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Revision 1.12 by elmex, Thu May 15 09:03:43 2008 UTC vs.
Revision 1.116 by root, Tue Feb 10 14:07:43 2009 UTC

1	package AnyEvent::Handle;	1	package AnyEvent::Handle;
2		2
3	no warnings;	3	no warnings;
4	use strict;	4	use strict qw(subs vars);
5		5
6	use AnyEvent ();	6	use AnyEvent ();
7	use AnyEvent::Util ();	7	use AnyEvent::Util qw(WSAEWOULDBLOCK);
8	use Scalar::Util ();	8	use Scalar::Util ();
9	use Carp ();	9	use Carp ();
10	use Fcntl ();	10	use Fcntl ();
11	use Errno qw/EAGAIN EINTR/;	11	use Errno qw(EAGAIN EINTR);
12		12
13	=head1 NAME	13	=head1 NAME
14		14
15	AnyEvent::Handle - non-blocking I/O on filehandles via AnyEvent	15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
16		16
17	=cut	17	=cut
18		18
19	our $VERSION = '0.02';	19	our $VERSION = 4.331;
20		20
21	=head1 SYNOPSIS	21	=head1 SYNOPSIS
22		22
23	use AnyEvent;	23	use AnyEvent;
24	use AnyEvent::Handle;	24	use AnyEvent::Handle;
25		25
26	my $cv = AnyEvent->condvar;	26	my $cv = AnyEvent->condvar;
27		27
28	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	28	my $handle =
29
30	#TODO
31
32	# or use the constructor to pass the callback:
33
34	my $ae_fh2 =
35	AnyEvent::Handle->new (	29	AnyEvent::Handle->new (
36	fh => \*STDIN,	30	fh => \*STDIN,
37	on_eof => sub {	31	on_eof => sub {
38	$cv->broadcast;	32	$cv->send;
39	},	33	},
40	#TODO
41	);	34	);
42		35
43	$cv->wait;	36	# send some request line
		37	$handle->push_write ("getinfo\015\012");
		38
		39	# read the response line
		40	$handle->push_read (line => sub {
		41	my ($handle, $line) = @_;
		42	warn "read line <$line>\n";
		43	$cv->send;
		44	});
		45
		46	$cv->recv;
44		47
45	=head1 DESCRIPTION	48	=head1 DESCRIPTION
46		49
47	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
48	filehandles (and sockets, see L<AnyEvent::Socket> for an easy way to make	51	filehandles. For utility functions for doing non-blocking connects and accepts
49	non-blocking resolves and connects).	52	on sockets see L<AnyEvent::Util>.
		53
		54	The L<AnyEvent::Intro> tutorial contains some well-documented
		55	AnyEvent::Handle examples.
50		56
51	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
52	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
53	treatment of characters applies to this module as well.	59	treatment of characters applies to this module as well.
54		60
…		…
67		73
68	=item fh => $filehandle [MANDATORY]	74	=item fh => $filehandle [MANDATORY]
69		75
70	The filehandle this L<AnyEvent::Handle> object will operate on.	76	The filehandle this L<AnyEvent::Handle> object will operate on.
71		77
72	NOTE: The filehandle will be set to non-blocking (using	78	NOTE: The filehandle will be set to non-blocking mode (using
73	AnyEvent::Util::fh_nonblocking).	79	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		80	that mode.
74		81
75	=item on_eof => $cb->($self) [MANDATORY]
76
77	Set the callback to be called on EOF.
78
79	=item on_error => $cb->($self)	82	=item on_eof => $cb->($handle)
80		83
		84	Set the callback to be called when an end-of-file condition is detected,
		85	i.e. in the case of a socket, when the other side has closed the
		86	connection cleanly.
		87
		88	For sockets, this just means that the other side has stopped sending data,
		89	you can still try to write data, and, in fact, one can return from the EOF
		90	callback and continue writing data, as only the read part has been shut
		91	down.
		92
		93	While not mandatory, it is I<highly> recommended to set an EOF callback,
		94	otherwise you might end up with a closed socket while you are still
		95	waiting for data.
		96
		97	If an EOF condition has been detected but no C<on_eof> callback has been
		98	set, then a fatal error will be raised with C<$!> set to <0>.
		99
		100	=item on_error => $cb->($handle, $fatal)
		101
81	This is the fatal error callback, that is called when, well, a fatal error	102	This is the error callback, which is called when, well, some error
82	ocurs, such as not being able to resolve the hostname, failure to connect	103	occured, such as not being able to resolve the hostname, failure to
83	or a read error.	104	connect or a read error.
84		105
85	The object will not be in a usable state when this callback has been	106	Some errors are fatal (which is indicated by C<$fatal> being true). On
86	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	Non-fatal errors can be retried by simply returning, but it is recommended
		113	to simply ignore this parameter and instead abondon the handle object
		114	when this callback is invoked. Examples of non-fatal errors are timeouts
		115	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
87		116
88	On callback entrance, the value of C<$!> contains the operating system	117	On callback entrance, the value of C<$!> contains the operating system
89	error (or C<ENOSPC> or C<EPIPE>).	118	error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).
90		119
91	While not mandatory, it is I<highly> recommended to set this callback, as	120	While not mandatory, it is I<highly> recommended to set this callback, as
92	you will not be notified of errors otherwise. The default simply calls	121	you will not be notified of errors otherwise. The default simply calls
93	die.	122	C<croak>.
94		123
95	=item on_read => $cb->($self)	124	=item on_read => $cb->($handle)
96		125
97	This sets the default read callback, which is called when data arrives	126	This sets the default read callback, which is called when data arrives
98	and no read request is in the queue.	127	and no read request is in the queue (unlike read queue callbacks, this
		128	callback will only be called when at least one octet of data is in the
		129	read buffer).
99		130
100	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	131	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
101	method or acces sthe C<$self->{rbuf}> member directly.	132	method or access the C<$handle->{rbuf}> member directly.
102		133
103	When an EOF condition is detected then AnyEvent::Handle will first try to	134	When an EOF condition is detected then AnyEvent::Handle will first try to
104	feed all the remaining data to the queued callbacks and C<on_read> before	135	feed all the remaining data to the queued callbacks and C<on_read> before
105	calling the C<on_eof> callback. If no progress can be made, then a fatal	136	calling the C<on_eof> callback. If no progress can be made, then a fatal
106	error will be raised (with C<$!> set to C<EPIPE>).	137	error will be raised (with C<$!> set to C<EPIPE>).
107		138
108	=item on_drain => $cb->()	139	=item on_drain => $cb->($handle)
109		140
110	This sets the callback that is called when the write buffer becomes empty	141	This sets the callback that is called when the write buffer becomes empty
111	(or when the callback is set and the buffer is empty already).	142	(or when the callback is set and the buffer is empty already).
112		143
113	To append to the write buffer, use the C<< ->push_write >> method.	144	To append to the write buffer, use the C<< ->push_write >> method.
114		145
		146	This callback is useful when you don't want to put all of your write data
		147	into the queue at once, for example, when you want to write the contents
		148	of some file to the socket you might not want to read the whole file into
		149	memory and push it into the queue, but instead only read more data from
		150	the file when the write queue becomes empty.
		151
		152	=item timeout => $fractional_seconds
		153
		154	If non-zero, then this enables an "inactivity" timeout: whenever this many
		155	seconds pass without a successful read or write on the underlying file
		156	handle, the C<on_timeout> callback will be invoked (and if that one is
		157	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		158
		159	Note that timeout processing is also active when you currently do not have
		160	any outstanding read or write requests: If you plan to keep the connection
		161	idle then you should disable the timout temporarily or ignore the timeout
		162	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		163	restart the timeout.
