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Revision 1.39 by root, Tue May 27 04:59:51 2008 UTC vs.
Revision 1.140 by root, Mon Jul 6 00:45:00 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 qw(WSAWOULDBLOCK);	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 file handles via AnyEvent	15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
16		16
17	=cut	17	=cut
18		18
19	our $VERSION = '0.04';	19	our $VERSION = 4.452;
20		20
21	=head1 SYNOPSIS	21	=head1 SYNOPSIS
22		22
23	use AnyEvent;	23	use AnyEvent;
24	use AnyEvent::Handle;	24	use AnyEvent::Handle;
…		…
27		27
28	my $handle =	28	my $handle =
29	AnyEvent::Handle->new (	29	AnyEvent::Handle->new (
30	fh => \*STDIN,	30	fh => \*STDIN,
31	on_eof => sub {	31	on_eof => sub {
32	$cv->broadcast;	32	$cv->send;
33	},	33	},
34	);	34	);
35		35
36	# send some request line	36	# send some request line
37	$handle->push_write ("getinfo\015\012");	37	$handle->push_write ("getinfo\015\012");
…		…
49		49
50	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
51	filehandles. For utility functions for doing non-blocking connects and accepts	51	filehandles. For utility functions for doing non-blocking connects and accepts
52	on sockets see L<AnyEvent::Util>.	52	on sockets see L<AnyEvent::Util>.
53		53
		54	The L<AnyEvent::Intro> tutorial contains some well-documented
		55	AnyEvent::Handle examples.
		56
54	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
55	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
56	treatment of characters applies to this module as well.	59	treatment of characters applies to this module as well.
57		60
58	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
…		…
60		63
61	=head1 METHODS	64	=head1 METHODS
62		65
63	=over 4	66	=over 4
64		67
65	=item B<new (%args)>	68	=item $handle = B<new> AnyEvent::TLS fh => $filehandle, key => value...
66		69
67	The constructor supports these arguments (all as key => value pairs).	70	The constructor supports these arguments (all as C<< key => value >> pairs).
68		71
69	=over 4	72	=over 4
70		73
71	=item fh => $filehandle [MANDATORY]	74	=item fh => $filehandle [MANDATORY]
72		75
73	The filehandle this L<AnyEvent::Handle> object will operate on.	76	The filehandle this L<AnyEvent::Handle> object will operate on.
74		77
75	NOTE: The filehandle will be set to non-blocking (using	78	NOTE: The filehandle will be set to non-blocking mode (using
76	AnyEvent::Util::fh_nonblocking).	79	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		80	that mode.
77		81
78	=item on_eof => $cb->($self)	82	=item on_eof => $cb->($handle)
79		83
80	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.
81		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
82	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,
83	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
84	waiting for data.	95	waiting for data.
85		96
86	=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>.
87		99
		100	=item on_error => $cb->($handle, $fatal, $message)
		101
88	This is the fatal error callback, that is called when, well, a fatal error	102	This is the error callback, which is called when, well, some error
89	occurs, such as not being able to resolve the hostname, failure to connect	103	occured, such as not being able to resolve the hostname, failure to
90	or a read error.	104	connect or a read error.
91		105
92	The object will not be in a usable state when this callback has been	106	Some errors are fatal (which is indicated by C<$fatal> being true). On
93	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>).
94		121
95	On callback entrance, the value of C<$!> contains the operating system	122	On callback entrance, the value of C<$!> contains the operating system
96	error (or C<ENOSPC>, C<EPIPE> or C<EBADMSG>).	123	error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
97		124	C<EPROTO>).
98	The callback should throw an exception. If it returns, then
99	AnyEvent::Handle will C<croak> for you.
100		125
101	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
102	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
103	die.	128	C<croak>.
104		129
105	=item on_read => $cb->($self)	130	=item on_read => $cb->($handle)
106		131
107	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
108	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).
109		136
110	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 >>
111	method or access the C<$self->{rbuf}> member directly.	138	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		139	must not enlarge or modify the read buffer, you can only remove data at
		140	the beginning from it.
112		141
113	When an EOF condition is detected then AnyEvent::Handle will first try to	142	When an EOF condition is detected then AnyEvent::Handle will first try to
114	feed all the remaining data to the queued callbacks and C<on_read> before	143	feed all the remaining data to the queued callbacks and C<on_read> before
115	calling the C<on_eof> callback. If no progress can be made, then a fatal	144	calling the C<on_eof> callback. If no progress can be made, then a fatal
116	error will be raised (with C<$!> set to C<EPIPE>).	145	error will be raised (with C<$!> set to C<EPIPE>).
117		146
118	=item on_drain => $cb->()	147	=item on_drain => $cb->($handle)
119		148
120	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
121	(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).
122		151
123	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.
124		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
125	=item rbuf_max => <bytes>	181	=item rbuf_max => <bytes>
126		182
127	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>)
128	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
129	avoid denial-of-service attacks.	185	avoid some forms of denial-of-service attacks.
130		186
131	For example, a server accepting connections from untrusted sources should	187	For example, a server accepting connections from untrusted sources should
132	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
133	(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
134	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
135	isn't finished).	191	isn't finished).
136		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
137	=item read_size => <bytes>	219	=item read_size => <bytes>
138		220
139	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
140	on each [loop iteration). Default: C<4096>.	222	try to read during each loop iteration, which affects memory
		223	requirements). Default: C<8192>.
141		224
142	=item low_water_mark => <bytes>	225	=item low_water_mark => <bytes>
143		226
144	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
145	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
146	considered empty.	229	considered empty.
147		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	peername verification (see C<verify_peername> in L<AnyEvent::TLS>).
