summaryrefslogtreecommitdiff
path: root/ext/json/lib/json/common.rb
blob: 13debd1366ca02e06d6340417e365f8b97b5e109 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
require 'json/version'

module JSON
  class << self
    # If _object_ is string-like parse the string and return the parsed result
    # as a Ruby data structure. Otherwise generate a JSON text from the Ruby
    # data structure object and return it.
    #
    # The _opts_ argument is passed through to generate/parse respectively, see
    # generate and parse for their documentation.
    def [](object, opts = {})
      if object.respond_to? :to_str
        JSON.parse(object.to_str, opts)
      else
        JSON.generate(object, opts)
      end
    end

    # Returns the JSON parser class, that is used by JSON. This might be either
    # JSON::Ext::Parser or JSON::Pure::Parser.
    attr_reader :parser

    # Set the JSON parser class _parser_ to be used by JSON.
    def parser=(parser) # :nodoc:
      @parser = parser
      remove_const :Parser if const_defined? :Parser
      const_set :Parser, parser
    end

    # Return the constant located at _path_. The format of _path_ has to be
    # either ::A::B::C or A::B::C. In any case A has to be located at the top
    # level (absolute namespace path?). If there doesn't exist a constant at
    # the given path, an ArgumentError is raised.
    def deep_const_get(path) # :nodoc:
      path.to_s.split(/::/).inject(Object) do |p, c|
        case
        when c.empty?             then p
        when p.const_defined?(c)  then p.const_get(c)
        else
          begin
            p.const_missing(c)
          rescue NameError => e
            raise ArgumentError, "can't get const #{path}: #{e}"
          end
        end
      end
    end

    # Set the module _generator_ to be used by JSON.
    def generator=(generator) # :nodoc:
      old, $VERBOSE = $VERBOSE, nil
      @generator = generator
      generator_methods = generator::GeneratorMethods
      for const in generator_methods.constants
        klass = deep_const_get(const)
        modul = generator_methods.const_get(const)
        klass.class_eval do
          instance_methods(false).each do |m|
            m.to_s == 'to_json' and remove_method m
          end
          include modul
        end
      end
      self.state = generator::State
      const_set :State, self.state
      const_set :SAFE_STATE_PROTOTYPE, State.new
      const_set :FAST_STATE_PROTOTYPE, State.new(
        :indent         => '',
        :space          => '',
        :object_nl      => "",
        :array_nl       => "",
        :max_nesting    => false
      )
      const_set :PRETTY_STATE_PROTOTYPE, State.new(
        :indent         => '  ',
        :space          => ' ',
        :object_nl      => "\n",
        :array_nl       => "\n"
      )
    ensure
      $VERBOSE = old
    end

    # Returns the JSON generator modul, that is used by JSON. This might be
    # either JSON::Ext::Generator or JSON::Pure::Generator.
    attr_reader :generator

    # Returns the JSON generator state class, that is used by JSON. This might
    # be either JSON::Ext::Generator::State or JSON::Pure::Generator::State.
    attr_accessor :state

    # This is create identifier, that is used to decide, if the _json_create_
    # hook of a class should be called. It defaults to 'json_class'.
    attr_accessor :create_id
  end
  self.create_id = 'json_class'

  NaN           = 0.0/0

  Infinity      = 1.0/0

  MinusInfinity = -Infinity

  # The base exception for JSON errors.
  class JSONError < StandardError; end

  # This exception is raised, if a parser error occurs.
  class ParserError < JSONError; end

  # This exception is raised, if the nesting of parsed datastructures is too
  # deep.
  class NestingError < ParserError; end

  # :stopdoc:
  class CircularDatastructure < NestingError; end
  # :startdoc:

  # This exception is raised, if a generator or unparser error occurs.
  class GeneratorError < JSONError; end
  # For backwards compatibility
  UnparserError = GeneratorError

  # This exception is raised, if the required unicode support is missing on the
  # system. Usually this means, that the iconv library is not installed.
  class MissingUnicodeSupport < JSONError; end

  module_function

  # Parse the JSON document _source_ into a Ruby data structure and return it.
  #
  # _opts_ can have the following
  # keys:
  # * *max_nesting*: The maximum depth of nesting allowed in the parsed data
  #   structures. Disable depth checking with :max_nesting => false, it defaults
  #   to 19.
  # * *allow_nan*: If set to true, allow NaN, Infinity and -Infinity in
  #   defiance of RFC 4627 to be parsed by the Parser. This option defaults
  #   to false.
  # * *symbolize_names*: If set to true, returns symbols for the names
  #   (keys) in a JSON object. Otherwise strings are returned, which is also
  #   the default.
  # * *create_additions*: If set to false, the Parser doesn't create
  #   additions even if a matchin class and create_id was found. This option
  #   defaults to true.
  # * *object_class*: Defaults to Hash
  # * *array_class*: Defaults to Array
  def parse(source, opts = {})
    Parser.new(source, opts).parse
  end

