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Revision 1.9 by root, Fri May 2 16:07:46 2008 UTC vs.
Revision 1.129 by root, Mon Jun 29 11:04:09 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 = 4.42;
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_error => $cb->($self) [MANDATORY]	82	=item on_eof => $cb->($handle)
76		83
77	This is the fatal error callback, that is called when a fatal error ocurs,	84	Set the callback to be called when an end-of-file condition is detected,
		85	i.e. in the case of a socket, when the other side has closed the
		86	connection cleanly.
		87
		88	For sockets, this just means that the other side has stopped sending data,
		89	you can still try to write data, and, in fact, one can return from the EOF
		90	callback and continue writing data, as only the read part has been shut
		91	down.
		92
		93	While not mandatory, it is I<highly> recommended to set an EOF callback,
		94	otherwise you might end up with a closed socket while you are still
		95	waiting for data.
		96
		97	If an EOF condition has been detected but no C<on_eof> callback has been
		98	set, then a fatal error will be raised with C<$!> set to <0>.
		99
		100	=item on_error => $cb->($handle, $fatal)
		101
		102	This is the error callback, which is called when, well, some error
78	such as not being able to resolve the hostname, failure to connect or a	103	occured, such as not being able to resolve the hostname, failure to
79	read error.	104	connect or a read error.
80		105
81	The object will not be in a usable state when this callback has been	106	Some errors are fatal (which is indicated by C<$fatal> being true). On
82	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.
83		111
		112	Non-fatal errors can be retried by simply returning, but it is recommended
		113	to simply ignore this parameter and instead abondon the handle object
		114	when this callback is invoked. Examples of non-fatal errors are timeouts
		115	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		116
84	On callback entrance, the value of C<$!> contains the opertaing system	117	On callback entrance, the value of C<$!> contains the operating system
85	error (or C<ENOSPC> or C<EPIPE>).	118	error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).
86		119
87	=item on_eof => $cb->($self) [MANDATORY]	120	While not mandatory, it is I<highly> recommended to set this callback, as
		121	you will not be notified of errors otherwise. The default simply calls
		122	C<croak>.
88		123
89	Set the callback to be called on EOF.
90
91	=item on_read => $cb->($self)	124	=item on_read => $cb->($handle)
92		125
93	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
94	and no read request is in the queue. If the read callback is C<undef>	127	and no read request is in the queue (unlike read queue callbacks, this
95	or has never been set, than AnyEvent::Handle will cease reading from the	128	callback will only be called when at least one octet of data is in the
96	filehandle.	129	read buffer).
97		130
98	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 >>
99	method or acces sthe C<$self->{rbuf}> member directly.	132	method or access the C<$handle->{rbuf}> member directly. Note that you
		133	must not enlarge or modify the read buffer, you can only remove data at
		134	the beginning from it.
100		135
101	When an EOF condition is detected then AnyEvent::Handle will first try to	136	When an EOF condition is detected then AnyEvent::Handle will first try to
102	feed all the remaining data to the queued callbacks and C<on_read> before	137	feed all the remaining data to the queued callbacks and C<on_read> before
103	calling the C<on_eof> callback. If no progress can be made, then a fatal	138	calling the C<on_eof> callback. If no progress can be made, then a fatal
104	error will be raised (with C<$!> set to C<EPIPE>).	139	error will be raised (with C<$!> set to C<EPIPE>).
105		140
106	=item on_drain => $cb->()	141	=item on_drain => $cb->($handle)
107		142
108	This sets the callback that is called when the write buffer becomes empty	143	This sets the callback that is called when the write buffer becomes empty
109	(or when the callback is set and the buffer is empty already).	144	(or when the callback is set and the buffer is empty already).
110		145
111	To append to the write buffer, use the C<< ->push_write >> method.	146	To append to the write buffer, use the C<< ->push_write >> method.
112		147
		148	This callback is useful when you don't want to put all of your write data
		149	into the queue at once, for example, when you want to write the contents
		150	of some file to the socket you might not want to read the whole file into
		151	memory and push it into the queue, but instead only read more data from
		152	the file when the write queue becomes empty.
		153
		154	=item timeout => $fractional_seconds
		155
		156	If non-zero, then this enables an "inactivity" timeout: whenever this many
		157	seconds pass without a successful read or write on the underlying file
		158	handle, the C<on_timeout> callback will be invoked (and if that one is
		159	missing, a non-fatal C<ETIMEDOUT> error will be raised).
		160
		161	Note that timeout processing is also active when you currently do not have
		162	any outstanding read or write requests: If you plan to keep the connection
		163	idle then you should disable the timout temporarily or ignore the timeout
		164	in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
		165	restart the timeout.
		166
		167	Zero (the default) disables this timeout.
		168
		169	=item on_timeout => $cb->($handle)
		170
		171	Called whenever the inactivity timeout passes. If you return from this
		172	callback, then the timeout will be reset as if some activity had happened,
		173	so this condition is not fatal in any way.
		174
113	=item rbuf_max => <bytes>	175	=item rbuf_max => <bytes>
114		176
115	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	177	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
116	when the read buffer ever (strictly) exceeds this size. This is useful to	178	when the read buffer ever (strictly) exceeds this size. This is useful to
117	avoid denial-of-service attacks.	179	avoid some forms of denial-of-service attacks.
118		180
119	For example, a server accepting connections from untrusted sources should	181	For example, a server accepting connections from untrusted sources should
120	be configured to accept only so-and-so much data that it cannot act on	182	be configured to accept only so-and-so much data that it cannot act on
121	(for example, when expecting a line, an attacker could send an unlimited	183	(for example, when expecting a line, an attacker could send an unlimited
122	amount of data without a callback ever being called as long as the line	184	amount of data without a callback ever being called as long as the line
123	isn't finished).	185	isn't finished).
124		186
		187	=item autocork => <boolean>
		188
		189	When disabled (the default), then C<push_write> will try to immediately
		190	write the data to the handle, if possible. This avoids having to register
		191	a write watcher and wait for the next event loop iteration, but can
		192	be inefficient if you write multiple small chunks (on the wire, this
		193	disadvantage is usually avoided by your kernel's nagle algorithm, see
		194	C<no_delay>, but this option can save costly syscalls).
		195
		196	When enabled, then writes will always be queued till the next event loop
		197	iteration. This is efficient when you do many small writes per iteration,
		198	but less efficient when you do a single write only per iteration (or when
		199	the write buffer often is full). It also increases write latency.
		200
		201	=item no_delay => <boolean>
		202
		203	When doing small writes on sockets, your operating system kernel might
		204	wait a bit for more data before actually sending it out. This is called
		205	the Nagle algorithm, and usually it is beneficial.
		206
		207	In some situations you want as low a delay as possible, which can be
		208	accomplishd by setting this option to a true value.
		209
		210	The default is your opertaing system's default behaviour (most likely
		211	enabled), this option explicitly enables or disables it, if possible.
		212
125	=item read_size => <bytes>	213	=item read_size => <bytes>
126		214
127	The default read block size (the amount of bytes this module will try to read	215	The default read block size (the amount of bytes this module will
128	on each [loop iteration). Default: C<4096>.	216	try to read during each loop iteration, which affects memory
		217	requirements). Default: C<8192>.
129		218
130	=item low_water_mark => <bytes>	219	=item low_water_mark => <bytes>
131		220
132	Sets the amount of bytes (default: C<0>) that make up an "empty" write	221	Sets the amount of bytes (default: C<0>) that make up an "empty" write
133	buffer: If the write reaches this size or gets even samller it is	222	buffer: If the write reaches this size or gets even samller it is
134	considered empty.	223	considered empty.
