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module Liquid
# Holds variables. Variables are only loaded "just in time"
# and are not evaluated as part of the render stage
#
# {{ monkey }}
# {{ user.name }}
#
# Variables can be combined with filters:
#
# {{ user | link }}
#
class Variable
FilterMarkupRegex = /#{FilterSeparator}\s*(.*)/om
FilterParser = /(?:\s+|#{QuotedFragment}|#{ArgumentSeparator})+/o
FilterArgsRegex = /(?:#{FilterArgumentSeparator}|#{ArgumentSeparator})\s*((?:\w+\s*\:\s*)?#{QuotedFragment})/o
JustTagAttributes = /\A#{TagAttributes}\z/o
MarkupWithQuotedFragment = /(#{QuotedFragment})(.*)/om
attr_accessor :filters, :name, :line_number
attr_reader :parse_context
alias_method :options, :parse_context
include ParserSwitching
def initialize(markup, parse_context)
@markup = markup
@name = nil
@parse_context = parse_context
@line_number = parse_context.line_number
parse_with_selected_parser(markup)
end
def raw
@markup
end
def markup_context(markup)
"in \"{{#{markup}}}\""
end
def lax_parse(markup)
@filters = []
return unless markup =~ MarkupWithQuotedFragment
name_markup = $1
filter_markup = $2
@name = Expression.parse(name_markup)
if filter_markup =~ FilterMarkupRegex
filters = $1.scan(FilterParser)
filters.each do |f|
next unless f =~ /\w+/
filtername = Regexp.last_match(0)
filterargs = f.scan(FilterArgsRegex).flatten
@filters << parse_filter_expressions(filtername, filterargs)
end
end
end
def strict_parse(markup)
@filters = []
p = Parser.new(markup)
@name = Expression.parse(p.expression)
while p.consume?(:pipe)
filtername = p.consume(:id)
filterargs = p.consume?(:colon) ? parse_filterargs(p) : []
@filters << parse_filter_expressions(filtername, filterargs)
end
p.consume(:end_of_string)
end
def parse_filterargs(p)
# first argument
filterargs = [p.argument]
# followed by comma separated others
filterargs << p.argument while p.consume?(:comma)
filterargs
end
def render(context)
obj = @filters.inject(context.evaluate(@name)) do |output, (filter_name, filter_args, filter_kwargs)|
filter_args = evaluate_filter_expressions(context, filter_args, filter_kwargs)
context.invoke(filter_name, output, *filter_args)
end
obj = context.apply_global_filter(obj)
taint_check(context, obj)
obj
end
private
def parse_filter_expressions(filter_name, unparsed_args)
filter_args = []
keyword_args = {}
unparsed_args.each do |a|
if matches = a.match(JustTagAttributes)
keyword_args[matches[1]] = Expression.parse(matches[2])
else
filter_args << Expression.parse(a)
end
end
result = [filter_name, filter_args]
result << keyword_args unless keyword_args.empty?
result
end
def evaluate_filter_expressions(context, filter_args, filter_kwargs)
parsed_args = filter_args.map{ |expr| context.evaluate(expr) }
if filter_kwargs
parsed_kwargs = {}
filter_kwargs.each do |key, expr|
parsed_kwargs[key] = context.evaluate(expr)
end
parsed_args << parsed_kwargs
end
parsed_args
end
def taint_check(context, obj)
return unless obj.tainted?
return if Template.taint_mode == :lax
@markup =~ QuotedFragment
name = Regexp.last_match(0)
error = TaintedError.new("variable '#{name}' is tainted and was not escaped")
error.line_number = line_number
error.template_name = context.template_name
case Template.taint_mode
when :warn
context.warnings << error
when :error
raise error
end
end
end
end