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Revision 1.6 by elmex, Mon Apr 28 09:27:47 2008 UTC vs.
Revision 1.108 by root, Tue Jan 6 20:08:05 2009 UTC

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

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