135		224
		225	Sometimes it can be beneficial (for performance reasons) to add data to
		226	the write buffer before it is fully drained, but this is a rare case, as
		227	the operating system kernel usually buffers data as well, so the default
		228	is good in almost all cases.
		229
		230	=item linger => <seconds>
		231
		232	If non-zero (default: C<3600>), then the destructor of the
		233	AnyEvent::Handle object will check whether there is still outstanding
		234	write data and will install a watcher that will write this data to the
		235	socket. No errors will be reported (this mostly matches how the operating
		236	system treats outstanding data at socket close time).
		237
		238	This will not work for partial TLS data that could not be encoded
		239	yet. This data will be lost. Calling the C<stoptls> method in time might
		240	help.
		241
		242	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
		243
		244	When this parameter is given, it enables TLS (SSL) mode, that means
		245	AnyEvent will start a TLS handshake as soon as the conenction has been
		246	established and will transparently encrypt/decrypt data afterwards.
		247
		248	TLS mode requires Net::SSLeay to be installed (it will be loaded
		249	automatically when you try to create a TLS handle): this module doesn't
		250	have a dependency on that module, so if your module requires it, you have
		251	to add the dependency yourself.
		252
		253	Unlike TCP, TLS has a server and client side: for the TLS server side, use
		254	C<accept>, and for the TLS client side of a connection, use C<connect>
		255	mode.
		256
		257	You can also provide your own TLS connection object, but you have
		258	to make sure that you call either C<Net::SSLeay::set_connect_state>
		259	or C<Net::SSLeay::set_accept_state> on it before you pass it to
		260	AnyEvent::Handle.
		261
		262	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		263	passing in the wrong integer will lead to certain crash. This most often
		264	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		265	segmentation fault.
		266
		267	See the C<< ->starttls >> method for when need to start TLS negotiation later.
		268
		269	=item tls_ctx => $ssl_ctx
		270
		271	Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
		272	(unless a connection object was specified directly). If this parameter is
		273	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
		274
		275	=item json => JSON or JSON::XS object
		276
		277	This is the json coder object used by the C<json> read and write types.
		278
		279	If you don't supply it, then AnyEvent::Handle will create and use a
		280	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		281	texts.
		282
		283	Note that you are responsible to depend on the JSON module if you want to
		284	use this functionality, as AnyEvent does not have a dependency itself.
		285
136	=back	286	=back
137		287
138	=cut	288	=cut
139		289
140	sub new {	290	sub new {
…		…
144		294
145	$self->{fh} or Carp::croak "mandatory argument fh is missing";	295	$self->{fh} or Carp::croak "mandatory argument fh is missing";
146		296
147	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;	297	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
148		298
149	$self->on_error ((delete $self->{on_error}) or Carp::croak "mandatory argument on_error is missing");	299	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
150	$self->on_eof ((delete $self->{on_eof} ) or Carp::croak "mandatory argument on_eof is missing");	300	if $self->{tls};
151		301
		302	$self->{_activity} = AnyEvent->now;
		303	$self->_timeout;
		304
152	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};	305	$self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
153	$self->on_read (delete $self->{on_read} ) if $self->{on_read};	306	$self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
		307
		308	$self->start_read
		309	if $self->{on_read};
154		310
155	$self	311	$self
156	}	312	}
157		313
158	sub _shutdown {	314	sub _shutdown {
159	my ($self) = @_;	315	my ($self) = @_;
160		316
161	delete $self->{rw};	317	delete @$self{qw(_tw _rw _ww fh rbuf wbuf on_read _queue)};
162	delete $self->{ww};
163	delete $self->{fh};
164	}
165		318
		319	&_freetls;
		320	}
		321
166	sub error {	322	sub _error {
167	my ($self) = @_;	323	my ($self, $errno, $fatal) = @_;
168		324
169	{
170	local $!;
171	$self->_shutdown;	325	$self->_shutdown
172	}	326	if $fatal;
173		327
		328	$! = $errno;
		329
		330	if ($self->{on_error}) {
174	$self->{on_error}($self);	331	$self->{on_error}($self, $fatal);
		332	} elsif ($self->{fh}) {
		333	Carp::croak "AnyEvent::Handle uncaught error: $!";
		334	}
175	}	335	}
176		336
177	=item $fh = $handle->fh	337	=item $fh = $handle->fh
178		338
179	This method returns the filehandle of the L<AnyEvent::Handle> object.	339	This method returns the file handle used to create the L<AnyEvent::Handle> object.
180		340
181	=cut	341	=cut
182		342
183	sub fh { $_[0]->{fh} }	343	sub fh { $_[0]{fh} }
184		344
185	=item $handle->on_error ($cb)	345	=item $handle->on_error ($cb)
186		346
187	Replace the current C<on_error> callback (see the C<on_error> constructor argument).	347	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
188		348
…		…
200		360
201	sub on_eof {	361	sub on_eof {
202	$_[0]{on_eof} = $_[1];	362	$_[0]{on_eof} = $_[1];
203	}	363	}
204		364
		365	=item $handle->on_timeout ($cb)
		366
		367	Replace the current C<on_timeout> callback, or disables the callback (but
		368	not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
		369	argument and method.
		370
		371	=cut
		372
		373	sub on_timeout {
		374	$_[0]{on_timeout} = $_[1];
		375	}
		376
		377	=item $handle->autocork ($boolean)
		378
		379	Enables or disables the current autocork behaviour (see C<autocork>
		380	constructor argument). Changes will only take effect on the next write.
		381
		382	=cut
		383
		384	sub autocork {
		385	$_[0]{autocork} = $_[1];
		386	}
		387
		388	=item $handle->no_delay ($boolean)
		389
		390	Enables or disables the C<no_delay> setting (see constructor argument of
		391	the same name for details).
		392
		393	=cut
		394
		395	sub no_delay {
		396	$_[0]{no_delay} = $_[1];
		397
		398	eval {
		399	local $SIG{__DIE__};
		400	setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
		401	};
		402	}
		403
		404	#############################################################################
		405
		406	=item $handle->timeout ($seconds)
		407
		408	Configures (or disables) the inactivity timeout.
		409
		410	=cut
		411
		412	sub timeout {
		413	my ($self, $timeout) = @_;
		414
		415	$self->{timeout} = $timeout;
		416	$self->_timeout;
		417	}
		418
		419	# reset the timeout watcher, as neccessary
		420	# also check for time-outs
		421	sub _timeout {
		422	my ($self) = @_;
		423
		424	if ($self->{timeout}) {
		425	my $NOW = AnyEvent->now;
		426
		427	# when would the timeout trigger?
		428	my $after = $self->{_activity} + $self->{timeout} - $NOW;
		429
		430	# now or in the past already?
		431	if ($after <= 0) {
		432	$self->{_activity} = $NOW;
		433
		434	if ($self->{on_timeout}) {
		435	$self->{on_timeout}($self);
		436	} else {
		437	$self->_error (&Errno::ETIMEDOUT);
		438	}
		439
		440	# callback could have changed timeout value, optimise
		441	return unless $self->{timeout};
		442
		443	# calculate new after
		444	$after = $self->{timeout};
		445	}
		446
		447	Scalar::Util::weaken $self;
		448	return unless $self; # ->error could have destroyed $self
		449
		450	$self->{_tw} ||= AnyEvent->timer (after => $after, cb => sub {
		451	delete $self->{_tw};
		452	$self->_timeout;
		453	});
		454	} else {
		455	delete $self->{_tw};
		456	}
		457	}
		458
205	#############################################################################	459	#############################################################################
206		460
207	=back	461	=back
208		462
209	=head2 WRITE QUEUE	463	=head2 WRITE QUEUE
…		…
212	for reading.	466	for reading.
