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Revision 1.233 by root, Thu Apr 5 06:14:10 2012 UTC

1	package AnyEvent::Handle;
2
3	no warnings;
4	use strict;
5
6	use AnyEvent ();
7	use AnyEvent::Util ();
8	use Scalar::Util ();
9	use Carp ();
10	use Fcntl ();
11	use Errno qw/EAGAIN EINTR/;
12
13	=head1 NAME	1	=head1 NAME
14		2
15	AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent	3	AnyEvent::Handle - non-blocking I/O on streaming handles via AnyEvent
16
17	This module is experimental.
18
19	=cut
20
21	our $VERSION = '0.04';
22		4
23	=head1 SYNOPSIS	5	=head1 SYNOPSIS
24		6
25	use AnyEvent;	7	use AnyEvent;
26	use AnyEvent::Handle;	8	use AnyEvent::Handle;
27		9
28	my $cv = AnyEvent->condvar;	10	my $cv = AnyEvent->condvar;
29		11
30	my $ae_fh = AnyEvent::Handle->new (fh => \*STDIN);	12	my $hdl; $hdl = new AnyEvent::Handle
31
32	#TODO
33
34	# or use the constructor to pass the callback:
35
36	my $ae_fh2 =
37	AnyEvent::Handle->new (
38	fh => \*STDIN,	13	fh => \*STDIN,
39	on_eof => sub {	14	on_error => sub {
40	$cv->broadcast;	15	my ($hdl, $fatal, $msg) = @_;
41	},	16	AE::log error => $msg;
42	#TODO	17	$hdl->destroy;
		18	$cv->send;
43	);	19	};
44		20
45	$cv->wait;	21	# send some request line
		22	$hdl->push_write ("getinfo\015\012");
		23
		24	# read the response line
		25	$hdl->push_read (line => sub {
		26	my ($hdl, $line) = @_;
		27	say "got line <$line>";
		28	$cv->send;
		29	});
		30
		31	$cv->recv;
46		32
47	=head1 DESCRIPTION	33	=head1 DESCRIPTION
48		34
49	This module is a helper module to make it easier to do event-based I/O on	35	This is a helper module to make it easier to do event-based I/O on
50	filehandles. For utility functions for doing non-blocking connects and accepts	36	stream-based filehandles (sockets, pipes, and other stream things).
51	on sockets see L<AnyEvent::Util>.
52		37
		38	The L<AnyEvent::Intro> tutorial contains some well-documented
		39	AnyEvent::Handle examples.
		40
53	In the following, when the documentation refers to of "bytes" then this	41	In the following, where the documentation refers to "bytes", it means
54	means characters. As sysread and syswrite are used for all I/O, their	42	characters. As sysread and syswrite are used for all I/O, their
55	treatment of characters applies to this module as well.	43	treatment of characters applies to this module as well.
		44
		45	At the very minimum, you should specify C<fh> or C<connect>, and the
		46	C<on_error> callback.
56		47
57	All callbacks will be invoked with the handle object as their first	48	All callbacks will be invoked with the handle object as their first
58	argument.	49	argument.
59		50
		51	=cut
		52
		53	package AnyEvent::Handle;
		54
		55	use Scalar::Util ();
		56	use List::Util ();
		57	use Carp ();
		58	use Errno qw(EAGAIN EINTR);
		59
		60	use AnyEvent (); BEGIN { AnyEvent::common_sense }
		61	use AnyEvent::Util qw(WSAEWOULDBLOCK);
		62
		63	our $VERSION = $AnyEvent::VERSION;
		64
		65	sub _load_func($) {
		66	my $func = $_[0];
		67
		68	unless (defined &$func) {
		69	my $pkg = $func;
		70	do {
		71	$pkg =~ s/::[^:]+$//
		72	or return;
		73	eval "require $pkg";
		74	} until defined &$func;
		75	}
		76
		77	\&$func
		78	}
		79
		80	sub MAX_READ_SIZE() { 131072 }
		81
60	=head1 METHODS	82	=head1 METHODS
61		83
62	=over 4	84	=over 4
63		85
64	=item B<new (%args)>	86	=item $handle = B<new> AnyEvent::Handle fh => $filehandle, key => value...
65		87
66	The constructor supports these arguments (all as key => value pairs).	88	The constructor supports these arguments (all as C<< key => value >> pairs).
67		89
68	=over 4	90	=over 4
69		91
70	=item fh => $filehandle [MANDATORY]	92	=item fh => $filehandle [C<fh> or C<connect> MANDATORY]
71		93
72	The filehandle this L<AnyEvent::Handle> object will operate on.	94	The filehandle this L<AnyEvent::Handle> object will operate on.
73
74	NOTE: The filehandle will be set to non-blocking (using	95	NOTE: The filehandle will be set to non-blocking mode (using
75	AnyEvent::Util::fh_nonblocking).	96	C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
		97	that mode.
76		98
77	=item on_eof => $cb->($self)	99	=item connect => [$host, $service] [C<fh> or C<connect> MANDATORY]
78		100
79	Set the callback to be called on EOF.	101	Try to connect to the specified host and service (port), using
		102	C<AnyEvent::Socket::tcp_connect>. The C<$host> additionally becomes the
		103	default C<peername>.
80		104
81	While not mandatory, it is highly recommended to set an eof callback,	105	You have to specify either this parameter, or C<fh>, above.
82	otherwise you might end up with a closed socket while you are still
83	waiting for data.
84		106
		107	It is possible to push requests on the read and write queues, and modify
		108	properties of the stream, even while AnyEvent::Handle is connecting.
		109
		110	When this parameter is specified, then the C<on_prepare>,
		111	C<on_connect_error> and C<on_connect> callbacks will be called under the
		112	appropriate circumstances:
		113
		114	=over 4
		115
85	=item on_error => $cb->($self)	116	=item on_prepare => $cb->($handle)
86		117
		118	This (rarely used) callback is called before a new connection is
		119	attempted, but after the file handle has been created (you can access that
		120	file handle via C<< $handle->{fh} >>). It could be used to prepare the
		121	file handle with parameters required for the actual connect (as opposed to
		122	settings that can be changed when the connection is already established).
		123
		124	The return value of this callback should be the connect timeout value in
		125	seconds (or C<0>, or C<undef>, or the empty list, to indicate that the
		126	default timeout is to be used).
		127
		128	=item on_connect => $cb->($handle, $host, $port, $retry->())
		129
		130	This callback is called when a connection has been successfully established.
		131
		132	The peer's numeric host and port (the socket peername) are passed as
		133	parameters, together with a retry callback. At the time it is called the
		134	read and write queues, EOF status, TLS status and similar properties of
		135	the handle will have been reset.
		136
		137	It is not allowed to use the read or write queues while the handle object
		138	is connecting.
		139
		140	If, for some reason, the handle is not acceptable, calling C<$retry> will
		141	continue with the next connection target (in case of multi-homed hosts or
		142	SRV records there can be multiple connection endpoints). The C<$retry>
		143	callback can be invoked after the connect callback returns, i.e. one can
		144	start a handshake and then decide to retry with the next host if the
		145	handshake fails.
		146
		147	In most cases, you should ignore the C<$retry> parameter.
		148
		149	=item on_connect_error => $cb->($handle, $message)
		150
		151	This callback is called when the connection could not be
		152	established. C<$!> will contain the relevant error code, and C<$message> a
		153	message describing it (usually the same as C<"$!">).
		154
		155	If this callback isn't specified, then C<on_error> will be called with a
		156	fatal error instead.
		157
		158	=back
		159
		160	=item on_error => $cb->($handle, $fatal, $message)
		161
87	This is the fatal error callback, that is called when, well, a fatal error	162	This is the error callback, which is called when, well, some error
88	occurs, such as not being able to resolve the hostname, failure to connect	163	occured, such as not being able to resolve the hostname, failure to
89	or a read error.	164	connect, or a read error.
90		165
91	The object will not be in a usable state when this callback has been	166	Some errors are fatal (which is indicated by C<$fatal> being true). On
92	called.	167	fatal errors the handle object will be destroyed (by a call to C<< ->
		168	destroy >>) after invoking the error callback (which means you are free to
		169	examine the handle object). Examples of fatal errors are an EOF condition
		170	with active (but unsatisfiable) read watchers (C<EPIPE>) or I/O errors. In
		171	cases where the other side can close the connection at will, it is
		172	often easiest to not report C<EPIPE> errors in this callback.
93		173
		174	AnyEvent::Handle tries to find an appropriate error code for you to check
		175	against, but in some cases (TLS errors), this does not work well.
		176
		177	If you report the error to the user, it is recommended to always output
		178	the C<$message> argument in human-readable error messages (you don't need
		179	to report C<"$!"> if you report C<$message>).
		180
		181	If you want to react programmatically to the error, then looking at C<$!>
		182	and comparing it against some of the documented C<Errno> values is usually
		183	better than looking at the C<$message>.
		184
		185	Non-fatal errors can be retried by returning, but it is recommended
		186	to simply ignore this parameter and instead abondon the handle object
		187	when this callback is invoked. Examples of non-fatal errors are timeouts
		188	C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
		189
94	On callback entrance, the value of C<$!> contains the operating system	190	On entry to the callback, the value of C<$!> contains the operating
95	error (or C<ENOSPC>, C<EPIPE> or C<EBADMSG>).	191	system error code (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT>, C<EBADMSG> or
		192	C<EPROTO>).
96		193
97	While not mandatory, it is I<highly> recommended to set this callback, as	194	While not mandatory, it is I<highly> recommended to set this callback, as
98	you will not be notified of errors otherwise. The default simply calls	195	you will not be notified of errors otherwise. The default just calls
99	die.	196	C<croak>.
100		197
101	=item on_read => $cb->($self)	198	=item on_read => $cb->($handle)
102		199
103	This sets the default read callback, which is called when data arrives	200	This sets the default read callback, which is called when data arrives
104	and no read request is in the queue.	201	and no read request is in the queue (unlike read queue callbacks, this
		202	callback will only be called when at least one octet of data is in the
		203	read buffer).
105		204
106	To access (and remove data from) the read buffer, use the C<< ->rbuf >>	205	To access (and remove data from) the read buffer, use the C<< ->rbuf >>
107	method or access the C<$self->{rbuf}> member directly.	206	method or access the C<< $handle->{rbuf} >> member directly. Note that you
		207	must not enlarge or modify the read buffer, you can only remove data at
		208	the beginning from it.
108		209
		210	You can also call C<< ->push_read (...) >> or any other function that
		211	modifies the read queue. Or do both. Or ...
		212
109	When an EOF condition is detected then AnyEvent::Handle will first try to	213	When an EOF condition is detected, AnyEvent::Handle will first try to
110	feed all the remaining data to the queued callbacks and C<on_read> before	214	feed all the remaining data to the queued callbacks and C<on_read> before
111	calling the C<on_eof> callback. If no progress can be made, then a fatal	215	calling the C<on_eof> callback. If no progress can be made, then a fatal
112	error will be raised (with C<$!> set to C<EPIPE>).	216	error will be raised (with C<$!> set to C<EPIPE>).
113		217
		218	Note that, unlike requests in the read queue, an C<on_read> callback
		219	doesn't mean you I<require> some data: if there is an EOF and there
		220	are outstanding read requests then an error will be flagged. With an
		221	C<on_read> callback, the C<on_eof> callback will be invoked.
		222
		223	=item on_eof => $cb->($handle)
		224
		225	Set the callback to be called when an end-of-file condition is detected,
		226	i.e. in the case of a socket, when the other side has closed the
		227	connection cleanly, and there are no outstanding read requests in the
		228	queue (if there are read requests, then an EOF counts as an unexpected
		229	connection close and will be flagged as an error).
		230
		231	For sockets, this just means that the other side has stopped sending data,
		232	you can still try to write data, and, in fact, one can return from the EOF
		233	callback and continue writing data, as only the read part has been shut
		234	down.
		235
		236	If an EOF condition has been detected but no C<on_eof> callback has been
		237	set, then a fatal error will be raised with C<$!> set to <0>.
		238
114	=item on_drain => $cb->()	239	=item on_drain => $cb->($handle)
115		240
116	This sets the callback that is called when the write buffer becomes empty	241	This sets the callback that is called once when the write buffer becomes
117	(or when the callback is set and the buffer is empty already).	242	empty (and immediately when the handle object is created).
118		243
119	To append to the write buffer, use the C<< ->push_write >> method.	244	To append to the write buffer, use the C<< ->push_write >> method.
		245
		246	This callback is useful when you don't want to put all of your write data
		247	into the queue at once, for example, when you want to write the contents
		248	of some file to the socket you might not want to read the whole file into
		249	memory and push it into the queue, but instead only read more data from
		250	the file when the write queue becomes empty.
		251
		252	=item timeout => $fractional_seconds
		253
		254	=item rtimeout => $fractional_seconds
		255
		256	=item wtimeout => $fractional_seconds
		257
		258	If non-zero, then these enables an "inactivity" timeout: whenever this
		259	many seconds pass without a successful read or write on the underlying
		260	file handle (or a call to C<timeout_reset>), the C<on_timeout> callback
		261	will be invoked (and if that one is missing, a non-fatal C<ETIMEDOUT>
		262	error will be raised).
		263
		264	There are three variants of the timeouts that work independently of each
		265	other, for both read and write (triggered when nothing was read I<OR>
		266	written), just read (triggered when nothing was read), and just write:
		267	C<timeout>, C<rtimeout> and C<wtimeout>, with corresponding callbacks
		268	C<on_timeout>, C<on_rtimeout> and C<on_wtimeout>, and reset functions
		269	C<timeout_reset>, C<rtimeout_reset>, and C<wtimeout_reset>.
		270
		271	Note that timeout processing is active even when you do not have any
		272	outstanding read or write requests: If you plan to keep the connection
		273	idle then you should disable the timeout temporarily or ignore the
		274	timeout in the corresponding C<on_timeout> callback, in which case
		275	AnyEvent::Handle will simply restart the timeout.
		276
		277	Zero (the default) disables the corresponding timeout.
		278
		279	=item on_timeout => $cb->($handle)
		280
		281	=item on_rtimeout => $cb->($handle)
		282
		283	=item on_wtimeout => $cb->($handle)
		284
		285	Called whenever the inactivity timeout passes. If you return from this
		286	callback, then the timeout will be reset as if some activity had happened,
		287	so this condition is not fatal in any way.
