Remove deprecation warnings for modern ActiveSupport.

lib/paperclip-meta.rb

@@ -6,14 +6,16 @@ class Attachment
     # If attachment deleted - destroy meta data
     def save
       if (not @queued_for_delete.empty?) and @queued_for_write.empty?
-        instance_write(:meta, ActiveSupport::Base64.encode64(Marshal.dump({}))) if instance.respond_to?(:"#{name}_meta=")
+        instance_write(:meta, meta_encode({})) if instance.respond_to?(:"#{name}_meta=")
       end
       original_save
     end
-      
+
     # If model has #{name}_meta column we getting sizes of processed
     # thumbnails and saving it to #{name}_meta column.
     def post_process_styles(*style_args)
+      # Check arity of :original_post_process_styles to maintain compatibility with
+      # Paperclip 2.3.9 and older.
       method(:original_post_process_styles).arity == 0 ? original_post_process_styles : original_post_process_styles(*style_args)
 
       if instance.respond_to?(:"#{name}_meta=")
@@ -28,29 +30,54 @@ def post_process_styles(*style_args)
           end
         end
 
-        instance_write(:meta, ActiveSupport::Base64.encode64(Marshal.dump(meta)))
+        instance_write(:meta, meta_encode(meta))
       end
     end
 
-    # Meta access methods
+    # Define meta accessors methods
     [:width, :height, :size].each do |meth|
       define_method(meth) do |*args|
         style = args.first || default_style
         meta_read(style, meth)
       end
     end
 
+    # Returns image dimesions ("WxH") for given style name. If style name not given,
+    # returns dimesions for default_style.
     def image_size(style = default_style)
       "#{width(style)}x#{height(style)}"
     end
 
     private
+    # Returns meta data for given style
     def meta_read(style, item)
       if instance.respond_to?(:"#{name}_meta") && instance_read(:meta)
-        if meta = Marshal.load(ActiveSupport::Base64.decode64(instance_read(:meta)))
+        if meta = meta_decode(instance_read(:meta))
           meta.key?(style) ? meta[style][item] : nil
         end
       end
-    end    
+    end
+
+    # Return encoded metadata as String
+    def meta_encode(meta)
+      # Use Base64 class if aviliable, to prevent
+      # ActiveSupport deprecation warnings.
+      if Module.const_defined? "Base64"
+        ::Base64.encode64(Marshal.dump(meta))
+      else
+       ActiveSupport::Base64.encode64(Marshal.dump(meta))
+      end
+    end
+
+    # Return decoded metadata as Object
+    def meta_decode(meta)
+      # Use Base64 class if aviliable, to prevent
+      # ActiveSupport deprecation warnings.
+      if Module.const_defined? "Base64"
+        Marshal.load(::Base64.decode64(meta))
+      else
+        Marshal.load(ActiveSupport::Base64.decode64(meta))
+      end
+    end
   end
 end