213		467
214	The write queue is very simple: you can add data to its end, and	468	The write queue is very simple: you can add data to its end, and
215	AnyEvent::Handle will automatically try to get rid of it for you.	469	AnyEvent::Handle will automatically try to get rid of it for you.
216		470
217	When data could be writtena nd the write buffer is shorter then the low	471	When data could be written and the write buffer is shorter then the low
218	water mark, the C<on_drain> callback will be invoked.	472	water mark, the C<on_drain> callback will be invoked.
219		473
220	=over 4	474	=over 4
221		475
222	=item $handle->on_drain ($cb)	476	=item $handle->on_drain ($cb)
…		…
230	my ($self, $cb) = @_;	484	my ($self, $cb) = @_;
231		485
232	$self->{on_drain} = $cb;	486	$self->{on_drain} = $cb;
233		487
234	$cb->($self)	488	$cb->($self)
235	if $cb && $self->{low_water_mark} >= length $self->{wbuf};	489	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
236	}	490	}
237		491
238	=item $handle->push_write ($data)	492	=item $handle->push_write ($data)
239		493
240	Queues the given scalar to be written. You can push as much data as you	494	Queues the given scalar to be written. You can push as much data as you
241	want (only limited by the available memory), as C<AnyEvent::Handle>	495	want (only limited by the available memory), as C<AnyEvent::Handle>
242	buffers it independently of the kernel.	496	buffers it independently of the kernel.
243		497
244	=cut	498	=cut
245		499
246	sub push_write {	500	sub _drain_wbuf {
247	my ($self, $data) = @_;	501	my ($self) = @_;
248		502
249	$self->{wbuf} .= $data;	503	if (!$self->{_ww} && length $self->{wbuf}) {
250		504
251	unless ($self->{ww}) {
252	Scalar::Util::weaken $self;	505	Scalar::Util::weaken $self;
		506
253	my $cb = sub {	507	my $cb = sub {
254	my $len = syswrite $self->{fh}, $self->{wbuf};	508	my $len = syswrite $self->{fh}, $self->{wbuf};
255		509
256	if ($len > 0) {	510	if ($len >= 0) {
257	substr $self->{wbuf}, 0, $len, "";	511	substr $self->{wbuf}, 0, $len, "";
258		512
		513	$self->{_activity} = AnyEvent->now;
259		514
260	$self->{on_drain}($self)	515	$self->{on_drain}($self)
261	if $self->{low_water_mark} >= length $self->{wbuf}	516	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
262	&& $self->{on_drain};	517	&& $self->{on_drain};
263		518
264	delete $self->{ww} unless length $self->{wbuf};	519	delete $self->{_ww} unless length $self->{wbuf};
265	} elsif ($! != EAGAIN && $! != EINTR) {	520	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
266	$self->error;	521	$self->_error ($!, 1);
267	}	522	}
268	};	523	};
269		524
		525	# try to write data immediately
		526	$cb->() unless $self->{autocork};
		527
		528	# if still data left in wbuf, we need to poll
270	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);	529	$self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
271		530	if length $self->{wbuf};
272	$cb->($self);
273	};	531	};
274	}	532	}
		533
		534	our %WH;
		535
		536	sub register_write_type($$) {
		537	$WH{$_[0]} = $_[1];
		538	}
		539
		540	sub push_write {
		541	my $self = shift;
		542
		543	if (@_ > 1) {
		544	my $type = shift;
		545
		546	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
		547	->($self, @_);
		548	}
		549
		550	if ($self->{tls}) {
		551	$self->{_tls_wbuf} .= $_[0];
		552
		553	&_dotls ($self);
		554	} else {
		555	$self->{wbuf} .= $_[0];
		556	$self->_drain_wbuf;
		557	}
		558	}
		559
		560	=item $handle->push_write (type => @args)
		561
		562	Instead of formatting your data yourself, you can also let this module do
		563	the job by specifying a type and type-specific arguments.
		564
		565	Predefined types are (if you have ideas for additional types, feel free to
		566	drop by and tell us):
		567
		568	=over 4
		569
		570	=item netstring => $string
		571
		572	Formats the given value as netstring
		573	(http://cr.yp.to/proto/netstrings.txt, this is not a recommendation to use them).
		574
		575	=cut
		576
		577	register_write_type netstring => sub {
		578	my ($self, $string) = @_;
		579
		580	(length $string) . ":$string,"
		581	};
		582
		583	=item packstring => $format, $data
		584
		585	An octet string prefixed with an encoded length. The encoding C<$format>
		586	uses the same format as a Perl C<pack> format, but must specify a single
		587	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		588	optional C<!>, C<< < >> or C<< > >> modifier).
		589
		590	=cut
		591
		592	register_write_type packstring => sub {
		593	my ($self, $format, $string) = @_;
		594
		595	pack "$format/a*", $string
		596	};
		597
		598	=item json => $array_or_hashref
		599
		600	Encodes the given hash or array reference into a JSON object. Unless you
		601	provide your own JSON object, this means it will be encoded to JSON text
		602	in UTF-8.
		603
		604	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		605	one end of a handle and read them at the other end without using any
		606	additional framing.
		607
		608	The generated JSON text is guaranteed not to contain any newlines: While
		609	this module doesn't need delimiters after or between JSON texts to be
		610	able to read them, many other languages depend on that.
		611
		612	A simple RPC protocol that interoperates easily with others is to send
		613	JSON arrays (or objects, although arrays are usually the better choice as
		614	they mimic how function argument passing works) and a newline after each
		615	JSON text:
		616
		617	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		618	$handle->push_write ("\012");
		619
		620	An AnyEvent::Handle receiver would simply use the C<json> read type and
		621	rely on the fact that the newline will be skipped as leading whitespace:
		622
		623	$handle->push_read (json => sub { my $array = $_[1]; ... });
		624
		625	Other languages could read single lines terminated by a newline and pass
		626	this line into their JSON decoder of choice.
		627
		628	=cut
		629
		630	register_write_type json => sub {
		631	my ($self, $ref) = @_;
		632
		633	require JSON;
		634
		635	$self->{json} ? $self->{json}->encode ($ref)
		636	: JSON::encode_json ($ref)
		637	};
		638
		639	=item storable => $reference
		640
		641	Freezes the given reference using L<Storable> and writes it to the
		642	handle. Uses the C<nfreeze> format.
		643
		644	=cut
		645
		646	register_write_type storable => sub {
		647	my ($self, $ref) = @_;
		648
		649	require Storable;
		650
		651	pack "w/a*", Storable::nfreeze ($ref)
		652	};
		653
		654	=back
		655
		656	=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
		657
		658	This function (not method) lets you add your own types to C<push_write>.
		659	Whenever the given C<type> is used, C<push_write> will invoke the code
		660	reference with the handle object and the remaining arguments.
		661
		662	The code reference is supposed to return a single octet string that will
		663	be appended to the write buffer.
		664
		665	Note that this is a function, and all types registered this way will be
		666	global, so try to use unique names.
		667
		668	=cut
275		669
276	#############################################################################	670	#############################################################################
277		671
278	=back	672	=back
279		673
…		…
286	ways, the "simple" way, using only C<on_read> and the "complex" way, using	680	ways, the "simple" way, using only C<on_read> and the "complex" way, using
287	a queue.	681	a queue.
