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Revision 1.20 by elmex, Sat May 24 08:16:50 2008 UTC vs.
Revision 1.136 by root, Fri Jul 3 21:44:14 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 AnyEvent::Util ();	7	use AnyEvent::Util qw(WSAEWOULDBLOCK);
8	use Scalar::Util ();	8	use Scalar::Util ();
9	use Carp ();	9	use Carp ();
10	use Fcntl ();	10	use Fcntl ();
11	use Errno qw/EAGAIN EINTR/;	11	use Errno qw(EAGAIN EINTR);
12		12
13	=head1 NAME	13	=head1 NAME
14		14
15	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
16		16
17	This module is experimental.
18
19	=cut	17	=cut
20		18
21	our $VERSION = '0.04';	19	our $VERSION = 4.452;
22		20
23	=head1 SYNOPSIS	21	=head1 SYNOPSIS
24		22
25	use AnyEvent;	23	use AnyEvent;
26	use AnyEvent::Handle;	24	use AnyEvent::Handle;
27		25
28	my $cv = AnyEvent->condvar;	26	my $cv = AnyEvent->condvar;
29		27
30	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	28	my $handle =
31
32	#TODO
33
34	# or use the constructor to pass the callback:
35
36	my $ae_fh2 =
37	AnyEvent::Handle->new (	29	AnyEvent::Handle->new (
38	fh => \*STDIN,	30	fh => \*STDIN,
39	on_eof => sub {	31	on_eof => sub {
40	$cv->broadcast;	32	$cv->send;
41	},	33	},
42	#TODO
43	);	34	);
44		35
45	$cv->wait;	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;
46		47
47	=head1 DESCRIPTION	48	=head1 DESCRIPTION
48		49
49	This module is a helper module to make it easier to do event-based I/O on	50	This module is a helper module to make it easier to do event-based I/O on
50	filehandles. For utility functions for doing non-blocking connects and accepts	51	filehandles. For utility functions for doing non-blocking connects and accepts
51	on sockets see L<AnyEvent::Util>.	52	on sockets see L<AnyEvent::Util>.
52		53
		54	The L<AnyEvent::Intro> tutorial contains some well-documented
		55	AnyEvent::Handle examples.
		56
53	In the following, when the documentation refers to of "bytes" then this	57	In the following, when the documentation refers to of "bytes" then this
54	means characters. As sysread and syswrite are used for all I/O, their	58	means characters. As sysread and syswrite are used for all I/O, their
55	treatment of characters applies to this module as well.	59	treatment of characters applies to this module as well.
56		60
57	All callbacks will be invoked with the handle object as their first	61	All callbacks will be invoked with the handle object as their first
…		…
59		63
60	=head1 METHODS	64	=head1 METHODS
61		65
62	=over 4	66	=over 4
63		67
64	=item B<new (%args)>	68	=item $handle = B<new> AnyEvent::TLS fh => $filehandle, key => value...
65		69
66	The constructor supports these arguments (all as key => value pairs).	70	The constructor supports these arguments (all as C<< key => value >> pairs).
67		71
68	=over 4	72	=over 4
69		73
70	=item fh => $filehandle [MANDATORY]	74	=item fh => $filehandle [MANDATORY]
71		75
72	The filehandle this L<AnyEvent::Handle> object will operate on.	76	The filehandle this L<AnyEvent::Handle> object will operate on.
73		77
74	NOTE: The filehandle will be set to non-blocking (using	78	NOTE: The filehandle will be set to non-blocking mode (using
75	AnyEvent::Util::fh_nonblocking).	79	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		80	that mode.
76		81
77	=item on_eof => $cb->($self)	82	=item on_eof => $cb->($handle)
78		83
79	Set the callback to be called on EOF.	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.
80		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
81	While not mandatory, it is highly recommended to set an eof callback,	93	While not mandatory, it is I<highly> recommended to set an EOF callback,
82	otherwise you might end up with a closed socket while you are still	94	otherwise you might end up with a closed socket while you are still
83	waiting for data.	95	waiting for data.
84		96
85	=item on_error => $cb->($self)	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>.
86		99
		100	=item on_error => $cb->($handle, $fatal, $message)
		101
87	This is the fatal error callback, that is called when, well, a fatal error	102	This is the error callback, which is called when, well, some error
88	occurs, such as not being able to resolve the hostname, failure to connect	103	occured, such as not being able to resolve the hostname, failure to
89	or a read error.	104	connect or a read error.
90		105
91	The object will not be in a usable state when this callback has been	106	Some errors are fatal (which is indicated by C<$fatal> being true). On
92	called.	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	AnyEvent::Handle tries to find an appropriate error code for you to check
		113	against, but in some cases (TLS errors), this does not work well. It is
		114	recommended to always output the C<$message> argument in human-readable
		115	error messages (it's usually the same as C<"$!">).
		116
		117	Non-fatal errors can be retried by simply returning, but it is recommended
		118	to simply ignore this parameter and instead abondon the handle object
		119	when this callback is invoked. Examples of non-fatal errors are timeouts
		120	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
93		121
94	On callback entrance, the value of C<$!> contains the operating system	122	On callback entrance, the value of C<$!> contains the operating system
95	error (or C<ENOSPC> or C<EPIPE>).	123	error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		124	C<EPROTO>).
96		125
97	While not mandatory, it is I<highly> recommended to set this callback, as	126	While not mandatory, it is I<highly> recommended to set this callback, as
98	you will not be notified of errors otherwise. The default simply calls	127	you will not be notified of errors otherwise. The default simply calls
99	die.	128	C<croak>.
100		129
101	=item on_read => $cb->($self)	130	=item on_read => $cb->($handle)
102		131
103	This sets the default read callback, which is called when data arrives	132	This sets the default read callback, which is called when data arrives
104	and no read request is in the queue.	133	and no read request is in the queue (unlike read queue callbacks, this
		134	callback will only be called when at least one octet of data is in the
		135	read buffer).
105		136
106	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	137	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
107	method or access the C<$self->{rbuf}> member directly.	138	method or access the C<$handle->{rbuf}> member directly. Note that you
		139	must not enlarge or modify the read buffer, you can only remove data at
		140	the beginning from it.
108		141
109	When an EOF condition is detected then AnyEvent::Handle will first try to	142	When an EOF condition is detected then AnyEvent::Handle will first try to
110	feed all the remaining data to the queued callbacks and C<on_read> before	143	feed all the remaining data to the queued callbacks and C<on_read> before
111	calling the C<on_eof> callback. If no progress can be made, then a fatal	144	calling the C<on_eof> callback. If no progress can be made, then a fatal
112	error will be raised (with C<$!> set to C<EPIPE>).	145	error will be raised (with C<$!> set to C<EPIPE>).
113		146
114	=item on_drain => $cb->()	147	=item on_drain => $cb->($handle)
115		148
116	This sets the callback that is called when the write buffer becomes empty	149	This sets the callback that is called when the write buffer becomes empty
117	(or when the callback is set and the buffer is empty already).	150	(or when the callback is set and the buffer is empty already).
118		151
119	To append to the write buffer, use the C<< ->push_write >> method.	152	To append to the write buffer, use the C<< ->push_write >> method.
120		153
		154	This callback is useful when you don't want to put all of your write data
		155	into the queue at once, for example, when you want to write the contents
		156	of some file to the socket you might not want to read the whole file into
		157	memory and push it into the queue, but instead only read more data from
		158	the file when the write queue becomes empty.
		159
		160	=item timeout => $fractional_seconds
		161
		162	If non-zero, then this enables an "inactivity" timeout: whenever this many
		163	seconds pass without a successful read or write on the underlying file
		164	handle, the C<on_timeout> callback will be invoked (and if that one is
		165	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		166
		167	Note that timeout processing is also active when you currently do not have
		168	any outstanding read or write requests: If you plan to keep the connection
		169	idle then you should disable the timout temporarily or ignore the timeout
		170	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		171	restart the timeout.
		172
		173	Zero (the default) disables this timeout.
		174
		175	=item on_timeout => $cb->($handle)
		176
		177	Called whenever the inactivity timeout passes. If you return from this
		178	callback, then the timeout will be reset as if some activity had happened,
		179	so this condition is not fatal in any way.
		180
121	=item rbuf_max => <bytes>	181	=item rbuf_max => <bytes>
122		182
123	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	183	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
124	when the read buffer ever (strictly) exceeds this size. This is useful to	184	when the read buffer ever (strictly) exceeds this size. This is useful to
125	avoid denial-of-service attacks.	185	avoid some forms of denial-of-service attacks.
