media file: memoize expensive methods in subclasses.

app/logical/media_file.rb

@@ -113,5 +113,5 @@ class MediaFile
     nil
   end
 
-  memoize :dimensions, :file_ext, :file_size, :md5, :is_corrupt?, :is_animated?
+  memoize :file_ext, :file_size, :md5
 end

app/logical/media_file/flash.rb

@@ -54,5 +54,6 @@ class MediaFile::Flash < MediaFile
 
     [width, height]
   end
+
   memoize :dimensions
 end

app/logical/media_file/image.rb

@@ -63,6 +63,8 @@ class MediaFile::Image < MediaFile
   end
 
   def image
-    @image ||= Vips::Image.new_from_file(file.path, fail: true)
+    Vips::Image.new_from_file(file.path, fail: true)
   end
+
+  memoize :image, :dimensions, :is_corrupt?, :is_animated_gif?, :is_animated_png?
 end

app/logical/media_file/ugoira.rb

@@ -88,5 +88,5 @@ class MediaFile::Ugoira < MediaFile
     MediaFile.open(tempfile)
   end
 
-  memoize :zipfile, :preview_frame
+  memoize :zipfile, :preview_frame, :dimensions
 end

app/logical/media_file/video.rb

@@ -31,5 +31,5 @@ class MediaFile::Video < MediaFile
     MediaFile.open(vp.path)
   end
 
-  memoize :video, :preview_frame
+  memoize :video, :preview_frame, :dimensions, :duration, :has_audio?
 end