delegate makefile configuration to v8

therubyracer now delegates all lookup for its v8
compilation dependencies to the libv8 gem.

if you pass the --with-system-v8 flag to the libv8
gem on install, try to configure therubyracer upon
compile with the following options.

--with-v8-include, --with-v8-lib and --with-v8-dir

Otherwise, it will configure therubyracer to use
its own vendored version of v8.

.gitignore

@@ -9,3 +9,4 @@ pkg/*
 tmp/*
 lib/libv8/build/*
 lib/libv8/VERSION
+/ext/libv8/.location.yml

Rakefile

@@ -63,7 +63,10 @@ task :binary => :compile do
   gemspec = get_binary_gemspec
   gemspec.extensions.clear
   # We don't need most things for the binary
-  gemspec.files = ['lib/libv8.rb', 'ext/libv8/arch.rb', 'lib/libv8/version.rb']
+  gemspec.files = []
+  gemspec.files += ['lib/libv8.rb', 'lib/libv8/version.rb']
+  gemspec.files += ['ext/libv8/arch.rb', 'ext/libv8/location.rb', 'ext/libv8/paths.rb']
+  gemspec.files += ['ext/libv8/.location.yml']
   # V8
   gemspec.files += Dir['vendor/v8/include/*']
   gemspec.files += Dir['vendor/v8/out/**/*.a']

ext/libv8/builder.rb

@@ -0,0 +1,20 @@
+require 'libv8/compiler'
+require 'libv8/arch'
+require 'libv8/make'
+
+module Libv8
+  class Builder
+    include Libv8::Arch
+    include Libv8::Compiler
+    include Libv8::Make
+
+    def build_libv8!
+      profile = enable_config('debug') ? 'debug' : 'release'
+
+      Dir.chdir(File.expand_path '../../../vendor/v8', __FILE__) do
+        puts `env CXX=#{compiler} LINK=#{compiler} #{make} #{libv8_arch}.#{profile} GYPFLAGS="-Dhost_arch=#{libv8_arch}"`
+      end
+      return $?.exitstatus
+    end
+  end
+end

ext/libv8/extconf.rb

@@ -1,16 +1,7 @@
 require 'mkmf'
 create_makefile('libv8')
-require File.expand_path '../arch.rb', __FILE__
-require File.expand_path '../make.rb', __FILE__
-require File.expand_path '../compiler.rb', __FILE__
 
-include Libv8::Arch
-include Libv8::Make
-include Libv8::Compiler
+require File.expand_path '../location', __FILE__
+location = with_config('system-v8') ? Libv8::Location::System.new : Libv8::Location::Vendor.new
 
-profile = enable_config('debug') ? 'debug' : 'release'
-
-Dir.chdir(File.expand_path '../../../vendor/v8', __FILE__) do
-  puts `env CXX=#{compiler} LINK=#{compiler} #{make} #{libv8_arch}.#{profile} GYPFLAGS="-Dhost_arch=#{libv8_arch}"`
-end
-exit $?.exitstatus
+exit location.install!

ext/libv8/location.rb

@@ -0,0 +1,81 @@
+require 'yaml'
+require 'pathname'
+require File.expand_path '../paths', __FILE__
+
+module Libv8
+  class Location
+    def install!
+      File.open(Pathname(__FILE__).dirname.join('.location.yml'), "w") do |f|
+        f.write self.to_yaml
+      end
+      return 0
+    end
+
+    def self.load!
+      File.open(Pathname(__FILE__).dirname.join('.location.yml')) do |f|
+        YAML.load f
+      end
+    end
+
+    class Vendor < Location
+      def install!
+        require File.expand_path '../builder', __FILE__
+        builder = Libv8::Builder.new
+        exit_status = builder.build_libv8!
+        super if exit_status == 0
+        verify_installation!
+        return exit_status
+      end
+      def configure(context = MkmfContext.new)
+        context.incflags.insert 0, Libv8::Paths.include_paths.map{|p| "-I#{p}"}.join(" ")  + " "
+        context.ldflags.insert 0, Libv8::Paths.object_paths.join(" ") + " "
+      end
+
+      def verify_installation!
+        Libv8::Paths.object_paths.each do |p|
+          fail ArchiveNotFound, p unless File.exists? p
+        end
+      end
+
+      class ArchiveNotFound < StandardError
+        def initialize(filename)
+          super "libv8 did not install properly, expected binary v8 archive '#{filename}'to exist, but it was not found"
+        end
+      end
+    end
+
+    class System < Location
+      def configure(context = MkmfContext.new)
+        context.dir_config('v8')
+        context.find_header('v8.h') or fail NotFoundError
+      end
+
+      class NotFoundError < StandardError
+        def initialize(*args)
+          super(<<-EOS)
+You have chosen to use the version of V8 found on your system
+and *not* the one that is bundle with the libv8 rubygem. However,
+it could not be located. please make sure you have a version of
+v8 that is compatible with #{Libv8::VERSION} installed. You may
+need to special --with-v8-dir options if it is in a non-standard
+location
+
+thanks,
+The Mgmt
+
+EOS
+        end
+      end
+    end
+
+    class MkmfContext
+      def incflags
+        $INCFLAGS
+      end
+
+      def ldflags
+        $LDFLAGS
+      end
+    end
+  end
+end

