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Comparing AnyEvent/lib/AnyEvent/Handle.pm (file contents):
Revision 1.44 by root, Thu May 29 00:00:07 2008 UTC vs.
Revision 1.137 by root, Sat Jul 4 23:58:52 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(WSAEWOULDBLOCK);	7	use AnyEvent::Util qw(WSAEWOULDBLOCK);
8	use Scalar::Util ();	8	use Scalar::Util ();
9	use Carp ();	9	use Carp ();
…		…
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 => $cb->($handle)	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
		97	If an EOF condition has been detected but no C<on_eof> callback has been
		98	set, then a fatal error will be raised with C<$!> set to <0>.
		99
86	=item on_error => $cb->($handle)	100	=item on_error => $cb->($handle, $fatal, $message)
87		101
88	This is the fatal error callback, that is called when, well, a fatal error	102	This is the error callback, which is called when, well, some error
89	occurs, such as not being able to resolve the hostname, failure to connect	103	occured, such as not being able to resolve the hostname, failure to
90	or a read error.	104	connect or a read error.
91		105
92	The object will not be in a usable state when this callback has been	106	Some errors are fatal (which is indicated by C<$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>, C<ETIMEDOUT> 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 => $cb->($handle)	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<$handle->{rbuf}> member directly.	138	method or access the C<$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>).
…		…
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
125	=item timeout => $fractional_seconds	160	=item timeout => $fractional_seconds
126		161
127	If non-zero, then this enables an "inactivity" timeout: whenever this many	162	If non-zero, then this enables an "inactivity" timeout: whenever this many
128	seconds pass without a successful read or write on the underlying file	163	seconds pass without a successful read or write on the underlying file
129	handle, the C<on_timeout> callback will be invoked (and if that one is	164	handle, the C<on_timeout> callback will be invoked (and if that one is
130	missing, an C<ETIMEDOUT> errror will be raised).	165	missing, a non-fatal C<ETIMEDOUT> error will be raised).
131		166
132	Note that timeout processing is also active when you currently do not have	167	Note that timeout processing is also active when you currently do not have
133	any outstanding read or write requests: If you plan to keep the connection	168	any outstanding read or write requests: If you plan to keep the connection
134	idle then you should disable the timout temporarily or ignore the timeout	169	idle then you should disable the timout temporarily or ignore the timeout
135	in the C<on_timeout> callback.	170	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		171	restart the timeout.
136		172
137	Zero (the default) disables this timeout.	173	Zero (the default) disables this timeout.
138		174
139	=item on_timeout => $cb->($handle)	175	=item on_timeout => $cb->($handle)
140		176
…		…
144		180
145	=item rbuf_max => <bytes>	181	=item rbuf_max => <bytes>
146		182
147	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>)
148	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
149	avoid denial-of-service attacks.	185	avoid some forms of denial-of-service attacks.
150		186
151	For example, a server accepting connections from untrusted sources should	187	For example, a server accepting connections from untrusted sources should
152	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
153	(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
154	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
155	isn't finished).	191	isn't finished).
156		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
157	=item read_size => <bytes>	219	=item read_size => <bytes>
158		220
159	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
160	on each [loop iteration). Default: C<4096>.	222	try to read during each loop iteration, which affects memory
		223	requirements). Default: C<8192>.
161		224
162	=item low_water_mark => <bytes>	225	=item low_water_mark => <bytes>
163		226
164	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
165	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
166	considered empty.	229	considered empty.
167		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
168	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	256	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
169		257
170	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
171	will start making tls handshake and will transparently encrypt/decrypt	259	AnyEvent will start a TLS handshake as soon as the conenction has been
172	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.
173		264
174	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
175	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.
176		269
177	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
178	connection, use C<connect> mode.	271	C<accept>, and for the TLS client side of a connection, use C<connect>
		272	mode.
179		273
180	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
181	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>
182	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
183	AnyEvent::Handle.	277	AnyEvent::Handle. Also, this module will take ownership of this connection
		278	object.
184		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
185	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.
186		290
187	=item tls_ctx => $ssl_ctx	291	=item tls_ctx => $anyevent_tls
188		292
189	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
190	(unless a connection object was specified directly). If this parameter is	294	(unless a connection object was specified directly). If this parameter is
191	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	295	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
192		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
193	=item json => JSON or JSON::XS object	301	=item json => JSON or JSON::XS object
194		302
195	This is the json coder object used by the C<json> read and write types.	303	This is the json coder object used by the C<json> read and write types.
196		304
197	If you don't supply it, then AnyEvent::Handle will create and use a	305	If you don't supply it, then AnyEvent::Handle will create and use a
198	suitable one, which will write and expect UTF-8 encoded JSON texts.	306	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		307	texts.
199		308
200	Note that you are responsible to depend on the JSON module if you want to	309	Note that you are responsible to depend on the JSON module if you want to
201	use this functionality, as AnyEvent does not have a dependency itself.	310	use this functionality, as AnyEvent does not have a dependency itself.