120		288
121	=item rbuf_max => <bytes>	289	=item rbuf_max => <bytes>
122		290
123	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)	291	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
124	when the read buffer ever (strictly) exceeds this size. This is useful to	292	when the read buffer ever (strictly) exceeds this size. This is useful to
125	avoid denial-of-service attacks.	293	avoid some forms of denial-of-service attacks.
126		294
127	For example, a server accepting connections from untrusted sources should	295	For example, a server accepting connections from untrusted sources should
128	be configured to accept only so-and-so much data that it cannot act on	296	be configured to accept only so-and-so much data that it cannot act on
129	(for example, when expecting a line, an attacker could send an unlimited	297	(for example, when expecting a line, an attacker could send an unlimited
130	amount of data without a callback ever being called as long as the line	298	amount of data without a callback ever being called as long as the line
131	isn't finished).	299	isn't finished).
132		300
		301	=item wbuf_max => <bytes>
		302
		303	If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
		304	when the write buffer ever (strictly) exceeds this size. This is useful to
		305	avoid some forms of denial-of-service attacks.
		306
		307	Although the units of this parameter is bytes, this is the I<raw> number
		308	of bytes not yet accepted by the kernel. This can make a difference when
		309	you e.g. use TLS, as TLS typically makes your write data larger (but it
		310	can also make it smaller due to compression).
		311
		312	As an example of when this limit is useful, take a chat server that sends
		313	chat messages to a client. If the client does not read those in a timely
		314	manner then the send buffer in the server would grow unbounded.
		315
		316	=item autocork => <boolean>
		317
		318	When disabled (the default), C<push_write> will try to immediately
		319	write the data to the handle if possible. This avoids having to register
		320	a write watcher and wait for the next event loop iteration, but can
		321	be inefficient if you write multiple small chunks (on the wire, this
		322	disadvantage is usually avoided by your kernel's nagle algorithm, see
		323	C<no_delay>, but this option can save costly syscalls).
		324
		325	When enabled, writes will always be queued till the next event loop
		326	iteration. This is efficient when you do many small writes per iteration,
		327	but less efficient when you do a single write only per iteration (or when
		328	the write buffer often is full). It also increases write latency.
		329
		330	=item no_delay => <boolean>
		331
		332	When doing small writes on sockets, your operating system kernel might
		333	wait a bit for more data before actually sending it out. This is called
		334	the Nagle algorithm, and usually it is beneficial.
		335
		336	In some situations you want as low a delay as possible, which can be
		337	accomplishd by setting this option to a true value.
		338
		339	The default is your operating system's default behaviour (most likely
		340	enabled). This option explicitly enables or disables it, if possible.
		341
		342	=item keepalive => <boolean>
		343
		344	Enables (default disable) the SO_KEEPALIVE option on the stream socket:
		345	normally, TCP connections have no time-out once established, so TCP
		346	connections, once established, can stay alive forever even when the other
		347	side has long gone. TCP keepalives are a cheap way to take down long-lived
		348	TCP connections when the other side becomes unreachable. While the default
		349	is OS-dependent, TCP keepalives usually kick in after around two hours,
		350	and, if the other side doesn't reply, take down the TCP connection some 10
		351	to 15 minutes later.
		352
		353	It is harmless to specify this option for file handles that do not support
		354	keepalives, and enabling it on connections that are potentially long-lived
		355	is usually a good idea.
		356
		357	=item oobinline => <boolean>
		358
		359	BSD majorly fucked up the implementation of TCP urgent data. The result
		360	is that almost no OS implements TCP according to the specs, and every OS
		361	implements it slightly differently.
		362
		363	If you want to handle TCP urgent data, then setting this flag (the default
		364	is enabled) gives you the most portable way of getting urgent data, by
		365	putting it into the stream.
		366
		367	Since BSD emulation of OOB data on top of TCP's urgent data can have
		368	security implications, AnyEvent::Handle sets this flag automatically
		369	unless explicitly specified. Note that setting this flag after
		370	establishing a connection I<may> be a bit too late (data loss could
		371	already have occured on BSD systems), but at least it will protect you
		372	from most attacks.
		373
133	=item read_size => <bytes>	374	=item read_size => <bytes>
134		375
135	The default read block size (the amount of bytes this module will try to read	376	The initial read block size, the number of bytes this module will try
136	on each [loop iteration). Default: C<4096>.	377	to read during each loop iteration. Each handle object will consume
		378	at least this amount of memory for the read buffer as well, so when
		379	handling many connections watch out for memory requirements). See also
		380	C<max_read_size>. Default: C<2048>.
		381
		382	=item max_read_size => <bytes>
		383
		384	The maximum read buffer size used by the dynamic adjustment
		385	algorithm: Each time AnyEvent::Handle can read C<read_size> bytes in
		386	one go it will double C<read_size> up to the maximum given by this
		387	option. Default: C<131072> or C<read_size>, whichever is higher.
137		388
138	=item low_water_mark => <bytes>	389	=item low_water_mark => <bytes>
139		390
140	Sets the amount of bytes (default: C<0>) that make up an "empty" write	391	Sets the number of bytes (default: C<0>) that make up an "empty" write
141	buffer: If the write reaches this size or gets even samller it is	392	buffer: If the buffer reaches this size or gets even samller it is
142	considered empty.	393	considered empty.
143		394
		395	Sometimes it can be beneficial (for performance reasons) to add data to
		396	the write buffer before it is fully drained, but this is a rare case, as
		397	the operating system kernel usually buffers data as well, so the default
		398	is good in almost all cases.
		399
		400	=item linger => <seconds>
		401
		402	If this is non-zero (default: C<3600>), the destructor of the
		403	AnyEvent::Handle object will check whether there is still outstanding
		404	write data and will install a watcher that will write this data to the
		405	socket. No errors will be reported (this mostly matches how the operating
		406	system treats outstanding data at socket close time).
		407
		408	This will not work for partial TLS data that could not be encoded
		409	yet. This data will be lost. Calling the C<stoptls> method in time might
		410	help.
		411
		412	=item peername => $string
		413
		414	A string used to identify the remote site - usually the DNS hostname
		415	(I<not> IDN!) used to create the connection, rarely the IP address.
		416
		417	Apart from being useful in error messages, this string is also used in TLS
		418	peername verification (see C<verify_peername> in L<AnyEvent::TLS>). This
		419	verification will be skipped when C<peername> is not specified or is
		420	C<undef>.
		421
144	=item tls => "accept" | "connect" | Net::SSLeay::SSL object	422	=item tls => "accept" | "connect" | Net::SSLeay::SSL object
145		423
146	When this parameter is given, it enables TLS (SSL) mode, that means it	424	When this parameter is given, it enables TLS (SSL) mode, that means
147	will start making tls handshake and will transparently encrypt/decrypt	425	AnyEvent will start a TLS handshake as soon as the connection has been
148	data.	426	established and will transparently encrypt/decrypt data afterwards.
		427
		428	All TLS protocol errors will be signalled as C<EPROTO>, with an
		429	appropriate error message.
149		430
150	TLS mode requires Net::SSLeay to be installed (it will be loaded	431	TLS mode requires Net::SSLeay to be installed (it will be loaded
151	automatically when you try to create a TLS handle).	432	automatically when you try to create a TLS handle): this module doesn't
		433	have a dependency on that module, so if your module requires it, you have
		434	to add the dependency yourself.
152		435
153	For the TLS server side, use C<accept>, and for the TLS client side of a	436	Unlike TCP, TLS has a server and client side: for the TLS server side, use
154	connection, use C<connect> mode.	437	C<accept>, and for the TLS client side of a connection, use C<connect>
		438	mode.
155		439
156	You can also provide your own TLS connection object, but you have	440	You can also provide your own TLS connection object, but you have
157	to make sure that you call either C<Net::SSLeay::set_connect_state>	441	to make sure that you call either C<Net::SSLeay::set_connect_state>
158	or C<Net::SSLeay::set_accept_state> on it before you pass it to	442	or C<Net::SSLeay::set_accept_state> on it before you pass it to
159	AnyEvent::Handle.	443	AnyEvent::Handle. Also, this module will take ownership of this connection
		444	object.
160		445
		446	At some future point, AnyEvent::Handle might switch to another TLS
		447	implementation, then the option to use your own session object will go
		448	away.
		449
		450	B<IMPORTANT:> since Net::SSLeay "objects" are really only integers,
		451	passing in the wrong integer will lead to certain crash. This most often
		452	happens when one uses a stylish C<< tls => 1 >> and is surprised about the
		453	segmentation fault.
		454
161	See the C<starttls> method if you need to start TLs negotiation later.	455	Use the C<< ->starttls >> method if you need to start TLS negotiation later.
162		456
163	=item tls_ctx => $ssl_ctx	457	=item tls_ctx => $anyevent_tls
164		458
165	Use the given Net::SSLeay::CTX object to create the new TLS connection	459	Use the given C<AnyEvent::TLS> object to create the new TLS connection
166	(unless a connection object was specified directly). If this parameter is	460	(unless a connection object was specified directly). If this
167	missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.	461	parameter is missing (or C<undef>), then AnyEvent::Handle will use
		462	C<AnyEvent::Handle::TLS_CTX>.
		463
		464	Instead of an object, you can also specify a hash reference with C<< key
		465	=> value >> pairs. Those will be passed to L<AnyEvent::TLS> to create a
		466	new TLS context object.
		467
		468	=item on_starttls => $cb->($handle, $success[, $error_message])
		469
		470	This callback will be invoked when the TLS/SSL handshake has finished. If
		471	C<$success> is true, then the TLS handshake succeeded, otherwise it failed
		472	(C<on_stoptls> will not be called in this case).
		473
		474	The session in C<< $handle->{tls} >> can still be examined in this
		475	callback, even when the handshake was not successful.
		476
		477	TLS handshake failures will not cause C<on_error> to be invoked when this
		478	callback is in effect, instead, the error message will be passed to C<on_starttls>.
		479
		480	Without this callback, handshake failures lead to C<on_error> being
		481	called as usual.
		482
		483	Note that you cannot just call C<starttls> again in this callback. If you
		484	need to do that, start an zero-second timer instead whose callback can
		485	then call C<< ->starttls >> again.
		486
		487	=item on_stoptls => $cb->($handle)
		488
		489	When a SSLv3/TLS shutdown/close notify/EOF is detected and this callback is
		490	set, then it will be invoked after freeing the TLS session. If it is not,
		491	then a TLS shutdown condition will be treated like a normal EOF condition
		492	on the handle.
		493
		494	The session in C<< $handle->{tls} >> can still be examined in this
		495	callback.
		496
		497	This callback will only be called on TLS shutdowns, not when the
		498	underlying handle signals EOF.
		499
		500	=item json => JSON or JSON::XS object
		501
		502	This is the json coder object used by the C<json> read and write types.
		503
		504	If you don't supply it, then AnyEvent::Handle will create and use a
		505	suitable one (on demand), which will write and expect UTF-8 encoded JSON
		506	texts.
		507
		508	Note that you are responsible to depend on the JSON module if you want to
		509	use this functionality, as AnyEvent does not have a dependency itself.
168		510
169	=back	511	=back
170		512
171	=cut	513	=cut
172		514
173	our (%RH, %WH);	515	sub new {
		516	my $class = shift;
		517	my $self = bless { @_ }, $class;
174		518
175	sub register_read_type($$) {	519	if ($self->{fh}) {
		520	$self->_start;
		521	return unless $self->{fh}; # could be gone by now
		522
		523	} elsif ($self->{connect}) {
		524	require AnyEvent::Socket;
		525
		526	$self->{peername} = $self->{connect}[0]
		527	unless exists $self->{peername};
		528
		529	$self->{_skip_drain_rbuf} = 1;
		530
		531	{
		532	Scalar::Util::weaken (my $self = $self);
		533
		534	$self->{_connect} =
		535	AnyEvent::Socket::tcp_connect (
		536	$self->{connect}[0],
		537	$self->{connect}[1],
		538	sub {
		539	my ($fh, $host, $port, $retry) = @_;
		540
		541	delete $self->{_connect}; # no longer needed
		542
		543	if ($fh) {
		544	$self->{fh} = $fh;
		545
		546	delete $self->{_skip_drain_rbuf};
		547	$self->_start;
		548
		549	$self->{on_connect}
		550	and $self->{on_connect}($self, $host, $port, sub {
		551	delete @$self{qw(fh _tw _rtw _wtw _ww _rw _eof _queue rbuf _wbuf tls _tls_rbuf _tls_wbuf)};
		552	$self->{_skip_drain_rbuf} = 1;
		553	&$retry;
		554	});
		555
		556	} else {
		557	if ($self->{on_connect_error}) {
		558	$self->{on_connect_error}($self, "$!");
		559	$self->destroy if $self;
		560	} else {
		561	$self->_error ($!, 1);
		562	}
		563	}
		564	},
		565	sub {
		566	local $self->{fh} = $_[0];
		567
		568	$self->{on_prepare}
		569	? $self->{on_prepare}->($self)
		570	: ()
		571	}
		572	);
		573	}
		574
		575	} else {
		576	Carp::croak "AnyEvent::Handle: either an existing fh or the connect parameter must be specified";
		577	}
		578
		579	$self
		580	}
		581
		582	sub _start {
		583	my ($self) = @_;
		584
		585	# too many clueless people try to use udp and similar sockets
		586	# with AnyEvent::Handle, do them a favour.
