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

Comparing JSON-XS/XS.pm (file contents):
Revision 1.42 by root, Thu Jun 14 23:58:57 2007 UTC vs.
Revision 1.62 by root, Thu Oct 11 22:52:52 2007 UTC

…		…
		1	=encoding utf-8
		2
1	=head1 NAME	3	=head1 NAME
2		4
3	JSON::XS - JSON serialising/deserialising, done correctly and fast	5	JSON::XS - JSON serialising/deserialising, done correctly and fast
		6
		7	JSON::XS - 正しくて高速な JSON シリアライザ/デシリアライザ
		8	(http://fleur.hio.jp/perldoc/mix/lib/JSON/XS.html)
4		9
5	=head1 SYNOPSIS	10	=head1 SYNOPSIS
6		11
7	use JSON::XS;	12	use JSON::XS;
8		13
9	# exported functions, they croak on error	14	# exported functions, they croak on error
10	# and expect/generate UTF-8	15	# and expect/generate UTF-8
11		16
12	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;	17	$utf8_encoded_json_text = to_json $perl_hash_or_arrayref;
13	$perl_hash_or_arrayref = from_json $utf8_encoded_json_text;	18	$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		19
19	# OO-interface	20	# OO-interface
20		21
21	$coder = JSON::XS->new->ascii->pretty->allow_nonref;	22	$coder = JSON::XS->new->ascii->pretty->allow_nonref;
22	$pretty_printed_unencoded = $coder->encode ($perl_scalar);	23	$pretty_printed_unencoded = $coder->encode ($perl_scalar);
85		86
86	package JSON::XS;	87	package JSON::XS;
87		88
88	use strict;	89	use strict;
89		90
90	BEGIN {
91	our $VERSION = '1.24';	91	our $VERSION = '1.5';
92	our @ISA = qw(Exporter);	92	our @ISA = qw(Exporter);
93		93
94	our @EXPORT = qw(to_json from_json objToJson jsonToObj);	94	our @EXPORT = qw(to_json from_json);
95	require Exporter;
96		95
97	require XSLoader;	96	use Exporter;
98	XSLoader::load JSON::XS::, $VERSION;	97	use XSLoader;
99	}
100		98
101	=head1 FUNCTIONAL INTERFACE	99	=head1 FUNCTIONAL INTERFACE
102		100
103	The following convinience methods are provided by this module. They are	101	The following convinience methods are provided by this module. They are
104	exported by default:	102	exported by default:
…		…
126	This function call is functionally identical to:	124	This function call is functionally identical to:
127		125
128	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)	126	$perl_scalar = JSON::XS->new->utf8->decode ($json_text)
129		127
130	except being faster.	128	except being faster.
		129
		130	=item $is_boolean = JSON::XS::is_bool $scalar
		131
		132	Returns true if the passed scalar represents either JSON::XS::true or
		133	JSON::XS::false, two constants that act like C<1> and C<0>, respectively
		134	and are used to represent JSON C<true> and C<false> values in Perl.
		135
		136	See MAPPING, below, for more information on how JSON values are mapped to
		137	Perl.
131		138
132	=back	139	=back
133		140
134		141
135	=head1 OBJECT-ORIENTED INTERFACE	142	=head1 OBJECT-ORIENTED INTERFACE
…		…
276		283
277	Example, space_before and indent disabled, space_after enabled:	284	Example, space_before and indent disabled, space_after enabled:
278		285
279	{"key": "value"}	286	{"key": "value"}
280		287
		288	=item $json = $json->relaxed ([$enable])
		289
		290	If C<$enable> is true (or missing), then C<decode> will accept some
		291	extensions to normal JSON syntax (see below). C<encode> will not be
		292	affected in anyway. I<Be aware that this option makes you accept invalid
		293	JSON texts as if they were valid!>. I suggest only to use this option to
		294	parse application-specific files written by humans (configuration files,
		295	resource files etc.)
		296
		297	If C<$enable> is false (the default), then C<decode> will only accept
		298	valid JSON texts.
		299
		300	Currently accepted extensions are:
		301
		302	=over 4
		303
		304	=item * list items can have an end-comma
		305
		306	JSON I<separates> array elements and key-value pairs with commas. This
		307	can be annoying if you write JSON texts manually and want to be able to
		308	quickly append elements, so this extension accepts comma at the end of
		309	such items not just between them:
		310
		311	[
		312	1,
		313	2, <- this comma not normally allowed
		314	]
		315	{
		316	"k1": "v1",
		317	"k2": "v2", <- this comma not normally allowed
		318	}
		319
		320	=item * shell-style '#'-comments
		321
		322	Whenever JSON allows whitespace, shell-style comments are additionally
		323	allowed. They are terminated by the first carriage-return or line-feed
		324	character, after which more white-space and comments are allowed.