126		186
127	For example, a server accepting connections from untrusted sources should	187	For example, a server accepting connections from untrusted sources should
128	be configured to accept only so-and-so much data that it cannot act on	188	be configured to accept only so-and-so much data that it cannot act on
129	(for example, when expecting a line, an attacker could send an unlimited	189	(for example, when expecting a line, an attacker could send an unlimited
130	amount of data without a callback ever being called as long as the line	190	amount of data without a callback ever being called as long as the line
131	isn't finished).	191	isn't finished).
132		192
		193	=item autocork => <boolean>
		194
		195	When disabled (the default), then C<push_write> will try to immediately
		196	write the data to the handle, if possible. This avoids having to register
		197	a write watcher and wait for the next event loop iteration, but can
		198	be inefficient if you write multiple small chunks (on the wire, this
		199	disadvantage is usually avoided by your kernel's nagle algorithm, see
		200	C<no_delay>, but this option can save costly syscalls).
		201
		202	When enabled, then writes will always be queued till the next event loop
		203	iteration. This is efficient when you do many small writes per iteration,
		204	but less efficient when you do a single write only per iteration (or when
		205	the write buffer often is full). It also increases write latency.
		206
		207	=item no_delay => <boolean>
		208
		209	When doing small writes on sockets, your operating system kernel might
		210	wait a bit for more data before actually sending it out. This is called
		211	the Nagle algorithm, and usually it is beneficial.
		212
		213	In some situations you want as low a delay as possible, which can be
		214	accomplishd by setting this option to a true value.
		215
		216	The default is your opertaing system's default behaviour (most likely
		217	enabled), this option explicitly enables or disables it, if possible.
		218
133	=item read_size => <bytes>	219	=item read_size => <bytes>
134		220
135	The default read block size (the amount of bytes this module will try to read	221	The default read block size (the amount of bytes this module will
136	on each [loop iteration). Default: C<4096>.	222	try to read during each loop iteration, which affects memory
		223	requirements). Default: C<8192>.
137		224
138	=item low_water_mark => <bytes>	225	=item low_water_mark => <bytes>
139		226
140	Sets the amount of bytes (default: C<0>) that make up an "empty" write	227	Sets the amount of bytes (default: C<0>) that make up an "empty" write
141	buffer: If the write reaches this size or gets even samller it is	228	buffer: If the write reaches this size or gets even samller it is
142	considered empty.	229	considered empty.
143		230
		231	Sometimes it can be beneficial (for performance reasons) to add data to
		232	the write buffer before it is fully drained, but this is a rare case, as
		233	the operating system kernel usually buffers data as well, so the default
		234	is good in almost all cases.
		235
		236	=item linger => <seconds>
		237
		238	If non-zero (default: C<3600>), then the destructor of the
		239	AnyEvent::Handle object will check whether there is still outstanding
		240	write data and will install a watcher that will write this data to the
		241	socket. No errors will be reported (this mostly matches how the operating
		242	system treats outstanding data at socket close time).
		243
		244	This will not work for partial TLS data that could not be encoded
		245	yet. This data will be lost. Calling the C<stoptls> method in time might
		246	help.
		247
		248	=item peername => $string
		249
		250	A string used to identify the remote site - usually the DNS hostname
		251	(I<not> IDN!) used to create the connection, rarely the IP address.
		252
		253	Apart from being useful in error messages, this string is also used in TLS
		254	common name verification (see C<verify_cn> in L<AnyEvent::TLS>).
		255
144	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	256	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
145		257
146	When this parameter is given, it enables TLS (SSL) mode, that means it	258	When this parameter is given, it enables TLS (SSL) mode, that means
147	will start making tls handshake and will transparently encrypt/decrypt	259	AnyEvent will start a TLS handshake as soon as the conenction has been
148	data.	260	established and will transparently encrypt/decrypt data afterwards.
149		261
150	For the TLS server side, use C<accept>, and for the TLS client side of a	262	All TLS protocol errors will be signalled as C<EPROTO>, with an
151	connection, use C<connect> mode.	263	appropriate error message.
		264
		265	TLS mode requires Net::SSLeay to be installed (it will be loaded
		266	automatically when you try to create a TLS handle): this module doesn't
		267	have a dependency on that module, so if your module requires it, you have
		268	to add the dependency yourself.
		269
		270	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		271	C<accept>, and for the TLS client side of a connection, use C<connect>
		272	mode.
152		273
153	You can also provide your own TLS connection object, but you have	274	You can also provide your own TLS connection object, but you have
154	to make sure that you call either C<Net::SSLeay::set_connect_state>	275	to make sure that you call either C<Net::SSLeay::set_connect_state>
155	or C<Net::SSLeay::set_accept_state> on it before you pass it to	276	or C<Net::SSLeay::set_accept_state> on it before you pass it to
156	AnyEvent::Handle.	277	AnyEvent::Handle. Also, this module will take ownership of this connection
		278	object.
157		279
158	=item tls_ctx => $ssl_ctx	280	At some future point, AnyEvent::Handle might switch to another TLS
		281	implementation, then the option to use your own session object will go
		282	away.
159		283
		284	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		285	passing in the wrong integer will lead to certain crash. This most often
		286	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		287	segmentation fault.
		288
		289	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		290
		291	=item tls_ctx => $anyevent_tls
		292
160	Use the given Net::SSLeay::CTX object to create the new TLS connection	293	Use the given C<AnyEvent::TLS> object to create the new TLS connection
161	(unless a connection object was specified directly). If this parameter is	294	(unless a connection object was specified directly). If this parameter is
162	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	295	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
163		296
		297	Instead of an object, you can also specify a hash reference with C<< key
		298	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		299	new TLS context object.
		300
		301	=item json => JSON or JSON::XS object
		302
		303	This is the json coder object used by the C<json> read and write types.
		304
		305	If you don't supply it, then AnyEvent::Handle will create and use a
		306	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		307	texts.
		308
		309	Note that you are responsible to depend on the JSON module if you want to
		310	use this functionality, as AnyEvent does not have a dependency itself.
		311
164	=back	312	=back
165		313
166	=cut	314	=cut
167		315
168	sub new {	316	sub new {
169	my $class = shift;	317	my $class = shift;
170
171	my $self = bless { @_ }, $class;	318	my $self = bless { @_ }, $class;
172		319
173	$self->{fh} or Carp::croak "mandatory argument fh is missing";	320	$self->{fh} or Carp::croak "mandatory argument fh is missing";
174		321
175	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	322	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
176		323
177	if ($self->{tls}) {	324	$self->{_activity} = AnyEvent->now;
178	require Net::SSLeay;	325	$self->_timeout;
		326
		327	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		328
179	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	329	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
180	}	330	if $self->{tls};
181		331
182	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
183	$self->on_error (delete $self->{on_error}) if $self->{on_error};
184	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	332	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
185	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
186		333
187	$self->start_read;	334	$self->start_read
		335	if $self->{on_read};
188		336
189	$self	337	$self->{fh} && $self
190	}	338	}
191		339
192	sub _shutdown {	340	sub _shutdown {
193	my ($self) = @_;	341	my ($self) = @_;
194		342
195	delete $self->{rw};	343	delete @$self{qw(_tw _rw _ww fh wbuf on_read _queue)};
196	delete $self->{ww};	344	$self->{_eof} = 1; # tell starttls et. al to stop trying
197	delete $self->{fh};
198	}
199		345
		346	&_freetls;
		347	}
		348
200	sub error {	349	sub _error {
201	my ($self) = @_;	350	my ($self, $errno, $fatal, $message) = @_;
202		351
203	{
204	local $!;
205	$self->_shutdown;	352	$self->_shutdown
206	}	353	if $fatal;
		354
		355	$! = $errno;
		356	$message ||= "$!";
207		357
208	if ($self->{on_error}) {	358	if ($self->{on_error}) {
209	$self->{on_error}($self);	359	$self->{on_error}($self, $fatal, $message);
210	} else {	360	} elsif ($self->{fh}) {
211	die "AnyEvent::Handle uncaught fatal error: $!";	361	Carp::croak "AnyEvent::Handle uncaught error: $message";
212	}	362	}
213	}	363	}
214		364
215	=item $fh = $handle->fh	365	=item $fh = $handle->fh
216		366
217	This method returns the filehandle of the L<AnyEvent::Handle> object.	367	This method returns the file handle used to create the L<AnyEvent::Handle> object.