202		311
203	=item filter_r => $cb
204
205	=item filter_w => $cb
206
207	These exist, but are undocumented at this time.
208
209	=back	312	=back
210		313
211	=cut	314	=cut
212		315
213	sub new {	316	sub new {
214	my $class = shift;	317	my $class = shift;
215
216	my $self = bless { @_ }, $class;	318	my $self = bless { @_ }, $class;
217		319
218	$self->{fh} or Carp::croak "mandatory argument fh is missing";	320	$self->{fh} or Carp::croak "mandatory argument fh is missing";
219		321
220	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	322	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
221
222	if ($self->{tls}) {
223	require Net::SSLeay;
224	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});
225	}
226
227	# $self->on_eof (delete $self->{on_eof} ) if $self->{on_eof}; # nop
228	# $self->on_error (delete $self->{on_error}) if $self->{on_error}; # nop
229	# $self->on_read (delete $self->{on_read} ) if $self->{on_read}; # nop
230	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};
231		323
232	$self->{_activity} = AnyEvent->now;	324	$self->{_activity} = AnyEvent->now;
233	$self->_timeout;	325	$self->_timeout;
234		326
		327	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		328
		329	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		330	if $self->{tls};
		331
		332	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
		333
235	$self->start_read;	334	$self->start_read
		335	if $self->{on_read};
236		336
237	$self	337	$self->{fh} && $self
238	}	338	}
239		339
240	sub _shutdown {	340	sub _shutdown {
241	my ($self) = @_;	341	my ($self) = @_;
242		342
243	delete $self->{_rw};	343	delete @$self{qw(_tw _rw _ww fh wbuf on_read _queue)};
244	delete $self->{_ww};	344	$self->{_eof} = 1; # tell starttls et. al to stop trying
245	delete $self->{fh};
246	}
247		345
		346	&_freetls;
		347	}
		348
248	sub error {	349	sub _error {
249	my ($self) = @_;	350	my ($self, $errno, $fatal, $message) = @_;
250		351
251	{
252	local $!;
253	$self->_shutdown;	352	$self->_shutdown
254	}	353	if $fatal;
255		354
256	$self->{on_error}($self)	355	$! = $errno;
		356	$message ||= "$!";
		357
257	if $self->{on_error};	358	if ($self->{on_error}) {
258		359	$self->{on_error}($self, $fatal, $message);
		360	} elsif ($self->{fh}) {
259	Carp::croak "AnyEvent::Handle uncaught fatal error: $!";	361	Carp::croak "AnyEvent::Handle uncaught error: $message";
		362	}
260	}	363	}
261		364
262	=item $fh = $handle->fh	365	=item $fh = $handle->fh
263		366
264	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.
265		368
266	=cut	369	=cut
267		370
268	sub fh { $_[0]{fh} }	371	sub fh { $_[0]{fh} }
269		372
…		…
287	$_[0]{on_eof} = $_[1];	390	$_[0]{on_eof} = $_[1];
288	}	391	}
289		392
290	=item $handle->on_timeout ($cb)	393	=item $handle->on_timeout ($cb)
291		394
292	Replace the current C<on_timeout> callback, or disables the callback	395	Replace the current C<on_timeout> callback, or disables the callback (but
293	(but not the timeout) if C<$cb> = C<undef>. See C<timeout> constructor	396	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
294	argument.	397	argument and method.
295		398
296	=cut	399	=cut
297		400
298	sub on_timeout {	401	sub on_timeout {
299	$_[0]{on_timeout} = $_[1];	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	};
300	}	430	}
301		431
302	#############################################################################	432	#############################################################################
303		433
304	=item $handle->timeout ($seconds)	434	=item $handle->timeout ($seconds)
…		…
328	# now or in the past already?	458	# now or in the past already?
