1 files changed, 83 insertions, 0 deletions
diff --git a/actionpack/lib/sprockets/compressors.rb b/actionpack/lib/sprockets/compressors.rb
new file mode 100644
index 0000000000..cb3e13314b
--- /dev/null
+++ b/actionpack/lib/sprockets/compressors.rb
@@ -0,0 +1,83 @@
+module Sprockets
+  module Compressors
+    @@css_compressors = {}
+    @@js_compressors = {}
+    @@default_css_compressor = nil
+    @@default_js_compressor = nil
+
+    def self.register_css_compressor(name, klass, options = {})
+      @@default_css_compressor = name.to_sym if options[:default] || @@default_css_compressor.nil?
+      @@css_compressors[name.to_sym] = {:klass => klass.to_s, :require => options[:require]}
+    end
+
+    def self.register_js_compressor(name, klass, options = {})
+      @@default_js_compressor = name.to_sym if options[:default] || @@default_js_compressor.nil?
+      @@js_compressors[name.to_sym] = {:klass => klass.to_s, :require => options[:require]}
+    end
+
+    def self.registered_css_compressor(name)
+      if name.respond_to?(:to_sym)
+        compressor = @@css_compressors[name.to_sym] || @@css_compressors[@@default_css_compressor]
+        require compressor[:require] if compressor[:require]
+        compressor[:klass].constantize.new
+      else
+        name
+      end
+    end
+
+    def self.registered_js_compressor(name)
+      if name.respond_to?(:to_sym)
+        compressor = @@js_compressors[name.to_sym] || @@js_compressors[@@default_js_compressor]
+        require compressor[:require] if compressor[:require]
+        compressor[:klass].constantize.new
+      else
+        name
+      end
+    end
+
+    # The default compressors must be registered in default plugins (ex. Sass-Rails)
+    register_css_compressor(:scss, 'Sass::Rails::Compressor', :require => 'sass/rails/compressor', :default => true)
+    register_js_compressor(:uglifier, 'Uglifier', :require => 'uglifier', :default => true)
+
+    # Automaticaly register some compressors
+    register_css_compressor(:yui, 'YUI::CssCompressor', :require => 'yui/compressor')
+    register_js_compressor(:closure, 'Closure::Compiler', :require => 'closure-compiler')
+    register_js_compressor(:yui, 'YUI::JavaScriptCompressor', :require => 'yui/compressor')
+  end
+
+  # An asset compressor which does nothing.
+  #
+  # This compressor simply returns the asset as-is, without any compression
+  # whatsoever. It is useful in development mode, when compression isn't
+  # needed but using the same asset pipeline as production is desired.
+  class NullCompressor #:nodoc:
+    def compress(content)
+      content
+    end
+  end
+
+  # An asset compressor which only initializes the underlying compression
+  # engine when needed.
+  #
+  # This postpones the initialization of the compressor until
+  # <code>#compress</code> is called the first time.
+  class LazyCompressor #:nodoc:
+    # Initializes a new LazyCompressor.
+    #
+    # The block should return a compressor when called, i.e. an object
+    # which responds to <code>#compress</code>.
+    def initialize(&block)
+      @block = block
+    end
+
+    def compress(content)
+      compressor.compress(content)
+    end
+
+    private
+
+    def compressor
+      @compressor ||= (@block.call || NullCompressor.new)
+    end
+  end
+end