Allow generation of multiple gems for Windows

- This allows build gems for both VC6 and MinGW builts of Ruby.

    Rake::ExtensionTask.new('my_extension', GEM_SPEC) do |ext|
      ext.cross_compile = true
      ext.cross_platform = ['i386-mswin32', 'i386-mingw32']
    end

This is highly experimental and exposed the need to refactor
ExtensionTask internals. Right now it fires the compilation
process twice, which is suboptimal.

7 files changed, 95 insertions, 13 deletions

diff --git a/features/cross-package-multi.feature b/features/cross-package-multi.feature
new file mode 100644
index 0000000..a40aa33
--- /dev/null
+++ b/features/cross-package-multi.feature
@@ -0,0 +1,15 @@
+Feature: Generate multiple Windows gems from Linux
+
+  In order to keep compatibility with versions of Ruby on Windows
+  As a Gem developer on Linux
+  I want to build binary gems for One-Click Installer (old and new versions)
+
+  Scenario: package multiple gems for Windows
+    Given that my gem source is all in place to target two platforms
+    And I'm running a POSIX operating system
+    And I've installed cross compile toolchain
+    And I've already successfully executed rake task 'cross compile'
+    When rake task 'cross native gem' is invoked
+    Then rake task 'cross native gem' succeeded
+    And gem for platform 'x86-mswin32' get generated
+    And gem for platform 'x86-mingw32' get generated
diff --git a/features/step_definitions/compilation.rb b/features/step_definitions/compilation.rb
index 2056ad9..35e72dd 100644
--- a/features/step_definitions/compilation.rb
+++ b/features/step_definitions/compilation.rb
@@ -8,6 +8,11 @@ Given /^a extension cross-compilable '(.*)'$/ do |extension_name|
   generate_source_code_for extension_name
 end
 
+Given /^a extension '(.*)' multi cross\-compilable$/ do |extension_name|
+  generate_multi_cross_compile_extension_task_for extension_name
+  generate_source_code_for extension_name
+end
+
 Given /^a extension '(.*)' with forced platform '(.*)'$/ do |extension_name, forced_platform|
   generate_extension_task_for extension_name, forced_platform
   generate_source_code_for extension_name
@@ -24,6 +29,12 @@ Given /^that my gem source is all in place$/ do
   Given "a extension cross-compilable 'extension_one'"
 end
 
+Given /^that my gem source is all in place to target two platforms$/ do
+  Given "a safe project directory"
+  Given "a gem named 'gem_abc'"
+  Given "a extension 'extension_one' multi cross-compilable"
+end
+
 Given /^not changed any file since$/ do
   # don't do anything, that's the purpose of this step!
 end
diff --git a/features/support/file_template_helpers.rb b/features/support/file_template_helpers.rb
index f4ea86c..76bed50 100644
--- a/features/support/file_template_helpers.rb
+++ b/features/support/file_template_helpers.rb
@@ -65,6 +65,16 @@ end
 EOF
   end
 
+  def template_rake_extension_multi_cross_compile(extension_name)
+    <<-EOF
+require 'rake/extensiontask'
+Rake::ExtensionTask.new("#{extension_name}", SPEC) do |ext|
+  ext.cross_compile = true
+  ext.cross_platform = ['i386-mswin32', 'i386-mingw32']
+end
+EOF
+  end
+
   def template_extconf(extension_name)
     <<-EOF
 require 'mkmf'
diff --git a/features/support/generator_helpers.rb b/features/support/generator_helpers.rb
index 2910781..c0a8e01 100644
--- a/features/support/generator_helpers.rb
+++ b/features/support/generator_helpers.rb
@@ -60,6 +60,21 @@ module GeneratorHelpers
     end
   end
 
+  def generate_multi_cross_compile_extension_task_for(extension_name)
+    # create folder structure
+    FileUtils.mkdir_p "ext/#{extension_name}"
+
+    return if File.exist?("tasks/#{extension_name}.rake")
+
+    # create specific extension rakefile
+    # Building a gem?
+    if File.exist?("tasks/gem.rake") then
+      File.open("tasks/gem.rake", 'a+') do |ext_in_gem|
+        ext_in_gem.puts template_rake_extension_multi_cross_compile(extension_name)
+      end
+    end
+  end
+
   def generate_source_code_for(extension_name)
     # source C file
     File.open("ext/#{extension_name}/source.c", 'w') do |c|
diff --git a/lib/rake/extensiontask.rb b/lib/rake/extensiontask.rb
index fb9315e..770d776 100644
--- a/lib/rake/extensiontask.rb
+++ b/lib/rake/extensiontask.rb
@@ -62,8 +62,13 @@ module Rake
       define_native_tasks if @gem_spec && @gem_spec.platform == 'ruby'
 