329	if ($after <= 0) {	459	if ($after <= 0) {
330	$self->{_activity} = $NOW;	460	$self->{_activity} = $NOW;
331		461
332	if ($self->{on_timeout}) {	462	if ($self->{on_timeout}) {
333	$self->{on_timeout}->($self);	463	$self->{on_timeout}($self);
334	} else {	464	} else {
335	$! = Errno::ETIMEDOUT;	465	$self->_error (&Errno::ETIMEDOUT);
336	$self->error;
337	}	466	}
338		467
339	# callbakx could have changed timeout value, optimise	468	# callback could have changed timeout value, optimise
340	return unless $self->{timeout};	469	return unless $self->{timeout};
341		470
342	# calculate new after	471	# calculate new after
343	$after = $self->{timeout};	472	$after = $self->{timeout};
344	}	473	}
345		474
346	Scalar::Util::weaken $self;	475	Scalar::Util::weaken $self;
		476	return unless $self; # ->error could have destroyed $self
347		477
348	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {	478	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
349	delete $self->{_tw};	479	delete $self->{_tw};
350	$self->_timeout;	480	$self->_timeout;
351	});	481	});
…		…
382	my ($self, $cb) = @_;	512	my ($self, $cb) = @_;
383		513
384	$self->{on_drain} = $cb;	514	$self->{on_drain} = $cb;
385		515
386	$cb->($self)	516	$cb->($self)
387	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	517	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
388	}	518	}
389		519
390	=item $handle->push_write ($data)	520	=item $handle->push_write ($data)
391		521
392	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
…		…
409	substr $self->{wbuf}, 0, $len, "";	539	substr $self->{wbuf}, 0, $len, "";
410		540
411	$self->{_activity} = AnyEvent->now;	541	$self->{_activity} = AnyEvent->now;
412		542
413	$self->{on_drain}($self)	543	$self->{on_drain}($self)
414	if $self->{low_water_mark} >= length $self->{wbuf}	544	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
415	&& $self->{on_drain};	545	&& $self->{on_drain};
416		546
417	delete $self->{_ww} unless length $self->{wbuf};	547	delete $self->{_ww} unless length $self->{wbuf};
418	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {	548	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
419	$self->error;	549	$self->_error ($!, 1);
420	}	550	}
421	};	551	};
422		552
423	# try to write data immediately	553	# try to write data immediately
424	$cb->();	554	$cb->() unless $self->{autocork};
425		555
426	# if still data left in wbuf, we need to poll	556	# if still data left in wbuf, we need to poll
427	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)	557	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
428	if length $self->{wbuf};	558	if length $self->{wbuf};
429	};	559	};
…		…
443		573
444	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	574	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
445	->($self, @_);	575	->($self, @_);
446	}	576	}
447		577
448	if ($self->{filter_w}) {	578	if ($self->{tls}) {
449	$self->{filter_w}->($self, \$_[0]);	579	$self->{_tls_wbuf} .= $_[0];
		580
		581	&_dotls ($self);
450	} else {	582	} else {
451	$self->{wbuf} .= $_[0];	583	$self->{wbuf} .= $_[0];
452	$self->_drain_wbuf;	584	$self->_drain_wbuf;
453	}	585	}
454	}	586	}
455		587
456	=item $handle->push_write (type => @args)	588	=item $handle->push_write (type => @args)
457		589
458	=item $handle->unshift_write (type => @args)
459
460	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
461	the job by specifying a type and type-specific arguments.	591	the job by specifying a type and type-specific arguments.
462		592
463	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
464	drop by and tell us):	594	drop by and tell us):
…		…
468	=item netstring => $string	598	=item netstring => $string
469		599
470	Formats the given value as netstring	600	Formats the given value as netstring
471	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).	601	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
472		602
473	=back
474
475	=cut	603	=cut
476		604
477	register_write_type netstring => sub {	605	register_write_type netstring => sub {
478	my ($self, $string) = @_;	606	my ($self, $string) = @_;
479		607
480	sprintf "%d:%s,", (length $string), $string	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
481	};	624	};
482		625
483	=item json => $array_or_hashref	626	=item json => $array_or_hashref
484		627
485	Encodes the given hash or array reference into a JSON object. Unless you	628	Encodes the given hash or array reference into a JSON object. Unless you
…		…
519		662
520	$self->{json} ? $self->{json}->encode ($ref)	663	$self->{json} ? $self->{json}->encode ($ref)
521	: JSON::encode_json ($ref)	664	: JSON::encode_json ($ref)
522	};	665	};
523		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
524	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)	705	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
525		706
526	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>.
527	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
528	reference with the handle object and the remaining arguments.	709	reference with the handle object and the remaining arguments.
…		…
548	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
549	a queue.	730	a queue.
550		731
551	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
552	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
553	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
554	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).
555		737
556	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
557	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
558	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
559	below).	741	done its job (see C<push_read>, below).
560		742
561	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
562	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.
563		745
564	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
565	the specified number of bytes which give an XML datagram.	747	the specified number of bytes which give an XML datagram.
566		748
567	# in the default state, expect some header bytes	749	# in the default state, expect some header bytes
568	$handle->on_read (sub {	750	$handle->on_read (sub {
569	# 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)
570	shift->unshift_read_chunk (4, sub {	752	shift->unshift_read (chunk => 4, sub {
571	# header arrived, decode	753	# header arrived, decode
572	my $len = unpack "N", $_[1];	754	my $len = unpack "N", $_[1];
573		755
574	# now read the payload	756	# now read the payload
575	shift->unshift_read_chunk ($len, sub {	757	shift->unshift_read (chunk => $len, sub {
576	my $xml = $_[1];	758	my $xml = $_[1];
577	# handle xml	759	# handle xml
578	});	760	});
579	});	761	});
580	});	762	});
581		763
582	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"
583	"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
584	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
585	pipeline sending both requests and manipulate the queue as necessary in	767	just pipeline sending both requests and manipulate the queue as necessary
586	the callbacks:	768	in the callbacks.