288		682
289	In the simple case, you just install an C<on_read> callback and whenever	683	In the simple case, you just install an C<on_read> callback and whenever
290	new data arrives, it will be called. You can then remove some data (if	684	new data arrives, it will be called. You can then remove some data (if
291	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	685	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
292	or not.	686	leave the data there if you want to accumulate more (e.g. when only a
		687	partial message has been received so far).
293		688
294	In the more complex case, you want to queue multiple callbacks. In this	689	In the more complex case, you want to queue multiple callbacks. In this
295	case, AnyEvent::Handle will call the first queued callback each time new	690	case, AnyEvent::Handle will call the first queued callback each time new
296	data arrives and removes it when it has done its job (see C<push_read>,	691	data arrives (also the first time it is queued) and removes it when it has
297	below).	692	done its job (see C<push_read>, below).
298		693
299	This way you can, for example, push three line-reads, followed by reading	694	This way you can, for example, push three line-reads, followed by reading
300	a chunk of data, and AnyEvent::Handle will execute them in order.	695	a chunk of data, and AnyEvent::Handle will execute them in order.
301		696
302	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	697	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
303	the specified number of bytes which give an XML datagram.	698	the specified number of bytes which give an XML datagram.
304		699
305	# in the default state, expect some header bytes	700	# in the default state, expect some header bytes
306	$handle->on_read (sub {	701	$handle->on_read (sub {
307	# some data is here, now queue the length-header-read (4 octets)	702	# some data is here, now queue the length-header-read (4 octets)
308	shift->unshift_read_chunk (4, sub {	703	shift->unshift_read (chunk => 4, sub {
309	# header arrived, decode	704	# header arrived, decode
310	my $len = unpack "N", $_[1];	705	my $len = unpack "N", $_[1];
311		706
312	# now read the payload	707	# now read the payload
313	shift->unshift_read_chunk ($len, sub {	708	shift->unshift_read (chunk => $len, sub {
314	my $xml = $_[1];	709	my $xml = $_[1];
315	# handle xml	710	# handle xml
316	});	711	});
317	});	712	});
318	});	713	});
319		714
320	Example 2: Implement a client for a protocol that replies either with	715	Example 2: Implement a client for a protocol that replies either with "OK"
321	"OK" and another line or "ERROR" for one request, and 64 bytes for the	716	and another line or "ERROR" for the first request that is sent, and 64
322	second request. Due tot he availability of a full queue, we can just	717	bytes for the second request. Due to the availability of a queue, we can
323	pipeline sending both requests and manipulate the queue as necessary in	718	just pipeline sending both requests and manipulate the queue as necessary
324	the callbacks:	719	in the callbacks.
325		720
326	# request one	721	When the first callback is called and sees an "OK" response, it will
		722	C<unshift> another line-read. This line-read will be queued I<before> the
		723	64-byte chunk callback.
		724
		725	# request one, returns either "OK + extra line" or "ERROR"
327	$handle->push_write ("request 1\015\012");	726	$handle->push_write ("request 1\015\012");
328		727
329	# we expect "ERROR" or "OK" as response, so push a line read	728	# we expect "ERROR" or "OK" as response, so push a line read
330	$handle->push_read_line (sub {	729	$handle->push_read (line => sub {
331	# if we got an "OK", we have to _prepend_ another line,	730	# if we got an "OK", we have to _prepend_ another line,
332	# so it will be read before the second request reads its 64 bytes	731	# so it will be read before the second request reads its 64 bytes
333	# which are already in the queue when this callback is called	732	# which are already in the queue when this callback is called
334	# we don't do this in case we got an error	733	# we don't do this in case we got an error
335	if ($_[1] eq "OK") {	734	if ($_[1] eq "OK") {
336	$_[0]->unshift_read_line (sub {	735	$_[0]->unshift_read (line => sub {
337	my $response = $_[1];	736	my $response = $_[1];
338	...	737	...
339	});	738	});
340	}	739	}
341	});	740	});
342		741
343	# request two	742	# request two, simply returns 64 octets
344	$handle->push_write ("request 2\015\012");	743	$handle->push_write ("request 2\015\012");
345		744
346	# simply read 64 bytes, always	745	# simply read 64 bytes, always
347	$handle->push_read_chunk (64, sub {	746	$handle->push_read (chunk => 64, sub {
348	my $response = $_[1];	747	my $response = $_[1];
349	...	748	...
350	});	749	});
351		750
352	=over 4	751	=over 4
353		752
		753	=cut
		754
354	sub _drain_rbuf {	755	sub _drain_rbuf {
355	my ($self) = @_;	756	my ($self) = @_;
356		757
357	return if exists $self->{in_drain};
358	local $self->{in_drain} = 1;	758	local $self->{_in_drain} = 1;
359		759
		760	if (
		761	defined $self->{rbuf_max}
		762	&& $self->{rbuf_max} < length $self->{rbuf}
		763	) {
		764	$self->_error (&Errno::ENOSPC, 1), return;
		765	}
		766
		767	while () {
		768	# we need to use a separate tls read buffer, as we must not receive data while
		769	# we are draining the buffer, and this can only happen with TLS.
		770	$self->{rbuf} .= delete $self->{_tls_rbuf} if exists $self->{_tls_rbuf};
		771
360	while (my $len = length $self->{rbuf}) {	772	my $len = length $self->{rbuf};
361	no strict 'refs';	773
362	if (@{ $self->{queue} }) {	774	if (my $cb = shift @{ $self->{_queue} }) {
363	if ($self->{queue}[0]($self)) {	775	unless ($cb->($self)) {
364	shift @{ $self->{queue} };
365	} elsif ($self->{eof}) {	776	if ($self->{_eof}) {
366	# no progress can be made (not enough data and no data forthcoming)	777	# no progress can be made (not enough data and no data forthcoming)
367	$! = &Errno::EPIPE; return $self->error;	778	$self->_error (&Errno::EPIPE, 1), return;
368	} else {	779	}
		780
		781	unshift @{ $self->{_queue} }, $cb;
369	return;	782	last;
370	}	783	}
371	} elsif ($self->{on_read}) {	784	} elsif ($self->{on_read}) {
		785	last unless $len;
		786
372	$self->{on_read}($self);	787	$self->{on_read}($self);
373		788
374	if (	789	if (
375	$self->{eof} # if no further data will arrive
376	&& $len == length $self->{rbuf} # and no data has been consumed	790	$len == length $self->{rbuf} # if no data has been consumed
377	&& !@{ $self->{queue} } # and the queue is still empty	791	&& !@{ $self->{_queue} } # and the queue is still empty
378	&& $self->{on_read} # and we still want to read data	792	&& $self->{on_read} # but we still have on_read
379	) {	793	) {
		794	# no further data will arrive
380	# then no progress can be made	795	# so no progress can be made
381	$! = &Errno::EPIPE; return $self->error;	796	$self->_error (&Errno::EPIPE, 1), return
		797	if $self->{_eof};
		798
		799	last; # more data might arrive
382	}	800	}
383	} else {	801	} else {
384	# read side becomes idle	802	# read side becomes idle
385	delete $self->{rw};	803	delete $self->{_rw} unless $self->{tls};
386	return;	804	last;
387	}	805	}
388	}	806	}
389		807
390	if ($self->{eof}) {	808	if ($self->{_eof}) {
391	$self->_shutdown;	809	if ($self->{on_eof}) {
392	$self->{on_eof}($self);	810	$self->{on_eof}($self)
		811	} else {
		812	$self->_error (0, 1);
		813	}
		814	}
		815
		816	# may need to restart read watcher
		817	unless ($self->{_rw}) {
		818	$self->start_read
		819	if $self->{on_read} || @{ $self->{_queue} };
393	}	820	}
394	}	821	}
395		822
396	=item $handle->on_read ($cb)	823	=item $handle->on_read ($cb)
397		824
…		…
403		830
404	sub on_read {	831	sub on_read {
405	my ($self, $cb) = @_;	832	my ($self, $cb) = @_;
406		833
407	$self->{on_read} = $cb;	834	$self->{on_read} = $cb;
408		835	$self->_drain_rbuf if $cb && !$self->{_in_drain};
409	unless ($self->{rw} || $self->{eof}) {
410	Scalar::Util::weaken $self;
411
412	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
413	my $len = sysread $self->{fh}, $self->{rbuf}, $self->{read_size} || 8192, length $self->{rbuf};
414
415	if ($len > 0) {
416	if (exists $self->{rbuf_max}) {
417	if ($self->{rbuf_max} < length $self->{rbuf}) {
418	$! = &Errno::ENOSPC; return $self->error;
419	}
420	}
421
422	} elsif (defined $len) {
423	$self->{eof} = 1;
424	delete $self->{rw};
425
426	} elsif ($! != EAGAIN && $! != EINTR) {
427	return $self->error;
428	}
429
430	$self->_drain_rbuf;
431	});
