lib/lookbook/preview.rb in lookbook-1.0.0.beta.4 vs lib/lookbook/preview.rb in lookbook-1.0.0.beta.5

@@ -120,18 +120,19 @@
 
       def exists?(path)
         !!find(path)
       end
 
-      def clear_cache
-        @previews = nil
+      def any?
+        all.any?
       end
 
       def all
         load_previews if preview_files.size > ViewComponent::Preview.descendants.size
 
-        return @previews if @previews.present?
+        @previews = nil if cache_stale?
+        return @previews unless @previews.nil?
 
         previews = ViewComponent::Preview.descendants.map do |p|
           new(p)
         rescue
           Rails.logger.error "[lookbook] error instantiating preview\n#{exception.full_message}"
@@ -142,19 +143,48 @@
             Rails.logger.error "[lookbook] preview error\n#{error.full_message}\n"
           end
         end
 
         sorted_previews = previews.compact.sort_by { |preview| [preview.position, preview.label] }
-        @previews ||= PreviewCollection.new(sorted_previews)
+        @previews = PreviewCollection.new(sorted_previews)
+        mark_as_cached if Lookbook.config.listen == true
+        @previews
       end
 
       def errors
         @errors ||= []
       end
 
+      def clear_cache
+        cache_dir = File.dirname(cache_marker_path)
+        FileUtils.mkdir_p(cache_dir) unless File.exists?(cache_dir)
+        File.write(cache_marker_path, Time.now.to_i)
+      end
+
       protected
 
+      def cache_marker_path
+        Rails.root.join("tmp/cache/lookbook-previews")
+      end
+
+      def cache_stale?
+        return false if !File.exists?(cache_marker_path)
+        cache_timestamp = File.read(cache_marker_path).to_i
+        if @last_cache_timestamp.nil? || cache_timestamp > @last_cache_timestamp
+          @last_cache_timestamp = cache_timestamp
+          true
+        else
+          false
+        end
+      end
+
+      def mark_as_cached
+        cache_dir = File.dirname(cache_marker_path)
+        FileUtils.mkdir_p(cache_dir) unless File.exists?(cache_dir)
+        File.write(cache_marker_path, Time.now)
+      end
+
       def load_previews
         @errors = []
         preview_files.each do |file|
           require_dependency file[:path]
         rescue SyntaxError, StandardError => exception
@@ -164,10 +194,10 @@
               file_name: file[:rel_path],
               file_path: file[:path])
           )
         end
       end
-
+    
       def preview_files
         files = Array(Lookbook.config.preview_paths).map do |preview_path|
           Dir["#{preview_path}/**/*preview.rb"].map do |path|
             {
               path: path,