		255
148	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	256	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
149		257
150	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
151	will start making tls handshake and will transparently encrypt/decrypt	259	AnyEvent will start a TLS handshake as soon as the conenction has been
152	data.	260	established and will transparently encrypt/decrypt data afterwards.
		261
		262	All TLS protocol errors will be signalled as C<EPROTO>, with an
		263	appropriate error message.
153		264
154	TLS mode requires Net::SSLeay to be installed (it will be loaded	265	TLS mode requires Net::SSLeay to be installed (it will be loaded
155	automatically when you try to create a TLS handle).	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.
156		269
157	For the TLS server side, use C<accept>, and for the TLS client side of a	270	Unlike TCP, TLS has a server and client side: for the TLS server side, use
158	connection, use C<connect> mode.	271	C<accept>, and for the TLS client side of a connection, use C<connect>
		272	mode.
159		273
160	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
161	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>
162	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
163	AnyEvent::Handle.	277	AnyEvent::Handle. Also, this module will take ownership of this connection
		278	object.
164		279
		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.
		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
165	See the C<starttls> method if you need to start TLs negotiation later.	289	See the C<< ->starttls >> method for when need to start TLS negotiation later.
166		290
167	=item tls_ctx => $ssl_ctx	291	=item tls_ctx => $anyevent_tls
168		292
169	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
170	(unless a connection object was specified directly). If this parameter is	294	(unless a connection object was specified directly). If this parameter is
171	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	295	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
172		296
173	=item filter_r => $cb	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.
174		300
175	=item filter_w => $cb	301	=item json => JSON or JSON::XS object
176		302
177	These exist, but are undocumented at this time.	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.
178		311
179	=back	312	=back
180		313
181	=cut	314	=cut
182		315
183	sub new {	316	sub new {
184	my $class = shift;	317	my $class = shift;
185
186	my $self = bless { @_ }, $class;	318	my $self = bless { @_ }, $class;
187		319
188	$self->{fh} or Carp::croak "mandatory argument fh is missing";	320	$self->{fh} or Carp::croak "mandatory argument fh is missing";
189		321
190	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	322	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
191		323
192	if ($self->{tls}) {	324	$self->{_activity} = AnyEvent->now;
193	require Net::SSLeay;	325	$self->_timeout;
		326
		327	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		328
194	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});	329	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
195	}	330	if $self->{tls};
196		331
197	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
198	$self->on_error (delete $self->{on_error}) if $self->{on_error};
199	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	332	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
200	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
201		333
202	$self->start_read;	334	$self->start_read
		335	if $self->{on_read};
203		336
204	$self	337	$self->{fh} && $self
205	}	338	}
206		339
207	sub _shutdown {	340	sub _shutdown {
208	my ($self) = @_;	341	my ($self) = @_;
209		342
210	delete $self->{_rw};	343	delete @$self{qw(_tw _rw _ww fh wbuf on_read _queue)};
211	delete $self->{_ww};	344	$self->{_eof} = 1; # tell starttls et. al to stop trying
212	delete $self->{fh};
213	}
214		345
		346	&_freetls;
		347	}
		348
215	sub error {	349	sub _error {
216	my ($self) = @_;	350	my ($self, $errno, $fatal, $message) = @_;
217		351
218	{
219	local $!;
220	$self->_shutdown;	352	$self->_shutdown
221	}	353	if $fatal;
222		354
223	$self->{on_error}($self)	355	$! = $errno;
		356	$message ||= "$!";
		357
224	if $self->{on_error};	358	if ($self->{on_error}) {
225		359	$self->{on_error}($self, $fatal, $message);
		360	} elsif ($self->{fh}) {
226	Carp::croak "AnyEvent::Handle uncaught fatal error: $!";	361	Carp::croak "AnyEvent::Handle uncaught error: $message";
		362	}
227	}	363	}
228		364
229	=item $fh = $handle->fh	365	=item $fh = $handle->fh
230		366
231	This method returns the file handle of the L<AnyEvent::Handle> object.	367	This method returns the file handle used to create the L<AnyEvent::Handle> object.
232		368
233	=cut	369	=cut
234		370
235	sub fh { $_[0]{fh} }	371	sub fh { $_[0]{fh} }
236		372
…		…
252		388
253	sub on_eof {	389	sub on_eof {
254	$_[0]{on_eof} = $_[1];	390	$_[0]{on_eof} = $_[1];
255	}	391	}
256		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 $self->{_tw};
		484	}
		485	}
		486
257	#############################################################################	487	#############################################################################
258		488
259	=back	489	=back
260		490
261	=head2 WRITE QUEUE	491	=head2 WRITE QUEUE
…		…
282	my ($self, $cb) = @_;	512	my ($self, $cb) = @_;
283		513
284	$self->{on_drain} = $cb;	514	$self->{on_drain} = $cb;
285		515
286	$cb->($self)	516	$cb->($self)
287	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	517	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
288	}	518	}
289		519
290	=item $handle->push_write ($data)	520	=item $handle->push_write ($data)
291		521
292	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
…		…
306	my $len = syswrite $self->{fh}, $self->{wbuf};	536	my $len = syswrite $self->{fh}, $self->{wbuf};
307		537
308	if ($len >= 0) {	538	if ($len >= 0) {
309	substr $self->{wbuf}, 0, $len, "";	539	substr $self->{wbuf}, 0, $len, "";
310		540
		541	$self->{_activity} = AnyEvent->now;
		542
311	$self->{on_drain}($self)	543	$self->{on_drain}($self)
312	if $self->{low_water_mark} >= length $self->{wbuf}	544	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
313	&& $self->{on_drain};	545	&& $self->{on_drain};
314		546
315	delete $self->{_ww} unless length $self->{wbuf};	547	delete $self->{_ww} unless length $self->{wbuf};
316	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAWOULDBLOCK) {	548	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
317	$self->error;	549	$self->_error ($!, 1);
318	}	550	}
319	};	551	};
320		552
321	# try to write data immediately	553	# try to write data immediately
322	$cb->();	554	$cb->() unless $self->{autocork};
323		555
324	# if still data left in wbuf, we need to poll	556	# if still data left in wbuf, we need to poll
325	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)	557	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
326	if length $self->{wbuf};	558	if length $self->{wbuf};
327	};	559	};
…		…
341		573
342	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	574	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
343	->($self, @_);	575	->($self, @_);
344	}	576	}
345		577
346	if ($self->{filter_w}) {	578	if ($self->{tls}) {
347	$self->{filter_w}->($self, \$_[0]);	579	$self->{_tls_wbuf} .= $_[0];
		580
		581	&_dotls ($self);
348	} else {	582	} else {
349	$self->{wbuf} .= $_[0];	583	$self->{wbuf} .= $_[0];
350	$self->_drain_wbuf;	584	$self->_drain_wbuf;
351	}	585	}
352	}	586	}
353		587
354	=item $handle->push_write (type => @args)	588	=item $handle->push_write (type => @args)
355		589
356	=item $handle->unshift_write (type => @args)
357
358	Instead of formatting your data yourself, you can also let this module do	590	Instead of formatting your data yourself, you can also let this module do
359	the job by specifying a type and type-specific arguments.	591	the job by specifying a type and type-specific arguments.