587		769
588	# 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"
589	$handle->push_write ("request 1\015\012");	775	$handle->push_write ("request 1\015\012");
590		776
591	# 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
592	$handle->push_read_line (sub {	778	$handle->push_read (line => sub {
593	# if we got an "OK", we have to _prepend_ another line,	779	# if we got an "OK", we have to _prepend_ another line,
594	# so it will be read before the second request reads its 64 bytes	780	# so it will be read before the second request reads its 64 bytes
595	# which are already in the queue when this callback is called	781	# which are already in the queue when this callback is called
596	# we don't do this in case we got an error	782	# we don't do this in case we got an error
597	if ($_[1] eq "OK") {	783	if ($_[1] eq "OK") {
598	$_[0]->unshift_read_line (sub {	784	$_[0]->unshift_read (line => sub {
599	my $response = $_[1];	785	my $response = $_[1];
600	...	786	...
601	});	787	});
602	}	788	}
603	});	789	});
604		790
605	# request two	791	# request two, simply returns 64 octets
606	$handle->push_write ("request 2\015\012");	792	$handle->push_write ("request 2\015\012");
607		793
608	# simply read 64 bytes, always	794	# simply read 64 bytes, always
609	$handle->push_read_chunk (64, sub {	795	$handle->push_read (chunk => 64, sub {
610	my $response = $_[1];	796	my $response = $_[1];
611	...	797	...
612	});	798	});
613		799
614	=over 4	800	=over 4
615		801
616	=cut	802	=cut
617		803
618	sub _drain_rbuf {	804	sub _drain_rbuf {
619	my ($self) = @_;	805	my ($self) = @_;
		806
		807	local $self->{_in_drain} = 1;
620		808
621	if (	809	if (
622	defined $self->{rbuf_max}	810	defined $self->{rbuf_max}
623	&& $self->{rbuf_max} < length $self->{rbuf}	811	&& $self->{rbuf_max} < length $self->{rbuf}
624	) {	812	) {
625	$! = &Errno::ENOSPC;	813	$self->_error (&Errno::ENOSPC, 1), return;
626	$self->error;
627	}	814	}
628		815
629	return if $self->{in_drain};	816	while () {
630	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};
631		820
632	while (my $len = length $self->{rbuf}) {	821	my $len = length $self->{rbuf};
633	no strict 'refs';	822
634	if (my $cb = shift @{ $self->{_queue} }) {	823	if (my $cb = shift @{ $self->{_queue} }) {
635	unless ($cb->($self)) {	824	unless ($cb->($self)) {
636	if ($self->{_eof}) {	825	if ($self->{_eof}) {
637	# 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)
638	$! = &Errno::EPIPE;	827	$self->_error (&Errno::EPIPE, 1), return;
639	$self->error;
640	}	828	}
641		829
642	unshift @{ $self->{_queue} }, $cb;	830	unshift @{ $self->{_queue} }, $cb;
643	return;	831	last;
644	}	832	}
645	} elsif ($self->{on_read}) {	833	} elsif ($self->{on_read}) {
		834	last unless $len;
		835
646	$self->{on_read}($self);	836	$self->{on_read}($self);
647		837
648	if (	838	if (
649	$self->{_eof} # if no further data will arrive
650	&& $len == length $self->{rbuf} # and no data has been consumed	839	$len == length $self->{rbuf} # if no data has been consumed
651	&& !@{ $self->{_queue} } # and the queue is still empty	840	&& !@{ $self->{_queue} } # and the queue is still empty
652	&& $self->{on_read} # and we still want to read data	841	&& $self->{on_read} # but we still have on_read
653	) {	842	) {
		843	# no further data will arrive
654	# then no progress can be made	844	# so no progress can be made
655	$! = &Errno::EPIPE;	845	$self->_error (&Errno::EPIPE, 1), return
656	$self->error;	846	if $self->{_eof};
		847
		848	last; # more data might arrive
657	}	849	}
658	} else {	850	} else {
659	# read side becomes idle	851	# read side becomes idle
660	delete $self->{_rw};	852	delete $self->{_rw} unless $self->{tls};
661	return;	853	last;
662	}	854	}
663	}	855	}
664		856
665	if ($self->{_eof}) {	857	if ($self->{_eof}) {
666	$self->_shutdown;	858	if ($self->{on_eof}) {
667	$self->{on_eof}($self)	859	$self->{on_eof}($self)
668	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} };
669	}	869	}
670	}	870	}
671		871
672	=item $handle->on_read ($cb)	872	=item $handle->on_read ($cb)
673		873
…		…
679		879
680	sub on_read {	880	sub on_read {
681	my ($self, $cb) = @_;	881	my ($self, $cb) = @_;
682		882
683	$self->{on_read} = $cb;	883	$self->{on_read} = $cb;
		884	$self->_drain_rbuf if $cb && !$self->{_in_drain};
684	}	885	}
685		886
686	=item $handle->rbuf	887	=item $handle->rbuf
687		888
688	Returns the read buffer (as a modifiable lvalue).	889	Returns the read buffer (as a modifiable lvalue).
689		890
690	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} >>
691	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.