		164
		165	Zero (the default) disables this timeout.
		166
		167	=item on_timeout => $cb->($handle)
		168
		169	Called whenever the inactivity timeout passes. If you return from this
		170	callback, then the timeout will be reset as if some activity had happened,
		171	so this condition is not fatal in any way.
		172
115	=item rbuf_max => <bytes>	173	=item rbuf_max => <bytes>
116		174
117	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	175	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
118	when the read buffer ever (strictly) exceeds this size. This is useful to	176	when the read buffer ever (strictly) exceeds this size. This is useful to
119	avoid denial-of-service attacks.	177	avoid some forms of denial-of-service attacks.
120		178
121	For example, a server accepting connections from untrusted sources should	179	For example, a server accepting connections from untrusted sources should
122	be configured to accept only so-and-so much data that it cannot act on	180	be configured to accept only so-and-so much data that it cannot act on
123	(for example, when expecting a line, an attacker could send an unlimited	181	(for example, when expecting a line, an attacker could send an unlimited
124	amount of data without a callback ever being called as long as the line	182	amount of data without a callback ever being called as long as the line
125	isn't finished).	183	isn't finished).
126		184
		185	=item autocork => <boolean>
		186
		187	When disabled (the default), then C<push_write> will try to immediately
		188	write the data to the handle, if possible. This avoids having to register
		189	a write watcher and wait for the next event loop iteration, but can
		190	be inefficient if you write multiple small chunks (on the wire, this
		191	disadvantage is usually avoided by your kernel's nagle algorithm, see
		192	C<no_delay>, but this option can save costly syscalls).
		193
		194	When enabled, then writes will always be queued till the next event loop
		195	iteration. This is efficient when you do many small writes per iteration,
		196	but less efficient when you do a single write only per iteration (or when
		197	the write buffer often is full). It also increases write latency.
		198
		199	=item no_delay => <boolean>
		200
		201	When doing small writes on sockets, your operating system kernel might
		202	wait a bit for more data before actually sending it out. This is called
		203	the Nagle algorithm, and usually it is beneficial.
		204
		205	In some situations you want as low a delay as possible, which can be
		206	accomplishd by setting this option to a true value.
		207
		208	The default is your opertaing system's default behaviour (most likely
		209	enabled), this option explicitly enables or disables it, if possible.
		210
127	=item read_size => <bytes>	211	=item read_size => <bytes>
128		212
129	The default read block size (the amount of bytes this module will try to read	213	The default read block size (the amount of bytes this module will
130	on each [loop iteration). Default: C<4096>.	214	try to read during each loop iteration, which affects memory
		215	requirements). Default: C<8192>.
131		216
132	=item low_water_mark => <bytes>	217	=item low_water_mark => <bytes>
133		218
134	Sets the amount of bytes (default: C<0>) that make up an "empty" write	219	Sets the amount of bytes (default: C<0>) that make up an "empty" write
135	buffer: If the write reaches this size or gets even samller it is	220	buffer: If the write reaches this size or gets even samller it is
136	considered empty.	221	considered empty.
137		222
		223	Sometimes it can be beneficial (for performance reasons) to add data to
		224	the write buffer before it is fully drained, but this is a rare case, as
		225	the operating system kernel usually buffers data as well, so the default
		226	is good in almost all cases.
		227
		228	=item linger => <seconds>
		229
		230	If non-zero (default: C<3600>), then the destructor of the
		231	AnyEvent::Handle object will check whether there is still outstanding
		232	write data and will install a watcher that will write this data to the
		233	socket. No errors will be reported (this mostly matches how the operating
		234	system treats outstanding data at socket close time).
		235
		236	This will not work for partial TLS data that could not be encoded
		237	yet. This data will be lost. Calling the C<stoptls> method in time might
		238	help.
		239
		240	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		241
		242	When this parameter is given, it enables TLS (SSL) mode, that means
		243	AnyEvent will start a TLS handshake as soon as the conenction has been
		244	established and will transparently encrypt/decrypt data afterwards.
		245
		246	TLS mode requires Net::SSLeay to be installed (it will be loaded
		247	automatically when you try to create a TLS handle): this module doesn't
		248	have a dependency on that module, so if your module requires it, you have
		249	to add the dependency yourself.
		250
		251	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		252	C<accept>, and for the TLS client side of a connection, use C<connect>
		253	mode.
		254
		255	You can also provide your own TLS connection object, but you have
		256	to make sure that you call either C<Net::SSLeay::set_connect_state>
		257	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		258	AnyEvent::Handle.
		259
		260	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		261	passing in the wrong integer will lead to certain crash. This most often
		262	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		263	segmentation fault.
		264
		265	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		266
		267	=item tls_ctx => $ssl_ctx
		268
		269	Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
		270	(unless a connection object was specified directly). If this parameter is
		271	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		272
		273	=item json => JSON or JSON::XS object
		274
		275	This is the json coder object used by the C<json> read and write types.
		276
		277	If you don't supply it, then AnyEvent::Handle will create and use a
		278	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		279	texts.
		280
		281	Note that you are responsible to depend on the JSON module if you want to
		282	use this functionality, as AnyEvent does not have a dependency itself.
		283
138	=back	284	=back
139		285
140	=cut	286	=cut
141		287
142	sub new {	288	sub new {
…		…
146		292
147	$self->{fh} or Carp::croak "mandatory argument fh is missing";	293	$self->{fh} or Carp::croak "mandatory argument fh is missing";
148		294
149	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	295	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
150		296
151	$self->on_eof ((delete $self->{on_eof} ) or Carp::croak "mandatory argument on_eof is missing");	297	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		298	if $self->{tls};
152		299
153	$self->on_error (delete $self->{on_error}) if $self->{on_error};	300	$self->{_activity} = AnyEvent->now;
		301	$self->_timeout;
		302
154	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	303	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
155	$self->on_read (delete $self->{on_read} ) if $self->{on_read};	304	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
156		305
157	$self->start_read;	306	$self->start_read
		307	if $self->{on_read};
158		308
159	$self	309	$self
160	}	310	}
161		311
162	sub _shutdown {	312	sub _shutdown {
163	my ($self) = @_;	313	my ($self) = @_;
164		314
		315	delete $self->{_tw};
165	delete $self->{rw};	316	delete $self->{_rw};
166	delete $self->{ww};	317	delete $self->{_ww};
167	delete $self->{fh};	318	delete $self->{fh};
168	}
169		319
		320	&_freetls;
		321
		322	delete $self->{on_read};
		323	delete $self->{_queue};
		324	}
		325
170	sub error {	326	sub _error {
171	my ($self) = @_;	327	my ($self, $errno, $fatal) = @_;
172		328
173	{
174	local $!;
175	$self->_shutdown;	329	$self->_shutdown
176	}	330	if $fatal;
		331
		332	$! = $errno;
177		333
178	if ($self->{on_error}) {	334	if ($self->{on_error}) {
179	$self->{on_error}($self);	335	$self->{on_error}($self, $fatal);
180	} else {	336	} elsif ($self->{fh}) {
181	die "AnyEvent::Handle uncaught fatal error: $!";	337	Carp::croak "AnyEvent::Handle uncaught error: $!";
182	}	338	}
183	}	339	}
184		340
185	=item $fh = $handle->fh	341	=item $fh = $handle->fh
186		342
187	This method returns the filehandle of the L<AnyEvent::Handle> object.	343	This method returns the file handle used to create the L<AnyEvent::Handle> object.
