[ViewVC] Diff of: cvs/JSON-XS/XS.pm

Comparing JSON-XS/XS.pm (file contents):
Revision 1.27 by root, Tue Apr 3 01:25:40 2007 UTC vs.
Revision 1.51 by root, Mon Jul 2 01:12:27 2007 UTC

…		…
9	# exported functions, they croak on error	9	# exported functions, they croak on error
10	# and expect/generate UTF-8	10	# and expect/generate UTF-8
11		11
12	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;	12	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;
13	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;	13	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;
14
15	# objToJson and jsonToObj aliases to to_json and from_json
16	# are exported for compatibility to the JSON module,
17	# but should not be used in new code.
18		14
19	# OO-interface	15	# OO-interface
20		16
21	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	17	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
22	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	18	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
…		…
85		81
86	package JSON::XS;	82	package JSON::XS;
87		83
88	use strict;	84	use strict;
89		85
90	BEGIN {
91	our $VERSION = '1.02';	86	our $VERSION = '1.4';
92	our @ISA = qw(Exporter);	87	our @ISA = qw(Exporter);
93		88
94	our @EXPORT = qw(to_json from_json objToJson jsonToObj);	89	our @EXPORT = qw(to_json from_json);
95	require Exporter;
96		90
97	require XSLoader;	91	use Exporter;
98	XSLoader::load JSON::XS::, $VERSION;	92	use XSLoader;
99	}
100		93
101	=head1 FUNCTIONAL INTERFACE	94	=head1 FUNCTIONAL INTERFACE
102		95
103	The following convinience methods are provided by this module. They are	96	The following convinience methods are provided by this module. They are
104	exported by default:	97	exported by default:
…		…
126	This function call is functionally identical to:	119	This function call is functionally identical to:
127		120
128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	121	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
129		122
130	except being faster.	123	except being faster.
		124
		125	=item $is_boolean = JSON::XS::is_bool $scalar
		126
		127	Returns true if the passed scalar represents either JSON::XS::true or
		128	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
		129	and are used to represent JSON C<true> and C<false> values in Perl.
		130
		131	See MAPPING, below, for more information on how JSON values are mapped to
		132	Perl.
131		133
132	=back	134	=back
133		135
134		136
135	=head1 OBJECT-ORIENTED INTERFACE	137	=head1 OBJECT-ORIENTED INTERFACE
…		…
154		156
155	If C<$enable> is true (or missing), then the C<encode> method will not	157	If C<$enable> is true (or missing), then the C<encode> method will not
156	generate characters outside the code range C<0..127> (which is ASCII). Any	158	generate characters outside the code range C<0..127> (which is ASCII). Any
157	unicode characters outside that range will be escaped using either a	159	unicode characters outside that range will be escaped using either a
158	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,	160	single \uXXXX (BMP characters) or a double \uHHHH\uLLLLL escape sequence,
159	as per RFC4627.	161	as per RFC4627. The resulting encoded JSON text can be treated as a native
		162	unicode string, an ascii-encoded, latin1-encoded or UTF-8 encoded string,
		163	or any other superset of ASCII.
160		164
161	If C<$enable> is false, then the C<encode> method will not escape Unicode	165	If C<$enable> is false, then the C<encode> method will not escape Unicode
162	characters unless required by the JSON syntax. This results in a faster	166	characters unless required by the JSON syntax or other flags. This results
163	and more compact format.	167	in a faster and more compact format.
		168
		169	The main use for this flag is to produce JSON texts that can be
		170	transmitted over a 7-bit channel, as the encoded JSON texts will not
		171	contain any 8 bit characters.