692		896
693	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>,
694	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
695	automatically manage the read buffer.	899	automatically manage the read buffer.
696		900
…		…
737	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	941	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
738	->($self, $cb, @_);	942	->($self, $cb, @_);
739	}	943	}
740		944
741	push @{ $self->{_queue} }, $cb;	945	push @{ $self->{_queue} }, $cb;
742	$self->_drain_rbuf;	946	$self->_drain_rbuf unless $self->{_in_drain};
743	}	947	}
744		948
745	sub unshift_read {	949	sub unshift_read {
746	my $self = shift;	950	my $self = shift;
747	my $cb = pop;	951	my $cb = pop;
…		…
753	->($self, $cb, @_);	957	->($self, $cb, @_);
754	}	958	}
755		959
756		960
757	unshift @{ $self->{_queue} }, $cb;	961	unshift @{ $self->{_queue} }, $cb;
758	$self->_drain_rbuf;	962	$self->_drain_rbuf unless $self->{_in_drain};
759	}	963	}
760		964
761	=item $handle->push_read (type => @args, $cb)	965	=item $handle->push_read (type => @args, $cb)
762		966
763	=item $handle->unshift_read (type => @args, $cb)	967	=item $handle->unshift_read (type => @args, $cb)
…		…
793	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	997	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
794	1	998	1
795	}	999	}
796	};	1000	};
797		1001
798	# compatibility with older API
799	sub push_read_chunk {
800	$_[0]->push_read (chunk => $_[1], $_[2]);
801	}
802
803	sub unshift_read_chunk {
804	$_[0]->unshift_read (chunk => $_[1], $_[2]);
805	}
806
807	=item line => [$eol, ]$cb->($handle, $line, $eol)	1002	=item line => [$eol, ]$cb->($handle, $line, $eol)
808		1003
809	The callback will be called only once a full line (including the end of	1004	The callback will be called only once a full line (including the end of
810	line marker, C<$eol>) has been read. This line (excluding the end of line	1005	line marker, C<$eol>) has been read. This line (excluding the end of line
811	marker) will be passed to the callback as second argument (C<$line>), and	1006	marker) will be passed to the callback as second argument (C<$line>), and
…		…
826	=cut	1021	=cut
827		1022
828	register_read_type line => sub {	1023	register_read_type line => sub {
829	my ($self, $cb, $eol) = @_;	1024	my ($self, $cb, $eol) = @_;
830		1025
831	$eol = qr|(\015?\012)| if @_ < 3;	1026	if (@_ < 3) {
832	$eol = quotemeta $eol unless ref $eol;	1027	# this is more than twice as fast as the generic code below
833	$eol = qr|^(.*?)($eol)|s;
834
835	sub {	1028	sub {
836	$_[0]{rbuf} =~ s/$eol// or return;	1029	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
837		1030
838	$cb->($_[0], $1, $2);	1031	$cb->($_[0], $1, $2);
839	1
840	}
841	};
842
843	# compatibility with older API
844	sub push_read_line {
845	my $self = shift;
846	$self->push_read (line => @_);
847	}
848
849	sub unshift_read_line {
850	my $self = shift;
851	$self->unshift_read (line => @_);
852	}
853
854	=item netstring => $cb->($handle, $string)
855
856	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
857
858	Throws an error with C<$!> set to EBADMSG on format violations.
859
860	=cut
861
862	register_read_type netstring => sub {
863	my ($self, $cb) = @_;
864
865	sub {
866	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
867	if ($_[0]{rbuf} =~ /[^0-9]/) {
868	$! = &Errno::EBADMSG;
869	$self->error;
870	}	1032	1
871	return;
872	}	1033	}
		1034	} else {
		1035	$eol = quotemeta $eol unless ref $eol;
		1036	$eol = qr|^(.*?)($eol)|s;
873		1037
874	my $len = $1;	1038	sub {
		1039	$_[0]{rbuf} =~ s/$eol// or return;
875		1040
876	$self->unshift_read (chunk => $len, sub {	1041	$cb->($_[0], $1, $2);
877	my $string = $_[1];
878	$_[0]->unshift_read (chunk => 1, sub {
879	if ($_[1] eq ",") {
880	$cb->($_[0], $string);
881	} else {
882	$! = &Errno::EBADMSG;
883	$self->error;
884	}
885	});	1042	1
886	});	1043	}
887
888	1
889	}	1044	}
890	};	1045	};
891		1046
892	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)	1047	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
893		1048
…		…
945	return 1;	1100	return 1;
946	}	1101	}
947		1102
948	# reject	1103	# reject
949	if ($reject && $$rbuf =~ $reject) {	1104	if ($reject && $$rbuf =~ $reject) {
950	$! = &Errno::EBADMSG;	1105	$self->_error (&Errno::EBADMSG);
951	$self->error;
952	}	1106	}
953		1107
954	# skip	1108	# skip
955	if ($skip && $$rbuf =~ $skip) {	1109	if ($skip && $$rbuf =~ $skip) {
956	$data .= substr $$rbuf, 0, $+[0], "";	1110	$data .= substr $$rbuf, 0, $+[0], "";
…		…
958		1112
959	()	1113	()
960	}	1114	}
961	};	1115	};
962		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
963	=item json => $cb->($handle, $hash_or_arrayref)	1199	=item json => $cb->($handle, $hash_or_arrayref)
964		1200
965	Reads a JSON object or array, decodes it and passes it to the callback.	1201	Reads a JSON object or array, decodes it and passes it to the
		1202	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
966		1203
967	If a C<json> object was passed to the constructor, then that will be used	1204	If a C<json> object was passed to the constructor, then that will be used
968	for the final decode, otherwise it will create a JSON coder expecting UTF-8.	1205	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
969		1206
970	This read type uses the incremental parser available with JSON version	1207	This read type uses the incremental parser available with JSON version
…		…
977	the C<json> write type description, above, for an actual example.	1214	the C<json> write type description, above, for an actual example.