		325
		326	[
		327	1, # this comment not allowed in JSON
		328	# neither this one...
		329	]
		330
		331	=back
		332
281	=item $json = $json->canonical ([$enable])	333	=item $json = $json->canonical ([$enable])
282		334
283	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects	335	If C<$enable> is true (or missing), then the C<encode> method will output JSON objects
284	by sorting their keys. This is adding a comparatively high overhead.	336	by sorting their keys. This is adding a comparatively high overhead.
285		337
…		…
309	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,	361	Example, encode a Perl scalar as JSON value with enabled C<allow_nonref>,
310	resulting in an invalid JSON text:	362	resulting in an invalid JSON text:
311		363
312	JSON::XS->new->allow_nonref->encode ("Hello, World!")	364	JSON::XS->new->allow_nonref->encode ("Hello, World!")
313	=> "Hello, World!"	365	=> "Hello, World!"
		366
		367	=item $json = $json->allow_blessed ([$enable])
		368
		369	If C<$enable> is true (or missing), then the C<encode> method will not
		370	barf when it encounters a blessed reference. Instead, the value of the
		371	B<convert_blessed> option will decide wether C<null> (C<convert_blessed>
		372	disabled or no C<to_json> method found) or a representation of the
		373	object (C<convert_blessed> enabled and C<to_json> method found) is being
		374	encoded. Has no effect on C<decode>.
		375
		376	If C<$enable> is false (the default), then C<encode> will throw an
		377	exception when it encounters a blessed object.
		378
		379	=item $json = $json->convert_blessed ([$enable])
		380
		381	If C<$enable> is true (or missing), then C<encode>, upon encountering a
		382	blessed object, will check for the availability of the C<TO_JSON> method
		383	on the object's class. If found, it will be called in scalar context
		384	and the resulting scalar will be encoded instead of the object. If no
		385	C<TO_JSON> method is found, the value of C<allow_blessed> will decide what
		386	to do.
		387
		388	The C<TO_JSON> method may safely call die if it wants. If C<TO_JSON>
		389	returns other blessed objects, those will be handled in the same
		390	way. C<TO_JSON> must take care of not causing an endless recursion cycle
		391	(== crash) in this case. The name of C<TO_JSON> was chosen because other
		392	methods called by the Perl core (== not by the user of the object) are
		393	usually in upper case letters and to avoid collisions with the C<to_json>
		394	function.
		395
		396	This setting does not yet influence C<decode> in any way, but in the
		397	future, global hooks might get installed that influence C<decode> and are
		398	enabled by this setting.
		399
		400	If C<$enable> is false, then the C<allow_blessed> setting will decide what
		401	to do when a blessed object is found.
		402
		403	=item $json = $json->filter_json_object ([$coderef->($hashref)])
		404
		405	When C<$coderef> is specified, it will be called from C<decode> each
		406	time it decodes a JSON object. The only argument is a reference to the
		407	newly-created hash. If the code references returns a single scalar (which
		408	need not be a reference), this value (i.e. a copy of that scalar to avoid
		409	aliasing) is inserted into the deserialised data structure. If it returns
		410	an empty list (NOTE: I<not> C<undef>, which is a valid scalar), the
		411	original deserialised hash will be inserted. This setting can slow down
		412	decoding considerably.
		413
		414	When C<$coderef> is omitted or undefined, any existing callback will
		415	be removed and C<decode> will not change the deserialised hash in any
		416	way.
		417
		418	Example, convert all JSON objects into the integer 5:
		419
		420	my $js = JSON::XS->new->filter_json_object (sub { 5 });
		421	# returns [5]
		422	$js->decode ('[{}]')
		423	# throw an exception because allow_nonref is not enabled
		424	# so a lone 5 is not allowed.
		425	$js->decode ('{"a":1, "b":2}');
		426
		427	=item $json = $json->filter_json_single_key_object ($key [=> $coderef->($value)])
		428
		429	Works remotely similar to C<filter_json_object>, but is only called for
		430	JSON objects having a single key named C<$key>.
		431
		432	This C<$coderef> is called before the one specified via
		433	C<filter_json_object>, if any. It gets passed the single value in the JSON
		434	object. If it returns a single value, it will be inserted into the data
		435	structure. If it returns nothing (not even C<undef> but the empty list),
		436	the callback from C<filter_json_object> will be called next, as if no
		437	single-key callback were specified.