164		172
165	JSON::XS->new->ascii (1)->encode ([chr 0x10401])	173	JSON::XS->new->ascii (1)->encode ([chr 0x10401])
166	=> ["\ud801\udc01"]	174	=> ["\ud801\udc01"]
		175
		176	=item $json = $json->latin1 ([$enable])
		177
		178	If C<$enable> is true (or missing), then the C<encode> method will encode
		179	the resulting JSON text as latin1 (or iso-8859-1), escaping any characters
		180	outside the code range C<0..255>. The resulting string can be treated as a
		181	latin1-encoded JSON text or a native unicode string. The C<decode> method
		182	will not be affected in any way by this flag, as C<decode> by default
		183	expects unicode, which is a strict superset of latin1.
		184
		185	If C<$enable> is false, then the C<encode> method will not escape Unicode
		186	characters unless required by the JSON syntax or other flags.
		187
		188	The main use for this flag is efficiently encoding binary data as JSON
		189	text, as most octets will not be escaped, resulting in a smaller encoded
		190	size. The disadvantage is that the resulting JSON text is encoded
		191	in latin1 (and must correctly be treated as such when storing and
		192	transfering), a rare encoding for JSON. It is therefore most useful when
		193	you want to store data structures known to contain binary data efficiently
		194	in files or databases, not when talking to other JSON encoders/decoders.
		195
		196	JSON::XS->new->latin1->encode (["\x{89}\x{abc}"]
		197	=> ["\x{89}\\u0abc"] # (perl syntax, U+abc escaped, U+89 not)
167		198
168	=item $json = $json->utf8 ([$enable])	199	=item $json = $json->utf8 ([$enable])
169		200
170	If C<$enable> is true (or missing), then the C<encode> method will encode	201	If C<$enable> is true (or missing), then the C<encode> method will encode
171	the JSON result into UTF-8, as required by many protocols, while the	202	the JSON result into UTF-8, as required by many protocols, while the
…		…
280	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,	311	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,
281	resulting in an invalid JSON text:	312	resulting in an invalid JSON text:
282		313
283	JSON::XS->new->allow_nonref->encode ("Hello, World!")	314	JSON::XS->new->allow_nonref->encode ("Hello, World!")
284	=> "Hello, World!"	315	=> "Hello, World!"
		316
		317	=item $json = $json->allow_blessed ([$enable])
		318
		319	If C<$enable> is true (or missing), then the C<encode> method will not
		320	barf when it encounters a blessed reference. Instead, the value of the
		321	B<convert_blessed> option will decide wether C<null> (C<convert_blessed>
		322	disabled or no C<to_json> method found) or a representation of the
		323	object (C<convert_blessed> enabled and C<to_json> method found) is being
		324	encoded. Has no effect on C<decode>.
		325
		326	If C<$enable> is false (the default), then C<encode> will throw an
		327	exception when it encounters a blessed object.
		328
		329	=item $json = $json->convert_blessed ([$enable])
		330
		331	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		332	blessed object, will check for the availability of the C<TO_JSON> method
		333	on the object's class. If found, it will be called in scalar context
		334	and the resulting scalar will be encoded instead of the object. If no
		335	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
		336	to do.
		337
		338	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
		339	returns other blessed objects, those will be handled in the same
		340	way. C<TO_JSON> must take care of not causing an endless recursion cycle
		341	(== crash) in this case. The name of C<TO_JSON> was chosen because other
		342	methods called by the Perl core (== not by the user of the object) are
		343	usually in upper case letters and to avoid collisions with the C<to_json>
		344	function.
		345
		346	This setting does not yet influence C<decode> in any way, but in the
		347	future, global hooks might get installed that influence C<decode> and are
		348	enabled by this setting.
		349
		350	If C<$enable> is false, then the C<allow_blessed> setting will decide what
		351	to do when a blessed object is found.
		352
		353	=item $json = $json->filter_json_object ([$coderef])
		354
		355	When C<$coderef> is specified, it will be called from C<decode> each
		356	time it decodes a JSON object. The only argument is a reference to the
		357	newly-created hash. If the code references returns a single scalar (which
		358	need not be a reference), this value (i.e. a copy of that scalar to avoid
		359	aliasing) is inserted into the deserialised data structure. If it returns
		360	an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the
		361	original deserialised hash will be inserted. This setting can slow down
		362	decoding considerably.