		587	my $type = getsockopt $self->{fh}, Socket::SOL_SOCKET (), Socket::SO_TYPE ();
		588	Carp::croak "AnyEvent::Handle: only stream sockets supported, anything else will NOT work!"
		589	if Socket::SOCK_STREAM () != (unpack "I", $type) && defined $type;
		590
		591	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
		592
		593	$self->{_activity} =
		594	$self->{_ractivity} =
		595	$self->{_wactivity} = AE::now;
		596
		597	$self->{read_size} ||= 2048;
		598	$self->{max_read_size} = $self->{read_size}
		599	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		600
		601	$self->timeout (delete $self->{timeout} ) if $self->{timeout};
		602	$self->rtimeout (delete $self->{rtimeout} ) if $self->{rtimeout};
		603	$self->wtimeout (delete $self->{wtimeout} ) if $self->{wtimeout};
		604
		605	$self->no_delay (delete $self->{no_delay} ) if exists $self->{no_delay} && $self->{no_delay};
		606	$self->keepalive (delete $self->{keepalive}) if exists $self->{keepalive} && $self->{keepalive};
		607
		608	$self->oobinline (exists $self->{oobinline} ? delete $self->{oobinline} : 1);
		609
		610	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
		611	if $self->{tls};
		612
		613	$self->on_drain (delete $self->{on_drain} ) if $self->{on_drain};
		614
		615	$self->start_read
		616	if $self->{on_read} || @{ $self->{_queue} };
		617
		618	$self->_drain_wbuf;
		619	}
		620
		621	sub _error {
		622	my ($self, $errno, $fatal, $message) = @_;
		623
		624	$! = $errno;
		625	$message ||= "$!";
		626
		627	if ($self->{on_error}) {
		628	$self->{on_error}($self, $fatal, $message);
		629	$self->destroy if $fatal;
		630	} elsif ($self->{fh} || $self->{connect}) {
		631	$self->destroy;
		632	Carp::croak "AnyEvent::Handle uncaught error: $message";
		633	}
		634	}
		635
		636	=item $fh = $handle->fh
		637
		638	This method returns the file handle used to create the L<AnyEvent::Handle> object.
		639
		640	=cut
		641
		642	sub fh { $_[0]{fh} }
		643
		644	=item $handle->on_error ($cb)
		645
		646	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
		647
		648	=cut
		649
		650	sub on_error {
		651	$_[0]{on_error} = $_[1];
		652	}
		653
		654	=item $handle->on_eof ($cb)
		655
		656	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
		657
		658	=cut
		659
		660	sub on_eof {
176	$RH{$_[0]} = $_[1];	661	$_[0]{on_eof} = $_[1];
177	}	662	}
178		663
		664	=item $handle->on_timeout ($cb)
		665
		666	=item $handle->on_rtimeout ($cb)
		667
		668	=item $handle->on_wtimeout ($cb)
		669
		670	Replace the current C<on_timeout>, C<on_rtimeout> or C<on_wtimeout>
		671	callback, or disables the callback (but not the timeout) if C<$cb> =
		672	C<undef>. See the C<timeout> constructor argument and method.
		673
		674	=cut
		675
		676	# see below
		677
		678	=item $handle->autocork ($boolean)
		679
		680	Enables or disables the current autocork behaviour (see C<autocork>
		681	constructor argument). Changes will only take effect on the next write.
		682
		683	=cut
		684
		685	sub autocork {
		686	$_[0]{autocork} = $_[1];
		687	}
		688
		689	=item $handle->no_delay ($boolean)
		690
		691	Enables or disables the C<no_delay> setting (see constructor argument of
		692	the same name for details).
		693
		694	=cut
		695
		696	sub no_delay {
		697	$_[0]{no_delay} = $_[1];
		698
		699	setsockopt $_[0]{fh}, Socket::IPPROTO_TCP (), Socket::TCP_NODELAY (), int $_[1]
		700	if $_[0]{fh};
		701	}
		702
		703	=item $handle->keepalive ($boolean)
		704
		705	Enables or disables the C<keepalive> setting (see constructor argument of
		706	the same name for details).
		707
		708	=cut
		709
		710	sub keepalive {
		711	$_[0]{keepalive} = $_[1];
		712
		713	eval {
		714	local $SIG{__DIE__};
		715	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		716	if $_[0]{fh};
		717	};
		718	}
		719
		720	=item $handle->oobinline ($boolean)
		721
		722	Enables or disables the C<oobinline> setting (see constructor argument of
		723	the same name for details).
		724
		725	=cut
		726
		727	sub oobinline {
		728	$_[0]{oobinline} = $_[1];
		729
		730	eval {
		731	local $SIG{__DIE__};
		732	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_OOBINLINE (), int $_[1]
		733	if $_[0]{fh};
		734	};
		735	}
		736
		737	=item $handle->keepalive ($boolean)
		738
		739	Enables or disables the C<keepalive> setting (see constructor argument of
		740	the same name for details).
		741
		742	=cut
		743
		744	sub keepalive {
		745	$_[0]{keepalive} = $_[1];
		746
		747	eval {
		748	local $SIG{__DIE__};
		749	setsockopt $_[0]{fh}, Socket::SOL_SOCKET (), Socket::SO_KEEPALIVE (), int $_[1]
		750	if $_[0]{fh};
		751	};
		752	}
		753
		754	=item $handle->on_starttls ($cb)
		755
		756	Replace the current C<on_starttls> callback (see the C<on_starttls> constructor argument).
		757
		758	=cut
		759
		760	sub on_starttls {
		761	$_[0]{on_starttls} = $_[1];
		762	}
		763
		764	=item $handle->on_stoptls ($cb)
		765
		766	Replace the current C<on_stoptls> callback (see the C<on_stoptls> constructor argument).
		767
		768	=cut
		769
		770	sub on_stoptls {
		771	$_[0]{on_stoptls} = $_[1];
		772	}
		773
		774	=item $handle->rbuf_max ($max_octets)
		775
		776	Configures the C<rbuf_max> setting (C<undef> disables it).
		777
		778	=item $handle->wbuf_max ($max_octets)
		779
		780	Configures the C<wbuf_max> setting (C<undef> disables it).
		781
		782	=cut
		783
		784	sub rbuf_max {
		785	$_[0]{rbuf_max} = $_[1];
		786	}
		787
		788	sub wbuf_max {
		789	$_[0]{wbuf_max} = $_[1];
		790	}
		791
		792	#############################################################################
		793
		794	=item $handle->timeout ($seconds)
		795
		796	=item $handle->rtimeout ($seconds)
		797
		798	=item $handle->wtimeout ($seconds)
		799
		800	Configures (or disables) the inactivity timeout.
		801
		802	The timeout will be checked instantly, so this method might destroy the
		803	handle before it returns.
		804
		805	=item $handle->timeout_reset
		806
		807	=item $handle->rtimeout_reset
		808
		809	=item $handle->wtimeout_reset
		810
		811	Reset the activity timeout, as if data was received or sent.
		812
		813	These methods are cheap to call.
		814
		815	=cut
		816
		817	for my $dir ("", "r", "w") {
		818	my $timeout = "${dir}timeout";
		819	my $tw = "_${dir}tw";
		820	my $on_timeout = "on_${dir}timeout";
		821	my $activity = "_${dir}activity";
		822	my $cb;
		823
		824	*$on_timeout = sub {
		825	$_[0]{$on_timeout} = $_[1];
		826	};
		827
		828	*$timeout = sub {
		829	my ($self, $new_value) = @_;
		830
		831	$new_value >= 0
		832	or Carp::croak "AnyEvent::Handle->$timeout called with negative timeout ($new_value), caught";
		833
		834	$self->{$timeout} = $new_value;
		835	delete $self->{$tw}; &$cb;
		836	};
		837
		838	*{"${dir}timeout_reset"} = sub {
		839	$_[0]{$activity} = AE::now;
		840	};
		841
		842	# main workhorse:
		843	# reset the timeout watcher, as neccessary
		844	# also check for time-outs
		845	$cb = sub {
		846	my ($self) = @_;
		847
		848	if ($self->{$timeout} && $self->{fh}) {
		849	my $NOW = AE::now;
		850
		851	# when would the timeout trigger?
		852	my $after = $self->{$activity} + $self->{$timeout} - $NOW;
		853
		854	# now or in the past already?
		855	if ($after <= 0) {
		856	$self->{$activity} = $NOW;
		857
		858	if ($self->{$on_timeout}) {
		859	$self->{$on_timeout}($self);
		860	} else {
		861	$self->_error (Errno::ETIMEDOUT);
		862	}
		863
		864	# callback could have changed timeout value, optimise
		865	return unless $self->{$timeout};
		866
		867	# calculate new after
		868	$after = $self->{$timeout};
		869	}
		870
		871	Scalar::Util::weaken $self;
		872	return unless $self; # ->error could have destroyed $self
		873
		874	$self->{$tw} ||= AE::timer $after, 0, sub {
		875	delete $self->{$tw};
		876	$cb->($self);
		877	};
		878	} else {
		879	delete $self->{$tw};
		880	}
		881	}
		882	}
		883
		884	#############################################################################
		885
		886	=back
		887
		888	=head2 WRITE QUEUE
		889
		890	AnyEvent::Handle manages two queues per handle, one for writing and one
		891	for reading.
		892
		893	The write queue is very simple: you can add data to its end, and
		894	AnyEvent::Handle will automatically try to get rid of it for you.
		895
		896	When data could be written and the write buffer is shorter then the low
		897	water mark, the C<on_drain> callback will be invoked once.
		898
		899	=over 4
		900
		901	=item $handle->on_drain ($cb)
		902
		903	Sets the C<on_drain> callback or clears it (see the description of
		904	C<on_drain> in the constructor).
		905
		906	This method may invoke callbacks (and therefore the handle might be
		907	destroyed after it returns).
		908
		909	=cut
		910
		911	sub on_drain {
		912	my ($self, $cb) = @_;
		913
		914	$self->{on_drain} = $cb;
		915
		916	$cb->($self)
		917	if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
		918	}
		919
		920	=item $handle->push_write ($data)
		921
		922	Queues the given scalar to be written. You can push as much data as
		923	you want (only limited by the available memory and C<wbuf_max>), as
		924	C<AnyEvent::Handle> buffers it independently of the kernel.
		925
		926	This method may invoke callbacks (and therefore the handle might be
		927	destroyed after it returns).
		928
		929	=cut
		930
		931	sub _drain_wbuf {
		932	my ($self) = @_;
		933
		934	if (!$self->{_ww} && length $self->{wbuf}) {
		935
		936	Scalar::Util::weaken $self;
		937
		938	my $cb = sub {
		939	my $len = syswrite $self->{fh}, $self->{wbuf};
		940
		941	if (defined $len) {
		942	substr $self->{wbuf}, 0, $len, "";
		943
		944	$self->{_activity} = $self->{_wactivity} = AE::now;
		945
		946	$self->{on_drain}($self)
		947	if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
		948	&& $self->{on_drain};
		949
		950	delete $self->{_ww} unless length $self->{wbuf};
		951	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
		952	$self->_error ($!, 1);
		953	}
		954	};
		955
		956	# try to write data immediately
		957	$cb->() unless $self->{autocork};
		958
		959	# if still data left in wbuf, we need to poll
		960	$self->{_ww} = AE::io $self->{fh}, 1, $cb
		961	if length $self->{wbuf};
		962
		963	if (
		964	defined $self->{wbuf_max}
		965	&& $self->{wbuf_max} < length $self->{wbuf}
		966	) {
		967	$self->_error (Errno::ENOSPC, 1), return;
		968	}
		969	};
		970	}
		971
		972	our %WH;
		973
		974	# deprecated
179	sub register_write_type($$) {	975	sub register_write_type($$) {
180	$WH{$_[0]} = $_[1];	976	$WH{$_[0]} = $_[1];
181	}	977	}
182		978
183	sub new {
184	my $class = shift;
185
186	my $self = bless { @_ }, $class;
187
188	$self->{fh} or Carp::croak "mandatory argument fh is missing";
189
190	AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
191
192	if ($self->{tls}) {
193	require Net::SSLeay;
194	$self->starttls (delete $self->{tls}, delete $self->{tls_ctx});
195	}
196
197	$self->on_eof (delete $self->{on_eof} ) if $self->{on_eof};
198	$self->on_error (delete $self->{on_error}) if $self->{on_error};
199	$self->on_drain (delete $self->{on_drain}) if $self->{on_drain};
200	$self->on_read (delete $self->{on_read} ) if $self->{on_read};
201
202	$self->start_read;
203
204	$self
205	}
206
207	sub _shutdown {
208	my ($self) = @_;
209
210	delete $self->{rw};
211	delete $self->{ww};
212	delete $self->{fh};
213	}
214
215	sub error {
216	my ($self) = @_;
217
218	{
219	local $!;
220	$self->_shutdown;
221	}
222
223	if ($self->{on_error}) {
224	$self->{on_error}($self);
225	} else {
226	Carp::croak "AnyEvent::Handle uncaught fatal error: $!";
227	}
228	}
229
230	=item $fh = $handle->fh
231
232	This method returns the file handle of the L<AnyEvent::Handle> object.
233
234	=cut
235
236	sub fh { $_[0]->{fh} }
237
238	=item $handle->on_error ($cb)
239
240	Replace the current C<on_error> callback (see the C<on_error> constructor argument).
241
242	=cut
243
244	sub on_error {
245	$_[0]{on_error} = $_[1];
246	}
247
248	=item $handle->on_eof ($cb)
249
250	Replace the current C<on_eof> callback (see the C<on_eof> constructor argument).
251
252	=cut
253
254	sub on_eof {
255	$_[0]{on_eof} = $_[1];
256	}
257
258	#############################################################################
259
260	=back
261
262	=head2 WRITE QUEUE
263
264	AnyEvent::Handle manages two queues per handle, one for writing and one
265	for reading.
