbuf}, length $self->{wbuf};	1481	my $len = syswrite $fh, $wbuf, length $wbuf;
336		1482
337	if (not defined $l) {	1483	if ($len > 0) {
338	return if $! == EAGAIN || $! == EINTR;	1484	substr $wbuf, 0, $len, "";
339	delete $self->{write_w};
340	$self->{on_error}->($self) if $self->{on_error};
341
342	} else {	1485	} else {
343	substr $self->{wbuf}, 0, $l, '';	1486	@linger = (); # end
344
345	if (length ($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	}	1487	}
355	});	1488	});
		1489	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1490	@linger = ();
		1491	});
		1492	}
		1493	}
		1494
		1495	=item $handle->destroy
		1496
		1497	Shuts down the handle object as much as possible - this call ensures that
		1498	no further callbacks will be invoked and resources will be freed as much
		1499	as possible. You must not call any methods on the object afterwards.
		1500
		1501	Normally, you can just "forget" any references to an AnyEvent::Handle
		1502	object and it will simply shut down. This works in fatal error and EOF
		1503	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1504	callback, so when you want to destroy the AnyEvent::Handle object from
		1505	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1506	that case.
		1507
		1508	The handle might still linger in the background and write out remaining
		1509	data, as specified by the C<linger> option, however.
		1510
		1511	=cut
		1512
		1513	sub destroy {
		1514	my ($self) = @_;
		1515
		1516	$self->DESTROY;
		1517	%$self = ();
		1518	}
		1519
		1520	=item AnyEvent::Handle::TLS_CTX
		1521
		1522	This function creates and returns the Net::SSLeay::CTX object used by
		1523	default for TLS mode.
		1524
		1525	The context is created like this:
		1526
		1527	Net::SSLeay::load_error_strings;
		1528	Net::SSLeay::SSLeay_add_ssl_algorithms;
		1529	Net::SSLeay::randomize;
		1530
		1531	my $CTX = Net::SSLeay::CTX_new;
		1532
		1533	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
		1534
		1535	=cut
		1536
		1537	our $TLS_CTX;
		1538
		1539	sub TLS_CTX() {
		1540	$TLS_CTX || do {
		1541	require Net::SSLeay;
		1542
		1543	Net::SSLeay::load_error_strings ();
		1544	Net::SSLeay::SSLeay_add_ssl_algorithms ();
		1545	Net::SSLeay::randomize ();
		1546
		1547	$TLS_CTX = Net::SSLeay::CTX_new ();
		1548
		1549	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
		1550
		1551	$TLS_CTX
		1552	}
356	}	1553	}
357		1554
358	=back	1555	=back
359		1556
		1557
		1558	=head1 NONFREQUENTLY ASKED QUESTIONS
		1559
		1560	=over 4
		1561
		1562	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1563	still get further invocations!
		1564
		1565	That's because AnyEvent::Handle keeps a reference to itself when handling
		1566	read or write callbacks.
		1567
		1568	It is only safe to "forget" the reference inside EOF or error callbacks,
		1569	from within all other callbacks, you need to explicitly call the C<<
		1570	->destroy >> method.
		1571
		1572	=item I get different callback invocations in TLS mode/Why can't I pause
		1573	reading?
		1574
		1575	Unlike, say, TCP, TLS connections do not consist of two independent
		1576	communication channels, one for each direction. Or put differently. The
		1577	read and write directions are not independent of each other: you cannot
		1578	write data unless you are also prepared to read, and vice versa.
		1579
		1580	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1581	callback invocations when you are not expecting any read data - the reason
		1582	is that AnyEvent::Handle always reads in TLS mode.
		1583
		1584	During the connection, you have to make sure that you always have a
		1585	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1586	connection (or when you no longer want to use it) you can call the
		1587	C<destroy> method.
		1588
		1589	=item How do I read data until the other side closes the connection?