		363
		364	When C<$coderef> is omitted or undefined, C<decode> will not change the
		365	deserialised hash in any way. This is maximally fast.
		366
		367	Example, convert all JSON objects into the integer 5:
		368
		369	my $js = JSON::XS->new->filter_json_object (sub { 5 });
		370	# returns [5]
		371	$js->decode ('[{}]')
		372	# throw an exception because allow_nonref is not enabled:
		373	$js->decode ('{"a":1, "b":2}');
		374
		375	=item $json = $json->filter_json_single_key_object ([$coderef])
		376
		377	Works like C<filter_json_object>, but is only called for JSON objects
		378	having only a single key.
		379
		380	This C<$coderef> is called before the one specified via
		381	C<filter_json_object>, if any. If it returns something, that will be
		382	inserted into the data structure. If it returns nothing, the callback
		383	from C<filter_json_object> will be called next. If you want to force
		384	insertion of single-key objects even in the presence of a mutating
		385	C<filter_json_object> callback, simply return the passed hash.
		386
		387	As this callback gets called less often then the C<filter_json_object>
		388	one, decoding speed will not usually suffer as much. Therefore, single-key
		389	objects make excellent targets to serialise Perl objects into, especially
		390	as single-key JSON objects are as close to the type-tagged value concept
		391	as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not
		392	support this in any way, so you need to make sure your data never looks
		393	like a serialised Perl hash.
		394
		395	Typical names for the single object key are C<__class_whatever__>, or
		396	C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
		397	things like C<__class_md5sum(classname)__>, to reduce the risk of clashing
		398	with real hashes.
		399
		400	Example, decode JSON objects of the form C<< { "__widget__" => <id> } >>
		401	into the corresponding C<< $WIDGET{<id>} >> object:
		402
		403	# return whatever is in $WIDGET{5}:
		404	JSON::XS
		405	->new
		406	->filter_json_single_key_object (sub {
		407	exists $_[0]{__widget__}
		408	? $WIDGET{ $_[0]{__widget__} }
		409	: ()
		410	})
		411	->decode ('{"__widget__": 5')
		412
		413	# this can be used with a TO_JSON method in some "widget" class
		414	# for serialisation to json:
		415	sub WidgetBase::TO_JSON {
		416	my ($self) = @_;
		417
		418	unless ($self->{id}) {
		419	$self->{id} = ..get..some..id..;
		420	$WIDGET{$self->{id}} = $self;
		421	}
		422
		423	{ __widget__ => $self->{id} }
		424	}
285		425
286	=item $json = $json->shrink ([$enable])	426	=item $json = $json->shrink ([$enable])
287		427
288	Perl usually over-allocates memory a bit when allocating space for	428	Perl usually over-allocates memory a bit when allocating space for
289	strings. This flag optionally resizes strings generated by either	429	strings. This flag optionally resizes strings generated by either
…		…
309	strings that look like integers or floats into integers or floats	449	strings that look like integers or floats into integers or floats
310	internally (there is no difference on the Perl level), saving space.	450	internally (there is no difference on the Perl level), saving space.
311		451
312	=item $json = $json->max_depth ([$maximum_nesting_depth])	452	=item $json = $json->max_depth ([$maximum_nesting_depth])
313		453
314	Sets the maximum nesting level (default C<4096>) accepted while encoding	454	Sets the maximum nesting level (default C<512>) accepted while encoding
315	or decoding. If the JSON text or Perl data structure has an equal or	455	or decoding. If the JSON text or Perl data structure has an equal or
316	higher nesting level then this limit, then the encoder and decoder will	456	higher nesting level then this limit, then the encoder and decoder will
317	stop and croak at that point.	457	stop and croak at that point.
