Commit b2a30218 authored by Rene Saarsoo's avatar Rene Saarsoo
Browse files

Switch again back to using ExecJS middle-layer. 

This is to allow third-party packaging of JSDuck without the
inconvenient dependency on therubyracer gem.

Fixes: #339
parent ce8312ca

jsduck.gemspec

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ Gem::Specification.new do |s| 
  s.add_dependency 'rdiscount'

  s.add_dependency 'json'

  s.add_dependency 'parallel'

  s.add_dependency 'execjs'

  s.add_dependency 'therubyracer', '>= 0.10.0', '< 0.11.0'

  s.add_dependency 'dimensions'

lib/jsduck/esprima.rb

+24 −9
Original line number Diff line number Diff line 
require 'v8'

require 'execjs'

require 'jsduck/util/json'

require 'jsduck/util/singleton'



module JsDuck



  # Runs Esprima.js through V8.

  # Runs Esprima.js through JavaScript runtime selected by ExecJS.

  # Normally this will be V8 engine within therubyracer gem, but when

  # JSDuck is installed through some other means than rubygems, then

  # one could use any of the runtimes supported by ExecJS.  (NodeJS

  # for example.)

  #

  # Initialized as singleton to avoid loading the esprima.js more

  # than once - otherwise performace will severely suffer.
@@ -12,23 +16,34 @@ module JsDuck 
    include Util::Singleton



    def initialize

      @v8 = V8::Context.new

      esprima = File.dirname(File.expand_path(__FILE__))+"/esprima/esprima.js";

      esprima_path = File.dirname(File.expand_path(__FILE__)) + "/esprima/esprima.js"

      esprima = IO.read(esprima_path)



      # Esprima attempts to assign to window.esprima, but our v8

      # engine has no global window variable defined.  So define our

      # own and then grab esprima out from it again.

      @v8.eval("var window = {};")

      @v8.load(esprima)

      @v8.eval("var esprima = window.esprima;")

      source = <<-EOJS

        if (typeof window === "undefined") {

            var window = {};

        }



        #{esprima}



        var esprima = window.esprima;



        function runEsprima(js) {

          return JSON.stringify(esprima.parse(js, {comment: true, range: true, raw: true}));

        }

      EOJS



      @context = ExecJS.compile(source)

    end



    # Parses JavaScript source code using Esprima.js

    #

    # Returns the resulting AST

    def parse(input)

      @v8['js'] = input

      json = @v8.eval("JSON.stringify(esprima.parse(js, {comment: true, range: true, raw: true}))")

      json = @context.call("runEsprima", input)

      return Util::Json.parse(json, :max_nesting => false)

    end