extract cache into its own class

lib/language_pack/base.rb

@@ -3,6 +3,7 @@
 require "yaml"
 require "digest/sha1"
 require "language_pack/shell_helpers"
+require "language_pack/cache"
 
 Encoding.default_external = Encoding::UTF_8 if defined?(Encoding)
 
@@ -12,15 +13,15 @@ class LanguagePack::Base
 
   VENDOR_URL = "https://s3.amazonaws.com/heroku-buildpack-ruby"
 
-  attr_reader :build_path, :cache_path
+  attr_reader :build_path, :cache
 
   # changes directory to the build_path
   # @param [String] the path of the build dir
   # @param [String] the path of the cache dir
   def initialize(build_path, cache_path=nil)
     @build_path = build_path
-    @cache_path = cache_path
-    @id = Digest::SHA1.hexdigest("#{Time.now.to_f}-#{rand(1000000)}")[0..10]
+    @cache      = LanguagePack::Cache.new(cache_path) if cache_path
+    @id         = Digest::SHA1.hexdigest("#{Time.now.to_f}-#{rand(1000000)}")[0..10]
 
     Dir.chdir build_path
   end
@@ -128,48 +129,5 @@ def build_log_message(args)
       end
     end.join(" ")
   end
-
-  # create a Pathname of the cache dir
-  # @return [Pathname] the cache dir
-  def cache_base
-    Pathname.new(cache_path)
-  end
-
-  # removes the the specified
-  # @param [String] relative path from the cache_base
-  def cache_clear(path)
-    target = (cache_base + path)
-    target.exist? && target.rmtree
-  end
-
-  # write cache contents
-  # @param [String] path of contents to store. it will be stored using this a relative path from the cache_base.
-  # @param [Boolean] defaults to true. if set to true, the cache store directory will be cleared before writing to it.
-  def cache_store(path, clear_first=true)
-    cache_clear(path) if clear_first
-    cache_copy path, (cache_base + path)
-  end
-
-  # load cache contents
-  # @param [String] relative path of the cache contents
-  def cache_load(path)
-    cache_copy (cache_base + path), path
-  end
-
-  # copy cache contents
-  # @param [String] source directory
-  # @param [String] destination directory
-  def cache_copy(from, to)
-    return false unless File.exist?(from)
-    FileUtils.mkdir_p File.dirname(to)
-    system("cp -a #{from}/. #{to}")
-  end
-
-  # check if the cache content exists
-  # @param [String] relative path of the cache contents
-  # @param [Boolean] true if the path exists in the cache and false if otherwise
-  def cache_exists?(path)
-    File.exists?(cache_base + path)
-  end
 end
 

lib/language_pack/cache.rb

@@ -0,0 +1,45 @@
+require "pathname"
+require "language_pack"
+
+class LanguagePack::Cache
+  def initialize(cache_path)
+    @cache_base = Pathname.new(cache_path)
+  end
+
+  # removes the the specified
+  # @param [String] relative path from the cache_base
+  def clear(path)
+    target = (@cache_base + path)
+    target.exist? && target.rmtree
+  end
+
+  # write cache contents
+  # @param [String] path of contents to store. it will be stored using this a relative path from the cache_base.
+  # @param [Boolean] defaults to true. if set to true, the cache store directory will be cleared before writing to it.
+  def store(path, clear_first=true)
+    clear(path) if clear_first
+    copy path, (@cache_base + path)
+  end
+
+  # load cache contents
+  # @param [String] relative path of the cache contents
+  def load(path)
+    copy (@cache_base + path), path
+  end
+
+  # copy cache contents
+  # @param [String] source directory
+  # @param [String] destination directory
+  def copy(from, to)
+    return false unless File.exist?(from)
+    FileUtils.mkdir_p File.dirname(to)
+    system("cp -a #{from}/. #{to}")
+  end
+
+  # check if the cache content exists
+  # @param [String] relative path of the cache contents
+  # @param [Boolean] true if the path exists in the cache and false if otherwise
+  def exists?(path)
+    File.exists?(@cache_base + path)
+  end
+end

lib/language_pack/ruby.rb

@@ -398,7 +398,7 @@ def build_bundler
       else
         # using --deployment is preferred if we can
         bundle_command += " --deployment"
-        cache_load ".bundle"
+        cache.load ".bundle"
       end
 
       version = run_stdout("bundle version").strip
@@ -429,8 +429,8 @@ def build_bundler
         log "bundle", :status => "success"
         puts "Cleaning up the bundler cache."
         pipe "bundle clean 2> /dev/null"
-        cache_store ".bundle"
-        cache_store "vendor/bundle"
+        cache.store ".bundle"
+        cache.store "vendor/bundle"
 
         # Keep gem cache out of the slug
         FileUtils.rm_rf("#{slug_vendor_base}/cache")
@@ -612,7 +612,7 @@ def bundler_cache
   end
 
   def load_bundler_cache
-    cache_load "vendor"
+    cache.load "vendor"
 
     full_ruby_version       = run_stdout(%q(ruby -v)).chomp
     rubygems_version        = run_stdout(%q(gem -v)).chomp
@@ -628,14 +628,14 @@ def load_bundler_cache
     # fix bug from v37 deploy
     if File.exists?("vendor/ruby_version")
       puts "Broken cache detected. Purging build cache."
-      cache_clear("vendor")
+      cache.clear("vendor")
       FileUtils.rm_rf("vendor/ruby_version")
       purge_bundler_cache
     # fix bug introduced in v38
     elsif !File.exists?(buildpack_version_cache) && File.exists?(ruby_version_cache)
       puts "Broken cache detected. Purging build cache."
       purge_bundler_cache
-    elsif cache_exists?(bundler_cache) && File.exists?(ruby_version_cache) && full_ruby_version != File.read(ruby_version_cache).chomp
+    elsif cache.exists?(bundler_cache) && File.exists?(ruby_version_cache) && full_ruby_version != File.read(ruby_version_cache).chomp
       puts "Ruby version change detected. Clearing bundler cache."
       puts "Old: #{File.read(ruby_version_cache).chomp}"
       puts "New: #{full_ruby_version}"
@@ -669,12 +669,12 @@ def load_bundler_cache
     File.open(rubygems_version_cache, 'w') do |file|
       file.puts rubygems_version
     end
-    cache_store heroku_metadata
+    cache.store heroku_metadata
   end
 
   def purge_bundler_cache
     FileUtils.rm_rf(bundler_cache)
-    cache_clear bundler_cache
+    cache.clear bundler_cache
     # need to reinstall language pack gems
     install_language_pack_gems
   end