360		592
361	Predefined types are (if you have ideas for additional types, feel free to	593	Predefined types are (if you have ideas for additional types, feel free to
362	drop by and tell us):	594	drop by and tell us):
…		…
366	=item netstring => $string	598	=item netstring => $string
367		599
368	Formats the given value as netstring	600	Formats the given value as netstring
369	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).	601	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
370		602
371	=back
372
373	=cut	603	=cut
374		604
375	register_write_type netstring => sub {	605	register_write_type netstring => sub {
376	my ($self, $string) = @_;	606	my ($self, $string) = @_;
377		607
378	sprintf "%d:%s,", (length $string), $string	608	(length $string) . ":$string,"
379	};	609	};
380		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
381	=item json => $array_or_hashref	626	=item json => $array_or_hashref
382		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
383	=item AnyEvent::Handle::register_write_type type => $coderef->($self, @args)	705	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
384		706
385	This function (not method) lets you add your own types to C<push_write>.	707	This function (not method) lets you add your own types to C<push_write>.
386	Whenever the given C<type> is used, C<push_write> will invoke the code	708	Whenever the given C<type> is used, C<push_write> will invoke the code
387	reference with the handle object and the remaining arguments.	709	reference with the handle object and the remaining arguments.
388		710
…		…
407	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
408	a queue.	730	a queue.
409		731
410	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
411	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
412	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
413	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).
414		737
415	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
416	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
417	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
418	below).	741	done its job (see C<push_read>, below).
419		742
420	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
421	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.
422		745
423	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
424	the specified number of bytes which give an XML datagram.	747	the specified number of bytes which give an XML datagram.
425		748
426	# in the default state, expect some header bytes	749	# in the default state, expect some header bytes
427	$handle->on_read (sub {	750	$handle->on_read (sub {
428	# 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)
429	shift->unshift_read_chunk (4, sub {	752	shift->unshift_read (chunk => 4, sub {
430	# header arrived, decode	753	# header arrived, decode
431	my $len = unpack "N", $_[1];	754	my $len = unpack "N", $_[1];
432		755
433	# now read the payload	756	# now read the payload
434	shift->unshift_read_chunk ($len, sub {	757	shift->unshift_read (chunk => $len, sub {
435	my $xml = $_[1];	758	my $xml = $_[1];
436	# handle xml	759	# handle xml
437	});	760	});
438	});	761	});
439	});	762	});
440		763
441	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"
442	"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
443	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
444	pipeline sending both requests and manipulate the queue as necessary in	767	just pipeline sending both requests and manipulate the queue as necessary
445	the callbacks:	768	in the callbacks.
446		769
447	# 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"
448	$handle->push_write ("request 1\015\012");	775	$handle->push_write ("request 1\015\012");
449		776
450	# 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
451	$handle->push_read_line (sub {	778	$handle->push_read (line => sub {
452	# if we got an "OK", we have to _prepend_ another line,	779	# if we got an "OK", we have to _prepend_ another line,
453	# so it will be read before the second request reads its 64 bytes	780	# so it will be read before the second request reads its 64 bytes
454	# which are already in the queue when this callback is called	781	# which are already in the queue when this callback is called
455	# we don't do this in case we got an error	782	# we don't do this in case we got an error
456	if ($_[1] eq "OK") {	783	if ($_[1] eq "OK") {
457	$_[0]->unshift_read_line (sub {	784	$_[0]->unshift_read (line => sub {
458	my $response = $_[1];	785	my $response = $_[1];
459	...	786	...
460	});	787	});
461	}	788	}
462	});	789	});
463		790
464	# request two	791	# request two, simply returns 64 octets
465	$handle->push_write ("request 2\015\012");	792	$handle->push_write ("request 2\015\012");
466		793
467	# simply read 64 bytes, always	794	# simply read 64 bytes, always
468	$handle->push_read_chunk (64, sub {	795	$handle->push_read (chunk => 64, sub {
469	my $response = $_[1];	796	my $response = $_[1];
470	...	797	...