266
267	The write queue is very simple: you can add data to its end, and
268	AnyEvent::Handle will automatically try to get rid of it for you.
269
270	When data could be written and the write buffer is shorter then the low
271	water mark, the C<on_drain> callback will be invoked.
272
273	=over 4
274
275	=item $handle->on_drain ($cb)
276
277	Sets the C<on_drain> callback or clears it (see the description of
278	C<on_drain> in the constructor).
279
280	=cut
281
282	sub on_drain {
283	my ($self, $cb) = @_;
284
285	$self->{on_drain} = $cb;
286
287	$cb->($self)
288	if $cb && $self->{low_water_mark} >= length $self->{wbuf};
289	}
290
291	=item $handle->push_write ($data)
292
293	Queues the given scalar to be written. You can push as much data as you
294	want (only limited by the available memory), as C<AnyEvent::Handle>
295	buffers it independently of the kernel.
296
297	=cut
298
299	sub _drain_wbuf {
300	my ($self) = @_;
301
302	if (!$self->{ww} && length $self->{wbuf}) {
303	Scalar::Util::weaken $self;
304	my $cb = sub {
305	my $len = syswrite $self->{fh}, $self->{wbuf};
306
307	if ($len >= 0) {
308	substr $self->{wbuf}, 0, $len, "";
309
310	$self->{on_drain}($self)
311	if $self->{low_water_mark} >= length $self->{wbuf}
312	&& $self->{on_drain};
313
314	delete $self->{ww} unless length $self->{wbuf};
315	} elsif ($! != EAGAIN && $! != EINTR) {
316	$self->error;
317	}
318	};
319
320	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb);
321
322	$cb->($self);
323	};
324	}
325
326	sub push_write {	979	sub push_write {
327	my $self = shift;	980	my $self = shift;
328		981
329	if (@_ > 1) {	982	if (@_ > 1) {
330	my $type = shift;	983	my $type = shift;
331		984
		985	@_ = ($WH{$type} ||= _load_func "$type\::anyevent_write_type"
332	@_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")	986	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_write")
333	->($self, @_);	987	->($self, @_);
334	}	988	}
335		989
		990	# we downgrade here to avoid hard-to-track-down bugs,
		991	# and diagnose the problem earlier and better.
		992
336	if ($self->{filter_w}) {	993	if ($self->{tls}) {
337	$self->{filter_w}->($self, \$_[0]);	994	utf8::downgrade $self->{_tls_wbuf} .= $_[0];
		995	&_dotls ($self) if $self->{fh};
338	} else {	996	} else {
339	$self->{wbuf} .= $_[0];	997	utf8::downgrade $self->{wbuf} .= $_[0];
340	$self->_drain_wbuf;	998	$self->_drain_wbuf if $self->{fh};
341	}	999	}
342	}	1000	}
343		1001
344	=item $handle->push_write (type => @args)	1002	=item $handle->push_write (type => @args)
345		1003
346	=item $handle->unshift_write (type => @args)
347
348	Instead of formatting your data yourself, you can also let this module do	1004	Instead of formatting your data yourself, you can also let this module
349	the job by specifying a type and type-specific arguments.	1005	do the job by specifying a type and type-specific arguments. You
		1006	can also specify the (fully qualified) name of a package, in which
		1007	case AnyEvent tries to load the package and then expects to find the
		1008	C<anyevent_write_type> function inside (see "custom write types", below).
350		1009
351	Predefined types are:	1010	Predefined types are (if you have ideas for additional types, feel free to
		1011	drop by and tell us):
352		1012
353	=over 4	1013	=over 4
354		1014
355	=item netstring => $string	1015	=item netstring => $string
356		1016
…		…
360	=cut	1020	=cut
361		1021
362	register_write_type netstring => sub {	1022	register_write_type netstring => sub {
363	my ($self, $string) = @_;	1023	my ($self, $string) = @_;
364		1024
365	sprintf "%d:%s,", (length $string), $string	1025	(length $string) . ":$string,"
366	};	1026	};
367		1027
		1028	=item packstring => $format, $data
		1029
		1030	An octet string prefixed with an encoded length. The encoding C<$format>
		1031	uses the same format as a Perl C<pack> format, but must specify a single
		1032	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1033	optional C<!>, C<< < >> or C<< > >> modifier).
		1034
		1035	=cut
		1036
		1037	register_write_type packstring => sub {
		1038	my ($self, $format, $string) = @_;
		1039
		1040	pack "$format/a*", $string
		1041	};
		1042
		1043	=item json => $array_or_hashref
		1044
		1045	Encodes the given hash or array reference into a JSON object. Unless you
		1046	provide your own JSON object, this means it will be encoded to JSON text
		1047	in UTF-8.
		1048
		1049	JSON objects (and arrays) are self-delimiting, so you can write JSON at
		1050	one end of a handle and read them at the other end without using any
		1051	additional framing.
		1052
		1053	The generated JSON text is guaranteed not to contain any newlines: While
		1054	this module doesn't need delimiters after or between JSON texts to be
		1055	able to read them, many other languages depend on that.
		1056
		1057	A simple RPC protocol that interoperates easily with others is to send
		1058	JSON arrays (or objects, although arrays are usually the better choice as
		1059	they mimic how function argument passing works) and a newline after each
		1060	JSON text:
		1061
		1062	$handle->push_write (json => ["method", "arg1", "arg2"]); # whatever
		1063	$handle->push_write ("\012");
		1064
		1065	An AnyEvent::Handle receiver would simply use the C<json> read type and
		1066	rely on the fact that the newline will be skipped as leading whitespace:
		1067
		1068	$handle->push_read (json => sub { my $array = $_[1]; ... });
		1069
		1070	Other languages could read single lines terminated by a newline and pass
		1071	this line into their JSON decoder of choice.
		1072
		1073	=cut
		1074
		1075	sub json_coder() {
		1076	eval { require JSON::XS; JSON::XS->new->utf8 }
		1077	|| do { require JSON; JSON->new->utf8 }
		1078	}
		1079
		1080	register_write_type json => sub {
		1081	my ($self, $ref) = @_;
		1082
		1083	my $json = $self->{json} ||= json_coder;
		1084
		1085	$json->encode ($ref)
		1086	};
		1087
		1088	=item storable => $reference
		1089
		1090	Freezes the given reference using L<Storable> and writes it to the
		1091	handle. Uses the C<nfreeze> format.
		1092
		1093	=cut
		1094
		1095	register_write_type storable => sub {
		1096	my ($self, $ref) = @_;
		1097
		1098	require Storable unless $Storable::VERSION;
		1099
		1100	pack "w/a*", Storable::nfreeze ($ref)
		1101	};
		1102
368	=back	1103	=back
369		1104
370	=cut	1105	=item $handle->push_shutdown
371		1106
		1107	Sometimes you know you want to close the socket after writing your data
		1108	before it was actually written. One way to do that is to replace your
		1109	C<on_drain> handler by a callback that shuts down the socket (and set
		1110	C<low_water_mark> to C<0>). This method is a shorthand for just that, and
		1111	replaces the C<on_drain> callback with:
372		1112
		1113	sub { shutdown $_[0]{fh}, 1 }
		1114
		1115	This simply shuts down the write side and signals an EOF condition to the
		1116	the peer.
		1117
		1118	You can rely on the normal read queue and C<on_eof> handling
		1119	afterwards. This is the cleanest way to close a connection.
		1120
		1121	This method may invoke callbacks (and therefore the handle might be
		1122	destroyed after it returns).
		1123
		1124	=cut
		1125
		1126	sub push_shutdown {
		1127	my ($self) = @_;
		1128
		1129	delete $self->{low_water_mark};
		1130	$self->on_drain (sub { shutdown $_[0]{fh}, 1 });
		1131	}
		1132
		1133	=item custom write types - Package::anyevent_write_type $handle, @args
		1134
		1135	Instead of one of the predefined types, you can also specify the name of
		1136	a package. AnyEvent will try to load the package and then expects to find
		1137	a function named C<anyevent_write_type> inside. If it isn't found, it
		1138	progressively tries to load the parent package until it either finds the
		1139	function (good) or runs out of packages (bad).
		1140
		1141	Whenever the given C<type> is used, C<push_write> will the function with
		1142	the handle object and the remaining arguments.
		1143
		1144	The function is supposed to return a single octet string that will be
		1145	appended to the write buffer, so you can mentally treat this function as a
		1146	"arguments to on-the-wire-format" converter.
		1147
		1148	Example: implement a custom write type C<join> that joins the remaining
		1149	arguments using the first one.
		1150
		1151	$handle->push_write (My::Type => " ", 1,2,3);
		1152
		1153	# uses the following package, which can be defined in the "My::Type" or in
		1154	# the "My" modules to be auto-loaded, or just about anywhere when the
		1155	# My::Type::anyevent_write_type is defined before invoking it.
		1156
		1157	package My::Type;
		1158
		1159	sub anyevent_write_type {
		1160	my ($handle, $delim, @args) = @_;
		1161
		1162	join $delim, @args
		1163	}
		1164
		1165	=cut
373		1166
374	#############################################################################	1167	#############################################################################
375		1168
376	=back	1169	=back
377		1170
…		…
384	ways, the "simple" way, using only C<on_read> and the "complex" way, using	1177	ways, the "simple" way, using only C<on_read> and the "complex" way, using
385	a queue.	1178	a queue.
386		1179
387	In the simple case, you just install an C<on_read> callback and whenever	1180	In the simple case, you just install an C<on_read> callback and whenever
388	new data arrives, it will be called. You can then remove some data (if	1181	new data arrives, it will be called. You can then remove some data (if
389	enough is there) from the read buffer (C<< $handle->rbuf >>) if you want	1182	enough is there) from the read buffer (C<< $handle->rbuf >>). Or you can
390	or not.	1183	leave the data there if you want to accumulate more (e.g. when only a
		1184	partial message has been received so far), or change the read queue with
		1185	e.g. C<push_read>.
391		1186
392	In the more complex case, you want to queue multiple callbacks. In this	1187	In the more complex case, you want to queue multiple callbacks. In this
393	case, AnyEvent::Handle will call the first queued callback each time new	1188	case, AnyEvent::Handle will call the first queued callback each time new
394	data arrives and removes it when it has done its job (see C<push_read>,	1189	data arrives (also the first time it is queued) and remove it when it has
395	below).	1190	done its job (see C<push_read>, below).
396		1191
397	This way you can, for example, push three line-reads, followed by reading	1192	This way you can, for example, push three line-reads, followed by reading
398	a chunk of data, and AnyEvent::Handle will execute them in order.	1193	a chunk of data, and AnyEvent::Handle will execute them in order.
399		1194
400	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by	1195	Example 1: EPP protocol parser. EPP sends 4 byte length info, followed by
401	the specified number of bytes which give an XML datagram.	1196	the specified number of bytes which give an XML datagram.
402		1197
403	# in the default state, expect some header bytes	1198	# in the default state, expect some header bytes
404	$handle->on_read (sub {	1199	$handle->on_read (sub {
405	# some data is here, now queue the length-header-read (4 octets)	1200	# some data is here, now queue the length-header-read (4 octets)
406	shift->unshift_read_chunk (4, sub {	1201	shift->unshift_read (chunk => 4, sub {
407	# header arrived, decode	1202	# header arrived, decode
408	my $len = unpack "N", $_[1];	1203	my $len = unpack "N", $_[1];
409		1204
410	# now read the payload	1205	# now read the payload
411	shift->unshift_read_chunk ($len, sub {	1206	shift->unshift_read (chunk => $len, sub {
412	my $xml = $_[1];	1207	my $xml = $_[1];
413	# handle xml	1208	# handle xml
414	});	1209	});
415	});	1210	});
416	});	1211	});
417		1212
418	Example 2: Implement a client for a protocol that replies either with	1213	Example 2: Implement a client for a protocol that replies either with "OK"
419	"OK" and another line or "ERROR" for one request, and 64 bytes for the	1214	and another line or "ERROR" for the first request that is sent, and 64
420	second request. Due tot he availability of a full queue, we can just	1215	bytes for the second request. Due to the availability of a queue, we can
421	pipeline sending both requests and manipulate the queue as necessary in	1216	just pipeline sending both requests and manipulate the queue as necessary
422	the callbacks:	1217	in the callbacks.
423		1218
424	# request one	1219	When the first callback is called and sees an "OK" response, it will
		1220	C<unshift> another line-read. This line-read will be queued I<before> the
		1221	64-byte chunk callback.
		1222
		1223	# request one, returns either "OK + extra line" or "ERROR"
425	$handle->push_write ("request 1\015\012");	1224	$handle->push_write ("request 1\015\012");
426		1225
427	# we expect "ERROR" or "OK" as response, so push a line read	1226	# we expect "ERROR" or "OK" as response, so push a line read
428	$handle->push_read_line (sub {	1227	$handle->push_read (line => sub {
429	# if we got an "OK", we have to _prepend_ another line,	1228	# if we got an "OK", we have to _prepend_ another line,
430	# so it will be read before the second request reads its 64 bytes	1229	# so it will be read before the second request reads its 64 bytes
431	# which are already in the queue when this callback is called	1230	# which are already in the queue when this callback is called
432	# we don't do this in case we got an error	1231	# we don't do this in case we got an error
433	if ($_[1] eq "OK") {	1232	if ($_[1] eq "OK") {
434	$_[0]->unshift_read_line (sub {	1233	$_[0]->unshift_read (line => sub {
435	my $response = $_[1];	1234	my $response = $_[1];
436	...	1235	...
437	});	1236	});
438	}	1237	}
439	});	1238	});
440		1239
441	# request two	1240	# request two, simply returns 64 octets
442	$handle->push_write ("request 2\015\012");	1241	$handle->push_write ("request 2\015\012");
443		1242
444	# simply read 64 bytes, always	1243	# simply read 64 bytes, always
445	$handle->push_read_chunk (64, sub {	1244	$handle->push_read (chunk => 64, sub {
446	my $response = $_[1];	1245	my $response = $_[1];
447	...	1246	...
