Replace thread_safe with concurrent-ruby

CHANGELOG.adoc

@@ -39,6 +39,10 @@ Improvements::
   * use shorthands %F and %T instead of %Y-%m-%d and %H:%M:%S to format time
   * read file in binary mode whenever contents are being normalized
 
+Build / Infrastructure::
+
+  * replace thread_safe with concurrent-ruby (PR #2822) (*@junaruga*)
+
 // tag::compact[]
 == 1.5.7.1 (2018-05-10) - @mojavelinux
 

Gemfile

@@ -4,25 +4,30 @@ source 'https://rubygems.org'
 gemspec
 
 group :development do
-  if (ruby_version = Gem::Version.new RUBY_VERSION) < (Gem::Version.new '2.1.0')
-    if ruby_version < (Gem::Version.new '2.0.0')
-      gem 'haml', '~> 4.0.0'
-      if ruby_version < (Gem::Version.new '1.9.3')
-        gem 'cucumber', '~> 1.3.0'
-        gem 'nokogiri', '~> 1.5.0'
-        gem 'slim', '~> 2.1.0'
-        gem 'tilt', '2.0.7'
+  ruby_version = Gem::Version.new RUBY_VERSION
+  gem 'concurrent-ruby', '~> 1.0.0' unless ruby_version < (Gem::Version.new '1.9.3')
+  if ruby_version < (Gem::Version.new '2.2.0')
+    if ruby_version < (Gem::Version.new '2.1.0')
+      if ruby_version < (Gem::Version.new '2.0.0')
+        gem 'haml', '~> 4.0.0'
+        if ruby_version < (Gem::Version.new '1.9.3')
+          gem 'cucumber', '~> 1.3.0'
+          gem 'nokogiri', '~> 1.5.0'
+          gem 'slim', '~> 2.1.0'
+          gem 'thread_safe', '0.3.6'
+          gem 'tilt', '2.0.7'
+        else
+          gem 'nokogiri', '~> 1.6.0'
+          gem 'slim', '<= 3.0.7'
+        end
       else
         gem 'nokogiri', '~> 1.6.0'
-        gem 'slim', '<= 3.0.7'
       end
     else
-      gem 'nokogiri', '~> 1.6.0'
+      gem 'nokogiri', '~> 1.7.0' if Gem::Platform.local =~ 'x86-mingw32' || Gem::Platform.local =~ 'x64-mingw32'
+      gem 'racc', '~> 1.4.0' if RUBY_VERSION == '2.1.0' && RUBY_ENGINE == 'rbx'
     end
-  elsif ruby_version < (Gem::Version.new '2.2.0')
-    gem 'nokogiri', '~> 1.7.0' if Gem::Platform.local =~ 'x86-mingw32' || Gem::Platform.local =~ 'x64-mingw32'
   end
-  gem 'racc', '~> 1.4.0' if RUBY_VERSION == '2.1.0' && RUBY_ENGINE == 'rbx'
 end
 
 group :doc do

asciidoctor.gemspec

@@ -51,7 +51,8 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rspec-expectations', '~> 2.14.0'
   # slim is needed for testing custom templates
   s.add_development_dependency 'slim', '~> 3.0.0'
-  s.add_development_dependency 'thread_safe', '~> 0.3.0'
+  # concurrent-ruby is defined in Gemfile due to enforcement of minimum required Ruby version
+  #s.add_development_dependency 'concurrent-ruby', '~> 1.0.0'
   # tilt is needed for testing custom templates
   s.add_development_dependency 'tilt', '~> 2.0.0'
   s.add_development_dependency 'minitest', '~> 5.3.0'

lib/asciidoctor/converter/factory.rb

@@ -23,7 +23,7 @@ module Converter
     # DocBook 5} and {DocBook45Converter DocBook 4.5}, as well as any custom
     # converters that have been discovered or explicitly registered.
     #
-    # If the {https://rubygems.org/gems/thread_safe thread_safe} gem is
+    # If the {https://rubygems.org/gems/concurrent-ruby concurrent-ruby} gem is
     # installed, access to the default factory is guaranteed to be thread safe.
     # Otherwise, a warning is issued to the user.
     class Factory
@@ -32,8 +32,8 @@ class << self
 