471	});	798	});
472		799
473	=over 4	800	=over 4
474		801
475	=cut	802	=cut
476		803
477	sub _drain_rbuf {	804	sub _drain_rbuf {
478	my ($self) = @_;	805	my ($self) = @_;
		806
		807	local $self->{_in_drain} = 1;
479		808
480	if (	809	if (
481	defined $self->{rbuf_max}	810	defined $self->{rbuf_max}
482	&& $self->{rbuf_max} < length $self->{rbuf}	811	&& $self->{rbuf_max} < length $self->{rbuf}
483	) {	812	) {
484	$! = &Errno::ENOSPC;	813	$self->_error (&Errno::ENOSPC, 1), return;
485	$self->error;
486	}	814	}
487		815
488	return if $self->{in_drain};	816	while () {
489	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};
490		820
491	while (my $len = length $self->{rbuf}) {	821	my $len = length $self->{rbuf};
492	no strict 'refs';	822
493	if (my $cb = shift @{ $self->{_queue} }) {	823	if (my $cb = shift @{ $self->{_queue} }) {
494	unless ($cb->($self)) {	824	unless ($cb->($self)) {
495	if ($self->{_eof}) {	825	if ($self->{_eof}) {
496	# 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)
497	$! = &Errno::EPIPE;	827	$self->_error (&Errno::EPIPE, 1), return;
498	$self->error;
499	}	828	}
500		829
501	unshift @{ $self->{_queue} }, $cb;	830	unshift @{ $self->{_queue} }, $cb;
502	return;	831	last;
503	}	832	}
504	} elsif ($self->{on_read}) {	833	} elsif ($self->{on_read}) {
		834	last unless $len;
		835
505	$self->{on_read}($self);	836	$self->{on_read}($self);
506		837
507	if (	838	if (
508	$self->{_eof} # if no further data will arrive
509	&& $len == length $self->{rbuf} # and no data has been consumed	839	$len == length $self->{rbuf} # if no data has been consumed
510	&& !@{ $self->{_queue} } # and the queue is still empty	840	&& !@{ $self->{_queue} } # and the queue is still empty
511	&& $self->{on_read} # and we still want to read data	841	&& $self->{on_read} # but we still have on_read
512	) {	842	) {
		843	# no further data will arrive
513	# then no progress can be made	844	# so no progress can be made
514	$! = &Errno::EPIPE;	845	$self->_error (&Errno::EPIPE, 1), return
515	$self->error;	846	if $self->{_eof};
		847
		848	last; # more data might arrive
516	}	849	}
517	} else {	850	} else {
518	# read side becomes idle	851	# read side becomes idle
519	delete $self->{_rw};	852	delete $self->{_rw} unless $self->{tls};
520	return;	853	last;
521	}	854	}
522	}	855	}
523		856
524	if ($self->{_eof}) {	857	if ($self->{_eof}) {
525	$self->_shutdown;	858	if ($self->{on_eof}) {
526	$self->{on_eof}($self)	859	$self->{on_eof}($self)
527	if $self->{on_eof};	860	} else {
		861	$self->_error (0, 1, "Unexpected end-of-file");
		862	}
		863	}
		864
		865	# may need to restart read watcher
		866	unless ($self->{_rw}) {
		867	$self->start_read
		868	if $self->{on_read} || @{ $self->{_queue} };
528	}	869	}
529	}	870	}
530		871
531	=item $handle->on_read ($cb)	872	=item $handle->on_read ($cb)
532		873
…		…
538		879
539	sub on_read {	880	sub on_read {
540	my ($self, $cb) = @_;	881	my ($self, $cb) = @_;
541		882
542	$self->{on_read} = $cb;	883	$self->{on_read} = $cb;
		884	$self->_drain_rbuf if $cb && !$self->{_in_drain};
543	}	885	}
544		886
545	=item $handle->rbuf	887	=item $handle->rbuf
546		888
547	Returns the read buffer (as a modifiable lvalue).	889	Returns the read buffer (as a modifiable lvalue).
548		890
549	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} >>
550	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.
551		896
552	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>,
553	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
554	automatically manage the read buffer.	899	automatically manage the read buffer.
555		900
…		…
596	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	941	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
597	->($self, $cb, @_);	942	->($self, $cb, @_);
598	}	943	}
599		944
600	push @{ $self->{_queue} }, $cb;	945	push @{ $self->{_queue} }, $cb;
601	$self->_drain_rbuf;	946	$self->_drain_rbuf unless $self->{_in_drain};
602	}	947	}
603		948
604	sub unshift_read {	949	sub unshift_read {
605	my $self = shift;	950	my $self = shift;
606	my $cb = pop;	951	my $cb = pop;
…		…
612	->($self, $cb, @_);	957	->($self, $cb, @_);
613	}	958	}
614		959
615		960
616	unshift @{ $self->{_queue} }, $cb;	961	unshift @{ $self->{_queue} }, $cb;
617	$self->_drain_rbuf;	962	$self->_drain_rbuf unless $self->{_in_drain};
618	}	963	}
619		964
620	=item $handle->push_read (type => @args, $cb)	965	=item $handle->push_read (type => @args, $cb)
621		966
622	=item $handle->unshift_read (type => @args, $cb)	967	=item $handle->unshift_read (type => @args, $cb)
…		…
628	Predefined types are (if you have ideas for additional types, feel free to	973	Predefined types are (if you have ideas for additional types, feel free to
629	drop by and tell us):	974	drop by and tell us):
630		975
631	=over 4	976	=over 4
632		977
633	=item chunk => $octets, $cb->($self, $data)	978	=item chunk => $octets, $cb->($handle, $data)
634		979
635	Invoke the callback only once C<$octets> bytes have been read. Pass the	980	Invoke the callback only once C<$octets> bytes have been read. Pass the
636	data read to the callback. The callback will never be called with less	981	data read to the callback. The callback will never be called with less
637	data.	982	data.