432	}
433	}	836	}
434		837
435	=item $handle->rbuf	838	=item $handle->rbuf
436		839
437	Returns the read buffer (as a modifiable lvalue).	840	Returns the read buffer (as a modifiable lvalue).
438		841
439	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	842	You can access the read buffer directly as the C<< ->{rbuf} >>
440	you want.	843	member, if you want. However, the only operation allowed on the
		844	read buffer (apart from looking at it) is removing data from its
		845	beginning. Otherwise modifying or appending to it is not allowed and will
		846	lead to hard-to-track-down bugs.
441		847
442	NOTE: The read buffer should only be used or modified if the C<on_read>,	848	NOTE: The read buffer should only be used or modified if the C<on_read>,
443	C<push_read> or C<unshift_read> methods are used. The other read methods	849	C<push_read> or C<unshift_read> methods are used. The other read methods
444	automatically manage the read buffer.	850	automatically manage the read buffer.
445		851
…		…
456	Append the given callback to the end of the queue (C<push_read>) or	862	Append the given callback to the end of the queue (C<push_read>) or
457	prepend it (C<unshift_read>).	863	prepend it (C<unshift_read>).
458		864
459	The callback is called each time some additional read data arrives.	865	The callback is called each time some additional read data arrives.
460		866
461	It must check wether enough data is in the read buffer already.	867	It must check whether enough data is in the read buffer already.
462		868
463	If not enough data is available, it must return the empty list or a false	869	If not enough data is available, it must return the empty list or a false
464	value, in which case it will be called repeatedly until enough data is	870	value, in which case it will be called repeatedly until enough data is
465	available (or an error condition is detected).	871	available (or an error condition is detected).
466		872
…		…
468	interested in (which can be none at all) and return a true value. After returning	874	interested in (which can be none at all) and return a true value. After returning
469	true, it will be removed from the queue.	875	true, it will be removed from the queue.
470		876
471	=cut	877	=cut
472		878
		879	our %RH;
		880
		881	sub register_read_type($$) {
		882	$RH{$_[0]} = $_[1];
		883	}
		884
473	sub push_read {	885	sub push_read {
474	my ($self, $cb) = @_;	886	my $self = shift;
		887	my $cb = pop;
475		888
		889	if (@_) {
		890	my $type = shift;
		891
		892	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")
		893	->($self, $cb, @_);
		894	}
		895
476	push @{ $self->{queue} }, $cb;	896	push @{ $self->{_queue} }, $cb;
477	$self->_drain_rbuf;	897	$self->_drain_rbuf unless $self->{_in_drain};
478	}	898	}
479		899
480	sub unshift_read {	900	sub unshift_read {
481	my ($self, $cb) = @_;	901	my $self = shift;
		902	my $cb = pop;
482		903
		904	if (@_) {
		905	my $type = shift;
		906
		907	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")
		908	->($self, $cb, @_);
		909	}
		910
		911
483	push @{ $self->{queue} }, $cb;	912	unshift @{ $self->{_queue} }, $cb;
484	$self->_drain_rbuf;	913	$self->_drain_rbuf unless $self->{_in_drain};
485	}	914	}
486		915
487	=item $handle->push_read_chunk ($len, $cb->($self, $data))	916	=item $handle->push_read (type => @args, $cb)
488		917
489	=item $handle->unshift_read_chunk ($len, $cb->($self, $data))	918	=item $handle->unshift_read (type => @args, $cb)
490		919
491	Append the given callback to the end of the queue (C<push_read_chunk>) or	920	Instead of providing a callback that parses the data itself you can chose
492	prepend it (C<unshift_read_chunk>).	921	between a number of predefined parsing formats, for chunks of data, lines
		922	etc.
493		923
494	The callback will be called only once C<$len> bytes have been read, and	924	Predefined types are (if you have ideas for additional types, feel free to
495	these C<$len> bytes will be passed to the callback.	925	drop by and tell us):
496		926
497	=cut	927	=over 4
498		928
499	sub _read_chunk($$) {	929	=item chunk => $octets, $cb->($handle, $data)
500	my ($len, $cb) = @_;	930
		931	Invoke the callback only once C<$octets> bytes have been read. Pass the
		932	data read to the callback. The callback will never be called with less
		933	data.
		934
		935	Example: read 2 bytes.
		936
		937	$handle->push_read (chunk => 2, sub {
		938	warn "yay ", unpack "H*", $_[1];
		939	});
		940
		941	=cut
		942
		943	register_read_type chunk => sub {
		944	my ($self, $cb, $len) = @_;
501		945
502	sub {	946	sub {
503	$len <= length $_[0]{rbuf} or return;	947	$len <= length $_[0]{rbuf} or return;
504	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	948	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
505	1	949	1
506	}	950	}
507	}	951	};
508		952
509	sub push_read_chunk {	953	=item line => [$eol, ]$cb->($handle, $line, $eol)
510	my ($self, $len, $cb) = @_;
511
512	$self->push_read (_read_chunk $len, $cb);
513	}
514
515
516	sub unshift_read_chunk {
517	my ($self, $len, $cb) = @_;
518
519	$self->unshift_read (_read_chunk $len, $cb);
520	}
521
522	=item $handle->push_read_line ([$eol, ]$cb->($self, $line, $eol))
523
524	=item $handle->unshift_read_line ([$eol, ]$cb->($self, $line, $eol))
525
526	Append the given callback to the end of the queue (C<push_read_line>) or
527	prepend it (C<unshift_read_line>).
528		954
529	The callback will be called only once a full line (including the end of	955	The callback will be called only once a full line (including the end of
530	line marker, C<$eol>) has been read. This line (excluding the end of line	956	line marker, C<$eol>) has been read. This line (excluding the end of line
531	marker) will be passed to the callback as second argument (C<$line>), and	957	marker) will be passed to the callback as second argument (C<$line>), and
532	the end of line marker as the third argument (C<$eol>).	958	the end of line marker as the third argument (C<$eol>).
…		…
543	Partial lines at the end of the stream will never be returned, as they are	969	Partial lines at the end of the stream will never be returned, as they are
544	not marked by the end of line marker.	970	not marked by the end of line marker.