318		458
319	Nesting level is defined by number of hash- or arrayrefs that the encoder	459	Nesting level is defined by number of hash- or arrayrefs that the encoder
…		…
322	given character in a string.	462	given character in a string.
323		463
324	Setting the maximum depth to one disallows any nesting, so that ensures	464	Setting the maximum depth to one disallows any nesting, so that ensures
325	that the object is only a single hash/object or array.	465	that the object is only a single hash/object or array.
326		466
327	The argument to C<max_depth> will be rounded up to the next nearest power	467	The argument to C<max_depth> will be rounded up to the next highest power
328	of two.	468	of two. If no argument is given, the highest possible setting will be
		469	used, which is rarely useful.
		470
		471	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		472
		473	=item $json = $json->max_size ([$maximum_string_size])
		474
		475	Set the maximum length a JSON text may have (in bytes) where decoding is
		476	being attempted. The default is C<0>, meaning no limit. When C<decode>
		477	is called on a string longer then this number of characters it will not
		478	attempt to decode the string but throw an exception. This setting has no
		479	effect on C<encode> (yet).
		480
		481	The argument to C<max_size> will be rounded up to the next B<highest>
		482	power of two (so may be more than requested). If no argument is given, the
		483	limit check will be deactivated (same as when C<0> is specified).
329		484
330	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	485	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
331		486
332	=item $json_text = $json->encode ($perl_scalar)	487	=item $json_text = $json->encode ($perl_scalar)
333		488
…		…
345		500
346	JSON numbers and strings become simple Perl scalars. JSON arrays become	501	JSON numbers and strings become simple Perl scalars. JSON arrays become
347	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes	502	Perl arrayrefs and JSON objects become Perl hashrefs. C<true> becomes
348	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.	503	C<1>, C<false> becomes C<0> and C<null> becomes C<undef>.
349		504
		505	=item ($perl_scalar, $characters) = $json->decode_prefix ($json_text)
		506
		507	This works like the C<decode> method, but instead of raising an exception
		508	when there is trailing garbage after the first JSON object, it will
		509	silently stop parsing there and return the number of characters consumed
		510	so far.
		511
		512	This is useful if your JSON texts are not delimited by an outer protocol
		513	(which is not the brightest thing to do in the first place) and you need
		514	to know where the JSON text ends.
		515
		516	JSON::XS->new->decode_prefix ("[1] the tail")
		517	=> ([], 3)
		518
350	=back	519	=back
351		520
352		521
353	=head1 MAPPING	522	=head1 MAPPING
354		523
…		…
358	(what you put in comes out as something equivalent).	527	(what you put in comes out as something equivalent).
359		528
360	For the more enlightened: note that in the following descriptions,	529	For the more enlightened: note that in the following descriptions,
361	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>	530	lowercase I<perl> refers to the Perl interpreter, while uppcercase I<Perl>
362	refers to the abstract Perl language itself.	531	refers to the abstract Perl language itself.
		532
363		533
364	=head2 JSON -> PERL	534	=head2 JSON -> PERL
365		535
366	=over 4	536	=over 4
367		537
…		…
388	conversion details, but an integer may take slightly less memory and might	558	conversion details, but an integer may take slightly less memory and might
389	represent more values exactly than (floating point) numbers.	559	represent more values exactly than (floating point) numbers.
390		560
391	=item true, false	561	=item true, false
392		562
393	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	563	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
394	this process. Future versions might represent those values differently,	564	respectively. They are overloaded to act almost exactly like the numbers
395	but they will be guarenteed to act like these integers would normally in	565	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