  # Parse the JSON document _source_ into a Ruby data structure and return it.
  # The bang version of the parse method, defaults to the more dangerous values
  # for the _opts_ hash, so be sure only to parse trusted _source_ documents.
  #
  # _opts_ can have the following keys:
  # * *max_nesting*: The maximum depth of nesting allowed in the parsed data
  #   structures. Enable depth checking with :max_nesting => anInteger. The parse!
  #   methods defaults to not doing max depth checking: This can be dangerous,
  #   if someone wants to fill up your stack.
  # * *allow_nan*: If set to true, allow NaN, Infinity, and -Infinity in
  #   defiance of RFC 4627 to be parsed by the Parser. This option defaults
  #   to true.
  # * *create_additions*: If set to false, the Parser doesn't create
  #   additions even if a matchin class and create_id was found. This option
  #   defaults to true.
  def parse!(source, opts = {})
    opts = {
      :max_nesting  => false,
      :allow_nan    => true
    }.update(opts)
    Parser.new(source, opts).parse
  end

  # Generate a JSON document from the Ruby data structure _obj_ and return
  # it. _state_ is * a JSON::State object,
  # * or a Hash like object (responding to to_hash),
  # * an object convertible into a hash by a to_h method,
  # that is used as or to configure a State object.
  #
  # It defaults to a state object, that creates the shortest possible JSON text
  # in one line, checks for circular data structures and doesn't allow NaN,
  # Infinity, and -Infinity.
  #
  # A _state_ hash can have the following keys:
  # * *indent*: a string used to indent levels (default: ''),
  # * *space*: a string that is put after, a : or , delimiter (default: ''),
  # * *space_before*: a string that is put before a : pair delimiter (default: ''),
  # * *object_nl*: a string that is put at the end of a JSON object (default: ''), 
  # * *array_nl*: a string that is put at the end of a JSON array (default: ''),
  # * *allow_nan*: true if NaN, Infinity, and -Infinity should be
  #   generated, otherwise an exception is thrown, if these values are
  #   encountered. This options defaults to false.
  # * *max_nesting*: The maximum depth of nesting allowed in the data
  #   structures from which JSON is to be generated. Disable depth checking
  #   with :max_nesting => false, it defaults to 19.
  #
  # See also the fast_generate for the fastest creation method with the least
  # amount of sanity checks, and the pretty_generate method for some
  # defaults for a pretty output.
  def generate(obj, opts = nil)
    state = SAFE_STATE_PROTOTYPE.dup
    if opts
      if opts.respond_to? :to_hash
        opts = opts.to_hash
      elsif opts.respond_to? :to_h
        opts = opts.to_h
      else
        raise TypeError, "can't convert #{opts.class} into Hash"
      end
      state = state.configure(opts)
    end
    state.generate(obj)
  end

  # :stopdoc:
  # I want to deprecate these later, so I'll first be silent about them, and
  # later delete them.
  alias unparse generate
  module_function :unparse
  # :startdoc:

  # Generate a JSON document from the Ruby data structure _obj_ and return it.
  # This method disables the checks for circles in Ruby objects.
  #
  # *WARNING*: Be careful not to pass any Ruby data structures with circles as
  # _obj_ argument, because this will cause JSON to go into an infinite loop.
  def fast_generate(obj, opts = nil)
    state = FAST_STATE_PROTOTYPE.dup
    if opts
      if opts.respond_to? :to_hash
        opts = opts.to_hash
      elsif opts.respond_to? :to_h
        opts = opts.to_h
      else
        raise TypeError, "can't convert #{opts.class} into Hash"
      end
      state.configure(opts)
    end
    state.generate(obj)
  end

  # :stopdoc:
  # I want to deprecate these later, so I'll first be silent about them, and later delete them.
  alias fast_unparse fast_generate
  module_function :fast_unparse
  # :startdoc:

  # Generate a JSON document from the Ruby data structure _obj_ and return it.
  # The returned document is a prettier form of the document returned by
  # #unparse.
  #
  # The _opts_ argument can be used to configure the generator, see the
  # generate method for a more detailed explanation.
  def pretty_generate(obj, opts = nil)
    state = PRETTY_STATE_PROTOTYPE.dup
    if opts
      if opts.respond_to? :to_hash
        opts = opts.to_hash
      elsif opts.respond_to? :to_h
        opts = opts.to_h
      else
        raise TypeError, "can't convert #{opts.class} into Hash"
      end
      state.configure(opts)
    end
    state.generate(obj)
  end

  # :stopdoc:
  # I want to deprecate these later, so I'll first be silent about them, and later delete them.
  alias pretty_unparse pretty_generate
  module_function :pretty_unparse
  # :startdoc:

  # Load a ruby data structure from a JSON _source_ and return it. A source can
  # either be a string-like object, an IO like object, or an object responding
  # to the read method. If _proc_ was given, it will be called with any nested
  # Ruby object as an argument recursively in depth first order.
  #
  # This method is part of the implementation of the load/dump interface of
  # Marshal and YAML.
  def load(source, proc = nil)
    if source.respond_to? :to_str
      source = source.to_str
    elsif source.respond_to? :to_io
      source = source.to_io.read
    else
      source = source.read
    end
    result = parse(source, :max_nesting => false, :allow_nan => true)
    recurse_proc(result, &proc) if proc
    result
  end

  def recurse_proc(result, &proc)
    case result
    when Array
      result.each { |x| recurse_proc x, &proc }
      proc.call result
    when Hash
      result.each { |x, y| recurse_proc x, &proc; recurse_proc y, &proc }
      proc.call result
    else
      proc.call result
    end
  end

  alias restore load
  module_function :restore

  # Dumps _obj_ as a JSON string, i.e. calls generate on the object and returns
  # the result.
  #
  # If anIO (an IO like object or an object that responds to the write method)
  # was given, the resulting JSON is written to it.
  #
  # If the number of nested arrays or objects exceeds _limit_ an ArgumentError
  # exception is raised. This argument is similar (but not exactly the
  # same!) to the _limit_ argument in Marshal.dump.
  #
  # This method is part of the implementation of the load/dump interface of
  # Marshal and YAML.
  def dump(obj, anIO = nil, limit = nil)
    if anIO and limit.nil?
      anIO = anIO.to_io if anIO.respond_to?(:to_io)
      unless anIO.respond_to?(:write)
        limit = anIO
        anIO = nil
      end
    end
    limit ||= 0
    result = generate(obj, :allow_nan => true, :max_nesting => limit)
    if anIO
      anIO.write result
      anIO
    else
      result
    end
  rescue JSON::NestingError
    raise ArgumentError, "exceed depth limit"
  end

  # Shortuct for iconv.
  if String.method_defined?(:encode)
    def self.iconv(to, from, string)
      string.encode(to, from)
    end
  else
    require 'iconv'
    def self.iconv(to, from, string)
      Iconv.iconv(to, from, string).first
    end
  end
end

module ::Kernel
  private

  # Outputs _objs_ to STDOUT as JSON strings in the shortest form, that is in
  # one line.
  def j(*objs)
    objs.each do |obj|
      puts JSON::generate(obj, :allow_nan => true, :max_nesting => false)
    end
    nil
  end

  # Ouputs _objs_ to STDOUT as JSON strings in a pretty format, with
  # indentation and over many lines.
  def jj(*objs)
    objs.each do |obj|
      puts JSON::pretty_generate(obj, :allow_nan => true, :max_nesting => false)
    end
    nil
  end

  # If _object_ is string-like parse the string and return the parsed result as
  # a Ruby data structure. Otherwise generate a JSON text from the Ruby data
  # structure object and return it.
  #
  # The _opts_ argument is passed through to generate/parse respectively, see
  # generate and parse for their documentation.
  def JSON(object, *args)
    if object.respond_to? :to_str
      JSON.parse(object.to_str, args.first)
    else
      JSON.generate(object, args.first)
    end
  end
end

class ::Class
  # Returns true, if this class can be used to create an instance
  # from a serialised JSON string. The class has to implement a class
  # method _json_create_ that expects a hash as first parameter, which includes
  # the required data.
  def json_creatable?
    respond_to?(:json_create)
  end
end