Class: Fluent::Config::LiteralParser

Inherits:
BasicParser show all
Defined in:
lib/fluent/config/literal_parser.rb

Direct Known Subclasses

V1Parser

Constant Summary collapse

LINE_BREAK =

A physical line break (LF, CR, or CRLF) inside a quoted string. CRLF is normalized to LF so that the same config text does not produce a different value depending on whether the file was saved with LF or CRLF. A lone CR is kept as-is, and an escaped "\r\n" still produces CRLF.

/\r\n|[\r\n]/
LINE_CONTINUATION =

A backslash immediately followed by a physical line break. It works as a line continuation, so both are stripped from the value.

/\\#{LINE_BREAK}/o

Constants inherited from BasicParser

BasicParser::LINE_END, BasicParser::SPACING, BasicParser::SPACING_WITHOUT_COMMENT, BasicParser::ZERO_OR_MORE_SPACING

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from BasicParser

#check, #eof?, #error_sample, #getch, #line_end, #parse_error!, #prev_match, #scan, #skip, #spacing, #spacing_without_comment

Methods included from BasicParser::ClassMethods

#def_literal, #def_symbol, #symbol

Constructor Details

#initialize(strscan, eval_context) ⇒ LiteralParser

Returns a new instance of LiteralParser.



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# File 'lib/fluent/config/literal_parser.rb', line 62

def initialize(strscan, eval_context)
  super(strscan)
  @eval_context = eval_context
  unless @eval_context.respond_to?(:use_nil)
    def @eval_context.use_nil
      raise SetNil
    end
  end
  unless @eval_context.respond_to?(:use_default)
    def @eval_context.use_default
      raise SetDefault
    end
  end
end

Class Method Details

.unescape_char(c) ⇒ Object 



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# File 'lib/fluent/config/literal_parser.rb', line 39

def self.unescape_char(c)
  case c
  when '"'
    '\"'
  when "'"
    "\\'"
  when '\\'
    '\\\\'
  when "\r"
    '\r'
  when "\n"
    '\n'
  when "\t"
    '\t'
  when "\f"
    '\f'
  when "\b"
    '\b'
  else
    c
  end
end

Instance Method Details

#eval_embedded_code(code) ⇒ Object 



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# File 'lib/fluent/config/literal_parser.rb', line 194

def eval_embedded_code(code)
  if @eval_context.nil?
    parse_error! "embedded code is not allowed in this file"
  end
  # Add hostname and worker_id to code for preventing unused warnings
  code = "hostname = Socket.gethostname\nworker_id = ENV['SERVERENGINE_WORKER_ID'] || ''\n" + code
  begin
    @eval_context.instance_eval(code)
  rescue SetNil
    nil
  rescue SetDefault
    :default
  end
end

#eval_escape_char(c) ⇒ Object 



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# File 'lib/fluent/config/literal_parser.rb', line 212

def eval_escape_char(c)
  case c
  when '"'
    '"'
  when "'"
    "'"
  when "r"
    "\r"
  when "n"
    "\n"
  when "t"
    "\t"
  when "f"
    "\f"
  when "b"
    "\b"
  when "0"
    "\0"
  when /[a-zA-Z0-9]/
    parse_error! "unexpected back-slash escape character '#{c}'"
  else  # symbols
    c
  end
end

#parse_literal(string_boundary_charset = LINE_END) ⇒ Object 



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# File 'lib/fluent/config/literal_parser.rb', line 77

def parse_literal(string_boundary_charset = LINE_END)
  spacing_without_comment

  value = if skip(/\[/)
            scan_json(true)
          elsif skip(/\{/)
            scan_json(false)
          else
            scan_string(string_boundary_charset)
          end
  value
end

#scan_double_quoted_string ⇒ Object 



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# File 'lib/fluent/config/literal_parser.rb', line 100

def scan_double_quoted_string
  string = []
  while true
    if skip(/\"/)
      if string.include?(nil)
        return nil
      elsif string.include?(:default)
        return :default
      else
        return string.join
      end
    elsif skip(LINE_CONTINUATION)
      next
    elsif s = scan(LINE_BREAK)
      string << (s == "\r\n" ? "\n" : s)
    elsif s = scan(/\\./)
      string << eval_escape_char(s[1,1])
    elsif skip(/\#\{/)
      string << eval_embedded_code(scan_embedded_code)
      skip(/\}/)
    elsif s = scan(/./)
      string << s
    else
      parse_error! "unexpected end of file in a double quoted string"
    end
  end
end