638		983
…		…
652	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	997	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
653	1	998	1
654	}	999	}
655	};	1000	};
656		1001
657	# compatibility with older API
658	sub push_read_chunk {
659	$_[0]->push_read (chunk => $_[1], $_[2]);
660	}
661
662	sub unshift_read_chunk {
663	$_[0]->unshift_read (chunk => $_[1], $_[2]);
664	}
665
666	=item line => [$eol, ]$cb->($self, $line, $eol)	1002	=item line => [$eol, ]$cb->($handle, $line, $eol)
667		1003
668	The callback will be called only once a full line (including the end of	1004	The callback will be called only once a full line (including the end of
669	line marker, C<$eol>) has been read. This line (excluding the end of line	1005	line marker, C<$eol>) has been read. This line (excluding the end of line
670	marker) will be passed to the callback as second argument (C<$line>), and	1006	marker) will be passed to the callback as second argument (C<$line>), and
671	the end of line marker as the third argument (C<$eol>).	1007	the end of line marker as the third argument (C<$eol>).
…		…
685	=cut	1021	=cut
686		1022
687	register_read_type line => sub {	1023	register_read_type line => sub {
688	my ($self, $cb, $eol) = @_;	1024	my ($self, $cb, $eol) = @_;
689		1025
690	$eol = qr|(\015?\012)| if @_ < 3;	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 {
691	$eol = quotemeta $eol unless ref $eol;	1035	$eol = quotemeta $eol unless ref $eol;
692	$eol = qr|^(.*?)($eol)|s;	1036	$eol = qr|^(.*?)($eol)|s;
693		1037
694	sub {	1038	sub {
695	$_[0]{rbuf} =~ s/$eol// or return;	1039	$_[0]{rbuf} =~ s/$eol// or return;
696		1040
697	$cb->($_[0], $1, $2);	1041	$cb->($_[0], $1, $2);
		1042	1
698	1	1043	}
699	}	1044	}
700	};	1045	};
701		1046
702	# compatibility with older API
703	sub push_read_line {
704	my $self = shift;
705	$self->push_read (line => @_);
706	}
707
708	sub unshift_read_line {
709	my $self = shift;
710	$self->unshift_read (line => @_);
711	}
712
713	=item netstring => $cb->($string)
714
715	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
716
717	Throws an error with C<$!> set to EBADMSG on format violations.
718
719	=cut
720
721	register_read_type netstring => sub {
722	my ($self, $cb) = @_;
723
724	sub {
725	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
726	if ($_[0]{rbuf} =~ /[^0-9]/) {
727	$! = &Errno::EBADMSG;
728	$self->error;
729	}
730	return;
731	}
732
733	my $len = $1;
734
735	$self->unshift_read (chunk => $len, sub {
736	my $string = $_[1];
737	$_[0]->unshift_read (chunk => 1, sub {
738	if ($_[1] eq ",") {
739	$cb->($_[0], $string);
740	} else {
741	$! = &Errno::EBADMSG;
742	$self->error;
743	}
744	});
745	});
746
747	1
748	}
749	};
750
751	=item regex => $accept[, $reject[, $skip], $cb->($data)	1047	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
752		1048
753	Makes a regex match against the regex object C<$accept> and returns	1049	Makes a regex match against the regex object C<$accept> and returns
754	everything up to and including the match.	1050	everything up to and including the match.
755		1051
756	Example: read a single line terminated by '\n'.	1052	Example: read a single line terminated by '\n'.
…		…
804	return 1;	1100	return 1;
805	}	1101	}
806		1102
807	# reject	1103	# reject
808	if ($reject && $$rbuf =~ $reject) {	1104	if ($reject && $$rbuf =~ $reject) {
809	$! = &Errno::EBADMSG;	1105	$self->_error (&Errno::EBADMSG);
810	$self->error;
811	}	1106	}
812		1107
813	# skip	1108	# skip
814	if ($skip && $$rbuf =~ $skip) {	1109	if ($skip && $$rbuf =~ $skip) {
815	$data .= substr $$rbuf, 0, $+[0], "";	1110	$data .= substr $$rbuf, 0, $+[0], "";
…		…
817		1112
818	()	1113	()
819	}	1114	}
820	};	1115	};
821		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
		1149	1
		1150	}
		1151	};
		1152
		1153	=item packstring => $format, $cb->($handle, $string)
		1154
		1155	An octet string prefixed with an encoded length. The encoding C<$format>
		1156	uses the same format as a Perl C<pack> format, but must specify a single
		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
822	=back	1300	=back
823		1301
824	=item AnyEvent::Handle::register_read_type type => $coderef->($self, $cb, @args)	1302	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
825		1303
826	This function (not method) lets you add your own types to C<push_read>.	1304	This function (not method) lets you add your own types to C<push_read>.
827		1305
828	Whenever the given C<type> is used, C<push_read> will invoke the code	1306	Whenever the given C<type> is used, C<push_read> will invoke the code
829	reference with the handle object, the callback and the remaining	1307	reference with the handle object, the callback and the remaining
…		…
831		1309
832	The code reference is supposed to return a callback (usually a closure)	1310	The code reference is supposed to return a callback (usually a closure)
833	that works as a plain read callback (see C<< ->push_read ($cb) >>).	1311	that works as a plain read callback (see C<< ->push_read ($cb) >>).
834		1312
835	It should invoke the passed callback when it is done reading (remember to	1313	It should invoke the passed callback when it is done reading (remember to
836	pass C<$self> as first argument as all other callbacks do that).	1314	pass C<$handle> as first argument as all other callbacks do that).
837		1315
838	Note that this is a function, and all types registered this way will be	1316	Note that this is a function, and all types registered this way will be
839	global, so try to use unique names.	1317	global, so try to use unique names.