218		368
219	=cut	369	=cut
220		370
221	sub fh { $_[0]->{fh} }	371	sub fh { $_[0]{fh} }
222		372
223	=item $handle->on_error ($cb)	373	=item $handle->on_error ($cb)
224		374
225	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	375	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
226		376
…		…
238		388
239	sub on_eof {	389	sub on_eof {
240	$_[0]{on_eof} = $_[1];	390	$_[0]{on_eof} = $_[1];
241	}	391	}
242		392
		393	=item $handle->on_timeout ($cb)
		394
		395	Replace the current C<on_timeout> callback, or disables the callback (but
		396	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		397	argument and method.
		398
		399	=cut
		400
		401	sub on_timeout {
		402	$_[0]{on_timeout} = $_[1];
		403	}
		404
		405	=item $handle->autocork ($boolean)
		406
		407	Enables or disables the current autocork behaviour (see C<autocork>
		408	constructor argument). Changes will only take effect on the next write.
		409
		410	=cut
		411
		412	sub autocork {
		413	$_[0]{autocork} = $_[1];
		414	}
		415
		416	=item $handle->no_delay ($boolean)
		417
		418	Enables or disables the C<no_delay> setting (see constructor argument of
		419	the same name for details).
		420
		421	=cut
		422
		423	sub no_delay {
		424	$_[0]{no_delay} = $_[1];
		425
		426	eval {
		427	local $SIG{__DIE__};
		428	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		429	};
		430	}
		431
		432	#############################################################################
		433
		434	=item $handle->timeout ($seconds)
		435
		436	Configures (or disables) the inactivity timeout.
		437
		438	=cut
		439
		440	sub timeout {
		441	my ($self, $timeout) = @_;
		442
		443	$self->{timeout} = $timeout;
		444	$self->_timeout;
		445	}
		446
		447	# reset the timeout watcher, as neccessary
		448	# also check for time-outs
		449	sub _timeout {
		450	my ($self) = @_;
		451
		452	if ($self->{timeout}) {
		453	my $NOW = AnyEvent->now;
		454
		455	# when would the timeout trigger?
		456	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		457
		458	# now or in the past already?
		459	if ($after <= 0) {
		460	$self->{_activity} = $NOW;
		461
		462	if ($self->{on_timeout}) {
		463	$self->{on_timeout}($self);
		464	} else {
		465	$self->_error (&Errno::ETIMEDOUT);
		466	}
		467
		468	# callback could have changed timeout value, optimise
		469	return unless $self->{timeout};
		470
		471	# calculate new after
		472	$after = $self->{timeout};
		473	}
		474
		475	Scalar::Util::weaken $self;
		476	return unless $self; # ->error could have destroyed $self
		477
		478	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		479	delete $self->{_tw};
		480	$self->_timeout;
		481	});
		482	} else {
		483	delete $self->{_tw};
		484	}
		485	}
		486
243	#############################################################################	487	#############################################################################
244		488
245	=back	489	=back
246		490
247	=head2 WRITE QUEUE	491	=head2 WRITE QUEUE
…		…
268	my ($self, $cb) = @_;	512	my ($self, $cb) = @_;
269		513
270	$self->{on_drain} = $cb;	514	$self->{on_drain} = $cb;
271		515
272	$cb->($self)	516	$cb->($self)
273	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	517	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
274	}	518	}
275		519
276	=item $handle->push_write ($data)	520	=item $handle->push_write ($data)
277		521
278	Queues the given scalar to be written. You can push as much data as you	522	Queues the given scalar to be written. You can push as much data as you
…		…
282	=cut	526	=cut
283		527
284	sub _drain_wbuf {	528	sub _drain_wbuf {
285	my ($self) = @_;	529	my ($self) = @_;
286		530
287	unless ($self->{ww}) {	531	if (!$self->{_ww} && length $self->{wbuf}) {
		532
288	Scalar::Util::weaken $self;	533	Scalar::Util::weaken $self;
		534
289	my $cb = sub {	535	my $cb = sub {
290	my $len = syswrite $self->{fh}, $self->{wbuf};	536	my $len = syswrite $self->{fh}, $self->{wbuf};
291		537
292	if ($len > 0) {	538	if ($len >= 0) {
293	substr $self->{wbuf}, 0, $len, "";	539	substr $self->{wbuf}, 0, $len, "";
294		540
		541	$self->{_activity} = AnyEvent->now;
		542
295	$self->{on_drain}($self)	543	$self->{on_drain}($self)
296	if $self->{low_water_mark} >= length $self->{wbuf}	544	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
297	&& $self->{on_drain};	545	&& $self->{on_drain};
298		546
299	delete $self->{ww} unless length $self->{wbuf};	547	delete $self->{_ww} unless length $self->{wbuf};
300	} elsif ($! != EAGAIN && $! != EINTR) {	548	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
301	$self->error;	549	$self->_error ($!, 1);
302	}	550	}
303	};	551	};
304		552
		553	# try to write data immediately
		554	$cb->() unless $self->{autocork};
		555
		556	# if still data left in wbuf, we need to poll
305	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	557	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
306		558	if length $self->{wbuf};
307	$cb->($self);
308	};	559	};
		560	}
		561
		562	our %WH;
		563
		564	sub register_write_type($$) {
		565	$WH{$_[0]} = $_[1];
309	}	566	}
310		567
311	sub push_write {	568	sub push_write {
312	my $self = shift;	569	my $self = shift;
313		570
		571	if (@_ > 1) {
		572	my $type = shift;
		573
		574	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		575	->($self, @_);
		576	}
		577
314	if ($self->{filter_w}) {	578	if ($self->{tls}) {
315	$self->{filter_w}->($self, \$_[0]);	579	$self->{_tls_wbuf} .= $_[0];
		580
		581	&_dotls ($self);
316	} else {	582	} else {
317	$self->{wbuf} .= $_[0];	583	$self->{wbuf} .= $_[0];
318	$self->_drain_wbuf;	584	$self->_drain_wbuf;
319	}	585	}
320	}	586	}
321		587
		588	=item $handle->push_write (type => @args)
		589
		590	Instead of formatting your data yourself, you can also let this module do
		591	the job by specifying a type and type-specific arguments.
		592
		593	Predefined types are (if you have ideas for additional types, feel free to
		594	drop by and tell us):
		595
		596	=over 4
		597
		598	=item netstring => $string
		599
		600	Formats the given value as netstring
		601	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		602
		603	=cut
		604
		605	register_write_type netstring => sub {
		606	my ($self, $string) = @_;
		607
		608	(length $string) . ":$string,"
		609	};
		610
		611	=item packstring => $format, $data
		612
		613	An octet string prefixed with an encoded length. The encoding C<$format>
		614	uses the same format as a Perl C<pack> format, but must specify a single
		615	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		616	optional C<!>, C<< < >> or C<< > >> modifier).
		617
		618	=cut
		619
		620	register_write_type packstring => sub {
		621	my ($self, $format, $string) = @_;
		622
		623	pack "$format/a*", $string
		624	};
		625
		626	=item json => $array_or_hashref
		627
		628	Encodes the given hash or array reference into a JSON object. Unless you
		629	provide your own JSON object, this means it will be encoded to JSON text
		630	in UTF-8.
		631
		632	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		633	one end of a handle and read them at the other end without using any
		634	additional framing.
		635
		636	The generated JSON text is guaranteed not to contain any newlines: While
		637	this module doesn't need delimiters after or between JSON texts to be
		638	able to read them, many other languages depend on that.
		639
		640	A simple RPC protocol that interoperates easily with others is to send
		641	JSON arrays (or objects, although arrays are usually the better choice as
		642	they mimic how function argument passing works) and a newline after each
		643	JSON text:
		644
		645	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		646	$handle->push_write ("\012");
		647
		648	An AnyEvent::Handle receiver would simply use the C<json> read type and
		649	rely on the fact that the newline will be skipped as leading whitespace:
		650
		651	$handle->push_read (json => sub { my $array = $_[1]; ... });
		652
		653	Other languages could read single lines terminated by a newline and pass
		654	this line into their JSON decoder of choice.