#scan_embedded_code ⇒ Object 



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# File 'lib/fluent/config/literal_parser.rb', line 168

def scan_embedded_code
  src = '"#{'+@ss.rest+"\n=begin\n=end\n}"

  seek = -1
  while (seek = src.index('}', seek + 1))
    unless Ripper.sexp(src[0..seek] + '"').nil? # eager parsing until valid expression
      break
    end
  end

  unless seek
    raise Fluent::ConfigParseError, @ss.rest
  end

  code = src[3, seek-3]

  if @ss.rest.length < code.length
    @ss.pos += @ss.rest.length
    parse_error! "expected end of embedded code but $end"
  end

  @ss.pos += code.length

  '"#{' + code + '}"'
end

#scan_json(is_array) ⇒ Object 



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# File 'lib/fluent/config/literal_parser.rb', line 237

def scan_json(is_array)
  result = nil
  # Yajl does not raise ParseError for incomplete json string, like '[1', '{"h"', '{"h":' or '{"h1":1'
  # This is the reason to use JSON module.

  buffer = (is_array ? "[" : "{")
  line_buffer = ""

  until result
    char = getch

    break if char.nil?

    if char == "#"
      # If this is out of json string literals, this object can be parsed correctly
      # '{"foo":"bar", #' -> '{"foo":"bar"}' (to check)
      parsed = nil
      begin
        parsed = JSON.parse(buffer + line_buffer.rstrip.sub(/,$/, '') + (is_array ? "]" : "}"), **Fluent::DEFAULT_JSON_PARSE_OPTIONS)
      rescue JSON::ParserError
        # This '#' is in json string literals
      end

      if parsed
        # ignore chars as comment before newline
        while (char = getch) != "\n"
          # ignore comment char
        end
        buffer << line_buffer + "\n"
        line_buffer = ""
      else
        if @ss.exist?(/^\{[^}]+\}/)
          # if it's interpolated string
          skip(/\{/)
          line_buffer << eval_embedded_code(scan_embedded_code)
          skip(/\}/)
        else
          # '#' is a char in json string
          line_buffer << char
        end
      end

      next # This char '#' MUST NOT terminate json object.
    end

    if char == "\n"
      buffer << line_buffer + "\n"
      line_buffer = ""
      next
    end

    line_buffer << char
    begin
      result = JSON.parse(buffer + line_buffer, **Fluent::DEFAULT_JSON_PARSE_OPTIONS)
    rescue JSON::ParserError
      # Incomplete json string yet
    end
  end

  unless result
    parse_error! "got incomplete JSON #{is_array ? 'array' : 'hash'} configuration"
  end

  JSON.dump(result)
end

#scan_nonquoted_string(boundary_charset = LINE_END) ⇒ Object 



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# File 'lib/fluent/config/literal_parser.rb', line 147

def scan_nonquoted_string(boundary_charset = LINE_END)
  charset = /(?!#{boundary_charset})./

  string = []
  while true
    if s = scan(/\#/)
      string << '#'
    elsif s = scan(charset)
      string << s
    else
      break
    end
  end

  if string.empty?
    return nil
  end

  string.join
end

#scan_single_quoted_string ⇒ Object 



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# File 'lib/fluent/config/literal_parser.rb', line 128

def scan_single_quoted_string
  string = []
  while true
    if skip(/\'/)
      return string.join
    elsif s = scan(/\\'/)
      string << "'"
    elsif s = scan(/\\\\/)
      string << "\\"
    elsif s = scan(LINE_BREAK)
      string << (s == "\r\n" ? "\n" : s)
    elsif s = scan(/./)
      string << s
    else
      parse_error! "unexpected end of file in a single quoted string"
    end
  end
end

#scan_string(string_boundary_charset = LINE_END) ⇒ Object 



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# File 'lib/fluent/config/literal_parser.rb', line 90

def scan_string(string_boundary_charset = LINE_END)
  if skip(/\"/)
    return scan_double_quoted_string
  elsif skip(/\'/)
    return scan_single_quoted_string
  else
    return scan_nonquoted_string(string_boundary_charset)
  end
end