Force Oj install and use for platforms != JRuby

- Add a Ruby extension that will install Oj when the platform is not
  JRuby
- Rollbar::JSON will force to use Oj if it's defined. If not it'll use
  the MultiJson.current_adapter

In summary. We'll use Oj for platforms != JRuby and any other one for JRuby.

Gemfile

@@ -11,6 +11,7 @@ gem "racc", :platform => :rbx
 gem "minitest", :platform => :rbx
 gem "rubinius-developer_tools", :platform => :rbx
 gem "rails", "4.2.3"
+gem 'oj', '~> 2.12.14', :platform => [:ruby, :rbx]
 
 gemspec
 gem 'byebug'

ext/mkrf_conf.rb

@@ -0,0 +1,38 @@
+require 'rubygems'
+require 'rubygems/command.rb'
+require 'rubygems/dependency_installer.rb'
+
+OJ_VERSION = '~> 2.12.14'
+
+def jruby?
+  defined?(JRUBY_VERSION) || (defined?(RUBY_ENGINE) && 'jruby' == RUBY_ENGINE)
+end
+
+def install_oj
+  begin
+    Gem::Command.build_args = ARGV
+
+    unless jruby?
+      $stdout.write "Installing oj because platform is not JRuby\n"
+
+      di = Gem::DependencyInstaller.new
+      di.install 'oj', OJ_VERSION
+    end
+  rescue => e
+    warn "#{$0}: #{e}"
+
+    exit!
+  end
+end
+
+def write_rakefile
+  $stdout.write "Writing fake Rakefile\n"
+
+  # Write fake Rakefile for rake since Makefile isn't used
+  File.open(File.join(File.dirname(__FILE__), 'Rakefile'), 'w') do |f|
+    f.write('task :default' + $/)
+  end
+end
+
+install_oj
+write_rakefile

gemfiles/rails30.gemfile

@@ -13,5 +13,6 @@ gem 'rubysl-test-unit', :platform => :rbx
 gem 'rubinius-developer_tools', :platform => :rbx
 gem 'rails', '3.0.20'
 gem 'hitimes', '< 1.2.2'
+gem 'oj', '~> 2.12.14', :platform => [:ruby, :rbx]
 
 gemspec :path => '../'

gemfiles/rails31.gemfile

@@ -12,5 +12,6 @@ gem "minitest", :platform => :rbx
 gem "rubysl-test-unit", :platform => :rbx
 gem "rubinius-developer_tools", :platform => :rbx
 gem "rails", "3.1.12"
+gem 'oj', '~> 2.12.14', :platform => [:ruby, :rbx]
 
 gemspec :path => "../"

gemfiles/rails32.gemfile

@@ -13,5 +13,6 @@ gem "minitest", :platform => :rbx
 gem "rubysl-test-unit", :platform => :rbx
 gem "rubinius-developer_tools", :platform => :rbx
 gem "rails", "3.2.22"
+gem 'oj', '~> 2.12.14', :platform => [:ruby, :rbx]
 
 gemspec :path => "../"

gemfiles/rails40.gemfile

@@ -13,5 +13,6 @@ gem "minitest", :platform => :rbx
 gem "rubysl-test-unit", :platform => :rbx
 gem "rubinius-developer_tools", :platform => :rbx
 gem "rails", "4.0.13"
+gem 'oj', '~> 2.12.14', :platform => [:ruby, :rbx]
 
 gemspec :path => "../"

gemfiles/rails41.gemfile

@@ -11,5 +11,6 @@ gem "racc", :platform => :rbx
 gem "minitest", :platform => :rbx
 gem "rubinius-developer_tools", :platform => :rbx
 gem "rails", "4.1.12"
+gem 'oj', '~> 2.12.14', :platform => [:ruby, :rbx]
 
 gemspec :path => "../"

gemfiles/rails42.gemfile

@@ -11,5 +11,6 @@ gem "racc", :platform => :rbx
 gem "minitest", :platform => :rbx
 gem "rubinius-developer_tools", :platform => :rbx
 gem "rails", "4.2.3"
+gem 'oj', '~> 2.12.14', :platform => [:ruby, :rbx]
 
 gemspec :path => "../"

lib/rollbar/json.rb

@@ -1,30 +1,46 @@
 require 'rollbar/json/oj'
 require 'rollbar/json/default'
 
+begin
+  require 'oj'
+rescue LoadError
+end
+
 module Rollbar
   module JSON
     extend self
 
