Class: JSON::Pure::Parser

Inherits:
StringScanner
  • Object
show all
Defined in:
lib/json/pure/parser.rb

Overview

This class implements the JSON parser that is used to parse a JSON string into a Ruby data structure.

Constant Summary collapse

STRING = 
/" ((?:[^\x0-\x1f"\\] |
     # escaped special characters:
    \\["\\\/bfnrt] |
    \\u[0-9a-fA-F]{4} |
     # match all but escaped special characters:
    \\[\x20-\x21\x23-\x2e\x30-\x5b\x5d-\x61\x63-\x65\x67-\x6d\x6f-\x71\x73\x75-\xff])*)
"/nx
INTEGER = 
/(-?0|-?[1-9]\d*)/
FLOAT = 
/(-?
(?:0|[1-9]\d*)
(?:
  \.\d+(?i:e[+-]?\d+) |
  \.\d+ |
  (?i:e[+-]?\d+)
)
)/x
NAN = 
/NaN/
INFINITY = 
/Infinity/
MINUS_INFINITY = 
/-Infinity/
OBJECT_OPEN = 
/\{/
OBJECT_CLOSE = 
/\}/
ARRAY_OPEN = 
/\[/
ARRAY_CLOSE = 
/\]/
PAIR_DELIMITER = 
/:/
COLLECTION_DELIMITER = 
/,/
TRUE = 
/true/
FALSE = 
/false/
NULL = 
/null/
IGNORE = 
%r(
  (?:
   //[^\n\r]*[\n\r]| # line comments
   /\*               # c-style comments
   (?:
    [^*/]|        # normal chars
    /[^*]|        # slashes that do not start a nested comment
    \*[^/]|       # asterisks that do not end this comment
    /(?=\*/)      # single slash before this comment's end 
   )*
     \*/               # the End of this comment
     |[ \t\r\n]+       # whitespaces: space, horicontal tab, lf, cr
  )+
)mx
UNPARSED = 
Object.new

Instance Method Summary collapse

Constructor Details

#initialize(source, opts = {}) ⇒ Parser

Creates a new JSON::Pure::Parser instance for the string source.

It will be configured by the opts hash. 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|nil|0, 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



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# File 'lib/json/pure/parser.rb', line 71

def initialize(source, opts = {})
  opts ||= {}
  if defined?(::Encoding)
    if source.encoding == ::Encoding::ASCII_8BIT
      b = source[0, 4].bytes.to_a
      source = case
               when b.size >= 4 && b[0] == 0 && b[1] == 0 && b[2] == 0
                 source.dup.force_encoding(::Encoding::UTF_32BE).encode!(::Encoding::UTF_8)
               when b.size >= 4 && b[0] == 0 && b[2] == 0
                 source.dup.force_encoding(::Encoding::UTF_16BE).encode!(::Encoding::UTF_8)
               when b.size >= 4 && b[1] == 0 && b[2] == 0 && b[3] == 0
                 source.dup.force_encoding(::Encoding::UTF_32LE).encode!(::Encoding::UTF_8)

               when b.size >= 4 && b[1] == 0 && b[3] == 0
                 source.dup.force_encoding(::Encoding::UTF_16LE).encode!(::Encoding::UTF_8)
               else
                 source.dup
               end
    else
      source = source.encode(::Encoding::UTF_8)
    end
    source.force_encoding(::Encoding::ASCII_8BIT)
  else
    b = source
    source = case
             when b.size >= 4 && b[0] == 0 && b[1] == 0 && b[2] == 0
               JSON.iconv('utf-8', 'utf-32be', b)
             when b.size >= 4 && b[0] == 0 && b[2] == 0
               JSON.iconv('utf-8', 'utf-16be', b)
             when b.size >= 4 && b[1] == 0 && b[2] == 0 && b[3] == 0
               JSON.iconv('utf-8', 'utf-32le', b)
             when b.size >= 4 && b[1] == 0 && b[3] == 0
               JSON.iconv('utf-8', 'utf-16le', b)
             else
               b
             end
  end
  super source
  if !opts.key?(:max_nesting) # defaults to 19
    @max_nesting = 19
  elsif opts[:max_nesting]
    @max_nesting = opts[:max_nesting]
  else
    @max_nesting = 0
  end
  @allow_nan = !!opts[:allow_nan]
  @symbolize_names = !!opts[:symbolize_names]
  ca = true
  ca = opts[:create_additions] if opts.key?(:create_additions)
  @create_id = ca ? JSON.create_id : nil
  @object_class = opts[:object_class] || Hash
  @array_class = opts[:array_class] || Array
end

Instance Method Details

#parse ⇒ Object

Parses the current JSON string source and returns the complete data structure as a result.



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# File 'lib/json/pure/parser.rb', line 129

def parse
  reset
  obj = nil
  until eos?
    case
    when scan(OBJECT_OPEN)
      obj and raise ParserError, "source '#{peek(20)}' not in JSON!"
      @current_nesting = 1
      obj = parse_object
    when scan(ARRAY_OPEN)
      obj and raise ParserError, "source '#{peek(20)}' not in JSON!"
      @current_nesting = 1
      obj = parse_array
    when skip(IGNORE)
      ;
    else
      raise ParserError, "source '#{peek(20)}' not in JSON!"
    end
  end
  obj or raise ParserError, "source did not contain any JSON!"
  obj
end