Force Tempfile extension when creating a Tempfile

This should fix the problem on animated file detection.

Fixes #851

NEWS

 Unreleased:
 
+* Bug fix: ThumbnailProcessor now correctly detects and preserve animated GIF.
+* Bug fix: File extension is now preserved in generated Tempfile from adapter.
 * Bug fix: Uploading file with unicode file name now won't raise an error when
   logging in the AWS is turned on.
 * Bug fix: Task "paperclip:refresh:missing_styles" now work correctly.

lib/paperclip/io_adapters/attachment_adapter.rb

@@ -52,7 +52,9 @@ module Paperclip
     end
 
     def copy_to_tempfile(src)
-      dest = Tempfile.new(src.original_filename)
+      extension = File.extname(src.original_filename)
+      basename = File.basename(src.original_filename, extension)
+      dest = Tempfile.new([basename, extension])
       dest.binmode
       if src.respond_to? :copy_to_local_file
         src.copy_to_local_file(:original, dest.path)

lib/paperclip/io_adapters/file_adapter.rb

@@ -56,7 +56,9 @@ module Paperclip
     private
 
     def copy_to_tempfile(src)
-      dest = Tempfile.new(original_filename)
+      extension = File.extname(original_filename)
+      basename = File.basename(original_filename, extension)
+      dest = Tempfile.new([basename, extension])
       dest.binmode
       FileUtils.cp(src.path, dest.path)
       dest

lib/paperclip/io_adapters/stringio_adapter.rb

@@ -47,7 +47,9 @@ module Paperclip
     private
 
     def copy_to_tempfile(src)
-      dest = Tempfile.new(original_filename)
+      extension = File.extname(original_filename)
+      basename = File.basename(original_filename, extension)
+      dest = Tempfile.new([basename, extension])
       dest.binmode
       while data = src.read(16*1024)
         dest.write(data)

lib/paperclip/io_adapters/uploaded_file_adapter.rb

@@ -50,7 +50,9 @@ module Paperclip
     private
 
     def copy_to_tempfile(src)
-      dest = Tempfile.new(original_filename)
+      extension = File.extname(original_filename)
+      basename = File.basename(original_filename, extension)
+      dest = Tempfile.new([basename, extension])
       dest.binmode
       FileUtils.cp(src.path, dest.path)
       dest

lib/paperclip/tempfile.rb

@@ -7,14 +7,16 @@ module Paperclip
     # taken from the comments on this blog post:
     # http://marsorange.com/archives/of-mogrify-ruby-tempfile-dynamic-class-definitions
     #
-    # This is Ruby 1.8.7's implementation.
-    def make_tmpname(basename, n)
+    # This is Ruby 1.9.3's implementation.
+    def make_tmpname(prefix_suffix, n)
       if RUBY_PLATFORM =~ /java/
-        case basename
+        case prefix_suffix
+        when String
+          prefix, suffix = prefix_suffix, ''
         when Array
-          prefix, suffix = *basename
+          prefix, suffix = *prefix_suffix
         else
-          prefix, suffix = basename, ''
+          raise ArgumentError, "unexpected prefix_suffix: #{prefix_suffix.inspect}"
         end
 
         t = Time.now.strftime("%y%m%d")