448	});	1247	});
449		1248
450	=over 4	1249	=over 4
451		1250
452	=cut	1251	=cut
453		1252
454	sub _drain_rbuf {	1253	sub _drain_rbuf {
455	my ($self) = @_;	1254	my ($self) = @_;
		1255
		1256	# avoid recursion
		1257	return if $self->{_skip_drain_rbuf};
		1258	local $self->{_skip_drain_rbuf} = 1;
		1259
		1260	while () {
		1261	# we need to use a separate tls read buffer, as we must not receive data while
		1262	# we are draining the buffer, and this can only happen with TLS.
		1263	$self->{rbuf} .= delete $self->{_tls_rbuf}
		1264	if exists $self->{_tls_rbuf};
		1265
		1266	my $len = length $self->{rbuf};
		1267
		1268	if (my $cb = shift @{ $self->{_queue} }) {
		1269	unless ($cb->($self)) {
		1270	# no progress can be made
		1271	# (not enough data and no data forthcoming)
		1272	$self->_error (Errno::EPIPE, 1), return
		1273	if $self->{_eof};
		1274
		1275	unshift @{ $self->{_queue} }, $cb;
		1276	last;
		1277	}
		1278	} elsif ($self->{on_read}) {
		1279	last unless $len;
		1280
		1281	$self->{on_read}($self);
		1282
		1283	if (
		1284	$len == length $self->{rbuf} # if no data has been consumed
		1285	&& !@{ $self->{_queue} } # and the queue is still empty
		1286	&& $self->{on_read} # but we still have on_read
		1287	) {
		1288	# no further data will arrive
		1289	# so no progress can be made
		1290	$self->_error (Errno::EPIPE, 1), return
		1291	if $self->{_eof};
		1292
		1293	last; # more data might arrive
		1294	}
		1295	} else {
		1296	# read side becomes idle
		1297	delete $self->{_rw} unless $self->{tls};
		1298	last;
		1299	}
		1300	}
		1301
		1302	if ($self->{_eof}) {
		1303	$self->{on_eof}
		1304	? $self->{on_eof}($self)
		1305	: $self->_error (0, 1, "Unexpected end-of-file");
		1306
		1307	return;
		1308	}
456		1309
457	if (	1310	if (
458	defined $self->{rbuf_max}	1311	defined $self->{rbuf_max}
459	&& $self->{rbuf_max} < length $self->{rbuf}	1312	&& $self->{rbuf_max} < length $self->{rbuf}
460	) {	1313	) {
461	$! = &Errno::ENOSPC; return $self->error;	1314	$self->_error (Errno::ENOSPC, 1), return;
462	}	1315	}
463		1316
464	return if $self->{in_drain};	1317	# may need to restart read watcher
465	local $self->{in_drain} = 1;	1318	unless ($self->{_rw}) {
466		1319	$self->start_read
467	while (my $len = length $self->{rbuf}) {	1320	if $self->{on_read} || @{ $self->{_queue} };
468	no strict 'refs';
469	if (my $cb = shift @{ $self->{queue} }) {
470	unless ($cb->($self)) {
471	if ($self->{eof}) {
472	# no progress can be made (not enough data and no data forthcoming)
473	$! = &Errno::EPIPE; return $self->error;
474	}
475
476	unshift @{ $self->{queue} }, $cb;
477	return;
478	}
479	} elsif ($self->{on_read}) {
480	$self->{on_read}($self);
481
482	if (
483	$self->{eof} # if no further data will arrive
484	&& $len == length $self->{rbuf} # and no data has been consumed
485	&& !@{ $self->{queue} } # and the queue is still empty
486	&& $self->{on_read} # and we still want to read data
487	) {
488	# then no progress can be made
489	$! = &Errno::EPIPE; return $self->error;
490	}
491	} else {
492	# read side becomes idle
493	delete $self->{rw};
494	return;
495	}
496	}
497
498	if ($self->{eof}) {
499	$self->_shutdown;
500	$self->{on_eof}($self)
501	if $self->{on_eof};
502	}	1321	}
503	}	1322	}
504		1323
505	=item $handle->on_read ($cb)	1324	=item $handle->on_read ($cb)
506		1325
507	This replaces the currently set C<on_read> callback, or clears it (when	1326	This replaces the currently set C<on_read> callback, or clears it (when
508	the new callback is C<undef>). See the description of C<on_read> in the	1327	the new callback is C<undef>). See the description of C<on_read> in the
509	constructor.	1328	constructor.
510		1329
		1330	This method may invoke callbacks (and therefore the handle might be
		1331	destroyed after it returns).
		1332
511	=cut	1333	=cut
512		1334
513	sub on_read {	1335	sub on_read {
514	my ($self, $cb) = @_;	1336	my ($self, $cb) = @_;
515		1337
516	$self->{on_read} = $cb;	1338	$self->{on_read} = $cb;
		1339	$self->_drain_rbuf if $cb;
517	}	1340	}
518		1341
519	=item $handle->rbuf	1342	=item $handle->rbuf
520		1343
521	Returns the read buffer (as a modifiable lvalue).	1344	Returns the read buffer (as a modifiable lvalue). You can also access the
		1345	read buffer directly as the C<< ->{rbuf} >> member, if you want (this is
		1346	much faster, and no less clean).
522		1347
523	You can access the read buffer directly as the C<< ->{rbuf} >> member, if	1348	The only operation allowed on the read buffer (apart from looking at it)
524	you want.	1349	is removing data from its beginning. Otherwise modifying or appending to
		1350	it is not allowed and will lead to hard-to-track-down bugs.
525		1351
526	NOTE: The read buffer should only be used or modified if the C<on_read>,	1352	NOTE: The read buffer should only be used or modified in the C<on_read>
527	C<push_read> or C<unshift_read> methods are used. The other read methods	1353	callback or when C<push_read> or C<unshift_read> are used with a single
528	automatically manage the read buffer.	1354	callback (i.e. untyped). Typed C<push_read> and C<unshift_read> methods
		1355	will manage the read buffer on their own.
529		1356
530	=cut	1357	=cut
531		1358
532	sub rbuf : lvalue {	1359	sub rbuf : lvalue {
533	$_[0]{rbuf}	1360	$_[0]{rbuf}
…		…
550		1377
551	If enough data was available, then the callback must remove all data it is	1378	If enough data was available, then the callback must remove all data it is
552	interested in (which can be none at all) and return a true value. After returning	1379	interested in (which can be none at all) and return a true value. After returning
553	true, it will be removed from the queue.	1380	true, it will be removed from the queue.
554		1381
		1382	These methods may invoke callbacks (and therefore the handle might be
		1383	destroyed after it returns).
		1384
555	=cut	1385	=cut
		1386
		1387	our %RH;
		1388
		1389	sub register_read_type($$) {
		1390	$RH{$_[0]} = $_[1];
		1391	}
556		1392
557	sub push_read {	1393	sub push_read {
558	my $self = shift;	1394	my $self = shift;
559	my $cb = pop;	1395	my $cb = pop;
560		1396
561	if (@_) {	1397	if (@_) {
562	my $type = shift;	1398	my $type = shift;
563		1399
		1400	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
564	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_read")	1401	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::push_read")
565	->($self, $cb, @_);	1402	->($self, $cb, @_);
566	}	1403	}
567		1404
568	push @{ $self->{queue} }, $cb;	1405	push @{ $self->{_queue} }, $cb;
569	$self->_drain_rbuf;	1406	$self->_drain_rbuf;
570	}	1407	}
571		1408
572	sub unshift_read {	1409	sub unshift_read {
573	my $self = shift;	1410	my $self = shift;
574	my $cb = pop;	1411	my $cb = pop;
575		1412
576	if (@_) {	1413	if (@_) {
577	my $type = shift;	1414	my $type = shift;
578		1415
		1416	$cb = ($RH{$type} ||= _load_func "$type\::anyevent_read_type"
579	$cb = ($RH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::unshift_read")	1417	or Carp::croak "unsupported/unloadable type '$type' passed to AnyEvent::Handle::unshift_read")
580	->($self, $cb, @_);	1418	->($self, $cb, @_);
581	}	1419	}
582		1420
583
584	unshift @{ $self->{queue} }, $cb;	1421	unshift @{ $self->{_queue} }, $cb;
585	$self->_drain_rbuf;	1422	$self->_drain_rbuf;
586	}	1423	}
587		1424
588	=item $handle->push_read (type => @args, $cb)	1425	=item $handle->push_read (type => @args, $cb)
589		1426
590	=item $handle->unshift_read (type => @args, $cb)	1427	=item $handle->unshift_read (type => @args, $cb)
591		1428
592	Instead of providing a callback that parses the data itself you can chose	1429	Instead of providing a callback that parses the data itself you can chose
593	between a number of predefined parsing formats, for chunks of data, lines	1430	between a number of predefined parsing formats, for chunks of data, lines
594	etc.	1431	etc. You can also specify the (fully qualified) name of a package, in
		1432	which case AnyEvent tries to load the package and then expects to find the
		1433	C<anyevent_read_type> function inside (see "custom read types", below).
595		1434
596	The types currently supported are:	1435	Predefined types are (if you have ideas for additional types, feel free to
		1436	drop by and tell us):
597		1437
598	=over 4	1438	=over 4
599		1439
600	=item chunk => $octets, $cb->($self, $data)	1440	=item chunk => $octets, $cb->($handle, $data)
601		1441
602	Invoke the callback only once C<$octets> bytes have been read. Pass the	1442	Invoke the callback only once C<$octets> bytes have been read. Pass the
603	data read to the callback. The callback will never be called with less	1443	data read to the callback. The callback will never be called with less
604	data.	1444	data.
605		1445
606	Example: read 2 bytes.	1446	Example: read 2 bytes.
607		1447
608	$handle->push_read (chunk => 2, sub {	1448	$handle->push_read (chunk => 2, sub {
609	warn "yay ", unpack "H*", $_[1];	1449	say "yay " . unpack "H*", $_[1];
610	});	1450	});
611		1451
612	=cut	1452	=cut
613		1453
614	register_read_type chunk => sub {	1454	register_read_type chunk => sub {
…		…
619	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");	1459	$cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
620	1	1460	1
621	}	1461	}
622	};	1462	};
623		1463
624	# compatibility with older API
625	sub push_read_chunk {
626	$_[0]->push_read (chunk => $_[1], $_[2]);
627	}
628
629	sub unshift_read_chunk {
630	$_[0]->unshift_read (chunk => $_[1], $_[2]);
631	}
632
633	=item line => [$eol, ]$cb->($self, $line, $eol)	1464	=item line => [$eol, ]$cb->($handle, $line, $eol)
634		1465
635	The callback will be called only once a full line (including the end of	1466	The callback will be called only once a full line (including the end of
636	line marker, C<$eol>) has been read. This line (excluding the end of line	1467	line marker, C<$eol>) has been read. This line (excluding the end of line
637	marker) will be passed to the callback as second argument (C<$line>), and	1468	marker) will be passed to the callback as second argument (C<$line>), and
638	the end of line marker as the third argument (C<$eol>).	1469	the end of line marker as the third argument (C<$eol>).
…		…
652	=cut	1483	=cut
653		1484
654	register_read_type line => sub {	1485	register_read_type line => sub {
655	my ($self, $cb, $eol) = @_;	1486	my ($self, $cb, $eol) = @_;
656		1487
657	$eol = qr|(\015?\012)| if @_ < 3;	1488	if (@_ < 3) {
		1489	# this is more than twice as fast as the generic code below
		1490	sub {
		1491	$_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
		1492
		1493	$cb->($_[0], "$1", "$2");
		1494	1
		1495	}
		1496	} else {
658	$eol = quotemeta $eol unless ref $eol;	1497	$eol = quotemeta $eol unless ref $eol;
659	$eol = qr|^(.*?)($eol)|s;	1498	$eol = qr|^(.*?)($eol)|s;
		1499
		1500	sub {
		1501	$_[0]{rbuf} =~ s/$eol// or return;
		1502
		1503	$cb->($_[0], "$1", "$2");
		1504	1
		1505	}
		1506	}
		1507	};
		1508
		1509	=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
		1510
		1511	Makes a regex match against the regex object C<$accept> and returns
		1512	everything up to and including the match.
		1513
		1514	Example: read a single line terminated by '\n'.
		1515
		1516	$handle->push_read (regex => qr<\n>, sub { ... });
		1517
		1518	If C<$reject> is given and not undef, then it determines when the data is
		1519	to be rejected: it is matched against the data when the C<$accept> regex
		1520	does not match and generates an C<EBADMSG> error when it matches. This is
		1521	useful to quickly reject wrong data (to avoid waiting for a timeout or a
		1522	receive buffer overflow).
		1523
		1524	Example: expect a single decimal number followed by whitespace, reject
		1525	anything else (not the use of an anchor).
		1526
		1527	$handle->push_read (regex => qr<^[0-9]+\s>, qr<[^0-9]>, sub { ... });
		1528
		1529	If C<$skip> is given and not C<undef>, then it will be matched against
		1530	the receive buffer when neither C<$accept> nor C<$reject> match,
		1531	and everything preceding and including the match will be accepted
		1532	unconditionally. This is useful to skip large amounts of data that you
		1533	know cannot be matched, so that the C<$accept> or C<$reject> regex do not
		1534	have to start matching from the beginning. This is purely an optimisation
		1535	and is usually worth it only when you expect more than a few kilobytes.
		1536
		1537	Example: expect a http header, which ends at C<\015\012\015\012>. Since we
		1538	expect the header to be very large (it isn't in practice, but...), we use
		1539	a skip regex to skip initial portions. The skip regex is tricky in that
		1540	it only accepts something not ending in either \015 or \012, as these are
		1541	required for the accept regex.