188		344
189	=cut	345	=cut
190		346
191	sub fh { $_[0]->{fh} }	347	sub fh { $_[0]{fh} }
192		348
193	=item $handle->on_error ($cb)	349	=item $handle->on_error ($cb)
194		350
195	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	351	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
196		352
…		…
208		364
209	sub on_eof {	365	sub on_eof {
210	$_[0]{on_eof} = $_[1];	366	$_[0]{on_eof} = $_[1];
211	}	367	}
212		368
		369	=item $handle->on_timeout ($cb)
		370
		371	Replace the current C<on_timeout> callback, or disables the callback (but
		372	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		373	argument and method.
		374
		375	=cut
		376
		377	sub on_timeout {
		378	$_[0]{on_timeout} = $_[1];
		379	}
		380
		381	=item $handle->autocork ($boolean)
		382
		383	Enables or disables the current autocork behaviour (see C<autocork>
		384	constructor argument). Changes will only take effect on the next write.
		385
		386	=cut
		387
		388	sub autocork {
		389	$_[0]{autocork} = $_[1];
		390	}
		391
		392	=item $handle->no_delay ($boolean)
		393
		394	Enables or disables the C<no_delay> setting (see constructor argument of
		395	the same name for details).
		396
		397	=cut
		398
		399	sub no_delay {
		400	$_[0]{no_delay} = $_[1];
		401
		402	eval {
		403	local $SIG{__DIE__};
		404	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		405	};
		406	}
		407
		408	#############################################################################
		409
		410	=item $handle->timeout ($seconds)
		411
		412	Configures (or disables) the inactivity timeout.
		413
		414	=cut
		415
		416	sub timeout {
		417	my ($self, $timeout) = @_;
		418
		419	$self->{timeout} = $timeout;
		420	$self->_timeout;
		421	}
		422
		423	# reset the timeout watcher, as neccessary
		424	# also check for time-outs
		425	sub _timeout {
		426	my ($self) = @_;
		427
		428	if ($self->{timeout}) {
		429	my $NOW = AnyEvent->now;
		430
		431	# when would the timeout trigger?
		432	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		433
		434	# now or in the past already?
		435	if ($after <= 0) {
		436	$self->{_activity} = $NOW;
		437
		438	if ($self->{on_timeout}) {
		439	$self->{on_timeout}($self);
		440	} else {
		441	$self->_error (&Errno::ETIMEDOUT);
		442	}
		443
		444	# callback could have changed timeout value, optimise
		445	return unless $self->{timeout};
		446
		447	# calculate new after
		448	$after = $self->{timeout};
		449	}
		450
		451	Scalar::Util::weaken $self;
		452	return unless $self; # ->error could have destroyed $self
		453
		454	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		455	delete $self->{_tw};
		456	$self->_timeout;
		457	});
		458	} else {
		459	delete $self->{_tw};
		460	}
		461	}
		462
213	#############################################################################	463	#############################################################################
214		464
215	=back	465	=back
216		466
217	=head2 WRITE QUEUE	467	=head2 WRITE QUEUE
…		…
220	for reading.	470	for reading.
221		471
222	The write queue is very simple: you can add data to its end, and	472	The write queue is very simple: you can add data to its end, and
223	AnyEvent::Handle will automatically try to get rid of it for you.	473	AnyEvent::Handle will automatically try to get rid of it for you.
224		474
225	When data could be writtena nd the write buffer is shorter then the low	475	When data could be written and the write buffer is shorter then the low
226	water mark, the C<on_drain> callback will be invoked.	476	water mark, the C<on_drain> callback will be invoked.
227		477
228	=over 4	478	=over 4
229		479
230	=item $handle->on_drain ($cb)	480	=item $handle->on_drain ($cb)
…		…
238	my ($self, $cb) = @_;	488	my ($self, $cb) = @_;
239		489
240	$self->{on_drain} = $cb;	490	$self->{on_drain} = $cb;
241		491
242	$cb->($self)	492	$cb->($self)
243	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	493	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
244	}	494	}
245		495
246	=item $handle->push_write ($data)	496	=item $handle->push_write ($data)
247		497
248	Queues the given scalar to be written. You can push as much data as you	498	Queues the given scalar to be written. You can push as much data as you
249	want (only limited by the available memory), as C<AnyEvent::Handle>	499	want (only limited by the available memory), as C<AnyEvent::Handle>
250	buffers it independently of the kernel.	500	buffers it independently of the kernel.
251		501
252	=cut	502	=cut
253		503
254	sub push_write {	504	sub _drain_wbuf {
255	my ($self, $data) = @_;	505	my ($self) = @_;
256		506
257	$self->{wbuf} .= $data;	507	if (!$self->{_ww} && length $self->{wbuf}) {
258		508
259	unless ($self->{ww}) {
260	Scalar::Util::weaken $self;	509	Scalar::Util::weaken $self;
		510
261	my $cb = sub {	511	my $cb = sub {
262	my $len = syswrite $self->{fh}, $self->{wbuf};	512	my $len = syswrite $self->{fh}, $self->{wbuf};
263		513
264	if ($len > 0) {	514	if ($len >= 0) {
265	substr $self->{wbuf}, 0, $len, "";	515	substr $self->{wbuf}, 0, $len, "";
266		516
		517	$self->{_activity} = AnyEvent->now;
267		518
268	$self->{on_drain}($self)	519	$self->{on_drain}($self)
269	if $self->{low_water_mark} >= length $self->{wbuf}	520	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
270	&& $self->{on_drain};	521	&& $self->{on_drain};
271		522
272	delete $self->{ww} unless length $self->{wbuf};	523	delete $self->{_ww} unless length $self->{wbuf};
273	} elsif ($! != EAGAIN && $! != EINTR) {	524	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
274	$self->error;	525	$self->_error ($!, 1);
275	}	526	}
276	};	527	};
277		528
		529	# try to write data immediately
		530	$cb->() unless $self->{autocork};
		531
		532	# if still data left in wbuf, we need to poll
278	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	533	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
279		534	if length $self->{wbuf};
280	$cb->($self);
281	};	535	};
282	}	536	}
		537
		538	our %WH;
		539
		540	sub register_write_type($$) {
		541	$WH{$_[0]} = $_[1];
		542	}
		543
		544	sub push_write {
		545	my $self = shift;
		546
		547	if (@_ > 1) {
		548	my $type = shift;
		549
		550	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		551	->($self, @_);
		552	}
		553
		554	if ($self->{tls}) {
		555	$self->{_tls_wbuf} .= $_[0];
		556
		557	&_dotls ($self);
		558	} else {
		559	$self->{wbuf} .= $_[0];
		560	$self->_drain_wbuf;
		561	}
		562	}
		563
		564	=item $handle->push_write (type => @args)
		565
		566	Instead of formatting your data yourself, you can also let this module do
		567	the job by specifying a type and type-specific arguments.
		568
		569	Predefined types are (if you have ideas for additional types, feel free to
		570	drop by and tell us):
		571
		572	=over 4
		573
		574	=item netstring => $string
		575
		576	Formats the given value as netstring
		577	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		578
		579	=cut
		580
		581	register_write_type netstring => sub {
		582	my ($self, $string) = @_;
		583
		584	(length $string) . ":$string,"
		585	};
		586
		587	=item packstring => $format, $data
		588
		589	An octet string prefixed with an encoded length. The encoding C<$format>
		590	uses the same format as a Perl C<pack> format, but must specify a single
		591	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		592	optional C<!>, C<< < >> or C<< > >> modifier).
		593
		594	=cut
		595
		596	register_write_type packstring => sub {
		597	my ($self, $format, $string) = @_;
		598
		599	pack "$format/a*", $string
		600	};
		601
		602	=item json => $array_or_hashref
		603
		604	Encodes the given hash or array reference into a JSON object. Unless you
		605	provide your own JSON object, this means it will be encoded to JSON text
		606	in UTF-8.
