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compiler.rb
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# frozen_string_literal: true #-- # ERB::Compiler # # Compiles ERB templates into Ruby code; the compiled code produces the # template result when evaluated. ERB::Compiler provides hooks to define how # generated output is handled. # # Internally ERB does something like this to generate the code returned by # ERB#src: # # compiler = ERB::Compiler.new('<>') # compiler.pre_cmd = ["_erbout=+''"] # compiler.put_cmd = "_erbout.<<" # compiler.insert_cmd = "_erbout.<<" # compiler.post_cmd = ["_erbout"] # # code, enc = compiler.compile("Got <%= obj %>!\n") # puts code # # <i>Generates</i>: # # #coding:UTF-8 # _erbout=+''; _erbout.<< "Got ".freeze; _erbout.<<(( obj ).to_s); _erbout.<< "!\n".freeze; _erbout # # By default the output is sent to the print method. For example: # # compiler = ERB::Compiler.new('<>') # code, enc = compiler.compile("Got <%= obj %>!\n") # puts code # # <i>Generates</i>: # # #coding:UTF-8 # print "Got ".freeze; print(( obj ).to_s); print "!\n".freeze # # == Evaluation # # The compiled code can be used in any context where the names in the code # correctly resolve. Using the last example, each of these print 'Got It!' # # Evaluate using a variable: # # obj = 'It' # eval code # # Evaluate using an input: # # mod = Module.new # mod.module_eval %{ # def get(obj) # #{code} # end # } # extend mod # get('It') # # Evaluate using an accessor: # # klass = Class.new Object # klass.class_eval %{ # attr_accessor :obj # def initialize(obj) # @obj = obj # end # def get_it # #{code} # end # } # klass.new('It').get_it # # Good! See also ERB#def_method, ERB#def_module, and ERB#def_class. class ERB::Compiler # :nodoc: class PercentLine # :nodoc: def initialize(str) @value = str end attr_reader :value alias :to_s :value end class Scanner # :nodoc: @scanner_map = {} class << self def register_scanner(klass, trim_mode, percent) @scanner_map[[trim_mode, percent]] = klass end alias :regist_scanner :register_scanner end def self.default_scanner=(klass) @default_scanner = klass end def self.make_scanner(src, trim_mode, percent) klass = @scanner_map.fetch([trim_mode, percent], @default_scanner) klass.new(src, trim_mode, percent) end DEFAULT_STAGS = %w(<%% <%= <%# <%).freeze DEFAULT_ETAGS = %w(%%> %>).freeze def initialize(src, trim_mode, percent) @src = src @stag = nil @stags = DEFAULT_STAGS @etags = DEFAULT_ETAGS end attr_accessor :stag attr_reader :stags, :etags def scan; end end class TrimScanner < Scanner # :nodoc: def initialize(src, trim_mode, percent) super @trim_mode = trim_mode @percent = percent if @trim_mode == '>' @scan_reg = /(.*?)(%>\r?\n|#{(stags + etags).join('|')}|\n|\z)/m @scan_line = self.method(:trim_line1) elsif @trim_mode == '<>' @scan_reg = /(.*?)(%>\r?\n|#{(stags + etags).join('|')}|\n|\z)/m @scan_line = self.method(:trim_line2) elsif @trim_mode == '-' @scan_reg = /(.*?)(^[ \t]*<%\-|<%\-|-%>\r?\n|-%>|#{(stags + etags).join('|')}|\z)/m @scan_line = self.method(:explicit_trim_line) else @scan_reg = /(.*?)(#{(stags + etags).join('|')}|\n|\z)/m @scan_line = self.method(:scan_line) end end def scan(&block) @stag = nil if @percent @src.each_line do |line| percent_line(line, &block) end else @scan_line.call(@src, &block) end nil end def percent_line(line, &block) if @stag || line[0] != ?% return @scan_line.call(line, &block) end line[0] = '' if line[0] == ?% @scan_line.call(line, &block) else yield(PercentLine.new(line.chomp)) end end def scan_line(line) line.scan(@scan_reg) do |tokens| tokens.each do |token| next if token.empty? yield(token) end end end def trim_line1(line) line.scan(@scan_reg) do |tokens| tokens.each do |token| next if token.empty? if token == "%>\n" || token == "%>\r\n" yield('%>') yield(:cr) else yield(token) end end end end def trim_line2(line) head = nil line.scan(@scan_reg) do |tokens| tokens.each do |token| next if token.empty? head = token unless head if token == "%>\n" || token == "%>\r\n" yield('%>') if is_erb_stag?(head) yield(:cr) else yield("\n") end head = nil else yield(token) head = nil if token == "\n" end end end end def explicit_trim_line(line) line.scan(@scan_reg) do |tokens| tokens.each do |token| next if token.empty? if @stag.nil? && /[ \t]*<%-/ =~ token yield('<%') elsif @stag && (token == "-%>\n" || token == "-%>\r\n") yield('%>') yield(:cr) elsif @stag && token == '-%>' yield('%>') else yield(token) end end end end ERB_STAG = %w(<%= <%# <%) def is_erb_stag?(s) ERB_STAG.member?(s) end end Scanner.default_scanner = TrimScanner begin require 'strscan' rescue LoadError else class SimpleScanner < Scanner # :nodoc: def scan stag_reg = (stags == DEFAULT_STAGS) ? /(.*?)(<%[%=#]?|\z)/m : /(.*?)