		1542
		1543	$handle->push_read (regex =>
		1544	qr<\015\012\015\012>,
		1545	undef, # no reject
		1546	qr<^.*[^\015\012]>,
		1547	sub { ... });
		1548
		1549	=cut
		1550
		1551	register_read_type regex => sub {
		1552	my ($self, $cb, $accept, $reject, $skip) = @_;
		1553
		1554	my $data;
		1555	my $rbuf = \$self->{rbuf};
660		1556
661	sub {	1557	sub {
662	$_[0]{rbuf} =~ s/$eol// or return;	1558	# accept
663		1559	if ($$rbuf =~ $accept) {
		1560	$data .= substr $$rbuf, 0, $+[0], "";
664	$cb->($_[0], $1, $2);	1561	$cb->($_[0], $data);
		1562	return 1;
		1563	}
665	1	1564
		1565	# reject
		1566	if ($reject && $$rbuf =~ $reject) {
		1567	$_[0]->_error (Errno::EBADMSG);
		1568	}
		1569
		1570	# skip
		1571	if ($skip && $$rbuf =~ $skip) {
		1572	$data .= substr $$rbuf, 0, $+[0], "";
		1573	}
		1574
		1575	()
666	}	1576	}
667	};	1577	};
668		1578
669	# compatibility with older API
670	sub push_read_line {
671	my $self = shift;
672	$self->push_read (line => @_);
673	}
674
675	sub unshift_read_line {
676	my $self = shift;
677	$self->unshift_read (line => @_);
678	}
679
680	=item netstring => $cb->($string)	1579	=item netstring => $cb->($handle, $string)
681		1580
682	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).	1581	A netstring (http://cr.yp.to/proto/netstrings.txt, this is not an endorsement).
683		1582
684	Throws an error with C<$!> set to EBADMSG on format violations.	1583	Throws an error with C<$!> set to EBADMSG on format violations.
685		1584
…		…
689	my ($self, $cb) = @_;	1588	my ($self, $cb) = @_;
690		1589
691	sub {	1590	sub {
692	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {	1591	unless ($_[0]{rbuf} =~ s/^(0|[1-9][0-9]*)://) {
693	if ($_[0]{rbuf} =~ /[^0-9]/) {	1592	if ($_[0]{rbuf} =~ /[^0-9]/) {
694	$! = &Errno::EBADMSG;	1593	$_[0]->_error (Errno::EBADMSG);
695	$self->error;
696	}	1594	}
697	return;	1595	return;
698	}	1596	}
699		1597
700	my $len = $1;	1598	my $len = $1;
701		1599
702	$self->unshift_read (chunk => $len, sub {	1600	$_[0]->unshift_read (chunk => $len, sub {
703	my $string = $_[1];	1601	my $string = $_[1];
704	$_[0]->unshift_read (chunk => 1, sub {	1602	$_[0]->unshift_read (chunk => 1, sub {
705	if ($_[1] eq ",") {	1603	if ($_[1] eq ",") {
706	$cb->($_[0], $string);	1604	$cb->($_[0], $string);
707	} else {	1605	} else {
708	$! = &Errno::EBADMSG;	1606	$_[0]->_error (Errno::EBADMSG);
709	$self->error;
710	}	1607	}
711	});	1608	});
712	});	1609	});
713		1610
714	1	1611	1
715	}	1612	}
716	};	1613	};
717		1614
		1615	=item packstring => $format, $cb->($handle, $string)
		1616
		1617	An octet string prefixed with an encoded length. The encoding C<$format>
		1618	uses the same format as a Perl C<pack> format, but must specify a single
		1619	integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
		1620	optional C<!>, C<< < >> or C<< > >> modifier).
		1621
		1622	For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
		1623	EPP uses a prefix of C<N> (4 octtes).
		1624
		1625	Example: read a block of data prefixed by its length in BER-encoded
		1626	format (very efficient).
		1627
		1628	$handle->push_read (packstring => "w", sub {
		1629	my ($handle, $data) = @_;
		1630	});
		1631
		1632	=cut
		1633
		1634	register_read_type packstring => sub {
		1635	my ($self, $cb, $format) = @_;
		1636
		1637	sub {
		1638	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1639	defined (my $len = eval { unpack $format, $_[0]{rbuf} })
		1640	or return;
		1641
		1642	$format = length pack $format, $len;
		1643
		1644	# bypass unshift if we already have the remaining chunk
		1645	if ($format + $len <= length $_[0]{rbuf}) {
		1646	my $data = substr $_[0]{rbuf}, $format, $len;
		1647	substr $_[0]{rbuf}, 0, $format + $len, "";
		1648	$cb->($_[0], $data);
		1649	} else {
		1650	# remove prefix
		1651	substr $_[0]{rbuf}, 0, $format, "";
		1652
		1653	# read remaining chunk
		1654	$_[0]->unshift_read (chunk => $len, $cb);
		1655	}
		1656
		1657	1
		1658	}
		1659	};
		1660
		1661	=item json => $cb->($handle, $hash_or_arrayref)
		1662
		1663	Reads a JSON object or array, decodes it and passes it to the
		1664	callback. When a parse error occurs, an C<EBADMSG> error will be raised.
		1665
		1666	If a C<json> object was passed to the constructor, then that will be used
		1667	for the final decode, otherwise it will create a JSON coder expecting UTF-8.
		1668
		1669	This read type uses the incremental parser available with JSON version
		1670	2.09 (and JSON::XS version 2.2) and above. You have to provide a
		1671	dependency on your own: this module will load the JSON module, but
		1672	AnyEvent does not depend on it itself.
		1673
		1674	Since JSON texts are fully self-delimiting, the C<json> read and write
		1675	types are an ideal simple RPC protocol: just exchange JSON datagrams. See
		1676	the C<json> write type description, above, for an actual example.
		1677
		1678	=cut
		1679
		1680	register_read_type json => sub {
		1681	my ($self, $cb) = @_;
		1682
		1683	my $json = $self->{json} ||= json_coder;
		1684
		1685	my $data;
		1686	my $rbuf = \$self->{rbuf};
		1687
		1688	sub {
		1689	my $ref = eval { $json->incr_parse ($_[0]{rbuf}) };
		1690
		1691	if ($ref) {
		1692	$_[0]{rbuf} = $json->incr_text;
		1693	$json->incr_text = "";
		1694	$cb->($_[0], $ref);
		1695
		1696	1
		1697	} elsif ($@) {
		1698	# error case
		1699	$json->incr_skip;
		1700
		1701	$_[0]{rbuf} = $json->incr_text;
		1702	$json->incr_text = "";
		1703
		1704	$_[0]->_error (Errno::EBADMSG);
		1705
		1706	()
		1707	} else {
		1708	$_[0]{rbuf} = "";
		1709
		1710	()
		1711	}
		1712	}
		1713	};
		1714
		1715	=item storable => $cb->($handle, $ref)
		1716
		1717	Deserialises a L<Storable> frozen representation as written by the
		1718	C<storable> write type (BER-encoded length prefix followed by nfreeze'd
		1719	data).
		1720
		1721	Raises C<EBADMSG> error if the data could not be decoded.
		1722
		1723	=cut
		1724
		1725	register_read_type storable => sub {
		1726	my ($self, $cb) = @_;
		1727
		1728	require Storable unless $Storable::VERSION;
		1729
		1730	sub {
		1731	# when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
		1732	defined (my $len = eval { unpack "w", $_[0]{rbuf} })
		1733	or return;
		1734
		1735	my $format = length pack "w", $len;
		1736
		1737	# bypass unshift if we already have the remaining chunk
		1738	if ($format + $len <= length $_[0]{rbuf}) {
		1739	my $data = substr $_[0]{rbuf}, $format, $len;
		1740	substr $_[0]{rbuf}, 0, $format + $len, "";
		1741
		1742	eval { $cb->($_[0], Storable::thaw ($data)); 1 }
		1743	or return $_[0]->_error (Errno::EBADMSG);
		1744	} else {
		1745	# remove prefix
		1746	substr $_[0]{rbuf}, 0, $format, "";
		1747
		1748	# read remaining chunk
		1749	$_[0]->unshift_read (chunk => $len, sub {
		1750	eval { $cb->($_[0], Storable::thaw ($_[1])); 1 }
		1751	or $_[0]->_error (Errno::EBADMSG);
		1752	});
		1753	}
		1754
		1755	1
		1756	}
		1757	};
		1758
718	=back	1759	=back
719		1760
		1761	=item custom read types - Package::anyevent_read_type $handle, $cb, @args
		1762
		1763	Instead of one of the predefined types, you can also specify the name
		1764	of a package. AnyEvent will try to load the package and then expects to
		1765	find a function named C<anyevent_read_type> inside. If it isn't found, it
		1766	progressively tries to load the parent package until it either finds the
		1767	function (good) or runs out of packages (bad).
		1768
		1769	Whenever this type is used, C<push_read> will invoke the function with the
		1770	handle object, the original callback and the remaining arguments.
		1771
		1772	The function is supposed to return a callback (usually a closure) that
		1773	works as a plain read callback (see C<< ->push_read ($cb) >>), so you can
		1774	mentally treat the function as a "configurable read type to read callback"
		1775	converter.
		1776
		1777	It should invoke the original callback when it is done reading (remember
		1778	to pass C<$handle> as first argument as all other callbacks do that,
		1779	although there is no strict requirement on this).
		1780
		1781	For examples, see the source of this module (F<perldoc -m
		1782	AnyEvent::Handle>, search for C<register_read_type>)).
		1783
720	=item $handle->stop_read	1784	=item $handle->stop_read
721		1785
722	=item $handle->start_read	1786	=item $handle->start_read
723		1787
724	In rare cases you actually do not want to read anything from the	1788	In rare cases you actually do not want to read anything from the
725	socket. In this case you can call C<stop_read>. Neither C<on_read> no	1789	socket. In this case you can call C<stop_read>. Neither C<on_read> nor
726	any queued callbacks will be executed then. To start reading again, call	1790	any queued callbacks will be executed then. To start reading again, call
727	C<start_read>.	1791	C<start_read>.
728		1792
		1793	Note that AnyEvent::Handle will automatically C<start_read> for you when
		1794	you change the C<on_read> callback or push/unshift a read callback, and it
		1795	will automatically C<stop_read> for you when neither C<on_read> is set nor
		1796	there are any read requests in the queue.
		1797
		1798	In older versions of this module (<= 5.3), these methods had no effect,
		1799	as TLS does not support half-duplex connections. In current versions they
		1800	work as expected, as this behaviour is required to avoid certain resource
		1801	attacks, where the program would be forced to read (and buffer) arbitrary
		1802	amounts of data before being able to send some data. The drawback is that
		1803	some readings of the the SSL/TLS specifications basically require this
		1804	attack to be working, as SSL/TLS implementations might stall sending data
		1805	during a rehandshake.
		1806
		1807	As a guideline, during the initial handshake, you should not stop reading,
		1808	and as a client, it might cause problems, depending on your application.
		1809
729	=cut	1810	=cut
730		1811
731	sub stop_read {	1812	sub stop_read {
732	my ($self) = @_;	1813	my ($self) = @_;
733		1814
734	delete $self->{rw};	1815	delete $self->{_rw};
735	}	1816	}
736		1817
737	sub start_read {	1818	sub start_read {
738	my ($self) = @_;	1819	my ($self) = @_;
739		1820
740	unless ($self->{rw} || $self->{eof}) {	1821	unless ($self->{_rw} || $self->{_eof} || !$self->{fh}) {
741	Scalar::Util::weaken $self;	1822	Scalar::Util::weaken $self;
742		1823
743	$self->{rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {	1824	$self->{_rw} = AE::io $self->{fh}, 0, sub {
744	my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf};	1825	my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
745	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;	1826	my $len = sysread $self->{fh}, $$rbuf, $self->{read_size}, length $$rbuf;
746		1827
747	if ($len > 0) {	1828	if ($len > 0) {
748	$self->{filter_r}	1829	$self->{_activity} = $self->{_ractivity} = AE::now;
749	? $self->{filter_r}->($self, $rbuf)	1830
		1831	if ($self->{tls}) {
		1832	Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
		1833
		1834	&_dotls ($self);
		1835	} else {
750	: $self->_drain_rbuf;	1836	$self->_drain_rbuf;
		1837	}
		1838
		1839	if ($len == $self->{read_size}) {
		1840	$self->{read_size} *= 2;
		1841	$self->{read_size} = $self->{max_read_size} || MAX_READ_SIZE
		1842	if $self->{read_size} > ($self->{max_read_size} || MAX_READ_SIZE);
		1843	}
751		1844
752	} elsif (defined $len) {	1845	} elsif (defined $len) {
753	delete $self->{rw};	1846	delete $self->{_rw};
754	$self->{eof} = 1;	1847	$self->{_eof} = 1;
755	$self->_drain_rbuf;	1848	$self->_drain_rbuf;
756		1849
757	} elsif ($! != EAGAIN && $! != EINTR) {	1850	} elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
758	return $self->error;	1851	return $self->_error ($!, 1);
759	}	1852	}
760	});	1853	};
761	}	1854	}
762	}	1855	}
763		1856
		1857	our $ERROR_SYSCALL;
		1858	our $ERROR_WANT_READ;
		1859
		1860	sub _tls_error {
		1861	my ($self, $err) = @_;
		1862
		1863	return $self->_error ($!, 1)
		1864	if $err == Net::SSLeay::ERROR_SYSCALL ();
		1865
		1866	my $err = Net::SSLeay::ERR_error_string (Net::SSLeay::ERR_get_error ());
		1867
		1868	# reduce error string to look less scary
		1869	$err =~ s/^error:[0-9a-fA-F]{8}:[^:]+:([^:]+):/\L$1: /;
		1870
		1871	if ($self->{_on_starttls}) {
		1872	(delete $self->{_on_starttls})->($self, undef, $err);
		1873	&_freetls;
		1874	} else {
		1875	&_freetls;
		1876	$self->_error (Errno::EPROTO, 1, $err);
		1877	}
		1878	}
		1879
		1880	# poll the write BIO and send the data if applicable
		1881	# also decode read data if possible
		1882	# this is basiclaly our TLS state machine
		1883	# more efficient implementations are possible with openssl,
		1884	# but not with the buggy and incomplete Net::SSLeay.