396	Perl.	566	the C<JSON::XS::is_bool> function.
397		567
398	=item null	568	=item null
399		569
400	A JSON null atom becomes C<undef> in Perl.	570	A JSON null atom becomes C<undef> in Perl.
401		571
402	=back	572	=back
		573
403		574
404	=head2 PERL -> JSON	575	=head2 PERL -> JSON
405		576
406	The mapping from Perl to JSON is slightly more difficult, as Perl is a	577	The mapping from Perl to JSON is slightly more difficult, as Perl is a
407	truly typeless language, so we can only guess which JSON type is meant by	578	truly typeless language, so we can only guess which JSON type is meant by
…		…
432	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can	603	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
433	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.	604	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
434		605
435	to_json [\0,JSON::XS::true] # yields [false,true]	606	to_json [\0,JSON::XS::true] # yields [false,true]
436		607
		608	=item JSON::XS::true, JSON::XS::false
		609
		610	These special values become JSON true and JSON false values,
		611	respectively. You cna alos use C<\1> and C<\0> directly if you want.
		612
437	=item blessed objects	613	=item blessed objects
438		614
439	Blessed objects are not allowed. JSON::XS currently tries to encode their	615	Blessed objects are not allowed. JSON::XS currently tries to encode their
440	underlying representation (hash- or arrayref), but this behaviour might	616	underlying representation (hash- or arrayref), but this behaviour might
441	change in future versions.	617	change in future versions.
…		…
562		738
563	Does not check input for validity.	739	Does not check input for validity.
564		740
565	=back	741	=back
566		742
		743
		744	=head2 JSON and YAML
		745
		746	You often hear that JSON is a subset (or a close subset) of YAML. This is,
		747	however, a mass hysteria and very far from the truth. In general, there is
		748	no way to configure JSON::XS to output a data structure as valid YAML.
		749
		750	If you really must use JSON::XS to generate YAML, you should use this
		751	algorithm (subject to change in future versions):
		752
		753	my $to_yaml = JSON::XS->new->utf8->space_after (1);
		754	my $yaml = $to_yaml->encode ($ref) . "\n";
		755
		756	This will usually generate JSON texts that also parse as valid
		757	YAML. Please note that YAML has hardcoded limits on (simple) object key
		758	lengths that JSON doesn't have, so you should make sure that your hash
		759	keys are noticably shorter than the 1024 characters YAML allows.
		760
		761	There might be other incompatibilities that I am not aware of. In general
		762	you should not try to generate YAML with a JSON generator or vice versa,
		763	or try to parse JSON with a YAML parser or vice versa: chances are high
		764	that you will run into severe interoperability problems.
		765
		766
567	=head2 SPEED	767	=head2 SPEED
568		768
569	It seems that JSON::XS is surprisingly fast, as shown in the following	769	It seems that JSON::XS is surprisingly fast, as shown in the following
570	tables. They have been generated with the help of the C<eg/bench> program	770	tables. They have been generated with the help of the C<eg/bench> program
571	in the JSON::XS distribution, to make it easy to compare on your own	771	in the JSON::XS distribution, to make it easy to compare on your own
572	system.	772	system.
