PERF: make development tolerable under sprockets 3

lib/freedom_patches/sprockets_patches.rb

@@ -0,0 +1,56 @@
+# This contains two patches to make sprockets more tolerable in dev
+#
+# 1. Stop computing asset paths which triggers sprockets to do mountains of work
+#     All our assets in dev are in the /assets folder anyway
+#
+# 2. Stop using a concatenator that does tons of work checking for semicolons when
+#     when rebuilding an asset
+
+if Rails.env == "development"
+  module ActionView::Helpers::AssetUrlHelper
+
+    def asset_path(source, options = {})
+      source = source.to_s
+      return "" unless source.present?
+      return source if source =~ URI_REGEXP
+
+      tail, source = source[/([\?#].+)$/], source.sub(/([\?#].+)$/, '')
+
+      if extname = compute_asset_extname(source, options)
+        source = "#{source}#{extname}"
+      end
+
+      if source[0] != ?/
+       # CODE REMOVED
+       # source = compute_asset_path(source, options)
+       source = "/assets/#{source}"
+      end
+
+      relative_url_root = defined?(config.relative_url_root) && config.relative_url_root
+      if relative_url_root
+        source = File.join(relative_url_root, source) unless source.starts_with?("#{relative_url_root}/")
+      end
+
+      if host = compute_asset_host(source, options)
+        source = File.join(host, source)
+      end
+
+      "#{source}#{tail}"
+    end
+    alias_method :path_to_asset, :asset_path # aliased to avoid conflicts with an asset_path named route
+  end
+
+  module ::SprocketHack
+    def self.concat_javascript_sources(buf, source)
+      if buf.bytesize > 0
+        # CODE REMOVED HERE
+        buf << ";" # unless string_end_with_semicolon?(buf)
+        buf << "\n" # unless buf.end_with?("\n")
+      end
+      buf << source
+    end
+  end
+
+  Sprockets.register_bundle_metadata_reducer 'application/javascript', :data, proc { "" }, ::SprocketHack.method(:concat_javascript_sources)
+
+end