		607
		608	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		609	one end of a handle and read them at the other end without using any
		610	additional framing.
		611
		612	The generated JSON text is guaranteed not to contain any newlines: While
		613	this module doesn't need delimiters after or between JSON texts to be
		614	able to read them, many other languages depend on that.
		615
		616	A simple RPC protocol that interoperates easily with others is to send
		617	JSON arrays (or objects, although arrays are usually the better choice as
		618	they mimic how function argument passing works) and a newline after each
		619	JSON text:
		620
		621	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		622	$handle->push_write ("\012");
		623
		624	An AnyEvent::Handle receiver would simply use the C<json> read type and
		625	rely on the fact that the newline will be skipped as leading whitespace:
		626
		627	$handle->push_read (json => sub { my $array = $_[1]; ... });
		628
		629	Other languages could read single lines terminated by a newline and pass
		630	this line into their JSON decoder of choice.
		631
		632	=cut
		633
		634	register_write_type json => sub {
		635	my ($self, $ref) = @_;
		636
		637	require JSON;
		638
		639	$self->{json} ? $self->{json}->encode ($ref)
		640	: JSON::encode_json ($ref)
		641	};
		642
		643	=item storable => $reference
		644
		645	Freezes the given reference using L<Storable> and writes it to the
		646	handle. Uses the C<nfreeze> format.
		647
		648	=cut
		649
		650	register_write_type storable => sub {
		651	my ($self, $ref) = @_;
		652
		653	require Storable;
		654
		655	pack "w/a*", Storable::nfreeze ($ref)
		656	};
		657
		658	=back
		659
		660	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		661
		662	This function (not method) lets you add your own types to C<push_write>.
		663	Whenever the given C<type> is used, C<push_write> will invoke the code
		664	reference with the handle object and the remaining arguments.
		665
		666	The code reference is supposed to return a single octet string that will
		667	be appended to the write buffer.
		668
		669	Note that this is a function, and all types registered this way will be
		670	global, so try to use unique names.
		671
		672	=cut
283		673
284	#############################################################################	674	#############################################################################
285		675
286	=back	676	=back
287		677
…		…
294	ways, the "simple" way, using only C<on_read> and the "complex" way, using	684	ways, the "simple" way, using only C<on_read> and the "complex" way, using
295	a queue.	685	a queue.
296		686
297	In the simple case, you just install an C<on_read> callback and whenever	687	In the simple case, you just install an C<on_read> callback and whenever
298	new data arrives, it will be called. You can then remove some data (if	688	new data arrives, it will be called. You can then remove some data (if
299	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	689	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
300	or not.	690	leave the data there if you want to accumulate more (e.g. when only a
		691	partial message has been received so far).
301		692
302	In the more complex case, you want to queue multiple callbacks. In this	693	In the more complex case, you want to queue multiple callbacks. In this
303	case, AnyEvent::Handle will call the first queued callback each time new	694	case, AnyEvent::Handle will call the first queued callback each time new
304	data arrives and removes it when it has done its job (see C<push_read>,	695	data arrives (also the first time it is queued) and removes it when it has
305	below).	696	done its job (see C<push_read>, below).
306		697
307	This way you can, for example, push three line-reads, followed by reading	698	This way you can, for example, push three line-reads, followed by reading
308	a chunk of data, and AnyEvent::Handle will execute them in order.	699	a chunk of data, and AnyEvent::Handle will execute them in order.
309		700
310	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	701	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
311	the specified number of bytes which give an XML datagram.	702	the specified number of bytes which give an XML datagram.
312		703
313	# in the default state, expect some header bytes	704	# in the default state, expect some header bytes
314	$handle->on_read (sub {	705	$handle->on_read (sub {
315	# some data is here, now queue the length-header-read (4 octets)	706	# some data is here, now queue the length-header-read (4 octets)
316	shift->unshift_read_chunk (4, sub {	707	shift->unshift_read (chunk => 4, sub {
317	# header arrived, decode	708	# header arrived, decode
318	my $len = unpack "N", $_[1];	709	my $len = unpack "N", $_[1];
319		710
320	# now read the payload	711	# now read the payload
321	shift->unshift_read_chunk ($len, sub {	712	shift->unshift_read (chunk => $len, sub {
322	my $xml = $_[1];	713	my $xml = $_[1];
323	# handle xml	714	# handle xml
324	});	715	});
325	});	716	});
326	});	717	});
327		718
328	Example 2: Implement a client for a protocol that replies either with	719	Example 2: Implement a client for a protocol that replies either with "OK"
329	"OK" and another line or "ERROR" for one request, and 64 bytes for the	720	and another line or "ERROR" for the first request that is sent, and 64
330	second request. Due tot he availability of a full queue, we can just	721	bytes for the second request. Due to the availability of a queue, we can
331	pipeline sending both requests and manipulate the queue as necessary in	722	just pipeline sending both requests and manipulate the queue as necessary
332	the callbacks:	723	in the callbacks.
333		724
334	# request one	725	When the first callback is called and sees an "OK" response, it will
		726	C<unshift> another line-read. This line-read will be queued I<before> the
		727	64-byte chunk callback.
		728
		729	# request one, returns either "OK + extra line" or "ERROR"
335	$handle->push_write ("request 1\015\012");	730	$handle->push_write ("request 1\015\012");
336		731
337	# we expect "ERROR" or "OK" as response, so push a line read	732	# we expect "ERROR" or "OK" as response, so push a line read
338	$handle->push_read_line (sub {	733	$handle->push_read (line => sub {
339	# if we got an "OK", we have to _prepend_ another line,	734	# if we got an "OK", we have to _prepend_ another line,
340	# so it will be read before the second request reads its 64 bytes	735	# so it will be read before the second request reads its 64 bytes
341	# which are already in the queue when this callback is called	736	# which are already in the queue when this callback is called
342	# we don't do this in case we got an error	737	# we don't do this in case we got an error
343	if ($_[1] eq "OK") {	738	if ($_[1] eq "OK") {
344	$_[0]->unshift_read_line (sub {	739	$_[0]->unshift_read (line => sub {
345	my $response = $_[1];	740	my $response = $_[1];
346	...	741	...
347	});	742	});
348	}	743	}
349	});	744	});
350		745
351	# request two	746	# request two, simply returns 64 octets
352	$handle->push_write ("request 2\015\012");	747	$handle->push_write ("request 2\015\012");
353		748
354	# simply read 64 bytes, always	749	# simply read 64 bytes, always
355	$handle->push_read_chunk (64, sub {	750	$handle->push_read (chunk => 64, sub {
356	my $response = $_[1];	751	my $response = $_[1];
357	...	752	...