		1590
		1591	If you just want to read your data into a perl scalar, the easiest way
		1592	to achieve this is by setting an C<on_read> callback that does nothing,
		1593	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1594	will be in C<$_[0]{rbuf}>:
		1595
		1596	$handle->on_read (sub { });
		1597	$handle->on_eof (undef);
		1598	$handle->on_error (sub {
		1599	my $data = delete $_[0]{rbuf};
		1600	undef $handle;
		1601	});
		1602
		1603	The reason to use C<on_error> is that TCP connections, due to latencies
		1604	and packets loss, might get closed quite violently with an error, when in
		1605	fact, all data has been received.
		1606
		1607	It is usually better to use acknowledgements when transferring data,
		1608	to make sure the other side hasn't just died and you got the data
		1609	intact. This is also one reason why so many internet protocols have an
		1610	explicit QUIT command.
		1611
		1612	=item I don't want to destroy the handle too early - how do I wait until
		1613	all data has been written?
		1614
		1615	After writing your last bits of data, set the C<on_drain> callback
		1616	and destroy the handle in there - with the default setting of
		1617	C<low_water_mark> this will be called precisely when all data has been
		1618	written to the socket:
		1619
		1620	$handle->push_write (...);
		1621	$handle->on_drain (sub {
		1622	warn "all data submitted to the kernel\n";
		1623	undef $handle;
		1624	});
		1625
		1626	=back
		1627
		1628
		1629	=head1 SUBCLASSING AnyEvent::Handle
		1630
		1631	In many cases, you might want to subclass AnyEvent::Handle.
		1632
		1633	To make this easier, a given version of AnyEvent::Handle uses these
		1634	conventions:
		1635
		1636	=over 4
		1637
		1638	=item * all constructor arguments become object members.
		1639
		1640	At least initially, when you pass a C<tls>-argument to the constructor it
		1641	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1642	mutated later on (for example C<tls> will hold the TLS connection object).
		1643
		1644	=item * other object member names are prefixed with an C<_>.
		1645
		1646	All object members not explicitly documented (internal use) are prefixed
		1647	with an underscore character, so the remaining non-C<_>-namespace is free
		1648	for use for subclasses.
		1649
		1650	=item * all members not documented here and not prefixed with an underscore
		1651	are free to use in subclasses.
		1652
		1653	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1654	member variables, but thats just life, at least it is documented.
		1655
		1656	=back
		1657
360	=head1 AUTHOR	1658	=head1 AUTHOR
361		1659
362	Robin Redeker, C<< <elmex at ta-sa.org> >>	1660	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
363
364	=head1 BUGS
365
366	Please report any bugs or feature requests to
367	C<bug-io-anyevent at rt.cpan.org>, or through the web interface at
368	L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=IO-AnyEvent>.
369	I will be notified, and then you'll automatically be notified of progress on
370	your bug as I make changes.
371
372	=head1 SUPPORT
373
374	You can find documentation for this module with the perldoc command.
375
376	perldoc AnyEvent::Handle
377
378	You can also look for information at:
379
380	=over 4
381
382	=item * AnnoCPAN: Annotated CPAN documentation
383
384	L<http://annocpan.org/dist/IO-AnyEvent>
385
386	=item * CPAN Ratings
387
388	L<http://cpanratings.perl.org/d/IO-AnyEvent>
389
390	=item * RT: CPAN's request tracker
391
392	L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=IO-AnyEvent>
393
394	=item * Search CPAN
395
396	L<http://search.cpan.org/dist/IO-AnyEvent>
397
398	=back
399
400	=head1 ACKNOWLEDGEMENTS
401
402	=head1 COPYRIGHT & LICENSE
403
404	Copyright 2008 Robin Redeker, all rights reserved.
405
406	This program is free software; you can redistribute it and/or modify it
407	under the same terms as Perl itself.
408		1661
409	=cut	1662	=cut
410		1663
411	1; # End of AnyEvent::Handle	1664	1; # End of AnyEvent::Handle

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