840		1318
841	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,	1319	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
…		…
844	=item $handle->stop_read	1322	=item $handle->stop_read
845		1323
846	=item $handle->start_read	1324	=item $handle->start_read
847		1325
848	In rare cases you actually do not want to read anything from the	1326	In rare cases you actually do not want to read anything from the
849	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1327	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
850	any queued callbacks will be executed then. To start reading again, call	1328	any queued callbacks will be executed then. To start reading again, call
851	C<start_read>.	1329	C<start_read>.
852		1330
		1331	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1332	you change the C<on_read> callback or push/unshift a read callback, and it
		1333	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1334	there are any read requests in the queue.
		1335
		1336	These methods will have no effect when in TLS mode (as TLS doesn't support
		1337	half-duplex connections).
		1338
853	=cut	1339	=cut
854		1340
855	sub stop_read {	1341	sub stop_read {
856	my ($self) = @_;	1342	my ($self) = @_;
857		1343
858	delete $self->{_rw};	1344	delete $self->{_rw} unless $self->{tls};
859	}	1345	}
860		1346
861	sub start_read {	1347	sub start_read {
862	my ($self) = @_;	1348	my ($self) = @_;
863		1349
864	unless ($self->{_rw} || $self->{_eof}) {	1350	unless ($self->{_rw} || $self->{_eof}) {
865	Scalar::Util::weaken $self;	1351	Scalar::Util::weaken $self;
866		1352
867	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1353	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
868	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1354	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
869	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;
870		1356
871	if ($len > 0) {	1357	if ($len > 0) {
872	$self->{filter_r}	1358	$self->{_activity} = AnyEvent->now;
873	? $self->{filter_r}->($self, $rbuf)	1359
874	: $self->_drain_rbuf;	1360	if ($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	}
875		1367
876	} elsif (defined $len) {	1368	} elsif (defined $len) {
877	delete $self->{_rw};	1369	delete $self->{_rw};
878	$self->{_eof} = 1;	1370	$self->{_eof} = 1;
879	$self->_drain_rbuf;	1371	$self->_drain_rbuf unless $self->{_in_drain};
880		1372
881	} elsif ($! != EAGAIN && $! != EINTR && $! != &AnyEvent::Util::WSAWOULDBLOCK) {	1373	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
882	return $self->error;	1374	return $self->_error ($!, 1);
883	}	1375	}
884	});	1376	});
885	}	1377	}
886	}	1378	}
887		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
		1387	return $self->_error ($!, 1)
		1388	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1389
		1390	my $err =Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1391
		1392	# reduce error string to look less scary
		1393	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1394
		1395	$self->_error (&Errno::EPROTO, 1, $err);
		1396	}
		1397
		1398	# poll the write BIO and send the data if applicable
		1399	# also decode read data if possible
		1400	# this is basiclaly our TLS state machine
		1401	# more efficient implementations are possible with openssl,
		1402	# but not with the buggy and incomplete Net::SSLeay.
888	sub _dotls {	1403	sub _dotls {
889	my ($self) = @_;	1404	my ($self) = @_;
890		1405
		1406	my $tmp;
		1407
891	if (length $self->{_tls_wbuf}) {	1408	if (length $self->{_tls_wbuf}) {
892	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {	1409	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
893	substr $self->{_tls_wbuf}, 0, $len, "";	1410	substr $self->{_tls_wbuf}, 0, $tmp, "";
894	}	1411	}
895	}
896		1412
		1413	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1414	return $self->_tls_error ($tmp)
		1415	if $tmp != $ERROR_WANT_READ
		1416	&& ($tmp != $ERROR_SYSCALL || $!)
		1417	&& $tmp != $ERROR_ZERO_RETURN;
		1418	}
		1419
		1420	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1421	unless (length $tmp) {
		1422	# let's treat SSL-eof as we treat normal EOF
		1423	delete $self->{_rw};
		1424	$self->{_eof} = 1;
		1425	&_freetls;
		1426	}
		1427
		1428	$self->{_tls_rbuf} .= $tmp;
		1429	$self->_drain_rbuf unless $self->{_in_drain};
		1430	$self->{tls} or return; # tls session might have gone away in callback
		1431	}
		1432
		1433	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1434	return $self->_tls_error ($tmp)
		1435	if $tmp != $ERROR_WANT_READ
		1436	&& ($tmp != $ERROR_SYSCALL || $!)
		1437	&& $tmp != $ERROR_ZERO_RETURN;
		1438
897	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {	1439	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
898	$self->{wbuf} .= $buf;	1440	$self->{wbuf} .= $tmp;
899	$self->_drain_wbuf;	1441	$self->_drain_wbuf;
900	}
901
902	while (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {
903	$self->{rbuf} .= $buf;
904	$self->_drain_rbuf;
905	}
906
907	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
908
909	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
910	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
911	$self->error;
912	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
913	$! = &Errno::EIO;
914	$self->error;
915	}
916
917	# all others are fine for our purposes
918	}	1442	}
919	}	1443	}
920		1444
921	=item $handle->starttls ($tls[, $tls_ctx])	1445	=item $handle->starttls ($tls[, $tls_ctx])
922		1446
…		…
925	C<starttls>.	1449	C<starttls>.
926		1450
927	The first argument is the same as the C<tls> constructor argument (either	1451	The first argument is the same as the C<tls> constructor argument (either
928	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1452	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
929		1453
930	The second argument is the optional C<Net::SSLeay::CTX> object that is	1454	The second argument is the optional C<AnyEvent::TLS> object that is used
931	used when AnyEvent::Handle has to create its own TLS connection object.	1455	when AnyEvent::Handle has to create its own TLS connection object, or
		1456	a hash reference with C<< key => value >> pairs that will be used to
		1457	construct a new context.
932		1458
933	The TLS connection object will end up in C<< $handle->{tls} >> after this	1459	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
934	call and can be used or changed to your liking. Note that the handshake	1460	context in C<< $handle->{tls_ctx} >> after this call and can be used or
935	might have already started when this function returns.	1461	changed to your liking. Note that the handshake might have already started
		1462	when this function returns.