358	});	753	});
359		754
360	=over 4	755	=over 4
…		…
362	=cut	757	=cut
363		758
364	sub _drain_rbuf {	759	sub _drain_rbuf {
365	my ($self) = @_;	760	my ($self) = @_;
366		761
367	return if $self->{in_drain};
368	local $self->{in_drain} = 1;	762	local $self->{_in_drain} = 1;
369		763
		764	if (
		765	defined $self->{rbuf_max}
		766	&& $self->{rbuf_max} < length $self->{rbuf}
		767	) {
		768	$self->_error (&Errno::ENOSPC, 1), return;
		769	}
		770
		771	while () {
		772	$self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
		773
370	while (my $len = length $self->{rbuf}) {	774	my $len = length $self->{rbuf};
371	no strict 'refs';	775
372	if (my $cb = shift @{ $self->{queue} }) {	776	if (my $cb = shift @{ $self->{_queue} }) {
373	if (!$cb->($self)) {	777	unless ($cb->($self)) {
374	if ($self->{eof}) {	778	if ($self->{_eof}) {
375	# no progress can be made (not enough data and no data forthcoming)	779	# no progress can be made (not enough data and no data forthcoming)
376	$! = &Errno::EPIPE; return $self->error;	780	$self->_error (&Errno::EPIPE, 1), return;
377	}	781	}
378		782
379	unshift @{ $self->{queue} }, $cb;	783	unshift @{ $self->{_queue} }, $cb;
380	return;	784	last;
381	}	785	}
382	} elsif ($self->{on_read}) {	786	} elsif ($self->{on_read}) {
		787	last unless $len;
		788
383	$self->{on_read}($self);	789	$self->{on_read}($self);
384		790
385	if (	791	if (
386	$self->{eof} # if no further data will arrive
387	&& $len == length $self->{rbuf} # and no data has been consumed	792	$len == length $self->{rbuf} # if no data has been consumed
388	&& !@{ $self->{queue} } # and the queue is still empty	793	&& !@{ $self->{_queue} } # and the queue is still empty
389	&& $self->{on_read} # and we still want to read data	794	&& $self->{on_read} # but we still have on_read
390	) {	795	) {
		796	# no further data will arrive
391	# then no progress can be made	797	# so no progress can be made
392	$! = &Errno::EPIPE; return $self->error;	798	$self->_error (&Errno::EPIPE, 1), return
		799	if $self->{_eof};
		800
		801	last; # more data might arrive
393	}	802	}
394	} else {	803	} else {
395	# read side becomes idle	804	# read side becomes idle
396	delete $self->{rw};	805	delete $self->{_rw} unless $self->{tls};
397	return;	806	last;
398	}	807	}
399	}	808	}
400		809
401	if ($self->{eof}) {	810	if ($self->{_eof}) {
402	$self->_shutdown;	811	if ($self->{on_eof}) {
403	$self->{on_eof}($self);	812	$self->{on_eof}($self)
		813	} else {
		814	$self->_error (0, 1);
		815	}
		816	}
		817
		818	# may need to restart read watcher
		819	unless ($self->{_rw}) {
		820	$self->start_read
		821	if $self->{on_read} || @{ $self->{_queue} };
404	}	822	}
405	}	823	}
406		824
407	=item $handle->on_read ($cb)	825	=item $handle->on_read ($cb)
408		826
…		…
414		832
415	sub on_read {	833	sub on_read {
416	my ($self, $cb) = @_;	834	my ($self, $cb) = @_;
417		835
418	$self->{on_read} = $cb;	836	$self->{on_read} = $cb;
		837	$self->_drain_rbuf if $cb && !$self->{_in_drain};
419	}	838	}
420		839
421	=item $handle->rbuf	840	=item $handle->rbuf
422		841
423	Returns the read buffer (as a modifiable lvalue).	842	Returns the read buffer (as a modifiable lvalue).
…		…
442	Append the given callback to the end of the queue (C<push_read>) or	861	Append the given callback to the end of the queue (C<push_read>) or
443	prepend it (C<unshift_read>).	862	prepend it (C<unshift_read>).
444		863
445	The callback is called each time some additional read data arrives.	864	The callback is called each time some additional read data arrives.
446		865
447	It must check wether enough data is in the read buffer already.	866	It must check whether enough data is in the read buffer already.
448		867
449	If not enough data is available, it must return the empty list or a false	868	If not enough data is available, it must return the empty list or a false
450	value, in which case it will be called repeatedly until enough data is	869	value, in which case it will be called repeatedly until enough data is
451	available (or an error condition is detected).	870	available (or an error condition is detected).
452		871
…		…
454	interested in (which can be none at all) and return a true value. After returning	873	interested in (which can be none at all) and return a true value. After returning
455	true, it will be removed from the queue.	874	true, it will be removed from the queue.
456		875
457	=cut	876	=cut
458		877
		878	our %RH;
		879
		880	sub register_read_type($$) {
		881	$RH{$_[0]} = $_[1];
		882	}
		883
459	sub push_read {	884	sub push_read {
460	my ($self, $cb) = @_;	885	my $self = shift;
		886	my $cb = pop;
461		887
		888	if (@_) {
		889	my $type = shift;
		890
		891	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		892	->($self, $cb, @_);
		893	}
		894
462	push @{ $self->{queue} }, $cb;	895	push @{ $self->{_queue} }, $cb;
463	$self->_drain_rbuf;	896	$self->_drain_rbuf unless $self->{_in_drain};
464	}	897	}
465		898
466	sub unshift_read {	899	sub unshift_read {
467	my ($self, $cb) = @_;	900	my $self = shift;
		901	my $cb = pop;
468		902
		903	if (@_) {
		904	my $type = shift;
		905
		906	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		907	->($self, $cb, @_);
		908	}
		909
		910
469	push @{ $self->{queue} }, $cb;	911	unshift @{ $self->{_queue} }, $cb;
470	$self->_drain_rbuf;	912	$self->_drain_rbuf unless $self->{_in_drain};
471	}	913	}
472		914
473	=item $handle->push_read_chunk ($len, $cb->($self, $data))	915	=item $handle->push_read (type => @args, $cb)
474		916
475	=item $handle->unshift_read_chunk ($len, $cb->($self, $data))	917	=item $handle->unshift_read (type => @args, $cb)
476		918
477	Append the given callback to the end of the queue (C<push_read_chunk>) or	919	Instead of providing a callback that parses the data itself you can chose
478	prepend it (C<unshift_read_chunk>).	920	between a number of predefined parsing formats, for chunks of data, lines
		921	etc.
479		922
480	The callback will be called only once C<$len> bytes have been read, and	923	Predefined types are (if you have ideas for additional types, feel free to
481	these C<$len> bytes will be passed to the callback.	924	drop by and tell us):
482		925
483	=cut	926	=over 4
484		927
485	sub _read_chunk($$) {	928	=item chunk => $octets, $cb->($handle, $data)
		929
		930	Invoke the callback only once C<$octets> bytes have been read. Pass the
		931	data read to the callback. The callback will never be called with less
		932	data.
		933
		934	Example: read 2 bytes.
		935
		936	$handle->push_read (chunk => 2, sub {
		937	warn "yay ", unpack "H*", $_[1];
		938	});
		939
		940	=cut
		941
		942	register_read_type chunk => sub {
486	my ($self, $len, $cb) = @_;	943	my ($self, $cb, $len) = @_;
487		944
488	sub {	945	sub {
489	$len <= length $_[0]{rbuf} or return;	946	$len <= length $_[0]{rbuf} or return;
490	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	947	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
491	1	948	1
492	}	949	}
493	}	950	};
494		951
495	sub push_read_chunk {	952	=item line => [$eol, ]$cb->($handle, $line, $eol)
496	$_[0]->push_read (&_read_chunk);
497	}
498
499
500	sub unshift_read_chunk {
501	$_[0]->unshift_read (&_read_chunk);
502	}
503
504	=item $handle->push_read_line ([$eol, ]$cb->($self, $line, $eol))
505
506	=item $handle->unshift_read_line ([$eol, ]$cb->($self, $line, $eol))
507
508	Append the given callback to the end of the queue (C<push_read_line>) or
509	prepend it (C<unshift_read_line>).
510		953
511	The callback will be called only once a full line (including the end of	954	The callback will be called only once a full line (including the end of
512	line marker, C<$eol>) has been read. This line (excluding the end of line	955	line marker, C<$eol>) has been read. This line (excluding the end of line
513	marker) will be passed to the callback as second argument (C<$line>), and	956	marker) will be passed to the callback as second argument (C<$line>), and
514	the end of line marker as the third argument (C<$eol>).	957	the end of line marker as the third argument (C<$eol>).