		438
		439	If C<$coderef> is omitted or undefined, the corresponding callback will be
		440	disabled. There can only ever be one callback for a given key.
		441
		442	As this callback gets called less often then the C<filter_json_object>
		443	one, decoding speed will not usually suffer as much. Therefore, single-key
		444	objects make excellent targets to serialise Perl objects into, especially
		445	as single-key JSON objects are as close to the type-tagged value concept
		446	as JSON gets (its basically an ID/VALUE tuple). Of course, JSON does not
		447	support this in any way, so you need to make sure your data never looks
		448	like a serialised Perl hash.
		449
		450	Typical names for the single object key are C<__class_whatever__>, or
		451	C<$__dollars_are_rarely_used__$> or C<}ugly_brace_placement>, or even
		452	things like C<__class_md5sum(classname)__>, to reduce the risk of clashing
		453	with real hashes.
		454
		455	Example, decode JSON objects of the form C<< { "__widget__" => <id> } >>
		456	into the corresponding C<< $WIDGET{<id>} >> object:
		457
		458	# return whatever is in $WIDGET{5}:
		459	JSON::XS
		460	->new
		461	->filter_json_single_key_object (__widget__ => sub {
		462	$WIDGET{ $_[0] }
		463	})
		464	->decode ('{"__widget__": 5')
		465
		466	# this can be used with a TO_JSON method in some "widget" class
		467	# for serialisation to json:
		468	sub WidgetBase::TO_JSON {
		469	my ($self) = @_;
		470
		471	unless ($self->{id}) {
		472	$self->{id} = ..get..some..id..;
		473	$WIDGET{$self->{id}} = $self;
		474	}
		475
		476	{ __widget__ => $self->{id} }
		477	}
314		478
315	=item $json = $json->shrink ([$enable])	479	=item $json = $json->shrink ([$enable])
316		480
317	Perl usually over-allocates memory a bit when allocating space for	481	Perl usually over-allocates memory a bit when allocating space for
318	strings. This flag optionally resizes strings generated by either	482	strings. This flag optionally resizes strings generated by either
…		…
351	given character in a string.	515	given character in a string.
352		516
353	Setting the maximum depth to one disallows any nesting, so that ensures	517	Setting the maximum depth to one disallows any nesting, so that ensures
354	that the object is only a single hash/object or array.	518	that the object is only a single hash/object or array.
355		519
356	The argument to C<max_depth> will be rounded up to the next nearest power	520	The argument to C<max_depth> will be rounded up to the next highest power
357	of two.	521	of two. If no argument is given, the highest possible setting will be
		522	used, which is rarely useful.
		523
		524	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
		525
		526	=item $json = $json->max_size ([$maximum_string_size])
		527
		528	Set the maximum length a JSON text may have (in bytes) where decoding is
		529	being attempted. The default is C<0>, meaning no limit. When C<decode>
		530	is called on a string longer then this number of characters it will not
		531	attempt to decode the string but throw an exception. This setting has no
		532	effect on C<encode> (yet).
		533
		534	The argument to C<max_size> will be rounded up to the next B<highest>
		535	power of two (so may be more than requested). If no argument is given, the
		536	limit check will be deactivated (same as when C<0> is specified).
358		537
359	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	538	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
360		539
361	=item $json_text = $json->encode ($perl_scalar)	540	=item $json_text = $json->encode ($perl_scalar)
362		541
…		…
424	are represented by the same codepoints in the Perl string, so no manual	603	are represented by the same codepoints in the Perl string, so no manual
425	decoding is necessary.	604	decoding is necessary.
426		605
427	=item number	606	=item number
428		607
429	A JSON number becomes either an integer or numeric (floating point)	608	A JSON number becomes either an integer, numeric (floating point) or
430	scalar in perl, depending on its range and any fractional parts. On the	609	string scalar in perl, depending on its range and any fractional parts. On
431	Perl level, there is no difference between those as Perl handles all the	610	the Perl level, there is no difference between those as Perl handles all
432	conversion details, but an integer may take slightly less memory and might	611	the conversion details, but an integer may take slightly less memory and
433	represent more values exactly than (floating point) numbers.	612	might represent more values exactly than (floating point) numbers.
		613
		614	If the number consists of digits only, JSON::XS will try to represent
		615	it as an integer value. If that fails, it will try to represent it as
		616	a numeric (floating point) value if that is possible without loss of
		617	precision. Otherwise it will preserve the number as a string value.