764	sub _dotls {	1885	sub _dotls {
765	my ($self) = @_;	1886	my ($self) = @_;
766		1887
		1888	my $tmp;
		1889
767	if (length $self->{tls_wbuf}) {	1890	if (length $self->{_tls_wbuf}) {
768	while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{tls_wbuf})) > 0) {	1891	while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
769	substr $self->{tls_wbuf}, 0, $len, "";	1892	substr $self->{_tls_wbuf}, 0, $tmp, "";
770	}	1893	}
771	}
772		1894
		1895	$tmp = Net::SSLeay::get_error ($self->{tls}, $tmp);
		1896	return $self->_tls_error ($tmp)
		1897	if $tmp != $ERROR_WANT_READ
		1898	&& ($tmp != $ERROR_SYSCALL || $!);
		1899	}
		1900
773	if (defined (my $buf = Net::SSLeay::BIO_read ($self->{tls_wbio}))) {	1901	while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
		1902	unless (length $tmp) {
		1903	$self->{_on_starttls}
		1904	and (delete $self->{_on_starttls})->($self, undef, "EOF during handshake"); # ???
		1905	&_freetls;
		1906
		1907	if ($self->{on_stoptls}) {
		1908	$self->{on_stoptls}($self);
		1909	return;
		1910	} else {
		1911	# let's treat SSL-eof as we treat normal EOF
		1912	delete $self->{_rw};
		1913	$self->{_eof} = 1;
		1914	}
		1915	}
		1916
		1917	$self->{_tls_rbuf} .= $tmp;
		1918	$self->_drain_rbuf;
		1919	$self->{tls} or return; # tls session might have gone away in callback
		1920	}
		1921
		1922	$tmp = Net::SSLeay::get_error ($self->{tls}, -1);
		1923	return $self->_tls_error ($tmp)
		1924	if $tmp != $ERROR_WANT_READ
		1925	&& ($tmp != $ERROR_SYSCALL || $!);
		1926
		1927	while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
774	$self->{wbuf} .= $buf;	1928	$self->{wbuf} .= $tmp;
775	$self->_drain_wbuf;	1929	$self->_drain_wbuf;
		1930	$self->{tls} or return; # tls session might have gone away in callback
776	}	1931	}
777		1932
778	while (defined (my $buf = Net::SSLeay::read ($self->{tls}))) {	1933	$self->{_on_starttls}
779	$self->{rbuf} .= $buf;	1934	and Net::SSLeay::state ($self->{tls}) == Net::SSLeay::ST_OK ()
780	$self->_drain_rbuf;	1935	and (delete $self->{_on_starttls})->($self, 1, "TLS/SSL connection established");
781	}
782
783	my $err = Net::SSLeay::get_error ($self->{tls}, -1);
784
785	if ($err!= Net::SSLeay::ERROR_WANT_READ ()) {
786	if ($err == Net::SSLeay::ERROR_SYSCALL ()) {
787	$self->error;
788	} elsif ($err == Net::SSLeay::ERROR_SSL ()) {
789	$! = &Errno::EIO;
790	$self->error;
791	}
792
793	# all others are fine for our purposes
794	}
795	}	1936	}
796		1937
797	=item $handle->starttls ($tls[, $tls_ctx])	1938	=item $handle->starttls ($tls[, $tls_ctx])
798		1939
799	Instead of starting TLS negotiation immediately when the AnyEvent::Handle	1940	Instead of starting TLS negotiation immediately when the AnyEvent::Handle
800	object is created, you can also do that at a later time by calling	1941	object is created, you can also do that at a later time by calling
801	C<starttls>.	1942	C<starttls>.
802		1943
		1944	Starting TLS is currently an asynchronous operation - when you push some
		1945	write data and then call C<< ->starttls >> then TLS negotiation will start
		1946	immediately, after which the queued write data is then sent.
		1947
803	The first argument is the same as the C<tls> constructor argument (either	1948	The first argument is the same as the C<tls> constructor argument (either
804	C<"connect">, C<"accept"> or an existing Net::SSLeay object).	1949	C<"connect">, C<"accept"> or an existing Net::SSLeay object).
805		1950
806	The second argument is the optional C<Net::SSLeay::CTX> object that is	1951	The second argument is the optional C<AnyEvent::TLS> object that is used
807	used when AnyEvent::Handle has to create its own TLS connection object.	1952	when AnyEvent::Handle has to create its own TLS connection object, or
		1953	a hash reference with C<< key => value >> pairs that will be used to
		1954	construct a new context.
808		1955
809	=cut	1956	The TLS connection object will end up in C<< $handle->{tls} >>, the TLS
		1957	context in C<< $handle->{tls_ctx} >> after this call and can be used or
		1958	changed to your liking. Note that the handshake might have already started
		1959	when this function returns.
810		1960
811	# TODO: maybe document...	1961	Due to bugs in OpenSSL, it might or might not be possible to do multiple
		1962	handshakes on the same stream. It is best to not attempt to use the
		1963	stream after stopping TLS.
		1964
		1965	This method may invoke callbacks (and therefore the handle might be
		1966	destroyed after it returns).
		1967
		1968	=cut
		1969
		1970	our %TLS_CACHE; #TODO not yet documented, should we?
		1971
812	sub starttls {	1972	sub starttls {
813	my ($self, $ssl, $ctx) = @_;	1973	my ($self, $tls, $ctx) = @_;
814		1974
815	$self->stoptls;	1975	Carp::croak "It is an error to call starttls on an AnyEvent::Handle object while TLS is already active, caught"
		1976	if $self->{tls};
816		1977
817	if ($ssl eq "accept") {	1978	$self->{tls} = $tls;
818	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1979	$self->{tls_ctx} = $ctx if @_ > 2;
819	Net::SSLeay::set_accept_state ($ssl);	1980
820	} elsif ($ssl eq "connect") {	1981	return unless $self->{fh};
821	$ssl = Net::SSLeay::new ($ctx || TLS_CTX ());	1982
822	Net::SSLeay::set_connect_state ($ssl);	1983	require Net::SSLeay;
		1984
		1985	$ERROR_SYSCALL = Net::SSLeay::ERROR_SYSCALL ();
		1986	$ERROR_WANT_READ = Net::SSLeay::ERROR_WANT_READ ();
		1987
		1988	$tls = delete $self->{tls};
		1989	$ctx = $self->{tls_ctx};
		1990
		1991	local $Carp::CarpLevel = 1; # skip ourselves when creating a new context or session
		1992
		1993	if ("HASH" eq ref $ctx) {
		1994	require AnyEvent::TLS;
		1995
		1996	if ($ctx->{cache}) {
		1997	my $key = $ctx+0;
		1998	$ctx = $TLS_CACHE{$key} ||= new AnyEvent::TLS %$ctx;
		1999	} else {
		2000	$ctx = new AnyEvent::TLS %$ctx;
		2001	}
		2002	}
823	}	2003
824		2004	$self->{tls_ctx} = $ctx || TLS_CTX ();
825	$self->{tls} = $ssl;	2005	$self->{tls} = $tls = $self->{tls_ctx}->_get_session ($tls, $self, $self->{peername});
826		2006
827	# basically, this is deep magic (because SSL_read should have the same issues)	2007	# basically, this is deep magic (because SSL_read should have the same issues)
828	# but the openssl maintainers basically said: "trust us, it just works".	2008	# but the openssl maintainers basically said: "trust us, it just works".
829	# (unfortunately, we have to hardcode constants because the abysmally misdesigned	2009	# (unfortunately, we have to hardcode constants because the abysmally misdesigned
830	# and mismaintained ssleay-module doesn't even offer them).	2010	# and mismaintained ssleay-module doesn't even offer them).
831	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html	2011	# http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
		2012	#
		2013	# in short: this is a mess.
		2014	#
		2015	# note that we do not try to keep the length constant between writes as we are required to do.
		2016	# we assume that most (but not all) of this insanity only applies to non-blocking cases,
		2017	# and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
		2018	# have identity issues in that area.
832	Net::SSLeay::CTX_set_mode ($self->{tls},	2019	# Net::SSLeay::CTX_set_mode ($ssl,
833	(eval { Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)	2020	# (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
834	| (eval { Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));	2021	# | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
		2022	Net::SSLeay::CTX_set_mode ($tls, 1|2);
835		2023
836	$self->{tls_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	2024	$self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
837	$self->{tls_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());	2025	$self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
838		2026
		2027	Net::SSLeay::BIO_write ($self->{_rbio}, $self->{rbuf});
		2028	$self->{rbuf} = "";
		2029
839	Net::SSLeay::set_bio ($ssl, $self->{tls_rbio}, $self->{tls_wbio});	2030	Net::SSLeay::set_bio ($tls, $self->{_rbio}, $self->{_wbio});
840		2031
841	$self->{filter_w} = sub {	2032	$self->{_on_starttls} = sub { $_[0]{on_starttls}(@_) }
842	$_[0]{tls_wbuf} .= ${$_[1]};	2033	if $self->{on_starttls};
843	&_dotls;	2034
844	};	2035	&_dotls; # need to trigger the initial handshake
845	$self->{filter_r} = sub {	2036	$self->start_read; # make sure we actually do read
846	Net::SSLeay::BIO_write ($_[0]{tls_rbio}, ${$_[1]});
847	&_dotls;
848	};
849	}	2037	}
850		2038
851	=item $handle->stoptls	2039	=item $handle->stoptls
852		2040
853	Destroys the SSL connection, if any. Partial read or write data will be	2041	Shuts down the SSL connection - this makes a proper EOF handshake by
854	lost.	2042	sending a close notify to the other side, but since OpenSSL doesn't
		2043	support non-blocking shut downs, it is not guaranteed that you can re-use
		2044	the stream afterwards.
		2045
		2046	This method may invoke callbacks (and therefore the handle might be
		2047	destroyed after it returns).
855		2048
856	=cut	2049	=cut
857		2050
858	sub stoptls {	2051	sub stoptls {
859	my ($self) = @_;	2052	my ($self) = @_;
860		2053
861	Net::SSLeay::free (delete $self->{tls}) if $self->{tls};	2054	if ($self->{tls} && $self->{fh}) {
862	delete $self->{tls_rbio};	2055	Net::SSLeay::shutdown ($self->{tls});
863	delete $self->{tls_wbio};	2056
864	delete $self->{tls_wbuf};	2057	&_dotls;
865	delete $self->{filter_r};	2058
866	delete $self->{filter_w};	2059	# # we don't give a shit. no, we do, but we can't. no...#d#
		2060	# # we, we... have to use openssl :/#d#
		2061	# &_freetls;#d#
		2062	}
867	}	2063	}
		2064
		2065	sub _freetls {
		2066	my ($self) = @_;
		2067
		2068	return unless $self->{tls};
		2069
		2070	$self->{tls_ctx}->_put_session (delete $self->{tls})
		2071	if $self->{tls} > 0;
		2072
		2073	delete @$self{qw(_rbio _wbio _tls_wbuf _on_starttls)};
		2074	}
		2075
		2076	=item $handle->resettls
		2077
		2078	This rarely-used method simply resets and TLS state on the handle, usually
		2079	causing data loss.
		2080
		2081	One case where it may be useful is when you want to skip over the data in
		2082	the stream but you are not interested in interpreting it, so data loss is
		2083	no concern.
		2084
		2085	=cut
		2086
		2087	*resettls = \&_freetls;
868		2088
869	sub DESTROY {	2089	sub DESTROY {
870	my $self = shift;	2090	my ($self) = @_;
871		2091
872	$self->stoptls;	2092	&_freetls;
		2093
		2094	my $linger = exists $self->{linger} ? $self->{linger} : 3600;
		2095
		2096	if ($linger && length $self->{wbuf} && $self->{fh}) {
		2097	my $fh = delete $self->{fh};
		2098	my $wbuf = delete $self->{wbuf};
		2099
		2100	my @linger;
		2101
		2102	push @linger, AE::io $fh, 1, sub {
		2103	my $len = syswrite $fh, $wbuf, length $wbuf;
		2104
		2105	if ($len > 0) {
		2106	substr $wbuf, 0, $len, "";
		2107	} elsif (defined $len || ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK)) {
		2108	@linger = (); # end
		2109	}
		2110	};
		2111	push @linger, AE::timer $linger, 0, sub {
		2112	@linger = ();
		2113	};
		2114	}
873	}	2115	}
		2116
		2117	=item $handle->destroy
		2118
		2119	Shuts down the handle object as much as possible - this call ensures that
		2120	no further callbacks will be invoked and as many resources as possible
		2121	will be freed. Any method you will call on the handle object after
		2122	destroying it in this way will be silently ignored (and it will return the
		2123	empty list).
		2124
		2125	Normally, you can just "forget" any references to an AnyEvent::Handle
		2126	object and it will simply shut down. This works in fatal error and EOF
		2127	callbacks, as well as code outside. It does I<NOT> work in a read or write
		2128	callback, so when you want to destroy the AnyEvent::Handle object from
		2129	within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
		2130	that case.
		2131
		2132	Destroying the handle object in this way has the advantage that callbacks
		2133	will be removed as well, so if those are the only reference holders (as
		2134	is common), then one doesn't need to do anything special to break any
		2135	reference cycles.
		2136
		2137	The handle might still linger in the background and write out remaining
		2138	data, as specified by the C<linger> option, however.