…		…
525	Partial lines at the end of the stream will never be returned, as they are	968	Partial lines at the end of the stream will never be returned, as they are
526	not marked by the end of line marker.	969	not marked by the end of line marker.
527		970
528	=cut	971	=cut
529		972
530	sub _read_line($$) {	973	register_read_type line => sub {
531	my $self = shift;	974	my ($self, $cb, $eol) = @_;
532	my $cb = pop;
533	my $eol = @_ ? shift : qr|(\015?\012)|;
534	my $pos;
535		975
		976	if (@_ < 3) {
		977	# this is more than twice as fast as the generic code below
		978	sub {
		979	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		980
		981	$cb->($_[0], $1, $2);
		982	1
		983	}
		984	} else {
536	$eol = qr|(\Q$eol\E)| unless ref $eol;	985	$eol = quotemeta $eol unless ref $eol;
537	$eol = qr|^(.*?)($eol)|;	986	$eol = qr|^(.*?)($eol)|s;
		987
		988	sub {
		989	$_[0]{rbuf} =~ s/$eol// or return;
		990
		991	$cb->($_[0], $1, $2);
		992	1
		993	}
		994	}
		995	};
		996
		997	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		998
		999	Makes a regex match against the regex object C<$accept> and returns
		1000	everything up to and including the match.
		1001
		1002	Example: read a single line terminated by '\n'.
		1003
		1004	$handle->push_read (regex => qr<\n>, sub { ... });
		1005
		1006	If C<$reject> is given and not undef, then it determines when the data is
		1007	to be rejected: it is matched against the data when the C<$accept> regex
		1008	does not match and generates an C<EBADMSG> error when it matches. This is
		1009	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1010	receive buffer overflow).
		1011
		1012	Example: expect a single decimal number followed by whitespace, reject
		1013	anything else (not the use of an anchor).
		1014
		1015	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1016
		1017	If C<$skip> is given and not C<undef>, then it will be matched against
		1018	the receive buffer when neither C<$accept> nor C<$reject> match,
		1019	and everything preceding and including the match will be accepted
		1020	unconditionally. This is useful to skip large amounts of data that you
		1021	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1022	have to start matching from the beginning. This is purely an optimisation
		1023	and is usually worth only when you expect more than a few kilobytes.
		1024
		1025	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1026	expect the header to be very large (it isn't in practise, but...), we use
		1027	a skip regex to skip initial portions. The skip regex is tricky in that
		1028	it only accepts something not ending in either \015 or \012, as these are
		1029	required for the accept regex.
		1030
		1031	$handle->push_read (regex =>
		1032	qr<\015\012\015\012>,
		1033	undef, # no reject
		1034	qr<^.*[^\015\012]>,
		1035	sub { ... });
		1036
		1037	=cut
		1038
		1039	register_read_type regex => sub {
		1040	my ($self, $cb, $accept, $reject, $skip) = @_;
		1041
		1042	my $data;
		1043	my $rbuf = \$self->{rbuf};
538		1044
539	sub {	1045	sub {
540	$_[0]{rbuf} =~ s/$eol// or return;	1046	# accept
		1047	if ($$rbuf =~ $accept) {
		1048	$data .= substr $$rbuf, 0, $+[0], "";
		1049	$cb->($self, $data);
		1050	return 1;
		1051	}
		1052
		1053	# reject
		1054	if ($reject && $$rbuf =~ $reject) {
		1055	$self->_error (&Errno::EBADMSG);
		1056	}
541		1057
542	$cb->($_[0], $1, $2);	1058	# skip
		1059	if ($skip && $$rbuf =~ $skip) {
		1060	$data .= substr $$rbuf, 0, $+[0], "";
		1061	}
		1062
		1063	()
		1064	}
		1065	};
		1066
		1067	=item netstring => $cb->($handle, $string)
		1068
		1069	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
		1070
		1071	Throws an error with C<$!> set to EBADMSG on format violations.
		1072
		1073	=cut
		1074
		1075	register_read_type netstring => sub {
		1076	my ($self, $cb) = @_;
		1077
		1078	sub {
		1079	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1080	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1081	$self->_error (&Errno::EBADMSG);
		1082	}
		1083	return;
		1084	}
		1085
		1086	my $len = $1;
		1087
		1088	$self->unshift_read (chunk => $len, sub {
		1089	my $string = $_[1];
		1090	$_[0]->unshift_read (chunk => 1, sub {
		1091	if ($_[1] eq ",") {
		1092	$cb->($_[0], $string);
		1093	} else {
		1094	$self->_error (&Errno::EBADMSG);
		1095	}
		1096	});
		1097	});
		1098
543	1	1099	1
544	}	1100	}
545	}	1101	};
546		1102
547	sub push_read_line {	1103	=item packstring => $format, $cb->($handle, $string)
548	$_[0]->push_read (&_read_line);
549	}
550		1104
551	sub unshift_read_line {	1105	An octet string prefixed with an encoded length. The encoding C<$format>
552	$_[0]->unshift_read (&_read_line);	1106	uses the same format as a Perl C<pack> format, but must specify a single
553	}	1107	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1108	optional C<!>, C<< < >> or C<< > >> modifier).
		1109
		1110	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1111	EPP uses a prefix of C<N> (4 octtes).
		1112
		1113	Example: read a block of data prefixed by its length in BER-encoded
		1114	format (very efficient).
		1115
		1116	$handle->push_read (packstring => "w", sub {
		1117	my ($handle, $data) = @_;
		1118	});
		1119
		1120	=cut
		1121
		1122	register_read_type packstring => sub {
		1123	my ($self, $cb, $format) = @_;
		1124
		1125	sub {
		1126	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1127	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1128	or return;
		1129
		1130	$format = length pack $format, $len;
		1131
		1132	# bypass unshift if we already have the remaining chunk
		1133	if ($format + $len <= length $_[0]{rbuf}) {
		1134	my $data = substr $_[0]{rbuf}, $format, $len;
		1135	substr $_[0]{rbuf}, 0, $format + $len, "";
		1136	$cb->($_[0], $data);
		1137	} else {
		1138	# remove prefix
		1139	substr $_[0]{rbuf}, 0, $format, "";
		1140
		1141	# read remaining chunk
		1142	$_[0]->unshift_read (chunk => $len, $cb);
		1143	}
		1144
		1145	1
		1146	}
		1147	};
		1148
		1149	=item json => $cb->($handle, $hash_or_arrayref)
		1150
		1151	Reads a JSON object or array, decodes it and passes it to the
		1152	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1153
		1154	If a C<json> object was passed to the constructor, then that will be used
		1155	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1156
		1157	This read type uses the incremental parser available with JSON version
		1158	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1159	dependency on your own: this module will load the JSON module, but
		1160	AnyEvent does not depend on it itself.
		1161
		1162	Since JSON texts are fully self-delimiting, the C<json> read and write
		1163	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1164	the C<json> write type description, above, for an actual example.
		1165
		1166	=cut
		1167
		1168	register_read_type json => sub {
		1169	my ($self, $cb) = @_;
		1170
		1171	require JSON;
		1172
		1173	my $data;
		1174	my $rbuf = \$self->{rbuf};
		1175
		1176	my $json = $self->{json} ||= JSON->new->utf8;
		1177
		1178	sub {
		1179	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1180
		1181	if ($ref) {
		1182	$self->{rbuf} = $json->incr_text;
		1183	$json->incr_text = "";
		1184	$cb->($self, $ref);
		1185
		1186	1
		1187	} elsif ($@) {
		1188	# error case
		1189	$json->incr_skip;
		1190
		1191	$self->{rbuf} = $json->incr_text;
		1192	$json->incr_text = "";
		1193
		1194	$self->_error (&Errno::EBADMSG);
		1195
		1196	()
		1197	} else {
		1198	$self->{rbuf} = "";
		1199
		1200	()
		1201	}
		1202	}
		1203	};
		1204
		1205	=item storable => $cb->($handle, $ref)
		1206
		1207	Deserialises a L<Storable> frozen representation as written by the
		1208	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1209	data).