545		971
546	=cut	972	=cut
547		973
548	sub _read_line($$) {	974	register_read_type line => sub {
549	my $cb = pop;	975	my ($self, $cb, $eol) = @_;
550	my $eol = @_ ? shift : qr|(\015?\012)|;
551	my $pos;
552		976
		977	if (@_ < 3) {
		978	# this is more than twice as fast as the generic code below
		979	sub {
		980	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		981
		982	$cb->($_[0], $1, $2);
		983	1
		984	}
		985	} else {
553	$eol = qr|(\Q$eol\E)| unless ref $eol;	986	$eol = quotemeta $eol unless ref $eol;
554	$eol = qr|^(.*?)($eol)|;	987	$eol = qr|^(.*?)($eol)|s;
		988
		989	sub {
		990	$_[0]{rbuf} =~ s/$eol// or return;
		991
		992	$cb->($_[0], $1, $2);
		993	1
		994	}
		995	}
		996	};
		997
		998	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		999
		1000	Makes a regex match against the regex object C<$accept> and returns
		1001	everything up to and including the match.
		1002
		1003	Example: read a single line terminated by '\n'.
		1004
		1005	$handle->push_read (regex => qr<\n>, sub { ... });
		1006
		1007	If C<$reject> is given and not undef, then it determines when the data is
		1008	to be rejected: it is matched against the data when the C<$accept> regex
		1009	does not match and generates an C<EBADMSG> error when it matches. This is
		1010	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1011	receive buffer overflow).
		1012
		1013	Example: expect a single decimal number followed by whitespace, reject
		1014	anything else (not the use of an anchor).
		1015
		1016	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1017
		1018	If C<$skip> is given and not C<undef>, then it will be matched against
		1019	the receive buffer when neither C<$accept> nor C<$reject> match,
		1020	and everything preceding and including the match will be accepted
		1021	unconditionally. This is useful to skip large amounts of data that you
		1022	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1023	have to start matching from the beginning. This is purely an optimisation
		1024	and is usually worth only when you expect more than a few kilobytes.
		1025
		1026	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1027	expect the header to be very large (it isn't in practise, but...), we use
		1028	a skip regex to skip initial portions. The skip regex is tricky in that
		1029	it only accepts something not ending in either \015 or \012, as these are
		1030	required for the accept regex.
		1031
		1032	$handle->push_read (regex =>
		1033	qr<\015\012\015\012>,
		1034	undef, # no reject
		1035	qr<^.*[^\015\012]>,
		1036	sub { ... });
		1037
		1038	=cut
		1039
		1040	register_read_type regex => sub {
		1041	my ($self, $cb, $accept, $reject, $skip) = @_;
		1042
		1043	my $data;
		1044	my $rbuf = \$self->{rbuf};
555		1045
556	sub {	1046	sub {
557	$_[0]{rbuf} =~ s/$eol// or return;	1047	# accept
		1048	if ($$rbuf =~ $accept) {
		1049	$data .= substr $$rbuf, 0, $+[0], "";
		1050	$cb->($self, $data);
		1051	return 1;
		1052	}
		1053
		1054	# reject
		1055	if ($reject && $$rbuf =~ $reject) {
		1056	$self->_error (&Errno::EBADMSG);
		1057	}
558		1058
559	$cb->($1, $2);	1059	# skip
		1060	if ($skip && $$rbuf =~ $skip) {
		1061	$data .= substr $$rbuf, 0, $+[0], "";
		1062	}
		1063
		1064	()
		1065	}
		1066	};
		1067
		1068	=item netstring => $cb->($handle, $string)
		1069
		1070	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
		1071
		1072	Throws an error with C<$!> set to EBADMSG on format violations.
		1073
		1074	=cut
		1075
		1076	register_read_type netstring => sub {
		1077	my ($self, $cb) = @_;
		1078
		1079	sub {
		1080	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
		1081	if ($_[0]{rbuf} =~ /[^0-9]/) {
		1082	$self->_error (&Errno::EBADMSG);
		1083	}
		1084	return;
		1085	}
		1086
		1087	my $len = $1;
		1088
		1089	$self->unshift_read (chunk => $len, sub {
		1090	my $string = $_[1];
		1091	$_[0]->unshift_read (chunk => 1, sub {
		1092	if ($_[1] eq ",") {
		1093	$cb->($_[0], $string);
		1094	} else {
		1095	$self->_error (&Errno::EBADMSG);
		1096	}
		1097	});
		1098	});
		1099
560	1	1100	1
561	}	1101	}
562	}	1102	};
563		1103
564	sub push_read_line {	1104	=item packstring => $format, $cb->($handle, $string)
565	my $self = shift;
566		1105
567	$self->push_read (&_read_line);	1106	An octet string prefixed with an encoded length. The encoding C<$format>
568	}	1107	uses the same format as a Perl C<pack> format, but must specify a single
		1108	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1109	optional C<!>, C<< < >> or C<< > >> modifier).
569		1110
570	sub unshift_read_line {	1111	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
571	my $self = shift;	1112	EPP uses a prefix of C<N> (4 octtes).
572		1113
573	$self->unshift_read (&_read_line);	1114	Example: read a block of data prefixed by its length in BER-encoded
574	}	1115	format (very efficient).
		1116
		1117	$handle->push_read (packstring => "w", sub {
		1118	my ($handle, $data) = @_;
		1119	});
		1120
		1121	=cut
		1122
		1123	register_read_type packstring => sub {
		1124	my ($self, $cb, $format) = @_;
		1125
		1126	sub {
		1127	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1128	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1129	or return;
		1130
		1131	$format = length pack $format, $len;
		1132
		1133	# bypass unshift if we already have the remaining chunk
		1134	if ($format + $len <= length $_[0]{rbuf}) {
		1135	my $data = substr $_[0]{rbuf}, $format, $len;
		1136	substr $_[0]{rbuf}, 0, $format + $len, "";
		1137	$cb->($_[0], $data);
		1138	} else {
		1139	# remove prefix
		1140	substr $_[0]{rbuf}, 0, $format, "";
		1141
		1142	# read remaining chunk
		1143	$_[0]->unshift_read (chunk => $len, $cb);
		1144	}
		1145
		1146	1
		1147	}
		1148	};
		1149
		1150	=item json => $cb->($handle, $hash_or_arrayref)
		1151
		1152	Reads a JSON object or array, decodes it and passes it to the
		1153	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1154
		1155	If a C<json> object was passed to the constructor, then that will be used
		1156	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1157
		1158	This read type uses the incremental parser available with JSON version
		1159	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1160	dependency on your own: this module will load the JSON module, but
		1161	AnyEvent does not depend on it itself.
		1162
		1163	Since JSON texts are fully self-delimiting, the C<json> read and write
		1164	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1165	the C<json> write type description, above, for an actual example.
		1166
		1167	=cut
		1168
		1169	register_read_type json => sub {
		1170	my ($self, $cb) = @_;
		1171
		1172	require JSON;
		1173
		1174	my $data;
		1175	my $rbuf = \$self->{rbuf};
		1176
		1177	my $json = $self->{json} ||= JSON->new->utf8;
		1178
		1179	sub {
		1180	my $ref = eval { $json->incr_parse ($self->{rbuf}) };
		1181
		1182	if ($ref) {
		1183	$self->{rbuf} = $json->incr_text;
		1184	$json->incr_text = "";
		1185	$cb->($self, $ref);
		1186
		1187	1
		1188	} elsif ($@) {
		1189	# error case
		1190	$json->incr_skip;
		1191
		1192	$self->{rbuf} = $json->incr_text;
		1193	$json->incr_text = "";
		1194
		1195	$self->_error (&Errno::EBADMSG);
		1196
		1197	()
		1198	} else {
		1199	$self->{rbuf} = "";
		1200
		1201	()
		1202	}
		1203	}
		1204	};
		1205
		1206	=item storable => $cb->($handle, $ref)
		1207
		1208	Deserialises a L<Storable> frozen representation as written by the
		1209	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1210	data).