978		1215
979	=cut	1216	=cut
980		1217
981	register_read_type json => sub {	1218	register_read_type json => sub {
982	my ($self, $cb, $accept, $reject, $skip) = @_;	1219	my ($self, $cb) = @_;
983		1220
984	require JSON;	1221	my $json = $self->{json} ||=
		1222	eval { require JSON::XS; JSON::XS->new->utf8 }
		1223	|| do { require JSON; JSON->new->utf8 };
985		1224
986	my $data;	1225	my $data;
987	my $rbuf = \$self->{rbuf};	1226	my $rbuf = \$self->{rbuf};
988		1227
989	my $json = $self->{json} ||= JSON->new->utf8;
990
991	sub {	1228	sub {
992	my $ref = $json->incr_parse ($self->{rbuf});	1229	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
993		1230
994	if ($ref) {	1231	if ($ref) {
995	$self->{rbuf} = $json->incr_text;	1232	$self->{rbuf} = $json->incr_text;
996	$json->incr_text = "";	1233	$json->incr_text = "";
997	$cb->($self, $ref);	1234	$cb->($self, $ref);
998		1235
999	1	1236	1
		1237	} elsif ($@) {
		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	()
1000	} else {	1247	} else {
1001	$self->{rbuf} = "";	1248	$self->{rbuf} = "";
		1249
1002	()	1250	()
1003	}	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
1004	}	1297	}
1005	};	1298	};
1006		1299
1007	=back	1300	=back
1008		1301
…		…
1029	=item $handle->stop_read	1322	=item $handle->stop_read
1030		1323
1031	=item $handle->start_read	1324	=item $handle->start_read
1032		1325
1033	In rare cases you actually do not want to read anything from the	1326	In rare cases you actually do not want to read anything from the
1034	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1327	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
1035	any queued callbacks will be executed then. To start reading again, call	1328	any queued callbacks will be executed then. To start reading again, call
1036	C<start_read>.	1329	C<start_read>.
1037		1330
		1331	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1332	you change the C<on_read> callback or push/unshift a read callback, and it
		1333	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1334	there are any read requests in the queue.
		1335
		1336	These methods will have no effect when in TLS mode (as TLS doesn't support
		1337	half-duplex connections).
		1338
1038	=cut	1339	=cut
1039		1340
1040	sub stop_read {	1341	sub stop_read {
1041	my ($self) = @_;	1342	my ($self) = @_;
1042		1343
1043	delete $self->{_rw};	1344	delete $self->{_rw} unless $self->{tls};
1044	}	1345	}
1045		1346
1046	sub start_read {	1347	sub start_read {
1047	my ($self) = @_;	1348	my ($self) = @_;
1048		1349
1049	unless ($self->{_rw} || $self->{_eof}) {	1350	unless ($self->{_rw} || $self->{_eof}) {
1050	Scalar::Util::weaken $self;	1351	Scalar::Util::weaken $self;
1051		1352
1052	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1353	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
1053	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1354	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1054	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;
1055		1356
1056	if ($len > 0) {	1357	if ($len > 0) {
1057	$self->{_activity} = AnyEvent->now;	1358	$self->{_activity} = AnyEvent->now;
1058		1359
1059	$self->{filter_r}	1360	if ($self->{tls}) {
1060	? $self->{filter_r}->($self, $rbuf)	1361	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1061	: $self->_drain_rbuf;	1362
		1363	&_dotls ($self);
		1364	} else {
		1365	$self->_drain_rbuf unless $self->{_in_drain};
		1366	}
1062		1367
1063	} elsif (defined $len) {	1368	} elsif (defined $len) {
1064	delete $self->{_rw};	1369	delete $self->{_rw};
1065	delete $self->{_ww};
1066	delete $self->{_tw};
1067	$self->{_eof} = 1;	1370	$self->{_eof} = 1;
1068	$self->_drain_rbuf;	1371	$self->_drain_rbuf unless $self->{_in_drain};
1069		1372
1070	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {	1373	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
1071	return $self->error;	1374	return $self->_error ($!, 1);
1072	}	1375	}
1073	});	1376	});
1074	}	1377	}
1075	}	1378	}
1076		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, $err);
		1396	}
		1397
		1398	# poll the write BIO and send the data if applicable
		1399	# also decode read data if possible
		1400	# this is basiclaly our TLS state machine
		1401	# more efficient implementations are possible with openssl,
		1402	# but not with the buggy and incomplete Net::SSLeay.