936		1463
937	=cut	1464	If it an error to start a TLS handshake more than once per
		1465	AnyEvent::Handle object (this is due to bugs in OpenSSL).
938		1466
939	# TODO: maybe document...	1467	=cut
		1468
		1469	our %TLS_CACHE; #TODO not yet documented, should we?
		1470
940	sub starttls {	1471	sub starttls {
941	my ($self, $ssl, $ctx) = @_;	1472	my ($self, $ssl, $ctx) = @_;
942		1473
943	$self->stoptls;	1474	require Net::SSLeay;
944		1475
945	if ($ssl eq "accept") {	1476	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
946	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1477	if $self->{tls};
947	Net::SSLeay::set_accept_state ($ssl);	1478
948	} elsif ($ssl eq "connect") {	1479	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
949	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1480	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
950	Net::SSLeay::set_connect_state ($ssl);	1481	$ERROR_ZERO_RETURN = Net::SSLeay::ERROR_ZERO_RETURN ();
		1482
		1483	$ctx ||= $self->{tls_ctx};
		1484
		1485	if ("HASH" eq ref $ctx) {
		1486	require AnyEvent::TLS;
		1487
		1488	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context
		1489
		1490	if ($ctx->{cache}) {
		1491	my $key = $ctx+0;
		1492	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1493	} else {
		1494	$ctx = new AnyEvent::TLS %$ctx;
		1495	}
		1496	}
951	}	1497
952		1498	$self->{tls_ctx} = $ctx || TLS_CTX ();
953	$self->{tls} = $ssl;	1499	$self->{tls} = $ssl = $self->{tls_ctx}->_get_session ($ssl, $self, $self->{peername});
954		1500
955	# basically, this is deep magic (because SSL_read should have the same issues)	1501	# basically, this is deep magic (because SSL_read should have the same issues)
956	# but the openssl maintainers basically said: "trust us, it just works".	1502	# but the openssl maintainers basically said: "trust us, it just works".
957	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1503	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
958	# and mismaintained ssleay-module doesn't even offer them).	1504	# and mismaintained ssleay-module doesn't even offer them).
959	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1505	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1506	#
		1507	# in short: this is a mess.
		1508	#
		1509	# note that we do not try to keep the length constant between writes as we are required to do.
		1510	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1511	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1512	# have identity issues in that area.
960	Net::SSLeay::CTX_set_mode ($self->{tls},	1513	# Net::SSLeay::CTX_set_mode ($ssl,
961	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	1514	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
962	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));	1515	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1516	Net::SSLeay::CTX_set_mode ($ssl, 1|2);
963		1517
964	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1518	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
965	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1519	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
966		1520
967	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});	1521	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
968		1522
969	$self->{filter_w} = sub {	1523	&_dotls; # need to trigger the initial handshake
970	$_[0]{_tls_wbuf} .= ${$_[1]};	1524	$self->start_read; # make sure we actually do read
971	&_dotls;
972	};
973	$self->{filter_r} = sub {
974	Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
975	&_dotls;
976	};
977	}	1525	}
978		1526
979	=item $handle->stoptls	1527	=item $handle->stoptls
980		1528
981	Destroys the SSL connection, if any. Partial read or write data will be	1529	Shuts down the SSL connection - this makes a proper EOF handshake by
982	lost.	1530	sending a close notify to the other side, but since OpenSSL doesn't
		1531	support non-blocking shut downs, it is not possible to re-use the stream
		1532	afterwards.
983		1533
984	=cut	1534	=cut
985		1535
986	sub stoptls {	1536	sub stoptls {
987	my ($self) = @_;	1537	my ($self) = @_;
988		1538
989	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	1539	if ($self->{tls}) {
		1540	Net::SSLeay::shutdown ($self->{tls});
990		1541
991	delete $self->{_rbio};	1542	&_dotls;
992	delete $self->{_wbio};	1543
993	delete $self->{_tls_wbuf};	1544	# we don't give a shit. no, we do, but we can't. no...
994	delete $self->{filter_r};	1545	# we, we... have to use openssl :/
995	delete $self->{filter_w};	1546	&_freetls;
		1547	}
		1548	}
		1549
		1550	sub _freetls {
		1551	my ($self) = @_;
		1552
		1553	return unless $self->{tls};
		1554
		1555	$self->{tls_ctx}->_put_session (delete $self->{tls});
		1556
		1557	delete @$self{qw(_rbio _wbio _tls_wbuf)};
996	}	1558	}
997		1559
998	sub DESTROY {	1560	sub DESTROY {
999	my $self = shift;	1561	my ($self) = @_;
1000		1562
1001	$self->stoptls;	1563	&_freetls;
		1564
		1565	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1566
		1567	if ($linger && length $self->{wbuf}) {
		1568	my $fh = delete $self->{fh};
		1569	my $wbuf = delete $self->{wbuf};
		1570
		1571	my @linger;
		1572
		1573	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
		1574	my $len = syswrite $fh, $wbuf, length $wbuf;
		1575
		1576	if ($len > 0) {
		1577	substr $wbuf, 0, $len, "";
		1578	} else {
		1579	@linger = (); # end
		1580	}
		1581	});
		1582	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1583	@linger = ();
		1584	});
		1585	}
		1586	}
		1587
		1588	=item $handle->destroy
		1589
		1590	Shuts down the handle object as much as possible - this call ensures that
		1591	no further callbacks will be invoked and resources will be freed as much
		1592	as possible. You must not call any methods on the object afterwards.
		1593
		1594	Normally, you can just "forget" any references to an AnyEvent::Handle
		1595	object and it will simply shut down. This works in fatal error and EOF
		1596	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1597	callback, so when you want to destroy the AnyEvent::Handle object from
		1598	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1599	that case.