		655
		656	=cut
		657
		658	register_write_type json => sub {
		659	my ($self, $ref) = @_;
		660
		661	require JSON;
		662
		663	$self->{json} ? $self->{json}->encode ($ref)
		664	: JSON::encode_json ($ref)
		665	};
		666
		667	=item storable => $reference
		668
		669	Freezes the given reference using L<Storable> and writes it to the
		670	handle. Uses the C<nfreeze> format.
		671
		672	=cut
		673
		674	register_write_type storable => sub {
		675	my ($self, $ref) = @_;
		676
		677	require Storable;
		678
		679	pack "w/a*", Storable::nfreeze ($ref)
		680	};
		681
		682	=back
		683
		684	=item $handle->push_shutdown
		685
		686	Sometimes you know you want to close the socket after writing your data
		687	before it was actually written. One way to do that is to replace your
		688	C<on_drain> handler by a callback that shuts down the socket. This method
		689	is a shorthand for just that, and replaces the C<on_drain> callback with:
		690
		691	sub { shutdown $_[0]{fh}, 1 } # for push_shutdown
		692
		693	This simply shuts down the write side and signals an EOF condition to the
		694	the peer.
		695
		696	You can rely on the normal read queue and C<on_eof> handling
		697	afterwards. This is the cleanest way to close a connection.
		698
		699	=cut
		700
		701	sub push_shutdown {
		702	$_[0]->{on_drain} = sub { shutdown $_[0]{fh}, 1 };
		703	}
		704
		705	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		706
		707	This function (not method) lets you add your own types to C<push_write>.
		708	Whenever the given C<type> is used, C<push_write> will invoke the code
		709	reference with the handle object and the remaining arguments.
		710
		711	The code reference is supposed to return a single octet string that will
		712	be appended to the write buffer.
		713
		714	Note that this is a function, and all types registered this way will be
		715	global, so try to use unique names.
		716
		717	=cut
		718
322	#############################################################################	719	#############################################################################
323		720
324	=back	721	=back
325		722
326	=head2 READ QUEUE	723	=head2 READ QUEUE
…		…
332	ways, the "simple" way, using only C<on_read> and the "complex" way, using	729	ways, the "simple" way, using only C<on_read> and the "complex" way, using
333	a queue.	730	a queue.
334		731
335	In the simple case, you just install an C<on_read> callback and whenever	732	In the simple case, you just install an C<on_read> callback and whenever
336	new data arrives, it will be called. You can then remove some data (if	733	new data arrives, it will be called. You can then remove some data (if
337	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	734	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
338	or not.	735	leave the data there if you want to accumulate more (e.g. when only a
		736	partial message has been received so far).
339		737
340	In the more complex case, you want to queue multiple callbacks. In this	738	In the more complex case, you want to queue multiple callbacks. In this
341	case, AnyEvent::Handle will call the first queued callback each time new	739	case, AnyEvent::Handle will call the first queued callback each time new
342	data arrives and removes it when it has done its job (see C<push_read>,	740	data arrives (also the first time it is queued) and removes it when it has
343	below).	741	done its job (see C<push_read>, below).
344		742
345	This way you can, for example, push three line-reads, followed by reading	743	This way you can, for example, push three line-reads, followed by reading
346	a chunk of data, and AnyEvent::Handle will execute them in order.	744	a chunk of data, and AnyEvent::Handle will execute them in order.
347		745
348	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	746	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
349	the specified number of bytes which give an XML datagram.	747	the specified number of bytes which give an XML datagram.
350		748
351	# in the default state, expect some header bytes	749	# in the default state, expect some header bytes
352	$handle->on_read (sub {	750	$handle->on_read (sub {
353	# some data is here, now queue the length-header-read (4 octets)	751	# some data is here, now queue the length-header-read (4 octets)
354	shift->unshift_read_chunk (4, sub {	752	shift->unshift_read (chunk => 4, sub {
355	# header arrived, decode	753	# header arrived, decode
356	my $len = unpack "N", $_[1];	754	my $len = unpack "N", $_[1];
357		755
358	# now read the payload	756	# now read the payload
359	shift->unshift_read_chunk ($len, sub {	757	shift->unshift_read (chunk => $len, sub {
360	my $xml = $_[1];	758	my $xml = $_[1];
361	# handle xml	759	# handle xml
362	});	760	});
363	});	761	});
364	});	762	});
365		763
366	Example 2: Implement a client for a protocol that replies either with	764	Example 2: Implement a client for a protocol that replies either with "OK"
367	"OK" and another line or "ERROR" for one request, and 64 bytes for the	765	and another line or "ERROR" for the first request that is sent, and 64
368	second request. Due tot he availability of a full queue, we can just	766	bytes for the second request. Due to the availability of a queue, we can
369	pipeline sending both requests and manipulate the queue as necessary in	767	just pipeline sending both requests and manipulate the queue as necessary
370	the callbacks:	768	in the callbacks.
371		769
372	# request one	770	When the first callback is called and sees an "OK" response, it will
		771	C<unshift> another line-read. This line-read will be queued I<before> the
		772	64-byte chunk callback.
		773
		774	# request one, returns either "OK + extra line" or "ERROR"
373	$handle->push_write ("request 1\015\012");	775	$handle->push_write ("request 1\015\012");
374		776
375	# we expect "ERROR" or "OK" as response, so push a line read	777	# we expect "ERROR" or "OK" as response, so push a line read
376	$handle->push_read_line (sub {	778	$handle->push_read (line => sub {
377	# if we got an "OK", we have to _prepend_ another line,	779	# if we got an "OK", we have to _prepend_ another line,
378	# so it will be read before the second request reads its 64 bytes	780	# so it will be read before the second request reads its 64 bytes
379	# which are already in the queue when this callback is called	781	# which are already in the queue when this callback is called
380	# we don't do this in case we got an error	782	# we don't do this in case we got an error
381	if ($_[1] eq "OK") {	783	if ($_[1] eq "OK") {
382	$_[0]->unshift_read_line (sub {	784	$_[0]->unshift_read (line => sub {
383	my $response = $_[1];	785	my $response = $_[1];
384	...	786	...
385	});	787	});
386	}	788	}
387	});	789	});
388		790
389	# request two	791	# request two, simply returns 64 octets
390	$handle->push_write ("request 2\015\012");	792	$handle->push_write ("request 2\015\012");
391		793
392	# simply read 64 bytes, always	794	# simply read 64 bytes, always
393	$handle->push_read_chunk (64, sub {	795	$handle->push_read (chunk => 64, sub {
394	my $response = $_[1];	796	my $response = $_[1];
395	...	797	...
396	});	798	});
397		799
398	=over 4	800	=over 4
399		801
400	=cut	802	=cut
401		803
402	sub _drain_rbuf {	804	sub _drain_rbuf {
403	my ($self) = @_;	805	my ($self) = @_;
		806
		807	local $self->{_in_drain} = 1;
404		808
405	if (	809	if (
406	defined $self->{rbuf_max}	810	defined $self->{rbuf_max}
407	&& $self->{rbuf_max} < length $self->{rbuf}	811	&& $self->{rbuf_max} < length $self->{rbuf}
408	) {	812	) {
409	$! = &Errno::ENOSPC; return $self->error;	813	$self->_error (&Errno::ENOSPC, 1), return;
410	}	814	}
411		815
412	return if $self->{in_drain};	816	while () {
413	local $self->{in_drain} = 1;	817	# we need to use a separate tls read buffer, as we must not receive data while
		818	# we are draining the buffer, and this can only happen with TLS.