		1210
		1211	Raises C<EBADMSG> error if the data could not be decoded.
		1212
		1213	=cut
		1214
		1215	register_read_type storable => sub {
		1216	my ($self, $cb) = @_;
		1217
		1218	require Storable;
		1219
		1220	sub {
		1221	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1222	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1223	or return;
		1224
		1225	my $format = length pack "w", $len;
		1226
		1227	# bypass unshift if we already have the remaining chunk
		1228	if ($format + $len <= length $_[0]{rbuf}) {
		1229	my $data = substr $_[0]{rbuf}, $format, $len;
		1230	substr $_[0]{rbuf}, 0, $format + $len, "";
		1231	$cb->($_[0], Storable::thaw ($data));
		1232	} else {
		1233	# remove prefix
		1234	substr $_[0]{rbuf}, 0, $format, "";
		1235
		1236	# read remaining chunk
		1237	$_[0]->unshift_read (chunk => $len, sub {
		1238	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1239	$cb->($_[0], $ref);
		1240	} else {
		1241	$self->_error (&Errno::EBADMSG);
		1242	}
		1243	});
		1244	}
		1245
		1246	1
		1247	}
		1248	};
		1249
		1250	=back
		1251
		1252	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1253
		1254	This function (not method) lets you add your own types to C<push_read>.
		1255
		1256	Whenever the given C<type> is used, C<push_read> will invoke the code
		1257	reference with the handle object, the callback and the remaining
		1258	arguments.
		1259
		1260	The code reference is supposed to return a callback (usually a closure)
		1261	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1262
		1263	It should invoke the passed callback when it is done reading (remember to
		1264	pass C<$handle> as first argument as all other callbacks do that).
		1265
		1266	Note that this is a function, and all types registered this way will be
		1267	global, so try to use unique names.
		1268
		1269	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1270	search for C<register_read_type>)).
554		1271
555	=item $handle->stop_read	1272	=item $handle->stop_read
556		1273
557	=item $handle->start_read	1274	=item $handle->start_read
558		1275
559	In rare cases you actually do not want to read anything form the	1276	In rare cases you actually do not want to read anything from the
560	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1277	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
561	any queued callbacks will be executed then. To start readign again, call	1278	any queued callbacks will be executed then. To start reading again, call
562	C<start_read>.	1279	C<start_read>.
		1280
		1281	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1282	you change the C<on_read> callback or push/unshift a read callback, and it
		1283	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1284	there are any read requests in the queue.
		1285
		1286	These methods will have no effect when in TLS mode (as TLS doesn't support
		1287	half-duplex connections).
563		1288
564	=cut	1289	=cut
565		1290
566	sub stop_read {	1291	sub stop_read {
567	my ($self) = @_;	1292	my ($self) = @_;
568		1293
569	delete $self->{rw};	1294	delete $self->{_rw} unless $self->{tls};
570	}	1295	}
571		1296
572	sub start_read {	1297	sub start_read {
573	my ($self) = @_;	1298	my ($self) = @_;
574		1299
575	unless ($self->{rw} || $self->{eof}) {	1300	unless ($self->{_rw} || $self->{_eof}) {
576	Scalar::Util::weaken $self;	1301	Scalar::Util::weaken $self;
577		1302
578	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1303	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1304	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
579	my $len = sysread $self->{fh}, $self->{rbuf}, $self->{read_size} || 8192, length $self->{rbuf};	1305	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
580		1306
581	if ($len > 0) {	1307	if ($len > 0) {
582	if (defined $self->{rbuf_max}) {	1308	$self->{_activity} = AnyEvent->now;
583	if ($self->{rbuf_max} < length $self->{rbuf}) {	1309
584	$! = &Errno::ENOSPC; return $self->error;	1310	if ($self->{tls}) {
585	}	1311	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1312
		1313	&_dotls ($self);
		1314	} else {
		1315	$self->_drain_rbuf unless $self->{_in_drain};
586	}	1316	}
587		1317
588	} elsif (defined $len) {	1318	} elsif (defined $len) {
589	$self->{eof} = 1;
590	delete $self->{rw};	1319	delete $self->{_rw};
		1320	$self->{_eof} = 1;
		1321	$self->_drain_rbuf unless $self->{_in_drain};
591		1322
592	} elsif ($! != EAGAIN && $! != EINTR) {	1323	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
593	return $self->error;	1324	return $self->_error ($!, 1);
594	}	1325	}
595
596	$self->_drain_rbuf;
597	});	1326	});
598	}	1327	}
599	}	1328	}
600		1329
		1330	# poll the write BIO and send the data if applicable
		1331	sub _dotls {
		1332	my ($self) = @_;
		1333
		1334	my $tmp;
		1335
		1336	if (length $self->{_tls_wbuf}) {
		1337	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
		1338	substr $self->{_tls_wbuf}, 0, $tmp, "";
		1339	}
		1340	}
		1341
		1342	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1343	unless (length $tmp) {
		1344	# let's treat SSL-eof as we treat normal EOF
		1345	delete $self->{_rw};
		1346	$self->{_eof} = 1;
		1347	&_freetls;
		1348	}
		1349
		1350	$self->{_tls_rbuf} .= $tmp;
		1351	$self->_drain_rbuf unless $self->{_in_drain};
		1352	$self->{tls} or return; # tls session might have gone away in callback
		1353	}
		1354
		1355	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1356
		1357	if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
		1358	if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
		1359	return $self->_error ($!, 1);
		1360	} elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
		1361	return $self->_error (&Errno::EIO, 1);
		1362	}
		1363
		1364	# all other errors are fine for our purposes
		1365	}
		1366
		1367	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1368	$self->{wbuf} .= $tmp;
		1369	$self->_drain_wbuf;
		1370	}
		1371	}
		1372
		1373	=item $handle->starttls ($tls[, $tls_ctx])
		1374
		1375	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1376	object is created, you can also do that at a later time by calling
		1377	C<starttls>.
		1378
		1379	The first argument is the same as the C<tls> constructor argument (either
		1380	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1381
		1382	The second argument is the optional C<Net::SSLeay::CTX> object that is
		1383	used when AnyEvent::Handle has to create its own TLS connection object.
		1384
		1385	The TLS connection object will end up in C<< $handle->{tls} >> after this
		1386	call and can be used or changed to your liking. Note that the handshake
		1387	might have already started when this function returns.
		1388
		1389	If it an error to start a TLS handshake more than once per
		1390	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1391
		1392	=cut
		1393
		1394	sub starttls {
		1395	my ($self, $ssl, $ctx) = @_;
		1396
		1397	require Net::SSLeay;
		1398
		1399	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
		1400	if $self->{tls};
		1401
		1402	if ($ssl eq "accept") {
		1403	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
		1404	Net::SSLeay::set_accept_state ($ssl);
		1405	} elsif ($ssl eq "connect") {
		1406	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
		1407	Net::SSLeay::set_connect_state ($ssl);
		1408	}
		1409
		1410	$self->{tls} = $ssl;
		1411
		1412	# basically, this is deep magic (because SSL_read should have the same issues)
		1413	# but the openssl maintainers basically said: "trust us, it just works".
		1414	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1415	# and mismaintained ssleay-module doesn't even offer them).
		1416	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1417	#
		1418	# in short: this is a mess.
		1419	#
		1420	# note that we do not try to keep the length constant between writes as we are required to do.
		1421	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1422	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1423	# have identity issues in that area.