573		773
574	First comes a comparison between various modules using a very short JSON	774	First comes a comparison between various modules using a very short
575	string:	775	single-line JSON string:
576		776
577	{"method": "handleMessage", "params": ["user1", "we were just talking"], "id": null}	777	{"method": "handleMessage", "params": ["user1", "we were just talking"], \
		778	"id": null, "array":[1,11,234,-5,1e5,1e7, true, false]}
578		779
579	It shows the number of encodes/decodes per second (JSON::XS uses the	780	It shows the number of encodes/decodes per second (JSON::XS uses
580	functional interface, while JSON::XS/2 uses the OO interface with	781	the functional interface, while JSON::XS/2 uses the OO interface
581	pretty-printing and hashkey sorting enabled). Higher is better:	782	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
		783	shrink). Higher is better:
582		784
		785	Storable \| 15779.925 \| 14169.946 \|
		786	-----------+------------+------------+
583	module \| encode \| decode \|	787	module \| encode \| decode \|
584	-----------\|------------\|------------\|	788	-----------\|------------\|------------\|
585	JSON \| 11488.516 \| 7823.035 \|	789	JSON \| 4990.842 \| 4088.813 \|
586	JSON::DWIW \| 94708.054 \| 129094.260 \|	790	JSON::DWIW \| 51653.990 \| 71575.154 \|
587	JSON::PC \| 63884.157 \| 128528.212 \|	791	JSON::PC \| 65948.176 \| 74631.744 \|
588	JSON::Syck \| 34898.677 \| 42096.911 \|	792	JSON::PP \| 8931.652 \| 3817.168 \|
589	JSON::XS \| 654027.064 \| 396423.669 \|	793	JSON::Syck \| 24877.248 \| 27776.848 \|
590	JSON::XS/2 \| 371564.190 \| 371725.613 \|	794	JSON::XS \| 388361.481 \| 227951.304 \|
		795	JSON::XS/2 \| 227951.304 \| 218453.333 \|
		796	JSON::XS/3 \| 338250.323 \| 218453.333 \|
		797	Storable \| 16500.016 \| 135300.129 \|
591	-----------+------------+------------+	798	-----------+------------+------------+
592		799
593	That is, JSON::XS is more than six times faster than JSON::DWIW on	800	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
594	encoding, more than three times faster on decoding, and about thirty times	801	about three times faster on decoding, and over fourty times faster
595	faster than JSON, even with pretty-printing and key sorting.	802	than JSON, even with pretty-printing and key sorting. It also compares
		803	favourably to Storable for small amounts of data.
596		804
597	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	805	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
598	search API (http://nanoref.com/yahooapis/mgPdGg):	806	search API (http://nanoref.com/yahooapis/mgPdGg):
599		807
600	module \| encode \| decode \|	808	module \| encode \| decode \|
601	-----------\|------------\|------------\|	809	-----------\|------------\|------------\|
602	JSON \| 273.023 \| 44.674 \|	810	JSON \| 55.260 \| 34.971 \|
603	JSON::DWIW \| 1089.383 \| 1145.704 \|	811	JSON::DWIW \| 825.228 \| 1082.513 \|
604	JSON::PC \| 3097.419 \| 2393.921 \|	812	JSON::PC \| 3571.444 \| 2394.829 \|
605	JSON::Syck \| 514.060 \| 843.053 \|	813	JSON::PP \| 210.987 \| 32.574 \|
606	JSON::XS \| 6479.668 \| 3636.364 \|	814	JSON::Syck \| 552.551 \| 787.544 \|
607	JSON::XS/2 \| 3774.221 \| 3599.124 \|	815	JSON::XS \| 5780.463 \| 4854.519 \|
		816	JSON::XS/2 \| 3869.998 \| 4798.975 \|
		817	JSON::XS/3 \| 5862.880 \| 4798.975 \|
		818	Storable \| 4445.002 \| 5235.027 \|
608	-----------+------------+------------+	819	-----------+------------+------------+
609		820
610	Again, JSON::XS leads by far.	821	Again, JSON::XS leads by far (except for Storable which non-surprisingly
		822	decodes faster).
611		823
612	On large strings containing lots of high unicode characters, some modules	824	On large strings containing lots of high unicode characters, some modules
613	(such as JSON::PC) seem to decode faster than JSON::XS, but the result	825	(such as JSON::PC) seem to decode faster than JSON::XS, but the result
614	will be broken due to missing (or wrong) unicode handling. Others refuse	826	will be broken due to missing (or wrong) unicode handling. Others refuse
615	to decode or encode properly, so it was impossible to prepare a fair	827	to decode or encode properly, so it was impossible to prepare a fair
…		…
628	Second, you need to avoid resource-starving attacks. That means you should	840	Second, you need to avoid resource-starving attacks. That means you should
629	limit the size of JSON texts you accept, or make sure then when your	841	limit the size of JSON texts you accept, or make sure then when your
630	resources run out, thats just fine (e.g. by using a separate process that	842	resources run out, thats just fine (e.g. by using a separate process that
631	can crash safely). The size of a JSON text in octets or characters is	843	can crash safely). The size of a JSON text in octets or characters is
632	usually a good indication of the size of the resources required to decode	844	usually a good indication of the size of the resources required to decode
633	it into a Perl structure.	845	it into a Perl structure. While JSON::XS can check the size of the JSON
		846	text, it might be too late when you already have it in memory, so you
		847	might want to check the size before you accept the string.
