/
literal_parser.rb
286 lines (252 loc) · 7.07 KB
/
literal_parser.rb
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#
# Fluentd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
require 'stringio'
require 'json'
require 'yajl'
require 'socket'
require 'ripper'
require 'fluent/config/basic_parser'
module Fluent
module Config
class LiteralParser < BasicParser
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
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
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
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
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 check(/[^"]#{LINE_END_WITHOUT_SPACING_AND_COMMENT}/)
if s = check(/[^\\]#{LINE_END_WITHOUT_SPACING_AND_COMMENT}/)
string << s
end
skip(/[^"]#{LINE_END_WITHOUT_SPACING_AND_COMMENT}/)
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
def scan_single_quoted_string
string = []
while true
if skip(/\'/)
return string.join
elsif s = scan(/\\'/)
string << "'"
elsif s = scan(/\\\\/)
string << "\\"
elsif s = scan(/./)
string << s
else
parse_error! "unexpected end of file in a single quoted string"
end
end
end
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
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 $end"
end
@ss.pos += code.length
'"#{' + code + '}"'
end
def eval_embedded_code(code)
if @eval_context.nil?
parse_error! "embedded code is not allowed in this file"
end
# Add hostname and worker_id to code for preventing unused warnings
code = <<EOM + code
hostname = Socket.gethostname
worker_id = ENV['SERVERENGINE_WORKER_ID'] || ''
EOM
begin
@eval_context.instance_eval(code)
rescue SetNil
nil
rescue SetDefault
:default
end
end
def eval_escape_char(c)
case c
when '"'
'"'
when "'"
"'"
when "r"
"\r"
when "n"
"\n"
when "t"
"\t"
when "f"
"\f"
when "b"
"\b"
when "0"
"\0"
when /[a-zA-Z0-9]/
parse_error! "unexpected back-slash escape character '#{c}'"
else # symbols
c
end
end
def scan_json(is_array)
result = nil
# Yajl does not raise ParseError for incomplete json string, like '[1', '{"h"', '{"h":' or '{"h1":1'
# This is the reason to use JSON module.
buffer = (is_array ? "[" : "{")
line_buffer = ""
until result
char = getch
break if char.nil?
if char == "#"
# If this is out of json string literals, this object can be parsed correctly
# '{"foo":"bar", #' -> '{"foo":"bar"}' (to check)
parsed = nil
begin
parsed = JSON.parse(buffer + line_buffer.rstrip.sub(/,$/, '') + (is_array ? "]" : "}"))
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
# '#' is a char in json string
line_buffer << char
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)
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
end
end
end