(#{stags.join('|')}|\z)/m etag_reg = (etags == DEFAULT_ETAGS) ? /(.*?)(%%?>|\z)/m : /(.*?)(#{etags.join('|')}|\z)/m scanner = StringScanner.new(@src) while ! scanner.eos? scanner.scan(@stag ? etag_reg : stag_reg) yield(scanner[1]) yield(scanner[2]) end end end Scanner.register_scanner(SimpleScanner, nil, false) class ExplicitScanner < Scanner # :nodoc: def scan stag_reg = /(.*?)(^[ \t]*<%-|<%-|#{stags.join('|')}|\z)/m etag_reg = /(.*?)(-%>|#{etags.join('|')}|\z)/m scanner = StringScanner.new(@src) while ! scanner.eos? scanner.scan(@stag ? etag_reg : stag_reg) yield(scanner[1]) elem = scanner[2] if /[ \t]*<%-/ =~ elem yield('<%') elsif elem == '-%>' yield('%>') yield(:cr) if scanner.scan(/(\r?\n|\z)/) else yield(elem) end end end end Scanner.register_scanner(ExplicitScanner, '-', false) end class Buffer # :nodoc: def initialize(compiler, enc=nil, frozen=nil) @compiler = compiler @line = [] @script = +'' @script << "#coding:#{enc}\n" if enc @script << "#frozen-string-literal:#{frozen}\n" unless frozen.nil? @compiler.pre_cmd.each do |x| push(x) end end attr_reader :script def push(cmd) @line << cmd end def cr @script << (@line.join('; ')) @line = [] @script << "\n" end def close return unless @line @compiler.post_cmd.each do |x| push(x) end @script << (@line.join('; ')) @line = nil end end def add_put_cmd(out, content) out.push("#{@put_cmd} #{content.dump}.freeze#{"\n" * content.count("\n")}") end def add_insert_cmd(out, content) out.push("#{@insert_cmd}((#{content}).to_s)") end # Compiles an ERB template into Ruby code. Returns an array of the code # and encoding like ["code", Encoding]. def compile(s) enc = s.encoding raise ArgumentError, "#{enc} is not ASCII compatible" if enc.dummy? s = s.b # see String#b magic_comment = detect_magic_comment(s, enc) out = Buffer.new(self, *magic_comment) self.content = +'' scanner = make_scanner(s) scanner.scan do |token| next if token.nil? next if token == '' if scanner.stag.nil? compile_stag(token, out, scanner) else compile_etag(token, out, scanner) end end add_put_cmd(out, content) if content.size > 0 out.close return out.script, *magic_comment end def compile_stag(stag, out, scanner) case stag when PercentLine add_put_cmd(out, content) if content.size > 0 self.content = +'' out.push(stag.to_s) out.cr when :cr out.cr when '<%', '<%=', '<%#' scanner.stag = stag add_put_cmd(out, content) if content.size > 0 self.content = +'' when "\n" content << "\n" add_put_cmd(out, content) self.content = +'' when '<%%' content << '<%' else content << stag end end def compile_etag(etag, out, scanner) case etag when '%>' compile_content(scanner.stag, out) scanner.stag = nil self.content = +'' when '%%>' content << '%>' else content << etag end end def compile_content(stag, out) case stag when '<%' if content[-1] == ?\n content.chop! out.push(content) out.cr else out.push(content) end when '<%=' add_insert_cmd(out, content) when '<%#' out.push("\n" * content.count("\n")) # only adjust lineno end end def prepare_trim_mode(mode) # :nodoc: case mode when 1 return [false, '>'] when 2 return [false, '<>'] when 0, nil return [false, nil] when String unless mode.match?(/\A(%|-|>|<>){1,2}\z/) warn_invalid_trim_mode(mode, uplevel: 5) end perc = mode.include?('%') if mode.include?('-') return [perc, '-'] elsif mode.include?('<>') return [perc, '<>'] elsif mode.include?('>') return [perc, '>'] else [perc, nil] end else warn_invalid_trim_mode(mode, uplevel: 5) return [false, nil] end end def make_scanner(src) # :nodoc: Scanner.make_scanner(src, @trim_mode, @percent) end # Construct a new compiler using the trim_mode. See ERB::new for available # trim modes. def initialize(trim_mode) @percent, @trim_mode = prepare_trim_mode(trim_mode) @put_cmd = 'print' @insert_cmd = @put_cmd @pre_cmd = [] @post_cmd = [] end attr_reader :percent, :trim_mode # The command to handle text that ends with a newline attr_accessor :put_cmd # The command to handle text that is inserted prior to a newline attr_accessor :insert_cmd # An array of commands prepended to compiled code attr_accessor :pre_cmd # An array of commands appended to compiled code attr_accessor :post_cmd private # A buffered text in #compile attr_accessor :content def detect_magic_comment(s, enc = nil) re = @percent ? /\G(?:<%#(.*)%>|%#(.*)\n)/ : /\G<%#(.*)%>/ frozen = nil s.scan(re) do comment = $+ comment = $1 if comment[/-\*-\s*([^\s].*?)\s*-\*-$/] case comment when %r"coding\s*[=:]\s*([[:alnum:]\-_]+)" enc = Encoding.find($1.sub(/-(?:mac|dos|unix)/i, '')) when %r"frozen[-_]string[-_]literal\s*:\s*([[:alnum:]]+)" frozen = $1 end end return enc, frozen end def warn_invalid_trim_mode(mode, uplevel:) warn "Invalid ERB trim mode: #{mode.inspect} (trim_mode: nil, 0, 1, 2, or String composed of '%' and/or '-', '>', '<>')", uplevel: uplevel + 1 end end