1077	sub _dotls {	1403	sub _dotls {
1078	my ($self) = @_;	1404	my ($self) = @_;
1079		1405
		1406	my $tmp;
		1407
1080	if (length $self->{_tls_wbuf}) {	1408	if (length $self->{_tls_wbuf}) {
1081	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {	1409	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
1082	substr $self->{_tls_wbuf}, 0, $len, "";	1410	substr $self->{_tls_wbuf}, 0, $tmp, "";
1083	}	1411	}
1084	}
1085		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
1086	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {	1439	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1087	$self->{wbuf} .= $buf;	1440	$self->{wbuf} .= $tmp;
1088	$self->_drain_wbuf;	1441	$self->_drain_wbuf;
1089	}
1090
1091	while (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {
1092	$self->{rbuf} .= $buf;
1093	$self->_drain_rbuf;
1094	}
1095
1096	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
1097
1098	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
1099	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
1100	$self->error;
1101	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
1102	$! = &Errno::EIO;
1103	$self->error;
1104	}
1105
1106	# all others are fine for our purposes
1107	}	1442	}
1108	}	1443	}
1109		1444
1110	=item $handle->starttls ($tls[, $tls_ctx])	1445	=item $handle->starttls ($tls[, $tls_ctx])
1111		1446
…		…
1114	C<starttls>.	1449	C<starttls>.
1115		1450
1116	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
1117	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1452	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
1118		1453
1119	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
1120	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.
1121		1458
1122	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
1123	call and can be used or changed to your liking. Note that the handshake	1460	context in C<< $handle->{tls_ctx} >> after this call and can be used or
1124	might have already started when this function returns.	1461	changed to your liking. Note that the handshake might have already started
		1462	when this function returns.
1125		1463
1126	=cut	1464	If it an error to start a TLS handshake more than once per
		1465	AnyEvent::Handle object (this is due to bugs in OpenSSL).
1127		1466
1128	# TODO: maybe document...	1467	=cut
		1468
		1469	our %TLS_CACHE; #TODO not yet documented, should we?
		1470
1129	sub starttls {	1471	sub starttls {
1130	my ($self, $ssl, $ctx) = @_;	1472	my ($self, $ssl, $ctx) = @_;
1131		1473
1132	$self->stoptls;	1474	require Net::SSLeay;
1133		1475
1134	if ($ssl eq "accept") {	1476	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
1135	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1477	if $self->{tls};
1136	Net::SSLeay::set_accept_state ($ssl);	1478
1137	} elsif ($ssl eq "connect") {	1479	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
1138	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1480	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
1139	Net::SSLeay::set_connect_state ($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	}
1140	}	1497
1141		1498	$self->{tls_ctx} = $ctx || TLS_CTX ();
1142	$self->{tls} = $ssl;	1499	$self->{tls} = $ssl = $self->{tls_ctx}->_get_session ($ssl, $self, $self->{peername});
1143		1500
1144	# basically, this is deep magic (because SSL_read should have the same issues)	1501	# basically, this is deep magic (because SSL_read should have the same issues)
1145	# but the openssl maintainers basically said: "trust us, it just works".	1502	# but the openssl maintainers basically said: "trust us, it just works".
1146	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	1503	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
1147	# and mismaintained ssleay-module doesn't even offer them).	1504	# and mismaintained ssleay-module doesn't even offer them).
1148	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	1505	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1506	#
		1507	# in short: this is a mess.
		1508	#
		1509	# note that we do not try to keep the length constant between writes as we are required to do.
		1510	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1511	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1512	# have identity issues in that area.
1149	Net::SSLeay::CTX_set_mode ($self->{tls},	1513	# Net::SSLeay::CTX_set_mode ($ssl,
1150	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	1514	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
1151	| (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);
1152		1517
1153	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1518	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1154	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	1519	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1155		1520
1156	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});	1521	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
1157		1522
1158	$self->{filter_w} = sub {	1523	&_dotls; # need to trigger the initial handshake
1159	$_[0]{_tls_wbuf} .= ${$_[1]};	1524	$self->start_read; # make sure we actually do read
1160	&_dotls;
1161	};
1162	$self->{filter_r} = sub {
1163	Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
1164	&_dotls;
1165	};
1166	}	1525	}
1167		1526
1168	=item $handle->stoptls	1527	=item $handle->stoptls
1169		1528
1170	Destroys the SSL connection, if any. Partial read or write data will be	1529	Shuts down the SSL connection - this makes a proper EOF handshake by
1171	lost.	1530	sending a close notify to the other side, but since OpenSSL doesn't
		1531	support non-blocking shut downs, it is not possible to re-use the stream
		1532	afterwards.