		1600
		1601	The handle might still linger in the background and write out remaining
		1602	data, as specified by the C<linger> option, however.
		1603
		1604	=cut
		1605
		1606	sub destroy {
		1607	my ($self) = @_;
		1608
		1609	$self->DESTROY;
		1610	%$self = ();
1002	}	1611	}
1003		1612
1004	=item AnyEvent::Handle::TLS_CTX	1613	=item AnyEvent::Handle::TLS_CTX
1005		1614
1006	This function creates and returns the Net::SSLeay::CTX object used by	1615	This function creates and returns the AnyEvent::TLS object used by default
1007	default for TLS mode.	1616	for TLS mode.
1008		1617
1009	The context is created like this:	1618	The context is created by calling L<AnyEvent::TLS> without any arguments.
1010
1011	Net::SSLeay::load_error_strings;
1012	Net::SSLeay::SSLeay_add_ssl_algorithms;
1013	Net::SSLeay::randomize;
1014
1015	my $CTX = Net::SSLeay::CTX_new;
1016
1017	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
1018		1619
1019	=cut	1620	=cut
1020		1621
1021	our $TLS_CTX;	1622	our $TLS_CTX;
1022		1623
1023	sub TLS_CTX() {	1624	sub TLS_CTX() {
1024	$TLS_CTX || do {	1625	$TLS_CTX ||= do {
1025	require Net::SSLeay;	1626	require AnyEvent::TLS;
1026		1627
1027	Net::SSLeay::load_error_strings ();	1628	new AnyEvent::TLS
1028	Net::SSLeay::SSLeay_add_ssl_algorithms ();
1029	Net::SSLeay::randomize ();
1030
1031	$TLS_CTX = Net::SSLeay::CTX_new ();
1032
1033	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
1034
1035	$TLS_CTX
1036	}	1629	}
1037	}	1630	}
1038		1631
1039	=back	1632	=back
		1633
		1634
		1635	=head1 NONFREQUENTLY ASKED QUESTIONS
		1636
		1637	=over 4
		1638
		1639	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1640	still get further invocations!
		1641
		1642	That's because AnyEvent::Handle keeps a reference to itself when handling
		1643	read or write callbacks.
		1644
		1645	It is only safe to "forget" the reference inside EOF or error callbacks,
		1646	from within all other callbacks, you need to explicitly call the C<<
		1647	->destroy >> method.
		1648
		1649	=item I get different callback invocations in TLS mode/Why can't I pause
		1650	reading?
		1651
		1652	Unlike, say, TCP, TLS connections do not consist of two independent
		1653	communication channels, one for each direction. Or put differently. The
		1654	read and write directions are not independent of each other: you cannot
		1655	write data unless you are also prepared to read, and vice versa.
		1656
		1657	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1658	callback invocations when you are not expecting any read data - the reason
		1659	is that AnyEvent::Handle always reads in TLS mode.
		1660
		1661	During the connection, you have to make sure that you always have a
		1662	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1663	connection (or when you no longer want to use it) you can call the
		1664	C<destroy> method.
		1665
		1666	=item How do I read data until the other side closes the connection?
		1667
		1668	If you just want to read your data into a perl scalar, the easiest way
		1669	to achieve this is by setting an C<on_read> callback that does nothing,
		1670	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1671	will be in C<$_[0]{rbuf}>:
		1672
		1673	$handle->on_read (sub { });
		1674	$handle->on_eof (undef);
		1675	$handle->on_error (sub {
		1676	my $data = delete $_[0]{rbuf};
		1677	undef $handle;
		1678	});
		1679
		1680	The reason to use C<on_error> is that TCP connections, due to latencies
		1681	and packets loss, might get closed quite violently with an error, when in
		1682	fact, all data has been received.
		1683
		1684	It is usually better to use acknowledgements when transferring data,
		1685	to make sure the other side hasn't just died and you got the data
		1686	intact. This is also one reason why so many internet protocols have an
		1687	explicit QUIT command.
		1688
		1689	=item I don't want to destroy the handle too early - how do I wait until
		1690	all data has been written?
		1691
		1692	After writing your last bits of data, set the C<on_drain> callback
		1693	and destroy the handle in there - with the default setting of
		1694	C<low_water_mark> this will be called precisely when all data has been
		1695	written to the socket:
		1696
		1697	$handle->push_write (...);
		1698	$handle->on_drain (sub {
		1699	warn "all data submitted to the kernel\n";
		1700	undef $handle;
		1701	});
		1702
		1703	=back
		1704
1040		1705
1041	=head1 SUBCLASSING AnyEvent::Handle	1706	=head1 SUBCLASSING AnyEvent::Handle
1042		1707
1043	In many cases, you might want to subclass AnyEvent::Handle.	1708	In many cases, you might want to subclass AnyEvent::Handle.
1044		1709
…		…
1048	=over 4	1713	=over 4
1049		1714
1050	=item * all constructor arguments become object members.	1715	=item * all constructor arguments become object members.
1051		1716
1052	At least initially, when you pass a C<tls>-argument to the constructor it	1717	At least initially, when you pass a C<tls>-argument to the constructor it
1053	will end up in C<< $handle->{tls} >>. Those members might be changes or	1718	will end up in C<< $handle->{tls} >>. Those members might be changed or
1054	mutated later on (for example C<tls> will hold the TLS connection object).	1719	mutated later on (for example C<tls> will hold the TLS connection object).
1055		1720
1056	=item * other object member names are prefixed with an C<_>.	1721	=item * other object member names are prefixed with an C<_>.
1057		1722
1058	All object members not explicitly documented (internal use) are prefixed	1723	All object members not explicitly documented (internal use) are prefixed

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