634		848
635	Third, JSON::XS recurses using the C stack when decoding objects and	849	Third, JSON::XS recurses using the C stack when decoding objects and
636	arrays. The C stack is a limited resource: for instance, on my amd64	850	arrays. The C stack is a limited resource: for instance, on my amd64
637	machine with 8MB of stack size I can decode around 180k nested arrays	851	machine with 8MB of stack size I can decode around 180k nested arrays but
638	but only 14k nested JSON objects. If that is exceeded, the program	852	only 14k nested JSON objects (due to perl itself recursing deeply on croak
639	crashes. Thats why the default nesting limit is set to 4096. If your	853	to free the temporary). If that is exceeded, the program crashes. to be
		854	conservative, the default nesting limit is set to 512. If your process
640	process has a smaller stack, you should adjust this setting accordingly	855	has a smaller stack, you should adjust this setting accordingly with the
641	with the C<max_depth> method.	856	C<max_depth> method.
642		857
643	And last but least, something else could bomb you that I forgot to think	858	And last but least, something else could bomb you that I forgot to think
644	of. In that case, you get to keep the pieces. I am alway sopen for hints,	859	of. In that case, you get to keep the pieces. I am always open for hints,
645	though...	860	though...
		861
		862	If you are using JSON::XS to return packets to consumption
		863	by javascript scripts in a browser you should have a look at
		864	L<http://jpsykes.com/47/practical-csrf-and-json-security> to see wether
		865	you are vulnerable to some common attack vectors (which really are browser
		866	design bugs, but it is still you who will have to deal with it, as major
		867	browser developers care only for features, not about doing security
		868	right).
646		869
647		870
648	=head1 BUGS	871	=head1 BUGS
649		872
650	While the goal of this module is to be correct, that unfortunately does	873	While the goal of this module is to be correct, that unfortunately does
…		…
652	still relatively early in its development. If you keep reporting bugs they	875	still relatively early in its development. If you keep reporting bugs they
653	will be fixed swiftly, though.	876	will be fixed swiftly, though.
654		877
655	=cut	878	=cut
656		879
		880	our $true = do { bless \(my $dummy = "1"), "JSON::XS::Boolean" };
		881	our $false = do { bless \(my $dummy = "0"), "JSON::XS::Boolean" };
		882
657	sub true() { \1 }	883	sub true() { $true }
658	sub false() { \0 }	884	sub false() { $false }
		885
		886	sub is_bool($) {
		887	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		888	# or UNIVERSAL::isa $_[0], "JSON::Literal"
		889	}
		890
		891	XSLoader::load "JSON::XS", $VERSION;
		892
		893	package JSON::XS::Boolean;
		894
		895	use overload
		896	"0+" => sub { ${$_[0]} },
		897	"++" => sub { $_[0] = ${$_[0]} + 1 },
		898	"--" => sub { $_[0] = ${$_[0]} - 1 },
		899	fallback => 1;
659		900
660	1;	901	1;
661		902
662	=head1 AUTHOR	903	=head1 AUTHOR
663		904

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Comparing JSON-XS/XS.pm (file contents): Revision 1.27 by root, Tue Apr 3 01:25:40 2007 UTC vs. Revision 1.51 by root, Mon Jul 2 01:12:27 2007 UTC

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Comparing JSON-XS/XS.pm (file contents):
Revision 1.27 by root, Tue Apr 3 01:25:40 2007 UTC vs.
Revision 1.51 by root, Mon Jul 2 01:12:27 2007 UTC