		1211
		1212	Raises C<EBADMSG> error if the data could not be decoded.
		1213
		1214	=cut
		1215
		1216	register_read_type storable => sub {
		1217	my ($self, $cb) = @_;
		1218
		1219	require Storable;
		1220
		1221	sub {
		1222	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1223	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1224	or return;
		1225
		1226	my $format = length pack "w", $len;
		1227
		1228	# bypass unshift if we already have the remaining chunk
		1229	if ($format + $len <= length $_[0]{rbuf}) {
		1230	my $data = substr $_[0]{rbuf}, $format, $len;
		1231	substr $_[0]{rbuf}, 0, $format + $len, "";
		1232	$cb->($_[0], Storable::thaw ($data));
		1233	} else {
		1234	# remove prefix
		1235	substr $_[0]{rbuf}, 0, $format, "";
		1236
		1237	# read remaining chunk
		1238	$_[0]->unshift_read (chunk => $len, sub {
		1239	if (my $ref = eval { Storable::thaw ($_[1]) }) {
		1240	$cb->($_[0], $ref);
		1241	} else {
		1242	$self->_error (&Errno::EBADMSG);
		1243	}
		1244	});
		1245	}
		1246
		1247	1
		1248	}
		1249	};
575		1250
576	=back	1251	=back
577		1252
		1253	=item AnyEvent::Handle::register_read_type type => $coderef->($handle, $cb, @args)
		1254
		1255	This function (not method) lets you add your own types to C<push_read>.
		1256
		1257	Whenever the given C<type> is used, C<push_read> will invoke the code
		1258	reference with the handle object, the callback and the remaining
		1259	arguments.
		1260
		1261	The code reference is supposed to return a callback (usually a closure)
		1262	that works as a plain read callback (see C<< ->push_read ($cb) >>).
		1263
		1264	It should invoke the passed callback when it is done reading (remember to
		1265	pass C<$handle> as first argument as all other callbacks do that).
		1266
		1267	Note that this is a function, and all types registered this way will be
		1268	global, so try to use unique names.
		1269
		1270	For examples, see the source of this module (F<perldoc -m AnyEvent::Handle>,
		1271	search for C<register_read_type>)).
		1272
		1273	=item $handle->stop_read
		1274
		1275	=item $handle->start_read
		1276
		1277	In rare cases you actually do not want to read anything from the
		1278	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
		1279	any queued callbacks will be executed then. To start reading again, call
		1280	C<start_read>.
		1281
		1282	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1283	you change the C<on_read> callback or push/unshift a read callback, and it
		1284	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1285	there are any read requests in the queue.
		1286
		1287	These methods will have no effect when in TLS mode (as TLS doesn't support
		1288	half-duplex connections).
		1289
		1290	=cut
		1291
		1292	sub stop_read {
		1293	my ($self) = @_;
		1294
		1295	delete $self->{_rw} unless $self->{tls};
		1296	}
		1297
		1298	sub start_read {
		1299	my ($self) = @_;
		1300
		1301	unless ($self->{_rw} || $self->{_eof}) {
		1302	Scalar::Util::weaken $self;
		1303
		1304	$self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
		1305	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
		1306	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
		1307
		1308	if ($len > 0) {
		1309	$self->{_activity} = AnyEvent->now;
		1310
		1311	if ($self->{tls}) {
		1312	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1313
		1314	&_dotls ($self);
		1315	} else {
		1316	$self->_drain_rbuf unless $self->{_in_drain};
		1317	}
		1318
		1319	} elsif (defined $len) {
		1320	delete $self->{_rw};
		1321	$self->{_eof} = 1;
		1322	$self->_drain_rbuf unless $self->{_in_drain};
		1323
		1324	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		1325	return $self->_error ($!, 1);
		1326	}
		1327	});
		1328	}
		1329	}
		1330
		1331	# poll the write BIO and send the data if applicable
		1332	sub _dotls {
		1333	my ($self) = @_;
		1334
		1335	my $tmp;
		1336
		1337	if (length $self->{_tls_wbuf}) {
		1338	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
		1339	substr $self->{_tls_wbuf}, 0, $tmp, "";
		1340	}
		1341	}
		1342
		1343	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1344	unless (length $tmp) {
		1345	# let's treat SSL-eof as we treat normal EOF
		1346	delete $self->{_rw};
		1347	$self->{_eof} = 1;
		1348	&_freetls;
		1349	}
		1350
		1351	$self->{_tls_rbuf} .= $tmp;
		1352	$self->_drain_rbuf unless $self->{_in_drain};
		1353	$self->{tls} or return; # tls session might have gone away in callback
		1354	}
		1355
		1356	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1357
		1358	if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
		1359	if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
		1360	return $self->_error ($!, 1);
		1361	} elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
		1362	return $self->_error (&Errno::EIO, 1);
		1363	}
		1364
		1365	# all other errors are fine for our purposes
		1366	}
		1367
		1368	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
		1369	$self->{wbuf} .= $tmp;
		1370	$self->_drain_wbuf;
		1371	}
		1372	}
		1373
		1374	=item $handle->starttls ($tls[, $tls_ctx])
		1375
		1376	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
		1377	object is created, you can also do that at a later time by calling
		1378	C<starttls>.
		1379
		1380	The first argument is the same as the C<tls> constructor argument (either
		1381	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
		1382
		1383	The second argument is the optional C<Net::SSLeay::CTX> object that is
		1384	used when AnyEvent::Handle has to create its own TLS connection object.
		1385
		1386	The TLS connection object will end up in C<< $handle->{tls} >> after this
		1387	call and can be used or changed to your liking. Note that the handshake
		1388	might have already started when this function returns.
		1389
		1390	If it an error to start a TLS handshake more than once per
		1391	AnyEvent::Handle object (this is due to bugs in OpenSSL).
		1392
		1393	=cut
		1394
		1395	sub starttls {
		1396	my ($self, $ssl, $ctx) = @_;
		1397
		1398	require Net::SSLeay;
		1399
		1400	Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
		1401	if $self->{tls};
		1402
		1403	if ($ssl eq "accept") {
		1404	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
		1405	Net::SSLeay::set_accept_state ($ssl);
		1406	} elsif ($ssl eq "connect") {
		1407	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
		1408	Net::SSLeay::set_connect_state ($ssl);
		1409	}
		1410
		1411	$self->{tls} = $ssl;
		1412
		1413	# basically, this is deep magic (because SSL_read should have the same issues)
		1414	# but the openssl maintainers basically said: "trust us, it just works".
		1415	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
		1416	# and mismaintained ssleay-module doesn't even offer them).
		1417	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		1418	#
		1419	# in short: this is a mess.
		1420	#
		1421	# note that we do not try to keep the length constant between writes as we are required to do.
		1422	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		1423	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		1424	# have identity issues in that area.
		1425	Net::SSLeay::CTX_set_mode ($self->{tls},
		1426	(eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
		1427	| (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		1428
		1429	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1430	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
		1431
		1432	Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
		1433
		1434	&_dotls; # need to trigger the initial handshake
		1435	$self->start_read; # make sure we actually do read
		1436	}
		1437
		1438	=item $handle->stoptls
		1439
		1440	Shuts down the SSL connection - this makes a proper EOF handshake by
		1441	sending a close notify to the other side, but since OpenSSL doesn't
		1442	support non-blocking shut downs, it is not possible to re-use the stream
		1443	afterwards.