		819	$self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
414		820
415	while (my $len = length $self->{rbuf}) {	821	my $len = length $self->{rbuf};
416	no strict 'refs';	822
417	if (my $cb = shift @{ $self->{queue} }) {	823	if (my $cb = shift @{ $self->{_queue} }) {
418	if (!$cb->($self)) {	824	unless ($cb->($self)) {
419	if ($self->{eof}) {	825	if ($self->{_eof}) {
420	# no progress can be made (not enough data and no data forthcoming)	826	# no progress can be made (not enough data and no data forthcoming)
421	$! = &Errno::EPIPE; return $self->error;	827	$self->_error (&Errno::EPIPE, 1), return;
422	}	828	}
423		829
424	unshift @{ $self->{queue} }, $cb;	830	unshift @{ $self->{_queue} }, $cb;
425	return;	831	last;
426	}	832	}
427	} elsif ($self->{on_read}) {	833	} elsif ($self->{on_read}) {
		834	last unless $len;
		835
428	$self->{on_read}($self);	836	$self->{on_read}($self);
429		837
430	if (	838	if (
431	$self->{eof} # if no further data will arrive
432	&& $len == length $self->{rbuf} # and no data has been consumed	839	$len == length $self->{rbuf} # if no data has been consumed
433	&& !@{ $self->{queue} } # and the queue is still empty	840	&& !@{ $self->{_queue} } # and the queue is still empty
434	&& $self->{on_read} # and we still want to read data	841	&& $self->{on_read} # but we still have on_read
435	) {	842	) {
		843	# no further data will arrive
436	# then no progress can be made	844	# so no progress can be made
437	$! = &Errno::EPIPE; return $self->error;	845	$self->_error (&Errno::EPIPE, 1), return
		846	if $self->{_eof};
		847
		848	last; # more data might arrive
438	}	849	}
439	} else {	850	} else {
440	# read side becomes idle	851	# read side becomes idle
441	delete $self->{rw};	852	delete $self->{_rw} unless $self->{tls};
442	return;	853	last;
443	}	854	}
444	}	855	}
445		856
446	if ($self->{eof}) {	857	if ($self->{_eof}) {
447	$self->_shutdown;	858	if ($self->{on_eof}) {
448	$self->{on_eof}($self)	859	$self->{on_eof}($self)
449	if $self->{on_eof};	860	} else {
		861	$self->_error (0, 1);
		862	}
		863	}
		864
		865	# may need to restart read watcher
		866	unless ($self->{_rw}) {
		867	$self->start_read
		868	if $self->{on_read} || @{ $self->{_queue} };
450	}	869	}
451	}	870	}
452		871
453	=item $handle->on_read ($cb)	872	=item $handle->on_read ($cb)
454		873
…		…
460		879
461	sub on_read {	880	sub on_read {
462	my ($self, $cb) = @_;	881	my ($self, $cb) = @_;
463		882
464	$self->{on_read} = $cb;	883	$self->{on_read} = $cb;
		884	$self->_drain_rbuf if $cb && !$self->{_in_drain};
465	}	885	}
466		886
467	=item $handle->rbuf	887	=item $handle->rbuf
468		888
469	Returns the read buffer (as a modifiable lvalue).	889	Returns the read buffer (as a modifiable lvalue).
470		890
471	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	891	You can access the read buffer directly as the C<< ->{rbuf} >>
472	you want.	892	member, if you want. However, the only operation allowed on the
		893	read buffer (apart from looking at it) is removing data from its
		894	beginning. Otherwise modifying or appending to it is not allowed and will
		895	lead to hard-to-track-down bugs.
473		896
474	NOTE: The read buffer should only be used or modified if the C<on_read>,	897	NOTE: The read buffer should only be used or modified if the C<on_read>,
475	C<push_read> or C<unshift_read> methods are used. The other read methods	898	C<push_read> or C<unshift_read> methods are used. The other read methods
476	automatically manage the read buffer.	899	automatically manage the read buffer.
477		900
…		…
500	interested in (which can be none at all) and return a true value. After returning	923	interested in (which can be none at all) and return a true value. After returning
501	true, it will be removed from the queue.	924	true, it will be removed from the queue.
502		925
503	=cut	926	=cut
504		927
		928	our %RH;
		929
		930	sub register_read_type($$) {
		931	$RH{$_[0]} = $_[1];
		932	}
		933
505	sub push_read {	934	sub push_read {
506	my ($self, $cb) = @_;	935	my $self = shift;
		936	my $cb = pop;
507		937
		938	if (@_) {
		939	my $type = shift;
		940
		941	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		942	->($self, $cb, @_);
		943	}
		944
508	push @{ $self->{queue} }, $cb;	945	push @{ $self->{_queue} }, $cb;
509	$self->_drain_rbuf;	946	$self->_drain_rbuf unless $self->{_in_drain};
510	}	947	}
511		948
512	sub unshift_read {	949	sub unshift_read {
513	my ($self, $cb) = @_;	950	my $self = shift;
		951	my $cb = pop;
514		952
		953	if (@_) {
		954	my $type = shift;
		955
		956	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		957	->($self, $cb, @_);
		958	}
		959
		960
515	push @{ $self->{queue} }, $cb;	961	unshift @{ $self->{_queue} }, $cb;
516	$self->_drain_rbuf;	962	$self->_drain_rbuf unless $self->{_in_drain};
517	}	963	}
518		964
519	=item $handle->push_read_chunk ($len, $cb->($self, $data))	965	=item $handle->push_read (type => @args, $cb)
520		966
521	=item $handle->unshift_read_chunk ($len, $cb->($self, $data))	967	=item $handle->unshift_read (type => @args, $cb)
522		968
523	Append the given callback to the end of the queue (C<push_read_chunk>) or	969	Instead of providing a callback that parses the data itself you can chose
524	prepend it (C<unshift_read_chunk>).	970	between a number of predefined parsing formats, for chunks of data, lines
		971	etc.
525		972
526	The callback will be called only once C<$len> bytes have been read, and	973	Predefined types are (if you have ideas for additional types, feel free to
527	these C<$len> bytes will be passed to the callback.	974	drop by and tell us):
528		975
529	=cut	976	=over 4
530		977
531	sub _read_chunk($$) {	978	=item chunk => $octets, $cb->($handle, $data)
		979
		980	Invoke the callback only once C<$octets> bytes have been read. Pass the
		981	data read to the callback. The callback will never be called with less
		982	data.
		983
		984	Example: read 2 bytes.
		985
		986	$handle->push_read (chunk => 2, sub {
		987	warn "yay ", unpack "H*", $_[1];
		988	});
		989
		990	=cut
		991
		992	register_read_type chunk => sub {
532	my ($self, $len, $cb) = @_;	993	my ($self, $cb, $len) = @_;
533		994
534	sub {	995	sub {
535	$len <= length $_[0]{rbuf} or return;	996	$len <= length $_[0]{rbuf} or return;
536	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	997	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
537	1	998	1
538	}	999	}
539	}	1000	};
540		1001
541	sub push_read_chunk {	1002	=item line => [$eol, ]$cb->($handle, $line, $eol)
542	$_[0]->push_read (&_read_chunk);
543	}
544
545
546	sub unshift_read_chunk {
547	$_[0]->unshift_read (&_read_chunk);
548	}
549
550	=item $handle->push_read_line ([$eol, ]$cb->($self, $line, $eol))
551
552	=item $handle->unshift_read_line ([$eol, ]$cb->($self, $line, $eol))
553
554	Append the given callback to the end of the queue (C<push_read_line>) or
555	prepend it (C<unshift_read_line>).
556		1003
557	The callback will be called only once a full line (including the end of	1004	The callback will be called only once a full line (including the end of
558	line marker, C<$eol>) has been read. This line (excluding the end of line	1005	line marker, C<$eol>) has been read. This line (excluding the end of line
559	marker) will be passed to the callback as second argument (C<$line>), and	1006	marker) will be passed to the callback as second argument (C<$line>), and
560	the end of line marker as the third argument (C<$eol>).	1007	the end of line marker as the third argument (C<$eol>).
…		…
571	Partial lines at the end of the stream will never be returned, as they are	1018	Partial lines at the end of the stream will never be returned, as they are
572	not marked by the end of line marker.	1019	not marked by the end of line marker.
573		1020
574	=cut	1021	=cut
575		1022
576	sub _read_line($$) {	1023	register_read_type line => sub {
577	my $self = shift;	1024	my ($self, $cb, $eol) = @_;
578	my $cb = pop;
579	my $eol = @_ ? shift : qr|(\015?\012)|;
580	my $pos;
581		1025
		1026	if (@_ < 3) {
		1027	# this is more than twice as fast as the generic code below
		1028	sub {
		1029	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1030
		1031	$cb->($_[0], $1, $2);
		1032	1
		1033	}
		1034	} else {
582	$eol = quotemeta $eol unless ref $eol;	1035	$eol = quotemeta $eol unless ref $eol;
583	$eol = qr|^(.*?)($eol)|s;	1036	$eol = qr|^(.*?)($eol)|s;
		1037
		1038	sub {
		1039	$_[0]{rbuf} =~ s/$eol// or return;
		1040
		1041	$cb->($_[0], $1, $2);
		1042	1
		1043	}
		1044	}
		1045	};
		1046
		1047	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1048
		1049	Makes a regex match against the regex object C<$accept> and returns
		1050	everything up to and including the match.