		618
		619	Numbers containing a fractional or exponential part will always be
		620	represented as numeric (floating point) values, possibly at a loss of
		621	precision.
		622
		623	This might create round-tripping problems as numbers might become strings,
		624	but as Perl is typeless there is no other way to do it.
434		625
435	=item true, false	626	=item true, false
436		627
437	These JSON atoms become C<0>, C<1>, respectively. Information is lost in	628	These JSON atoms become C<JSON::XS::true> and C<JSON::XS::false>,
438	this process. Future versions might represent those values differently,	629	respectively. They are overloaded to act almost exactly like the numbers
439	but they will be guarenteed to act like these integers would normally in	630	C<1> and C<0>. You can check wether a scalar is a JSON boolean by using
440	Perl.	631	the C<JSON::XS::is_bool> function.
441		632
442	=item null	633	=item null
443		634
444	A JSON null atom becomes C<undef> in Perl.	635	A JSON null atom becomes C<undef> in Perl.
445		636
…		…
477	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can	668	C<1>, which get turned into C<false> and C<true> atoms in JSON. You can
478	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.	669	also use C<JSON::XS::false> and C<JSON::XS::true> to improve readability.
479		670
480	to_json [\0,JSON::XS::true] # yields [false,true]	671	to_json [\0,JSON::XS::true] # yields [false,true]
481		672
		673	=item JSON::XS::true, JSON::XS::false
		674
		675	These special values become JSON true and JSON false values,
		676	respectively. You can also use C<\1> and C<\0> directly if you want.
		677
482	=item blessed objects	678	=item blessed objects
483		679
484	Blessed objects are not allowed. JSON::XS currently tries to encode their	680	Blessed objects are not allowed. JSON::XS currently tries to encode their
485	underlying representation (hash- or arrayref), but this behaviour might	681	underlying representation (hash- or arrayref), but this behaviour might
486	change in future versions.	682	change in future versions.
…		…
649	It shows the number of encodes/decodes per second (JSON::XS uses	845	It shows the number of encodes/decodes per second (JSON::XS uses
650	the functional interface, while JSON::XS/2 uses the OO interface	846	the functional interface, while JSON::XS/2 uses the OO interface
651	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables	847	with pretty-printing and hashkey sorting enabled, JSON::XS/3 enables
652	shrink). Higher is better:	848	shrink). Higher is better:
653		849
		850	Storable \| 15779.925 \| 14169.946 \|
		851	-----------+------------+------------+
654	module \| encode \| decode \|	852	module \| encode \| decode \|
655	-----------\|------------\|------------\|	853	-----------\|------------\|------------\|
656	JSON \| 7645.468 \| 4208.613 \|	854	JSON \| 4990.842 \| 4088.813 \|
657	JSON::DWIW \| 40721.398 \| 77101.176 \|	855	JSON::DWIW \| 51653.990 \| 71575.154 \|
658	JSON::PC \| 65948.176 \| 78251.940 \|	856	JSON::PC \| 65948.176 \| 74631.744 \|
659	JSON::Syck \| 22844.793 \| 26479.192 \|	857	JSON::PP \| 8931.652 \| 3817.168 \|
		858	JSON::Syck \| 24877.248 \| 27776.848 \|
660	JSON::XS \| 388361.481 \| 199728.762 \|	859	JSON::XS \| 388361.481 \| 227951.304 \|
661	JSON::XS/2 \| 218453.333 \| 192399.266 \|	860	JSON::XS/2 \| 227951.304 \| 218453.333 \|
662	JSON::XS/3 \| 338250.323 \| 192399.266 \|	861	JSON::XS/3 \| 338250.323 \| 218453.333 \|
663	Storable \| 15779.925 \| 14169.946 \|	862	Storable \| 16500.016 \| 135300.129 \|
664	-----------+------------+------------+	863	-----------+------------+------------+
665		864
666	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,	865	That is, JSON::XS is about five times faster than JSON::DWIW on encoding,
667	about three times faster on decoding, and over fourty times faster	866	about three times faster on decoding, and over fourty times faster
668	than JSON, even with pretty-printing and key sorting. It also compares	867	than JSON, even with pretty-printing and key sorting. It also compares
…		…
671	Using a longer test string (roughly 18KB, generated from Yahoo! Locals	870	Using a longer test string (roughly 18KB, generated from Yahoo! Locals
