1 files changed, 133 insertions, 0 deletions
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb b/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
new file mode 100644
index 0000000000..15f8e10b7f
--- /dev/null
+++ b/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
@@ -0,0 +1,133 @@
+require 'active_support/core_ext/class/attribute'
+require 'active_support/core_ext/string/inflections'
+require 'active_support/core_ext/file'
+require 'action_view/helpers/tag_helper'
+
+module ActionView
+  module Helpers
+    module AssetTagHelper
+
+      class AssetIncludeTag
+        attr_reader :config, :asset_paths
+
+        class_attribute :expansions
+        self.expansions = { }
+
+        def initialize(config, asset_paths)
+          @config = config
+          @asset_paths = asset_paths
+        end
+
+        def asset_name
+          raise NotImplementedError
+        end
+
+        def extension
+          raise NotImplementedError
+        end
+
+        def custom_dir
+          raise NotImplementedError
+        end
+
+        def asset_tag(source, options)
+          raise NotImplementedError
+        end
+
+        def include_tag(*sources)
+          options = sources.extract_options!.stringify_keys
+          concat  = options.delete("concat")
+          cache   = concat || options.delete("cache")
+          recursive = options.delete("recursive")
+
+          if concat || (config.perform_caching && cache)
+            joined_name = (cache == true ? "all" : cache) + ".#{extension}"
+            joined_path = File.join((joined_name[/^#{File::SEPARATOR}/] ? config.assets_dir : custom_dir), joined_name)
+            unless config.perform_caching && File.exists?(joined_path)
+              write_asset_file_contents(joined_path, compute_paths(sources, recursive))
+            end
+            asset_tag(joined_name, options)
+          else
+            sources = expand_sources(sources, recursive)
+            ensure_sources!(sources) if cache
+            sources.collect { |source| asset_tag(source, options) }.join("\n").html_safe
+          end
+        end
+
+
+        private
+
+          def path_to_asset(source, include_host = true)
+            asset_paths.compute_public_path(source, asset_name.to_s.pluralize, extension, include_host)
+          end
+
+          def compute_paths(*args)
+            expand_sources(*args).collect { |source| asset_paths.compute_public_path(source, asset_name.pluralize, extension, false) }
+          end
+
+          def expand_sources(sources, recursive)
+            if sources.first == :all
+              collect_asset_files(custom_dir, ('**' if recursive), "*.#{extension}")
+            else
+              sources.collect do |source|
+                determine_source(source, expansions)
+              end.flatten
+            end
+          end
+
+          def ensure_sources!(sources)
+            sources.each do |source|
+              asset_file_path!(path_to_asset(source, false))
+            end
+            return sources
+          end
+
+          def collect_asset_files(*path)
+            dir = path.first
+
+            Dir[File.join(*path.compact)].collect do |file|
+              file[-(file.size - dir.size - 1)..-1].sub(/\.\w+$/, '')
+            end.sort
+          end
+
+          def determine_source(source, collection)
+            case source
+            when Symbol
+              collection[source] || raise(ArgumentError, "No expansion found for #{source.inspect}")
+            else
+              source
+            end
+          end
+
+          def join_asset_file_contents(paths)
+            paths.collect { |path| File.read(asset_file_path!(path, true)) }.join("\n\n")
+          end
+
+          def write_asset_file_contents(joined_asset_path, asset_paths)
+            FileUtils.mkdir_p(File.dirname(joined_asset_path))
+            File.atomic_write(joined_asset_path) { |cache| cache.write(join_asset_file_contents(asset_paths)) }
+
+            # Set mtime to the latest of the combined files to allow for
+            # consistent ETag without a shared filesystem.
+            mt = asset_paths.map { |p| File.mtime(asset_file_path(p)) }.max
+            File.utime(mt, mt, joined_asset_path)
+          end
+
+          def asset_file_path(path)
+            File.join(config.assets_dir, path.split('?').first)
+          end
+
+          def asset_file_path!(path, error_if_file_is_uri = false)
+            if asset_paths.is_uri?(path)
+              raise(Errno::ENOENT, "Asset file #{path} is uri and cannot be merged into single file") if error_if_file_is_uri
+            else
+              absolute_path = asset_file_path(path)
+              raise(Errno::ENOENT, "Asset file not found at '#{absolute_path}'" ) unless File.exist?(absolute_path)
+              return absolute_path
+            end
+          end
+      end
+
+    end
+  end
+end