		1444
		1445	=cut
		1446
		1447	sub stoptls {
		1448	my ($self) = @_;
		1449
		1450	if ($self->{tls}) {
		1451	Net::SSLeay::shutdown ($self->{tls});
		1452
		1453	&_dotls;
		1454
		1455	# we don't give a shit. no, we do, but we can't. no...
		1456	# we, we... have to use openssl :/
		1457	&_freetls;
		1458	}
		1459	}
		1460
		1461	sub _freetls {
		1462	my ($self) = @_;
		1463
		1464	return unless $self->{tls};
		1465
		1466	Net::SSLeay::free (delete $self->{tls});
		1467
		1468	delete @$self{qw(_rbio _wbio _tls_wbuf)};
		1469	}
		1470
		1471	sub DESTROY {
		1472	my ($self) = @_;
		1473
		1474	&_freetls;
		1475
		1476	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		1477
		1478	if ($linger && length $self->{wbuf}) {
		1479	my $fh = delete $self->{fh};
		1480	my $wbuf = delete $self->{wbuf};
		1481
		1482	my @linger;
		1483
		1484	push @linger, AnyEvent->io (fh => $fh, poll => "w", cb => sub {
		1485	my $len = syswrite $fh, $wbuf, length $wbuf;
		1486
		1487	if ($len > 0) {
		1488	substr $wbuf, 0, $len, "";
		1489	} else {
		1490	@linger = (); # end
		1491	}
		1492	});
		1493	push @linger, AnyEvent->timer (after => $linger, cb => sub {
		1494	@linger = ();
		1495	});
		1496	}
		1497	}
		1498
		1499	=item $handle->destroy
		1500
		1501	Shuts down the handle object as much as possible - this call ensures that
		1502	no further callbacks will be invoked and resources will be freed as much
		1503	as possible. You must not call any methods on the object afterwards.
		1504
		1505	Normally, you can just "forget" any references to an AnyEvent::Handle
		1506	object and it will simply shut down. This works in fatal error and EOF
		1507	callbacks, as well as code outside. It does I<NOT> work in a read or write
		1508	callback, so when you want to destroy the AnyEvent::Handle object from
		1509	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		1510	that case.
		1511
		1512	The handle might still linger in the background and write out remaining
		1513	data, as specified by the C<linger> option, however.
		1514
		1515	=cut
		1516
		1517	sub destroy {
		1518	my ($self) = @_;
		1519
		1520	$self->DESTROY;
		1521	%$self = ();
		1522	}
		1523
		1524	=item AnyEvent::Handle::TLS_CTX
		1525
		1526	This function creates and returns the Net::SSLeay::CTX object used by
		1527	default for TLS mode.
		1528
		1529	The context is created like this:
		1530
		1531	Net::SSLeay::load_error_strings;
		1532	Net::SSLeay::SSLeay_add_ssl_algorithms;
		1533	Net::SSLeay::randomize;
		1534
		1535	my $CTX = Net::SSLeay::CTX_new;
		1536
		1537	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
		1538
		1539	=cut
		1540
		1541	our $TLS_CTX;
		1542
		1543	sub TLS_CTX() {
		1544	$TLS_CTX || do {
		1545	require Net::SSLeay;
		1546
		1547	Net::SSLeay::load_error_strings ();
		1548	Net::SSLeay::SSLeay_add_ssl_algorithms ();
		1549	Net::SSLeay::randomize ();
		1550
		1551	$TLS_CTX = Net::SSLeay::CTX_new ();
		1552
		1553	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
		1554
		1555	$TLS_CTX
		1556	}
		1557	}
		1558
		1559	=back
		1560
		1561
		1562	=head1 NONFREQUENTLY ASKED QUESTIONS
		1563
		1564	=over 4
		1565
		1566	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		1567	still get further invocations!
		1568
		1569	That's because AnyEvent::Handle keeps a reference to itself when handling
		1570	read or write callbacks.
		1571
		1572	It is only safe to "forget" the reference inside EOF or error callbacks,
		1573	from within all other callbacks, you need to explicitly call the C<<
		1574	->destroy >> method.
		1575
		1576	=item I get different callback invocations in TLS mode/Why can't I pause
		1577	reading?
		1578
		1579	Unlike, say, TCP, TLS connections do not consist of two independent
		1580	communication channels, one for each direction. Or put differently. The
		1581	read and write directions are not independent of each other: you cannot
		1582	write data unless you are also prepared to read, and vice versa.
		1583
		1584	This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
		1585	callback invocations when you are not expecting any read data - the reason
		1586	is that AnyEvent::Handle always reads in TLS mode.
		1587
		1588	During the connection, you have to make sure that you always have a
		1589	non-empty read-queue, or an C<on_read> watcher. At the end of the
		1590	connection (or when you no longer want to use it) you can call the
		1591	C<destroy> method.
		1592
		1593	=item How do I read data until the other side closes the connection?
		1594
		1595	If you just want to read your data into a perl scalar, the easiest way
		1596	to achieve this is by setting an C<on_read> callback that does nothing,
		1597	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		1598	will be in C<$_[0]{rbuf}>:
		1599
		1600	$handle->on_read (sub { });
		1601	$handle->on_eof (undef);
		1602	$handle->on_error (sub {
		1603	my $data = delete $_[0]{rbuf};
		1604	undef $handle;
		1605	});
		1606
		1607	The reason to use C<on_error> is that TCP connections, due to latencies
		1608	and packets loss, might get closed quite violently with an error, when in
		1609	fact, all data has been received.
		1610
		1611	It is usually better to use acknowledgements when transferring data,
		1612	to make sure the other side hasn't just died and you got the data
		1613	intact. This is also one reason why so many internet protocols have an
		1614	explicit QUIT command.
		1615
		1616	=item I don't want to destroy the handle too early - how do I wait until
		1617	all data has been written?
		1618
		1619	After writing your last bits of data, set the C<on_drain> callback
		1620	and destroy the handle in there - with the default setting of
		1621	C<low_water_mark> this will be called precisely when all data has been
		1622	written to the socket:
		1623
		1624	$handle->push_write (...);
		1625	$handle->on_drain (sub {
		1626	warn "all data submitted to the kernel\n";
		1627	undef $handle;
		1628	});
		1629
		1630	=back
		1631
		1632
		1633	=head1 SUBCLASSING AnyEvent::Handle
		1634
		1635	In many cases, you might want to subclass AnyEvent::Handle.
		1636
		1637	To make this easier, a given version of AnyEvent::Handle uses these
		1638	conventions:
		1639
		1640	=over 4
		1641
		1642	=item * all constructor arguments become object members.
		1643
		1644	At least initially, when you pass a C<tls>-argument to the constructor it
		1645	will end up in C<< $handle->{tls} >>. Those members might be changed or
		1646	mutated later on (for example C<tls> will hold the TLS connection object).
		1647
		1648	=item * other object member names are prefixed with an C<_>.
		1649
		1650	All object members not explicitly documented (internal use) are prefixed
		1651	with an underscore character, so the remaining non-C<_>-namespace is free
		1652	for use for subclasses.
		1653
		1654	=item * all members not documented here and not prefixed with an underscore
		1655	are free to use in subclasses.
		1656
		1657	Of course, new versions of AnyEvent::Handle may introduce more "public"
		1658	member variables, but thats just life, at least it is documented.
		1659
		1660	=back
		1661
578	=head1 AUTHOR	1662	=head1 AUTHOR
579		1663
580	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	1664	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
581		1665
582	=cut	1666	=cut

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