		1051
		1052	Example: read a single line terminated by '\n'.
		1053
		1054	$handle->push_read (regex => qr<\n>, sub { ... });
		1055
		1056	If C<$reject> is given and not undef, then it determines when the data is
		1057	to be rejected: it is matched against the data when the C<$accept> regex
		1058	does not match and generates an C<EBADMSG> error when it matches. This is
		1059	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1060	receive buffer overflow).
		1061
		1062	Example: expect a single decimal number followed by whitespace, reject
		1063	anything else (not the use of an anchor).
		1064
		1065	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1066
		1067	If C<$skip> is given and not C<undef>, then it will be matched against
		1068	the receive buffer when neither C<$accept> nor C<$reject> match,
		1069	and everything preceding and including the match will be accepted
		1070	unconditionally. This is useful to skip large amounts of data that you
		1071	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1072	have to start matching from the beginning. This is purely an optimisation
		1073	and is usually worth only when you expect more than a few kilobytes.
		1074
		1075	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1076	expect the header to be very large (it isn't in practise, but...), we use
		1077	a skip regex to skip initial portions. The skip regex is tricky in that
		1078	it only accepts something not ending in either \015 or \012, as these are
		1079	required for the accept regex.
		1080
		1081	$handle->push_read (regex =>
		1082	qr<\015\012\015\012>,
		1083	undef, # no reject
		1084	qr<^.*[^\015\012]>,
		1085	sub { ... });
		1086
		1087	=cut
		1088
		1089	register_read_type regex => sub {
		1090	my ($self, $cb, $accept, $reject, $skip) = @_;
		1091
		1092	my $data;
		1093	my $rbuf = \$self->{rbuf};
584		1094
585	sub {	1095	sub {
586	$_[0]{rbuf} =~ s/$eol// or return;	1096	# accept
		1097	if ($$rbuf =~ $accept) {
		1098	$data .= substr $$rbuf, 0, $+[0], "";
		1099	$cb->($self, $data);
		1100	return 1;
		1101	}
		1102
		1103	# reject
		1104	if ($reject && $$rbuf =~ $reject) {
		1105	$self->_error (&Errno::EBADMSG);
		1106	}
587		1107
588	$cb->($_[0], $1, $2);	1108	# skip
		1109	if ($skip && $$rbuf =~ $skip) {
		1110	$data .= substr $$rbuf, 0, $+[0], "";
		1111	}
		1112
		1113	()
		1114	}
		1115	};
		1116
		1117	=item netstring => $cb->($handle, $string)
		1118
		1119	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
		1120
		1121	Throws an error with C<$!> set to EBADMSG on format violations.
		1122
		1123	=cut
		1124
		1125	register_read_type netstring => sub {
		1126	my ($self, $cb) = @_;
		1127
		1128	sub {
		1129	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1130	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1131	$self->_error (&Errno::EBADMSG);
		1132	}
		1133	return;
		1134	}
		1135
		1136	my $len = $1;
		1137
		1138	$self->unshift_read (chunk => $len, sub {
		1139	my $string = $_[1];
		1140	$_[0]->unshift_read (chunk => 1, sub {
		1141	if ($_[1] eq ",") {
		1142	$cb->($_[0], $string);
		1143	} else {
		1144	$self->_error (&Errno::EBADMSG);
		1145	}
		1146	});
		1147	});
		1148
589	1	1149	1
590	}	1150	}
591	}	1151	};
592		1152
593	sub push_read_line {	1153	=item packstring => $format, $cb->($handle, $string)
594	$_[0]->push_read (&_read_line);
595	}
596		1154
597	sub unshift_read_line {	1155	An octet string prefixed with an encoded length. The encoding C<$format>
598	$_[0]->unshift_read (&_read_line);	1156	uses the same format as a Perl C<pack> format, but must specify a single
599	}	1157	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1158	optional C<!>, C<< < >> or C<< > >> modifier).
		1159
		1160	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1161	EPP uses a prefix of C<N> (4 octtes).
		1162
		1163	Example: read a block of data prefixed by its length in BER-encoded
		1164	format (very efficient).
		1165
		1166	$handle->push_read (packstring => "w", sub {
		1167	my ($handle, $data) = @_;
		1168	});
		1169
		1170	=cut
		1171
		1172	register_read_type packstring => sub {
		1173	my ($self, $cb, $format) = @_;
		1174
		1175	sub {
		1176	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1177	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1178	or return;
		1179
		1180	$format = length pack $format, $len;
		1181
		1182	# bypass unshift if we already have the remaining chunk
		1183	if ($format + $len <= length $_[0]{rbuf}) {
		1184	my $data = substr $_[0]{rbuf}, $format, $len;
		1185	substr $_[0]{rbuf}, 0, $format + $len, "";
		1186	$cb->($_[0], $data);
		1187	} else {
		1188	# remove prefix
		1189	substr $_[0]{rbuf}, 0, $format, "";
		1190
		1191	# read remaining chunk
		1192	$_[0]->unshift_read (chunk => $len, $cb);
		1193	}
		1194
		1195	1
		1196	}
		1197	};
		1198
		1199	=item json => $cb->($handle, $hash_or_arrayref)
		1200
		1201	Reads a JSON object or array, decodes it and passes it to the
		1202	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1203
		1204	If a C<json> object was passed to the constructor, then that will be used
		1205	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1206
		1207	This read type uses the incremental parser available with JSON version
		1208	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1209	dependency on your own: this module will load the JSON module, but
		1210	AnyEvent does not depend on it itself.
		1211
		1212	Since JSON texts are fully self-delimiting, the C<json> read and write
		1213	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1214	the C<json> write type description, above, for an actual example.
		1215
		1216	=cut
		1217
		1218	register_read_type json => sub {
		1219	my ($self, $cb) = @_;
		1220
		1221	my $json = $self->{json} ||=
		1222	eval { require JSON::XS; JSON::XS->new->utf8 }
		1223	|| do { require JSON; JSON->new->utf8 };
		1224
		1225	my $data;
		1226	my $rbuf = \$self->{rbuf};
		1227
		1228	sub {
		1229	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1230
		1231	if ($ref) {
		1232	$self->{rbuf} = $json->incr_text;
		1233	$json->incr_text = "";
		1234	$cb->($self, $ref);
		1235
		1236	1
		1237	} elsif ($@) {
		1238	# error case
		1239	$json->incr_skip;
		1240
		1241	$self->{rbuf} = $json->incr_text;
		1242	$json->incr_text = "";
		1243
		1244	$self->_error (&Errno::EBADMSG);
		1245
		1246	()
		1247	} else {
		1248	$self->{rbuf} = "";
		1249
		1250	()
		1251	}
		1252	}
		1253	};
		1254
		1255	=item storable => $cb->($handle, $ref)
		1256
		1257	Deserialises a L<Storable> frozen representation as written by the
		1258	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1259	data).
		1260
		1261	Raises C<EBADMSG> error if the data could not be decoded.
		1262
		1263	=cut
		1264
		1265	register_read_type storable => sub {
		1266	my ($self, $cb) = @_;
		1267
		1268	require Storable;
		1269
		1270	sub {
		1271	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1272	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1273	or return;
		1274
		1275	my $format = length pack "w", $len;
		1276
		1277	# bypass unshift if we already have the remaining chunk
		1278	if ($format + $len <= length $_[0]{rbuf}) {
		1279	my $data = substr $_[0]{rbuf}, $format, $len;
		1280	substr $_[0]{rbuf}, 0, $format + $len, "";
		1281	$cb->($_[0], Storable::thaw ($data));
		1282	} else {
		1283	# remove prefix
		1284	substr $_[0]{rbuf}, 0, $format, "";
		1285
		1286	# read remaining chunk
		1287	$_[0]->unshift_read (chunk => $len, sub {
		1288	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1289	$cb->($_[0], $ref);
		1290	} else {
		1291	$self->_error (&Errno::EBADMSG);
		1292	}
		1293	});
		1294	}
		1295
		1296	1
		1297	}
		1298	};
		1299
		1300	=back
		1301
		1302	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1303
		1304	This function (not method) lets you add your own types to C<push_read>.
		1305
		1306	Whenever the given C<type> is used, C<push_read> will invoke the code
		1307	reference with the handle object, the callback and the remaining
		1308	arguments.