		2139
		2140	=cut
		2141
		2142	sub destroy {
		2143	my ($self) = @_;
		2144
		2145	$self->DESTROY;
		2146	%$self = ();
		2147	bless $self, "AnyEvent::Handle::destroyed";
		2148	}
		2149
		2150	sub AnyEvent::Handle::destroyed::AUTOLOAD {
		2151	#nop
		2152	}
		2153
		2154	=item $handle->destroyed
		2155
		2156	Returns false as long as the handle hasn't been destroyed by a call to C<<
		2157	->destroy >>, true otherwise.
		2158
		2159	Can be useful to decide whether the handle is still valid after some
		2160	callback possibly destroyed the handle. For example, C<< ->push_write >>,
		2161	C<< ->starttls >> and other methods can call user callbacks, which in turn
		2162	can destroy the handle, so work can be avoided by checking sometimes:
		2163
		2164	$hdl->starttls ("accept");
		2165	return if $hdl->destroyed;
		2166	$hdl->push_write (...
		2167
		2168	Note that the call to C<push_write> will silently be ignored if the handle
		2169	has been destroyed, so often you can just ignore the possibility of the
		2170	handle being destroyed.
		2171
		2172	=cut
		2173
		2174	sub destroyed { 0 }
		2175	sub AnyEvent::Handle::destroyed::destroyed { 1 }
874		2176
875	=item AnyEvent::Handle::TLS_CTX	2177	=item AnyEvent::Handle::TLS_CTX
876		2178
877	This function creates and returns the Net::SSLeay::CTX object used by	2179	This function creates and returns the AnyEvent::TLS object used by default
878	default for TLS mode.	2180	for TLS mode.
879		2181
880	The context is created like this:	2182	The context is created by calling L<AnyEvent::TLS> without any arguments.
881
882	Net::SSLeay::load_error_strings;
883	Net::SSLeay::SSLeay_add_ssl_algorithms;
884	Net::SSLeay::randomize;
885
886	my $CTX = Net::SSLeay::CTX_new;
887
888	Net::SSLeay::CTX_set_options $CTX, Net::SSLeay::OP_ALL
889		2183
890	=cut	2184	=cut
891		2185
892	our $TLS_CTX;	2186	our $TLS_CTX;
893		2187
894	sub TLS_CTX() {	2188	sub TLS_CTX() {
895	$TLS_CTX || do {	2189	$TLS_CTX ||= do {
896	require Net::SSLeay;	2190	require AnyEvent::TLS;
897		2191
898	Net::SSLeay::load_error_strings ();	2192	new AnyEvent::TLS
899	Net::SSLeay::SSLeay_add_ssl_algorithms ();
900	Net::SSLeay::randomize ();
901
902	$TLS_CTX = Net::SSLeay::CTX_new ();
903
904	Net::SSLeay::CTX_set_options ($TLS_CTX, Net::SSLeay::OP_ALL ());
905
906	$TLS_CTX
907	}	2193	}
908	}	2194	}
909		2195
910	=back	2196	=back
911		2197
		2198
		2199	=head1 NONFREQUENTLY ASKED QUESTIONS
		2200
		2201	=over 4
		2202
		2203	=item I C<undef> the AnyEvent::Handle reference inside my callback and
		2204	still get further invocations!
		2205
		2206	That's because AnyEvent::Handle keeps a reference to itself when handling
		2207	read or write callbacks.
		2208
		2209	It is only safe to "forget" the reference inside EOF or error callbacks,
		2210	from within all other callbacks, you need to explicitly call the C<<
		2211	->destroy >> method.
		2212
		2213	=item Why is my C<on_eof> callback never called?
		2214
		2215	Probably because your C<on_error> callback is being called instead: When
		2216	you have outstanding requests in your read queue, then an EOF is
		2217	considered an error as you clearly expected some data.
		2218
		2219	To avoid this, make sure you have an empty read queue whenever your handle
		2220	is supposed to be "idle" (i.e. connection closes are O.K.). You can set
		2221	an C<on_read> handler that simply pushes the first read requests in the
		2222	queue.
		2223
		2224	See also the next question, which explains this in a bit more detail.
		2225
		2226	=item How can I serve requests in a loop?
		2227
		2228	Most protocols consist of some setup phase (authentication for example)
		2229	followed by a request handling phase, where the server waits for requests
		2230	and handles them, in a loop.
		2231
		2232	There are two important variants: The first (traditional, better) variant
		2233	handles requests until the server gets some QUIT command, causing it to
		2234	close the connection first (highly desirable for a busy TCP server). A
		2235	client dropping the connection is an error, which means this variant can
		2236	detect an unexpected detection close.
		2237
		2238	To handle this case, always make sure you have a on-empty read queue, by
		2239	pushing the "read request start" handler on it:
		2240
		2241	# we assume a request starts with a single line
		2242	my @start_request; @start_request = (line => sub {
		2243	my ($hdl, $line) = @_;
		2244
		2245	... handle request
		2246
		2247	# push next request read, possibly from a nested callback
		2248	$hdl->push_read (@start_request);
		2249	});
		2250
		2251	# auth done, now go into request handling loop
		2252	# now push the first @start_request
		2253	$hdl->push_read (@start_request);
		2254
		2255	By always having an outstanding C<push_read>, the handle always expects
		2256	some data and raises the C<EPIPE> error when the connction is dropped
		2257	unexpectedly.
		2258
		2259	The second variant is a protocol where the client can drop the connection
		2260	at any time. For TCP, this means that the server machine may run out of
		2261	sockets easier, and in general, it means you cannot distinguish a protocl
		2262	failure/client crash from a normal connection close. Nevertheless, these
		2263	kinds of protocols are common (and sometimes even the best solution to the
		2264	problem).
		2265
		2266	Having an outstanding read request at all times is possible if you ignore
		2267	C<EPIPE> errors, but this doesn't help with when the client drops the
		2268	connection during a request, which would still be an error.
		2269
		2270	A better solution is to push the initial request read in an C<on_read>
		2271	callback. This avoids an error, as when the server doesn't expect data
		2272	(i.e. is idly waiting for the next request, an EOF will not raise an
		2273	error, but simply result in an C<on_eof> callback. It is also a bit slower
		2274	and simpler:
		2275
		2276	# auth done, now go into request handling loop
		2277	$hdl->on_read (sub {
		2278	my ($hdl) = @_;
		2279
		2280	# called each time we receive data but the read queue is empty
		2281	# simply start read the request
		2282
		2283	$hdl->push_read (line => sub {
		2284	my ($hdl, $line) = @_;
		2285
		2286	... handle request
		2287
		2288	# do nothing special when the request has been handled, just
		2289	# let the request queue go empty.
		2290	});
		2291	});
		2292
		2293	=item I get different callback invocations in TLS mode/Why can't I pause
		2294	reading?
		2295
		2296	Unlike, say, TCP, TLS connections do not consist of two independent
		2297	communication channels, one for each direction. Or put differently, the
		2298	read and write directions are not independent of each other: you cannot
		2299	write data unless you are also prepared to read, and vice versa.
		2300
		2301	This means that, in TLS mode, you might get C<on_error> or C<on_eof>
		2302	callback invocations when you are not expecting any read data - the reason
		2303	is that AnyEvent::Handle always reads in TLS mode.
		2304
		2305	During the connection, you have to make sure that you always have a
		2306	non-empty read-queue, or an C<on_read> watcher. At the end of the
		2307	connection (or when you no longer want to use it) you can call the
		2308	C<destroy> method.
		2309
		2310	=item How do I read data until the other side closes the connection?
		2311
		2312	If you just want to read your data into a perl scalar, the easiest way
		2313	to achieve this is by setting an C<on_read> callback that does nothing,
		2314	clearing the C<on_eof> callback and in the C<on_error> callback, the data
		2315	will be in C<$_[0]{rbuf}>:
		2316
		2317	$handle->on_read (sub { });
		2318	$handle->on_eof (undef);
		2319	$handle->on_error (sub {
		2320	my $data = delete $_[0]{rbuf};
		2321	});
		2322
		2323	Note that this example removes the C<rbuf> member from the handle object,
		2324	which is not normally allowed by the API. It is expressly permitted in
		2325	this case only, as the handle object needs to be destroyed afterwards.
		2326
		2327	The reason to use C<on_error> is that TCP connections, due to latencies
		2328	and packets loss, might get closed quite violently with an error, when in
		2329	fact all data has been received.
		2330
		2331	It is usually better to use acknowledgements when transferring data,
		2332	to make sure the other side hasn't just died and you got the data
		2333	intact. This is also one reason why so many internet protocols have an
		2334	explicit QUIT command.
		2335
		2336	=item I don't want to destroy the handle too early - how do I wait until
		2337	all data has been written?
		2338
		2339	After writing your last bits of data, set the C<on_drain> callback
		2340	and destroy the handle in there - with the default setting of
		2341	C<low_water_mark> this will be called precisely when all data has been
		2342	written to the socket:
		2343
		2344	$handle->push_write (...);
		2345	$handle->on_drain (sub {
		2346	AE::log debug => "All data submitted to the kernel.";
		2347	undef $handle;
		2348	});
		2349
		2350	If you just want to queue some data and then signal EOF to the other side,
		2351	consider using C<< ->push_shutdown >> instead.
		2352
		2353	=item I want to contact a TLS/SSL server, I don't care about security.
		2354
		2355	If your TLS server is a pure TLS server (e.g. HTTPS) that only speaks TLS,
		2356	connect to it and then create the AnyEvent::Handle with the C<tls>
		2357	parameter:
		2358
		2359	tcp_connect $host, $port, sub {
		2360	my ($fh) = @_;
		2361
		2362	my $handle = new AnyEvent::Handle
		2363	fh => $fh,
		2364	tls => "connect",
		2365	on_error => sub { ... };
		2366
		2367	$handle->push_write (...);
		2368	};
		2369
		2370	=item I want to contact a TLS/SSL server, I do care about security.
		2371
		2372	Then you should additionally enable certificate verification, including
		2373	peername verification, if the protocol you use supports it (see
		2374	L<AnyEvent::TLS>, C<verify_peername>).
		2375
		2376	E.g. for HTTPS:
		2377
		2378	tcp_connect $host, $port, sub {
		2379	my ($fh) = @_;
		2380
		2381	my $handle = new AnyEvent::Handle
		2382	fh => $fh,
		2383	peername => $host,
		2384	tls => "connect",
		2385	tls_ctx => { verify => 1, verify_peername => "https" },
		2386	...
		2387
		2388	Note that you must specify the hostname you connected to (or whatever
		2389	"peername" the protocol needs) as the C<peername> argument, otherwise no
		2390	peername verification will be done.
		2391
		2392	The above will use the system-dependent default set of trusted CA
		2393	certificates. If you want to check against a specific CA, add the
		2394	C<ca_file> (or C<ca_cert>) arguments to C<tls_ctx>:
		2395
		2396	tls_ctx => {
		2397	verify => 1,
		2398	verify_peername => "https",
		2399	ca_file => "my-ca-cert.pem",
		2400	},
		2401
		2402	=item I want to create a TLS/SSL server, how do I do that?
		2403
		2404	Well, you first need to get a server certificate and key. You have
		2405	three options: a) ask a CA (buy one, use cacert.org etc.) b) create a
		2406	self-signed certificate (cheap. check the search engine of your choice,
		2407	there are many tutorials on the net) or c) make your own CA (tinyca2 is a
		2408	nice program for that purpose).
		2409
		2410	Then create a file with your private key (in PEM format, see
		2411	L<AnyEvent::TLS>), followed by the certificate (also in PEM format). The
		2412	file should then look like this:
		2413
		2414	-----BEGIN RSA PRIVATE KEY-----
		2415	...header data
		2416	... lots of base64'y-stuff
		2417	-----END RSA PRIVATE KEY-----
		2418
		2419	-----BEGIN CERTIFICATE-----
		2420	... lots of base64'y-stuff
		2421	-----END CERTIFICATE-----
		2422
		2423	The important bits are the "PRIVATE KEY" and "CERTIFICATE" parts. Then
		2424	specify this file as C<cert_file>:
		2425
		2426	tcp_server undef, $port, sub {
		2427	my ($fh) = @_;
		2428
		2429	my $handle = new AnyEvent::Handle
		2430	fh => $fh,
		2431	tls => "accept",
		2432	tls_ctx => { cert_file => "my-server-keycert.pem" },
		2433	...
		2434
		2435	When you have intermediate CA certificates that your clients might not
		2436	know about, just append them to the C<cert_file>.
		2437
		2438	=back
		2439
		2440	=head1 SUBCLASSING AnyEvent::Handle
		2441
		2442	In many cases, you might want to subclass AnyEvent::Handle.
		2443
		2444	To make this easier, a given version of AnyEvent::Handle uses these
		2445	conventions:
		2446
		2447	=over 4
		2448
		2449	=item * all constructor arguments become object members.
		2450
		2451	At least initially, when you pass a C<tls>-argument to the constructor it
		2452	will end up in C<< $handle->{tls} >>. Those members might be changed or
		2453	mutated later on (for example C<tls> will hold the TLS connection object).
		2454
		2455	=item * other object member names are prefixed with an C<_>.
		2456
		2457	All object members not explicitly documented (internal use) are prefixed
		2458	with an underscore character, so the remaining non-C<_>-namespace is free
		2459	for use for subclasses.
		2460
		2461	=item * all members not documented here and not prefixed with an underscore
		2462	are free to use in subclasses.
		2463
		2464	Of course, new versions of AnyEvent::Handle may introduce more "public"
		2465	member variables, but that's just life. At least it is documented.
		2466
		2467	=back
		2468
912	=head1 AUTHOR	2469	=head1 AUTHOR
913		2470
914	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.	2471	Robin Redeker C<< <elmex at ta-sa.org> >>, Marc Lehmann <schmorp@schmorp.de>.
915		2472
916	=cut	2473	=cut
917		2474
918	1; # End of AnyEvent::Handle	2475	1
		2476

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