672	search API (http://nanoref.com/yahooapis/mgPdGg):	871	search API (http://nanoref.com/yahooapis/mgPdGg):
673		872
674	module \| encode \| decode \|	873	module \| encode \| decode \|
675	-----------\|------------\|------------\|	874	-----------\|------------\|------------\|
676	JSON \| 254.685 \| 37.665 \|	875	JSON \| 55.260 \| 34.971 \|
677	JSON::DWIW \| 843.343 \| 1049.731 \|	876	JSON::DWIW \| 825.228 \| 1082.513 \|
678	JSON::PC \| 3602.116 \| 2307.352 \|	877	JSON::PC \| 3571.444 \| 2394.829 \|
		878	JSON::PP \| 210.987 \| 32.574 \|
679	JSON::Syck \| 505.107 \| 787.899 \|	879	JSON::Syck \| 552.551 \| 787.544 \|
680	JSON::XS \| 5747.196 \| 3690.220 \|	880	JSON::XS \| 5780.463 \| 4854.519 \|
681	JSON::XS/2 \| 3968.121 \| 3676.634 \|	881	JSON::XS/2 \| 3869.998 \| 4798.975 \|
682	JSON::XS/3 \| 6105.246 \| 3662.508 \|	882	JSON::XS/3 \| 5862.880 \| 4798.975 \|
683	Storable \| 4417.337 \| 5285.161 \|	883	Storable \| 4445.002 \| 5235.027 \|
684	-----------+------------+------------+	884	-----------+------------+------------+
685		885
686	Again, JSON::XS leads by far (except for Storable which non-surprisingly	886	Again, JSON::XS leads by far (except for Storable which non-surprisingly
687	decodes faster).	887	decodes faster).
688		888
…		…
705	Second, you need to avoid resource-starving attacks. That means you should	905	Second, you need to avoid resource-starving attacks. That means you should
706	limit the size of JSON texts you accept, or make sure then when your	906	limit the size of JSON texts you accept, or make sure then when your
707	resources run out, thats just fine (e.g. by using a separate process that	907	resources run out, thats just fine (e.g. by using a separate process that
708	can crash safely). The size of a JSON text in octets or characters is	908	can crash safely). The size of a JSON text in octets or characters is
709	usually a good indication of the size of the resources required to decode	909	usually a good indication of the size of the resources required to decode
710	it into a Perl structure.	910	it into a Perl structure. While JSON::XS can check the size of the JSON
		911	text, it might be too late when you already have it in memory, so you
		912	might want to check the size before you accept the string.
711		913
712	Third, JSON::XS recurses using the C stack when decoding objects and	914	Third, JSON::XS recurses using the C stack when decoding objects and
713	arrays. The C stack is a limited resource: for instance, on my amd64	915	arrays. The C stack is a limited resource: for instance, on my amd64
714	machine with 8MB of stack size I can decode around 180k nested arrays but	916	machine with 8MB of stack size I can decode around 180k nested arrays but
715	only 14k nested JSON objects (due to perl itself recursing deeply on croak	917	only 14k nested JSON objects (due to perl itself recursing deeply on croak
…		…
738	still relatively early in its development. If you keep reporting bugs they	940	still relatively early in its development. If you keep reporting bugs they
739	will be fixed swiftly, though.	941	will be fixed swiftly, though.
740		942
741	=cut	943	=cut
742		944
		945	our $true = do { bless \(my $dummy = 1), "JSON::XS::Boolean" };
		946	our $false = do { bless \(my $dummy = 0), "JSON::XS::Boolean" };
		947
743	sub true() { \1 }	948	sub true() { $true }
744	sub false() { \0 }	949	sub false() { $false }
		950
		951	sub is_bool($) {
		952	UNIVERSAL::isa $_[0], "JSON::XS::Boolean"
		953	# or UNIVERSAL::isa $_[0], "JSON::Literal"
		954	}
		955
		956	XSLoader::load "JSON::XS", $VERSION;
		957
		958	package JSON::XS::Boolean;
		959
		960	use overload
		961	"0+" => sub { ${$_[0]} },
		962	"++" => sub { $_[0] = ${$_[0]} + 1 },
		963	"--" => sub { $_[0] = ${$_[0]} - 1 },
		964	fallback => 1;
745		965
746	1;	966	1;
747		967
748	=head1 AUTHOR	968	=head1 AUTHOR
749		969

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Comparing JSON-XS/XS.pm (file contents): Revision 1.42 by root, Thu Jun 14 23:58:57 2007 UTC vs. Revision 1.62 by root, Thu Oct 11 22:52:52 2007 UTC

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Comparing JSON-XS/XS.pm (file contents):
Revision 1.42 by root, Thu Jun 14 23:58:57 2007 UTC vs.
Revision 1.62 by root, Thu Oct 11 22:52:52 2007 UTC