1172		1533
1173	=cut	1534	=cut
1174		1535
1175	sub stoptls {	1536	sub stoptls {
1176	my ($self) = @_;	1537	my ($self) = @_;
1177		1538
1178	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	1539	if ($self->{tls}) {
		1540	Net::SSLeay::shutdown ($self->{tls});
1179		1541
1180	delete $self->{_rbio};	1542	&_dotls;
1181	delete $self->{_wbio};	1543
1182	delete $self->{_tls_wbuf};	1544	# we don't give a shit. no, we do, but we can't. no...
1183	delete $self->{filter_r};	1545	# we, we... have to use openssl :/
1184	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)};
1185	}	1558	}
1186		1559
1187	sub DESTROY {	1560	sub DESTROY {
1188	my $self = shift;	1561	my ($self) = @_;
1189		1562
1190	$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 = ();
1191	}	1611	}
1192		1612
1193	=item AnyEvent::Handle::TLS_CTX	1613	=item AnyEvent::Handle::TLS_CTX
1194		1614
1195	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
1196	default for TLS mode.	1616	for TLS mode.
1197		1617
1198	The context is created like this:	1618	The context is created by calling L<AnyEvent::TLS> without any arguments.
1199
1200	Net::SSLeay::load_error_strings;
1201	Net::SSLeay::SSLeay_add_ssl_algorithms;
1202	Net::SSLeay::randomize;
1203
1204	my $CTX = Net::SSLeay::CTX_new;
1205
1206	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
1207		1619
1208	=cut	1620	=cut
1209		1621
1210	our $TLS_CTX;	1622	our $TLS_CTX;
1211		1623
1212	sub TLS_CTX() {	1624	sub TLS_CTX() {
1213	$TLS_CTX || do {	1625	$TLS_CTX ||= do {
1214	require Net::SSLeay;	1626	require AnyEvent::TLS;
1215		1627
1216	Net::SSLeay::load_error_strings ();	1628	new AnyEvent::TLS
1217	Net::SSLeay::SSLeay_add_ssl_algorithms ();
1218	Net::SSLeay::randomize ();
1219
1220	$TLS_CTX = Net::SSLeay::CTX_new ();
1221
1222	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
1223
1224	$TLS_CTX
1225	}	1629	}
1226	}	1630	}
1227		1631
1228	=back	1632	=back
		1633
		1634
		1635	=head1 NONFREQUENTLY ASKED QUESTIONS
		1636
		1637	=over 4
		1638
		1639	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1640	still get further invocations!
		1641
		1642	That's because AnyEvent::Handle keeps a reference to itself when handling
		1643	read or write callbacks.
		1644
		1645	It is only safe to "forget" the reference inside EOF or error callbacks,
		1646	from within all other callbacks, you need to explicitly call the C<<
		1647	->destroy >> method.
		1648
		1649	=item I get different callback invocations in TLS mode/Why can't I pause
		1650	reading?
		1651
		1652	Unlike, say, TCP, TLS connections do not consist of two independent
		1653	communication channels, one for each direction. Or put differently. The
		1654	read and write directions are not independent of each other: you cannot
		1655	write data unless you are also prepared to read, and vice versa.
		1656
		1657	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1658	callback invocations when you are not expecting any read data - the reason
		1659	is that AnyEvent::Handle always reads in TLS mode.
		1660
		1661	During the connection, you have to make sure that you always have a
		1662	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1663	connection (or when you no longer want to use it) you can call the
		1664	C<destroy> method.
		1665
		1666	=item How do I read data until the other side closes the connection?
		1667
		1668	If you just want to read your data into a perl scalar, the easiest way
		1669	to achieve this is by setting an C<on_read> callback that does nothing,
		1670	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1671	will be in C<$_[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
1229		1705
1230	=head1 SUBCLASSING AnyEvent::Handle	1706	=head1 SUBCLASSING AnyEvent::Handle
1231		1707
1232	In many cases, you might want to subclass AnyEvent::Handle.	1708	In many cases, you might want to subclass AnyEvent::Handle.
1233		1709
…		…
1237	=over 4	1713	=over 4
1238		1714
1239	=item * all constructor arguments become object members.	1715	=item * all constructor arguments become object members.
1240		1716
1241	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
1242	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
1243	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).
1244		1720
1245	=item * other object member names are prefixed with an C<_>.	1721	=item * other object member names are prefixed with an C<_>.
1246		1722
1247	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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