         # Public: Retrieves a singleton instance of {Factory Converter::Factory}.
         #
-        # If the thread_safe gem is installed, the registry of converters is
-        # initialized as a ThreadSafe::Cache. Otherwise, a warning is issued and
+        # If the concurrent-ruby gem is installed, the registry of converters is
+        # initialized as a Concurrent::Hash. Otherwise, a warning is issued and
         # the registry of converters is initialized using a normal Hash.
         #
         # initialize_singleton - A Boolean to indicate whether the singleton should
@@ -44,14 +44,16 @@ class << self
         # Returns the default [Factory] singleton instance
         def default initialize_singleton = true
           return @__default__ || new unless initialize_singleton
-          # FIXME this assignment is not thread_safe, may need to use a ::Threadsafe helper here
+          # FIXME this assignment itself may not be thread safe; may need to use a helper here
           @__default__ ||= begin
-            # NOTE .to_s hides require from Opal
-            require 'thread_safe'.to_s unless defined? ::ThreadSafe
-            new ::ThreadSafe::Cache.new
+            unless defined? ::Concurrent::Hash
+              # NOTE .to_s hides require from Opal
+              require ::RUBY_MIN_VERSION_1_9 ? 'concurrent/hash'.to_s : 'asciidoctor/core_ext/1.8.7/concurrent/hash'.to_s
+            end
+            new ::Concurrent::Hash.new
           rescue ::LoadError
             include Logging unless include? Logging
-            logger.warn 'gem \'thread_safe\' is not installed. This gem is recommended when registering custom converters.'
+            logger.warn 'gem \'concurrent-ruby\' is not installed. This gem is recommended when registering custom converters.'
             new
           end
         end

lib/asciidoctor/converter/template.rb

@@ -1,5 +1,3 @@
-autoload :ThreadSafe, 'thread_safe'
-
 # encoding: UTF-8
 module Asciidoctor
   # A {Converter} implementation that uses templates composed in template
@@ -22,8 +20,8 @@ module Asciidoctor
   # backend format (e.g., "html5").
   #
   # As an optimization, scan results and templates are cached for the lifetime
-  # of the Ruby process. If the {https://rubygems.org/gems/thread_safe
-  # thread_safe} gem is installed, these caches are guaranteed to be thread
+  # of the Ruby process. If the {https://rubygems.org/gems/concurrent-ruby
+  # concurrent-ruby} gem is installed, these caches are guaranteed to be thread
   # safe. If this gem is not present, there is no such guarantee and a warning
   # will be issued.
   class Converter::TemplateConverter < Converter::Base
@@ -36,8 +34,10 @@ class Converter::TemplateConverter < Converter::Base
     }
 
     begin
-      # triggers autoload of thread_safe
-      @caches = { :scans => ::ThreadSafe::Cache.new, :templates => ::ThreadSafe::Cache.new }
+      unless defined? ::Concurrent::Hash
+        require ::RUBY_MIN_VERSION_1_9 ? 'concurrent/hash' : 'asciidoctor/core_ext/1.8.7/concurrent/hash'
+      end
+      @caches = { :scans => ::Concurrent::Hash.new, :templates => ::Concurrent::Hash.new }
     rescue ::LoadError
       @caches = { :scans => {}, :templates => {} }
     end
@@ -76,7 +76,7 @@ def initialize backend, template_dirs, opts = {}
       end
       case opts[:template_cache]
       when true
-        logger.warn 'gem \'thread_safe\' is not installed. This gem is recommended when using the built-in template cache.' unless defined? ::ThreadSafe::Cache
+        logger.warn 'gem \'concurrent-ruby\' is not installed. This gem is recommended when using the built-in template cache.' unless defined? ::Concurrent::Hash
         @caches = self.class.caches
       when ::Hash
         @caches = opts[:template_cache]

lib/asciidoctor/core_ext/1.8.7/concurrent/hash.rb

@@ -0,0 +1,5 @@
+require 'thread_safe'
+
+module Concurrent
+  Hash = ::ThreadSafe::Cache
+end

test/converter_test.rb

@@ -171,8 +171,8 @@
         doc = Asciidoctor::Document.new [], :template_dir => template_dir
         doc.converter
         caches = Asciidoctor::Converter::TemplateConverter.caches
-        if defined? ::ThreadSafe::Cache
-          assert_kind_of ::ThreadSafe::Cache, caches[:templates]
+        if defined? ::Concurrent::Hash
+          assert_kind_of ::Concurrent::Hash, caches[:templates]
           refute_empty caches[:templates]
           paragraph_template_before = caches[:templates].values.find {|t| File.basename(t.file) == 'block_paragraph.html.haml' }
           refute_nil paragraph_template_before