-    attr_writer :adapter_module
+    attr_writer :options_module
 
     def dump(object)
-      MultiJson.dump(object, adapter_options)
+      with_adapter { MultiJson.dump(object, adapter_options) }
     end
 
     def load(string)
-      MultiJson.load(string, adapter_options)
+      with_adapter { MultiJson.load(string, adapter_options) }
+    end
+
+    def with_adapter(&block)
+      MultiJson.with_adapter(detect_multi_json_adapter, &block)
+    end
+
+    def detect_multi_json_adapter
+      options = {}
+      options[:adapter] = :oj if defined?(Oj)
+
+      MultiJson.current_adapter(options)
     end
 
     def adapter_options
-      adapter_module.options
+      options_module.options
     end
 
-    def adapter_module
-      @adapter_module ||= find_adapter_module
+    def options_module
+      @options_module ||= find_options_module
     end
 
-    def find_adapter_module
-      module_name = multi_json_adapter_module
+    def find_options_module
+      module_name = multi_json_adapter_module_name
 
       begin
         const_get(module_name)
@@ -40,7 +56,7 @@ def find_adapter_module
     # Ex: MultiJson::Adapters::JsonGem
     #
     # In this method we just get the last module name.
-    def multi_json_adapter_module
+    def multi_json_adapter_module_name
       MultiJson.current_adapter.name[/^MultiJson::Adapters::(.*)$/, 1]
     end
   end

rollbar.gemspec

@@ -5,6 +5,8 @@ Gem::Specification.new do |gem|
   gem.authors       = ["Rollbar, Inc."]
   gem.email         = ["support@rollbar.com"]
   gem.description   = %q{Easy and powerful exception tracking for Ruby}
+  gem.extensions << 'ext/mkrf_conf.rb'
+
   gem.executables   = ['rollbar-rails-runner']
   gem.summary       = %q{Reports exceptions to Rollbar}
   gem.homepage      = "https://rollbar.com"
@@ -29,5 +31,4 @@ Gem::Specification.new do |gem|
   gem.add_development_dependency 'rake', '>= 0.9.0'
   gem.add_development_dependency 'redis'
   gem.add_runtime_dependency     'multi_json'
-  gem.add_development_dependency 'oj', '~> 2.12.14'
 end

spec/rollbar/json_spec.rb

@@ -55,23 +55,42 @@ module MissingCustomOptions
     end
   end
 
+  describe '.with_adapter' do
+    let(:object) { double(:foo => 'bar') }
+    let(:callback) do
+      proc { object.foo }
+    end
+    let(:adapter) { described_class.detect_multi_json_adapter }
+
+    it 'calls mock.something with an adapter' do
+      expect(MultiJson).to receive(:with_adapter).with(adapter).and_call_original
+      expect(object).to receive(:foo).once
+
+      described_class.with_adapter(&callback)
+    end
+  end
+
+  describe '.detect_multi_json_adapter' do
+
+  end
+
   describe '.adapter_options' do
     it 'calls .options in adapter module' do
-      expect(described_class.adapter_module).to receive(:options)
+      expect(described_class.options_module).to receive(:options)
 
       described_class.adapter_options
     end
   end
 
-  describe '.adapter_module' do
-    before { described_class.adapter_module = nil }
+  describe '.options_module' do
+    before { described_class.options_module = nil }
 
     context 'with a defined rollbar adapter' do
       let(:expected_adapter) { Rollbar::JSON::MockAdapter }
 
       it 'returns the correct options' do
         MultiJson.with_adapter(MultiJson::Adapters::MockAdapter) do
-          expect(described_class.adapter_module).to be(expected_adapter)
+          expect(described_class.options_module).to be(expected_adapter)
         end
       end
     end
@@ -81,7 +100,7 @@ module MissingCustomOptions
 
       it 'returns the correct options' do
         MultiJson.with_adapter(MultiJson::Adapters::MissingCustomOptions) do
-          expect(described_class.adapter_module).to be(expected_adapter)
+          expect(described_class.options_module).to be(expected_adapter)
         end
       end
     end

spec/spec_helper.rb

@@ -6,9 +6,6 @@
 require 'database_cleaner'
 require 'genspec'
 require 'multi_json'
-require 'oj'
-
-MultiJson.use(:oj)
 
 namespace :dummy do
   load 'spec/dummyapp/Rakefile'