       # only define cross platform functionality when enabled
-      # FIXME: there is no value for having this on Windows or JRuby
-      define_cross_platform_tasks if @cross_compile
+      return unless @cross_compile
+
+      if cross_platform.is_a?(Array) then
+        cross_platform.each { |platf| define_cross_platform_tasks(platf) }
+      else
+        define_cross_platform_tasks(cross_platform)
+      end
     end
 
     private
@@ -218,7 +223,7 @@ module Rake
       end
     end
 
-    def define_cross_platform_tasks
+    def define_cross_platform_tasks(for_platform)
       config_path = File.expand_path("~/.rake-compiler/config.yml")
       ruby_ver = ENV['RUBY_CC_VERSION'] || RUBY_VERSION
 
@@ -231,7 +236,7 @@ module Rake
       config_file = YAML.load_file(config_path)
 
       # tmp_path
-      tmp_path = "#{@tmp_dir}/#{cross_platform}/#{@name}"
+      tmp_path = "#{@tmp_dir}/#{for_platform}/#{@name}"
 
       unless rbconfig_file = config_file["rbconfig-#{ruby_ver}"] then
         warn "no configuration section for specified version of Ruby (rbconfig-#{ruby_ver})"
@@ -239,7 +244,7 @@ module Rake
       end
 
       # define compilation tasks for cross platfrom!
-      define_compile_tasks(cross_platform)
+      define_compile_tasks(for_platform)
 
       # chain fake.rb and rbconfig.rb to Makefile generation
       file "#{tmp_path}/Makefile" => ["#{tmp_path}/fake.rb", "#{tmp_path}/rbconfig.rb"]
@@ -257,27 +262,31 @@ module Rake
       end
 
       # now define native tasks for cross compiled files
-      define_native_tasks(cross_platform) if @gem_spec && @gem_spec.platform == 'ruby'
+      define_native_tasks(for_platform) if @gem_spec && @gem_spec.platform == 'ruby'
 
       # create cross task
       task 'cross' do
         # clear compile dependencies
-        Rake::Task['compile'].prerequisites.clear
+        Rake::Task['compile'].prerequisites.reject! { |t| !compiles_cross_platform.include?(t) }
 
         # chain the cross platform ones
-        task 'compile' => ["compile:#{cross_platform}"]
+        task 'compile' => ["compile:#{for_platform}"]
 
         # clear lib/binary dependencies and trigger cross platform ones
         # check if lib/binary is defined (damn bundle versus so versus dll)
-        if Rake::Task.task_defined?("#{@lib_dir}/#{binary(cross_platform)}") then
-          Rake::Task["#{@lib_dir}/#{binary(cross_platform)}"].prerequisites.clear
+        if Rake::Task.task_defined?("#{@lib_dir}/#{binary(for_platform)}") then
+          Rake::Task["#{@lib_dir}/#{binary(for_platform)}"].prerequisites.clear
         end
-        file "#{@lib_dir}/#{binary(cross_platform)}" => ["copy:#{@name}:#{cross_platform}"]
+
+        # FIXME: targeting multiple platforms copies the file twice
+        file "#{@lib_dir}/#{binary(for_platform)}" => ["copy:#{@name}:#{for_platform}"]
 
         # if everything for native task is in place
         if @gem_spec && @gem_spec.platform == 'ruby' then
-          Rake::Task['native'].prerequisites.clear
-          task 'native' => ["native:#{cross_platform}"]
+          # double check: only cross platform native tasks should be here
+          # FIXME: Sooo brittle
+          Rake::Task['native'].prerequisites.reject! { |t| !natives_cross_platform.include?(t) }
+          task 'native' => ["native:#{for_platform}"]
         end
       end
     end
@@ -306,6 +315,14 @@ module Rake
      @source_files ||= FileList["#{@ext_dir}/#{@source_pattern}"]
     end
 
+    def compiles_cross_platform
+      [*@cross_platform].map { |p| "compile:#{p}" }
+    end
+
+    def natives_cross_platform
+      [*@cross_platform].map { |p| "native:#{p}" }
+    end
+
     def fake_rb(version)
       <<-FAKE_RB
         class Object
diff --git a/spec/lib/rake/extensiontask_spec.rb b/spec/lib/rake/extensiontask_spec.rb
index 0d72592..15c35d7 100644
--- a/spec/lib/rake/extensiontask_spec.rb
+++ b/spec/lib/rake/extensiontask_spec.rb
@@ -355,6 +355,18 @@ describe Rake::ExtensionTask do
           end
         end
       end
+
+      context '(cross for multiple platforms)' do
+        it 'should define task for each supplied platform' do
+          @ext = Rake::ExtensionTask.new('extension_one', @spec) do |ext|
+            ext.cross_compile = true
+            ext.cross_platform = ['universal-known', 'universal-unknown']
+          end
+
+          Rake::Task.should have_defined('compile:universal-known')
+          Rake::Task.should have_defined('compile:universal-unknown')
+        end
+      end
     end
   end
 
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 9c3c7bf..c534666 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -9,5 +9,7 @@ require 'spec'
 require File.expand_path(File.join(File.dirname(__FILE__), 'support/capture_output_helper'))
 
 Spec::Runner.configure do |config|
+  config.predicate_matchers[:have_defined] = :task_defined?
+
   include CaptureOutputHelper
 end