		1309
		1310	The code reference is supposed to return a callback (usually a closure)
		1311	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1312
		1313	It should invoke the passed callback when it is done reading (remember to
		1314	pass C<$handle> as first argument as all other callbacks do that).
		1315
		1316	Note that this is a function, and all types registered this way will be
		1317	global, so try to use unique names.
		1318
		1319	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1320	search for C<register_read_type>)).
600		1321
601	=item $handle->stop_read	1322	=item $handle->stop_read
602		1323
603	=item $handle->start_read	1324	=item $handle->start_read
604		1325
605	In rare cases you actually do not want to read anything from the	1326	In rare cases you actually do not want to read anything from the
606	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1327	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
607	any queued callbacks will be executed then. To start readign again, call	1328	any queued callbacks will be executed then. To start reading again, call
608	C<start_read>.	1329	C<start_read>.
		1330
		1331	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1332	you change the C<on_read> callback or push/unshift a read callback, and it
		1333	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1334	there are any read requests in the queue.
		1335
		1336	These methods will have no effect when in TLS mode (as TLS doesn't support
		1337	half-duplex connections).
609		1338
610	=cut	1339	=cut
611		1340
612	sub stop_read {	1341	sub stop_read {
613	my ($self) = @_;	1342	my ($self) = @_;
614		1343
615	delete $self->{rw};	1344	delete $self->{_rw} unless $self->{tls};
616	}	1345	}
617		1346
618	sub start_read {	1347	sub start_read {
619	my ($self) = @_;	1348	my ($self) = @_;
620		1349
621	unless ($self->{rw} || $self->{eof}) {	1350	unless ($self->{_rw} || $self->{_eof}) {
622	Scalar::Util::weaken $self;	1351	Scalar::Util::weaken $self;
623		1352
624	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1353	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
625	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1354	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
626	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1355	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
627		1356
628	if ($len > 0) {	1357	if ($len > 0) {
629	$self->{filter_r}	1358	$self->{_activity} = AnyEvent->now;
630	? $self->{filter_r}->($self, $rbuf)	1359
631	: $self->_drain_rbuf;	1360	if ($self->{tls}) {
		1361	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1362
		1363	&_dotls ($self);
		1364	} else {
		1365	$self->_drain_rbuf unless $self->{_in_drain};
		1366	}
632		1367
633	} elsif (defined $len) {	1368	} elsif (defined $len) {
634	delete $self->{rw};	1369	delete $self->{_rw};
635	$self->{eof} = 1;	1370	$self->{_eof} = 1;
636	$self->_drain_rbuf;	1371	$self->_drain_rbuf unless $self->{_in_drain};
637		1372
638	} elsif ($! != EAGAIN && $! != EINTR) {	1373	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
639	return $self->error;	1374	return $self->_error ($!, 1);
640	}	1375	}
641	});	1376	});
642	}	1377	}
643	}	1378	}
644		1379
		1380	our $ERROR_SYSCALL;
		1381	our $ERROR_WANT_READ;
		1382	our $ERROR_ZERO_RETURN;
		1383
		1384	sub _tls_error {
		1385	my ($self, $err) = @_;
		1386	warn "$err,$!\n";#d#
		1387
		1388	return $self->_error ($!, 1)
		1389	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1390
		1391	$self->_error (&Errno::EPROTO, 1,
		1392	Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ()));
		1393	}
		1394
		1395	# poll the write BIO and send the data if applicable
		1396	# also decode read data if possible
		1397	# this is basiclaly our TLS state machine
		1398	# more efficient implementations are possible with openssl,
		1399	# but not with the buggy and incomplete Net::SSLeay.
645	sub _dotls {	1400	sub _dotls {
646	my ($self) = @_;	1401	my ($self) = @_;
647		1402
		1403	my $tmp;
		1404
648	if (length $self->{tls_wbuf}) {	1405	if (length $self->{_tls_wbuf}) {
649	my $len = Net::SSLeay::write ($self->{tls}, $self->{tls_wbuf});	1406	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
650	substr $self->{tls_wbuf}, 0, $len, "" if $len > 0;	1407	substr $self->{_tls_wbuf}, 0, $tmp, "";
651	}	1408	}
652		1409
		1410	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1411	return $self->_tls_error ($tmp)
		1412	if $tmp != $ERROR_WANT_READ
		1413	&& ($tmp != $ERROR_SYSCALL || $!)
		1414	&& $tmp != $ERROR_ZERO_RETURN;
		1415	}
		1416
653	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{tls_wbio}))) {	1417	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1418	unless (length $tmp) {
		1419	# let's treat SSL-eof as we treat normal EOF
		1420	delete $self->{_rw};
		1421	$self->{_eof} = 1;
		1422	&_freetls;
		1423	}
		1424
		1425	$self->{_tls_rbuf} .= $tmp;
		1426	$self->_drain_rbuf unless $self->{_in_drain};
		1427	$self->{tls} or return; # tls session might have gone away in callback
		1428	}
		1429
		1430	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1431	return $self->_tls_error ($tmp)
		1432	if $tmp != $ERROR_WANT_READ
		1433	&& ($tmp != $ERROR_SYSCALL || $!)
		1434	&& $tmp != $ERROR_ZERO_RETURN;
		1435
		1436	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
654	$self->{wbuf} .= $buf;	1437	$self->{wbuf} .= $tmp;
655	$self->_drain_wbuf;	1438	$self->_drain_wbuf;
656	}	1439	}
657
658	if (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {
659	$self->{rbuf} .= $buf;
660	$self->_drain_rbuf;
661	} elsif (
662	(my $err = Net::SSLeay::get_error ($self->{tls}, -1))
663	!= Net::SSLeay::ERROR_WANT_READ ()
664	) {
665	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
666	$self->error;
667	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
668	$! = &Errno::EIO;
669	$self->error;
670	}
671
672	# all others are fine for our purposes
673	}
674	}	1440	}
675		1441
676	# TODO: maybe document...	1442	=item $handle->starttls ($tls[, $tls_ctx])
		1443
		1444	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1445	object is created, you can also do that at a later time by calling
		1446	C<starttls>.
		1447
		1448	The first argument is the same as the C<tls> constructor argument (either
		1449	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1450
		1451	The second argument is the optional C<AnyEvent::TLS> object that is used
		1452	when AnyEvent::Handle has to create its own TLS connection object, or
		1453	a hash reference with C<< key => value >> pairs that will be used to
		1454	construct a new context.
		1455
		1456	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1457	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1458	changed to your liking. Note that the handshake might have already started
		1459	when this function returns.
		1460
		1461	If it an error to start a TLS handshake more than once per
		1462	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1463
		1464	=cut
		1465
677	sub starttls {	1466	sub starttls {
678	my ($self, $ssl, $ctx) = @_;	1467	my ($self, $ssl, $ctx) = @_;
679		1468
680	if ($ssl eq "accept") {	1469	require Net::SSLeay;
681	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1470
682	Net::SSLeay::set_accept_state ($ssl);	1471	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
683	} elsif ($ssl eq "connect") {	1472	if $self->{tls};
684	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1473
685	Net::SSLeay::set_connect_state ($ssl);	1474	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1475	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1476	$ERROR_ZERO_RETURN = Net::SSLeay::ERROR_ZERO_RETURN ();
		1477
		1478	$ctx ||= $self->{tls_ctx};
		1479
		1480	if ("HASH" eq ref $ctx) {
		1481	require AnyEvent::TLS;
		1482
		1483	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context
		1484	$ctx = new AnyEvent::TLS %$ctx;
		1485	}
686	}	1486
		1487	$self->{tls_ctx} = $ctx || TLS_CTX ();
		1488	$self->{tls} = $ssl = $self->{tls_ctx}->_get_session ($ssl, $self, $self->{peername});
687		1489
688	$self->{tls} = $ssl;	1490	# basically, this is deep magic (because SSL_read should have the same issues)
		1491	# but the openssl maintainers basically said: "trust us, it just works".
		1492	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1493	# and mismaintained ssleay-module doesn't even offer them).
		1494	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1495	#
		1496	# in short: this is a mess.
		1497	#
		1498	# note that we do not try to keep the length constant between writes as we are required to do.
		1499	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1500	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1501	# have identity issues in that area.