		1424	Net::SSLeay::CTX_set_mode ($self->{tls},
		1425	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1426	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1427
		1428	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1429	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1430
		1431	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
		1432
		1433	&_dotls; # need to trigger the initial handshake
		1434	$self->start_read; # make sure we actually do read
		1435	}
		1436
		1437	=item $handle->stoptls
		1438
		1439	Shuts down the SSL connection - this makes a proper EOF handshake by
		1440	sending a close notify to the other side, but since OpenSSL doesn't
		1441	support non-blocking shut downs, it is not possible to re-use the stream
		1442	afterwards.
		1443
		1444	=cut
		1445
		1446	sub stoptls {
		1447	my ($self) = @_;
		1448
		1449	if ($self->{tls}) {
		1450	Net::SSLeay::shutdown ($self->{tls});
		1451
		1452	&_dotls;
		1453
		1454	# we don't give a shit. no, we do, but we can't. no...
		1455	# we, we... have to use openssl :/
		1456	&_freetls;
		1457	}
		1458	}
		1459
		1460	sub _freetls {
		1461	my ($self) = @_;
		1462
		1463	return unless $self->{tls};
		1464
		1465	Net::SSLeay::free (delete $self->{tls});
		1466
		1467	delete @$self{qw(_rbio _wbio _tls_wbuf)};
		1468	}
		1469
		1470	sub DESTROY {
		1471	my $self = shift;
		1472
		1473	&_freetls;
		1474
		1475	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1476
		1477	if ($linger && length $self->{wbuf}) {
		1478	my $fh = delete $self->{fh};
		1479	my $wbuf = delete $self->{wbuf};
		1480
		1481	my @linger;
		1482
		1483	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
		1484	my $len = syswrite $fh, $wbuf, length $wbuf;
		1485
		1486	if ($len > 0) {
		1487	substr $wbuf, 0, $len, "";
		1488	} else {
		1489	@linger = (); # end
		1490	}
		1491	});
		1492	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1493	@linger = ();
		1494	});
		1495	}
		1496	}
		1497
		1498	=item $handle->destroy
		1499
		1500	Shuts down the handle object as much as possible - this call ensures that
		1501	no further callbacks will be invoked and resources will be freed as much
		1502	as possible. You must not call any methods on the object afterwards.
		1503
		1504	Normally, you can just "forget" any references to an AnyEvent::Handle
		1505	object and it will simply shut down. This works in fatal error and EOF
		1506	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1507	callback, so when you want to destroy the AnyEvent::Handle object from
		1508	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1509	that case.
		1510
		1511	The handle might still linger in the background and write out remaining
		1512	data, as specified by the C<linger> option, however.
		1513
		1514	=cut
		1515
		1516	sub destroy {
		1517	my ($self) = @_;
		1518
		1519	$self->DESTROY;
		1520	%$self = ();
		1521	}
		1522
		1523	=item AnyEvent::Handle::TLS_CTX
		1524
		1525	This function creates and returns the Net::SSLeay::CTX object used by
		1526	default for TLS mode.
		1527
		1528	The context is created like this:
		1529
		1530	Net::SSLeay::load_error_strings;
		1531	Net::SSLeay::SSLeay_add_ssl_algorithms;
		1532	Net::SSLeay::randomize;
		1533
		1534	my $CTX = Net::SSLeay::CTX_new;
		1535
		1536	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
		1537
		1538	=cut
		1539
		1540	our $TLS_CTX;
		1541
		1542	sub TLS_CTX() {
		1543	$TLS_CTX || do {
		1544	require Net::SSLeay;
		1545
		1546	Net::SSLeay::load_error_strings ();
		1547	Net::SSLeay::SSLeay_add_ssl_algorithms ();
		1548	Net::SSLeay::randomize ();
		1549
		1550	$TLS_CTX = Net::SSLeay::CTX_new ();
		1551
		1552	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
		1553
		1554	$TLS_CTX
		1555	}
		1556	}
		1557
601	=back	1558	=back
602		1559
		1560
		1561	=head1 NONFREQUENTLY ASKED QUESTIONS
		1562
		1563	=over 4
		1564
		1565	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1566	still get further invocations!
		1567
		1568	That's because AnyEvent::Handle keeps a reference to itself when handling
		1569	read or write callbacks.
		1570
		1571	It is only safe to "forget" the reference inside EOF or error callbacks,
		1572	from within all other callbacks, you need to explicitly call the C<<
		1573	->destroy >> method.
		1574
		1575	=item I get different callback invocations in TLS mode/Why can't I pause
		1576	reading?
		1577
		1578	Unlike, say, TCP, TLS connections do not consist of two independent
		1579	communication channels, one for each direction. Or put differently. The
		1580	read and write directions are not independent of each other: you cannot
		1581	write data unless you are also prepared to read, and vice versa.
		1582
		1583	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1584	callback invocations when you are not expecting any read data - the reason
		1585	is that AnyEvent::Handle always reads in TLS mode.
		1586
		1587	During the connection, you have to make sure that you always have a
		1588	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1589	connection (or when you no longer want to use it) you can call the
		1590	C<destroy> method.
		1591
		1592	=item How do I read data until the other side closes the connection?
		1593
		1594	If you just want to read your data into a perl scalar, the easiest way
		1595	to achieve this is by setting an C<on_read> callback that does nothing,
		1596	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1597	will be in C<$_[0]{rbuf}>:
		1598
		1599	$handle->on_read (sub { });
		1600	$handle->on_eof (undef);
		1601	$handle->on_error (sub {
		1602	my $data = delete $_[0]{rbuf};
		1603	undef $handle;
		1604	});
		1605
		1606	The reason to use C<on_error> is that TCP connections, due to latencies
		1607	and packets loss, might get closed quite violently with an error, when in
		1608	fact, all data has been received.
		1609
		1610	It is usually better to use acknowledgements when transferring data,
		1611	to make sure the other side hasn't just died and you got the data
		1612	intact. This is also one reason why so many internet protocols have an
		1613	explicit QUIT command.
		1614
		1615	=item I don't want to destroy the handle too early - how do I wait until
		1616	all data has been written?
		1617
		1618	After writing your last bits of data, set the C<on_drain> callback
		1619	and destroy the handle in there - with the default setting of
		1620	C<low_water_mark> this will be called precisely when all data has been
		1621	written to the socket:
		1622
		1623	$handle->push_write (...);
		1624	$handle->on_drain (sub {
		1625	warn "all data submitted to the kernel\n";
		1626	undef $handle;
		1627	});
		1628
		1629	=back
		1630
		1631
		1632	=head1 SUBCLASSING AnyEvent::Handle
		1633
		1634	In many cases, you might want to subclass AnyEvent::Handle.
		1635
		1636	To make this easier, a given version of AnyEvent::Handle uses these
		1637	conventions:
		1638
		1639	=over 4
		1640
		1641	=item * all constructor arguments become object members.
		1642
		1643	At least initially, when you pass a C<tls>-argument to the constructor it
		1644	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1645	mutated later on (for example C<tls> will hold the TLS connection object).
		1646
		1647	=item * other object member names are prefixed with an C<_>.
		1648
		1649	All object members not explicitly documented (internal use) are prefixed
		1650	with an underscore character, so the remaining non-C<_>-namespace is free
		1651	for use for subclasses.
		1652
		1653	=item * all members not documented here and not prefixed with an underscore
		1654	are free to use in subclasses.
		1655
		1656	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1657	member variables, but thats just life, at least it is documented.
		1658
		1659	=back
		1660
603	=head1 AUTHOR	1661	=head1 AUTHOR
604		1662
605	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	1663	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
606		1664
607	=cut	1665	=cut

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