ext/libv8/paths.rb

@@ -0,0 +1,38 @@
+require 'rbconfig'
+require File.expand_path '../arch', __FILE__
+
+module Libv8
+  module Paths
+    module_function
+
+    def include_paths
+      ["#{vendored_source_path}/include"]
+    end
+
+    def object_paths
+      [libv8_object(:base), libv8_object(:snapshot)]
+    end
+
+    def config
+      RbConfig::MAKEFILE_CONFIG
+    end
+
+    def libv8_object(name)
+      filename = "#{libv8_profile}/libv8_#{name}.#{config['LIBEXT']}"
+      unless File.exists? filename
+        filename = "#{libv8_profile}/obj.target/tools/gyp/libv8_#{name}.#{config['LIBEXT']}"
+      end
+      return filename
+    end
+
+    def libv8_profile
+      base = "#{vendored_source_path}/out/#{Libv8::Arch.libv8_arch}"
+      debug = "#{base}.debug"
+      File.exists?(debug) ? debug : "#{base}.release"
+    end
+
+    def vendored_source_path
+      File.expand_path "../../../vendor/v8", __FILE__
+    end
+  end
+end

lib/libv8.rb

@@ -1,61 +1,9 @@
-require 'rbconfig'
+require 'libv8/version'
+require 'libv8/location'
 
-require 'libv8/arch'
 module Libv8
-
-  module_function
-
-  def config
-    Config::MAKEFILE_CONFIG
-  end
-
-  def libv8_object(name)
-    filename = "#{libv8_profile}/libv8_#{name}.#{config['LIBEXT']}"
-    unless File.exists? filename
-      filename = "#{libv8_profile}/obj.target/tools/gyp/libv8_#{name}.#{config['LIBEXT']}"
-    end
-    return filename
-  end
-
-  def libv8_profile
-    base = "#{libv8_source_path}/out/#{Libv8::Arch.libv8_arch}"
-    debug = "#{base}.debug"
-    File.exists?(debug) ? debug : "#{base}.release"
-  end
-
-  def libv8_base
-    libv8_object :base
-  end
-
-  def libv8_snapshot
-    libv8_object :snapshot
-  end
-
-  def libv8_nosnapshot
-    libv8_object :nosnapshot
-  end
-
-  def libv8_objects(*names)
-    names = [:base, :snapshot] if names.empty?
-    names.map do |name|
-      fail "no libv8 object #{name}" unless File.exists?(object = libv8_object(name))
-      object
-    end
-  end
-
-  def libv8_ldflags
-    "-L#{libv8_base} -L#{libv8_snapshot}"
-  end
-
-  def libv8_include_flags
-    "-I#{libv8_include_path}"
-  end
-
-  def libv8_include_path
-    "#{libv8_source_path}/include"
-  end
-
-  def libv8_source_path
-    File.expand_path "../../vendor/v8", __FILE__
+  def self.configure_makefile
+    location = Location.load!
+    location.configure
   end
 end

lib/libv8/version.rb

@@ -1,3 +1,3 @@
 module Libv8
-  VERSION = "3.11.8.3"
+  VERSION = "3.11.8.5"
 end

libv8.gemspec

@@ -24,7 +24,8 @@ Gem::Specification.new do |s|
   s.extensions = ["ext/libv8/extconf.rb"]
   s.require_paths = ["lib", "ext"]
 
-  s.add_development_dependency "rake", "~> 0.9.2"
+  s.add_development_dependency "rake"
   s.add_development_dependency "rake-compiler"
   s.add_development_dependency "rspec"
+  s.add_development_dependency "rspec-spies"
 end

spec/location_spec.rb

@@ -0,0 +1,51 @@
+require 'spec_helper'
+
+describe "libv8 locations" do
+  before do
+    @context = mock(:CompilationContext)
+  end
+  describe "the system location" do
+    before do
+      @location = Libv8::Location::System.new
+      @context.stub(:dir_config)
+    end
+    describe "configuring a compliation context with it" do
+      before do
+        @context.stub(:find_header) {true}
+        @location.configure @context
+      end
+      it "adds the include path to the front of the include flags" do
+        @context.should have_received(:dir_config).with 'v8'
+        @context.should have_received(:find_header).with 'v8.h'
+      end
+    end
+    describe "when the v8.h header cannot be found" do
+      before do
+        @context.stub(:find_header) {false}
+      end
+      it "raises a NotFoundError" do
+        expect {@location.configure @context}.to raise_error Libv8::Location::System::NotFoundError
+      end
+    end
+  end
+
+  describe "the vendor location" do
+    before do
+      @location = Libv8::Location::Vendor.new
+      @context.stub(:incflags) {@incflags ||= "-I/usr/include -I/usr/local/include"}
+      @context.stub(:ldflags) {@ldflags ||= "-lobjc -lpthread"}
+
+      Libv8::Paths.stub(:include_paths) {["/frp/v8/include"]}
+      Libv8::Paths.stub(:object_paths) {["/frp/v8/obj/libv8_base.a", "/frp/v8/obj/libv8_snapshot.a"]}
+      @location.configure @context
+    end
+
+    it "prepends its own incflags before any pre-existing ones" do
+      @context.incflags.should eql "-I/frp/v8/include -I/usr/include -I/usr/local/include"
+    end
+
+    it "prepends the locations of any libv8 objects on the the ldflags" do
+      @context.ldflags.should eql "/frp/v8/obj/libv8_base.a /frp/v8/obj/libv8_snapshot.a -lobjc -lpthread"
+    end
+  end
+end

spec/spec_helper.rb

@@ -1,2 +1,4 @@
 $:.unshift File.expand_path '../../lib', __FILE__
-require 'libv8'
+require 'rspec'
+require 'rspec-spies'
+require 'libv8'