		1502	# Net::SSLeay::CTX_set_mode ($ssl,
		1503	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1504	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1505	Net::SSLeay::CTX_set_mode ($ssl, 1|2);
689		1506
690	$self->{tls_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1507	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
691	$self->{tls_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1508	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
692		1509
693	Net::SSLeay::set_bio ($ssl, $self->{tls_rbio}, $self->{tls_wbio});	1510	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
694		1511
695	$self->{filter_w} = sub {	1512	&_dotls; # need to trigger the initial handshake
696	$_[0]{tls_wbuf} .= ${$_[1]};	1513	$self->start_read; # make sure we actually do read
		1514	}
		1515
		1516	=item $handle->stoptls
		1517
		1518	Shuts down the SSL connection - this makes a proper EOF handshake by
		1519	sending a close notify to the other side, but since OpenSSL doesn't
		1520	support non-blocking shut downs, it is not possible to re-use the stream
		1521	afterwards.
		1522
		1523	=cut
		1524
		1525	sub stoptls {
		1526	my ($self) = @_;
		1527
		1528	if ($self->{tls}) {
		1529	Net::SSLeay::shutdown ($self->{tls});
		1530
697	&_dotls;	1531	&_dotls;
		1532
		1533	# we don't give a shit. no, we do, but we can't. no...
		1534	# we, we... have to use openssl :/
		1535	&_freetls;
698	};	1536	}
699	$self->{filter_r} = sub {	1537	}
700	Net::SSLeay::BIO_write ($_[0]{tls_rbio}, ${$_[1]});	1538
701	&_dotls;	1539	sub _freetls {
		1540	my ($self) = @_;
		1541
		1542	return unless $self->{tls};
		1543
		1544	$self->{tls_ctx}->_put_session (delete $self->{tls});
702	};	1545
		1546	delete @$self{qw(_rbio _wbio _tls_wbuf)};
703	}	1547	}
704		1548
705	sub DESTROY {	1549	sub DESTROY {
706	my $self = shift;	1550	my ($self) = @_;
707		1551
708	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	1552	&_freetls;
		1553
		1554	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1555
		1556	if ($linger && length $self->{wbuf}) {
		1557	my $fh = delete $self->{fh};
		1558	my $wbuf = delete $self->{wbuf};
		1559
		1560	my @linger;
		1561
		1562	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
		1563	my $len = syswrite $fh, $wbuf, length $wbuf;
		1564
		1565	if ($len > 0) {
		1566	substr $wbuf, 0, $len, "";
		1567	} else {
		1568	@linger = (); # end
		1569	}
		1570	});
		1571	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1572	@linger = ();
		1573	});
		1574	}
		1575	}
		1576
		1577	=item $handle->destroy
		1578
		1579	Shuts down the handle object as much as possible - this call ensures that
		1580	no further callbacks will be invoked and resources will be freed as much
		1581	as possible. You must not call any methods on the object afterwards.
		1582
		1583	Normally, you can just "forget" any references to an AnyEvent::Handle
		1584	object and it will simply shut down. This works in fatal error and EOF
		1585	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1586	callback, so when you want to destroy the AnyEvent::Handle object from
		1587	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1588	that case.
		1589
		1590	The handle might still linger in the background and write out remaining
		1591	data, as specified by the C<linger> option, however.
		1592
		1593	=cut
		1594
		1595	sub destroy {
		1596	my ($self) = @_;
		1597
		1598	$self->DESTROY;
		1599	%$self = ();
709	}	1600	}
710		1601
711	=item AnyEvent::Handle::TLS_CTX	1602	=item AnyEvent::Handle::TLS_CTX
712		1603
713	This function creates and returns the Net::SSLeay::CTX object used by	1604	This function creates and returns the AnyEvent::TLS object used by default
714	default for TLS mode.	1605	for TLS mode.
715		1606
716	The context is created like this:	1607	The context is created by calling L<AnyEvent::TLS> without any arguments.
717
718	Net::SSLeay::load_error_strings;
719	Net::SSLeay::SSLeay_add_ssl_algorithms;
720	Net::SSLeay::randomize;
721
722	my $CTX = Net::SSLeay::CTX_new;
723
724	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
725		1608
726	=cut	1609	=cut
727		1610
728	our $TLS_CTX;	1611	our $TLS_CTX;
729		1612
730	sub TLS_CTX() {	1613	sub TLS_CTX() {
731	$TLS_CTX || do {	1614	$TLS_CTX ||= do {
732	require Net::SSLeay;	1615	require AnyEvent::TLS;
733		1616
734	Net::SSLeay::load_error_strings ();	1617	new AnyEvent::TLS
735	Net::SSLeay::SSLeay_add_ssl_algorithms ();
736	Net::SSLeay::randomize ();
737
738	$TLS_CTX = Net::SSLeay::CTX_new ();
739
740	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
741
742	$TLS_CTX
743	}	1618	}
744	}	1619	}
745		1620
746	=back	1621	=back
747		1622
		1623
		1624	=head1 NONFREQUENTLY ASKED QUESTIONS
		1625
		1626	=over 4
		1627
		1628	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1629	still get further invocations!
		1630
		1631	That's because AnyEvent::Handle keeps a reference to itself when handling
		1632	read or write callbacks.
		1633
		1634	It is only safe to "forget" the reference inside EOF or error callbacks,
		1635	from within all other callbacks, you need to explicitly call the C<<
		1636	->destroy >> method.
		1637
		1638	=item I get different callback invocations in TLS mode/Why can't I pause
		1639	reading?
		1640
		1641	Unlike, say, TCP, TLS connections do not consist of two independent
		1642	communication channels, one for each direction. Or put differently. The
		1643	read and write directions are not independent of each other: you cannot
		1644	write data unless you are also prepared to read, and vice versa.
		1645
		1646	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1647	callback invocations when you are not expecting any read data - the reason
		1648	is that AnyEvent::Handle always reads in TLS mode.
		1649
		1650	During the connection, you have to make sure that you always have a
		1651	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1652	connection (or when you no longer want to use it) you can call the
		1653	C<destroy> method.
		1654
		1655	=item How do I read data until the other side closes the connection?
		1656
		1657	If you just want to read your data into a perl scalar, the easiest way
		1658	to achieve this is by setting an C<on_read> callback that does nothing,
		1659	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1660	will be in C<$_[0]{rbuf}>:
		1661
		1662	$handle->on_read (sub { });
		1663	$handle->on_eof (undef);
		1664	$handle->on_error (sub {
		1665	my $data = delete $_[0]{rbuf};
		1666	undef $handle;
		1667	});
		1668
		1669	The reason to use C<on_error> is that TCP connections, due to latencies
		1670	and packets loss, might get closed quite violently with an error, when in
		1671	fact, all data has been received.
		1672
		1673	It is usually better to use acknowledgements when transferring data,
		1674	to make sure the other side hasn't just died and you got the data
		1675	intact. This is also one reason why so many internet protocols have an
		1676	explicit QUIT command.
		1677
		1678	=item I don't want to destroy the handle too early - how do I wait until
		1679	all data has been written?
		1680
		1681	After writing your last bits of data, set the C<on_drain> callback
		1682	and destroy the handle in there - with the default setting of
		1683	C<low_water_mark> this will be called precisely when all data has been
		1684	written to the socket:
		1685
		1686	$handle->push_write (...);
		1687	$handle->on_drain (sub {
		1688	warn "all data submitted to the kernel\n";
		1689	undef $handle;
		1690	});
		1691
		1692	=back
		1693
		1694
		1695	=head1 SUBCLASSING AnyEvent::Handle
		1696
		1697	In many cases, you might want to subclass AnyEvent::Handle.
		1698
		1699	To make this easier, a given version of AnyEvent::Handle uses these
		1700	conventions:
		1701
		1702	=over 4
		1703
		1704	=item * all constructor arguments become object members.
		1705
		1706	At least initially, when you pass a C<tls>-argument to the constructor it
		1707	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1708	mutated later on (for example C<tls> will hold the TLS connection object).
		1709
		1710	=item * other object member names are prefixed with an C<_>.
		1711
		1712	All object members not explicitly documented (internal use) are prefixed
		1713	with an underscore character, so the remaining non-C<_>-namespace is free
		1714	for use for subclasses.
		1715
		1716	=item * all members not documented here and not prefixed with an underscore
		1717	are free to use in subclasses.
		1718
		1719	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1720	member variables, but thats just life, at least it is documented.
		1721
		1722	=back
		1723
748	=head1 AUTHOR	1724	=head1 AUTHOR
749		1725
750	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	1726	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
751		1727
752	=cut	1728	=cut

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