From 82a952e0dc0cc992019f3a37e2005a3b1847c02f Mon Sep 17 00:00:00 2001
From: Bob Potter <bobby.potter@gmail.com>
Date: Sat, 1 Nov 2014 13:40:41 -0700
Subject: [PATCH 1/3] Improve performance of Message#find_attachment

- Don't trigger exceptions for flow control.
- Retrieve each header only once (at most).
---
 lib/mail/message.rb | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/lib/mail/message.rb b/lib/mail/message.rb
index 5a4ece0de..239afd506 100644
--- a/lib/mail/message.rb
+++ b/lib/mail/message.rb
@@ -2118,23 +2118,30 @@ def init_with_string(string)
 
     # Returns the filename of the attachment (if it exists) or returns nil
     def find_attachment
-      content_type_name = header[:content_type].filename rescue nil
-      content_disp_name = header[:content_disposition].filename rescue nil
-      content_loc_name  = header[:content_location].location rescue nil
-      case
-      when content_type && content_type_name
-        filename = content_type_name
-      when content_disposition && content_disp_name
-        filename = content_disp_name
-      when content_location && content_loc_name
-        filename = content_loc_name
-      else
-        filename = nil
-      end
+      filename = find_attachment_filename
       filename = Mail::Encodings.decode_encode(filename, :decode) if filename rescue filename
       filename
     end
 
+    def find_attachment_filename
+      content_type_header = header[:content_type]
+      if content_type_header && (filename = content_type_header.filename)
+        return filename
+      end
+
+      content_disposition_header = header[:content_disposition]
+      if content_disposition_header && (filename = content_disposition_header.filename)
+        return filename
+      end
+
+      content_location_header = header[:content_location]
+      if content_location_header && (filename = content_location_header.location)
+        return filename
+      end
+
+      return nil
+    end
+
     def do_delivery
       begin
         if perform_deliveries

From 3d1dfe7ec341827d5037c1ae337ec5e4dc32d283 Mon Sep 17 00:00:00 2001
From: Bob Potter <bobby.potter@gmail.com>
Date: Mon, 1 Dec 2014 18:15:56 -0800
Subject: [PATCH 2/3] Cleanup repetition in Message#find_attachment_filename

---
 lib/mail/message.rb | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/lib/mail/message.rb b/lib/mail/message.rb
index 239afd506..5604c9904 100644
--- a/lib/mail/message.rb
+++ b/lib/mail/message.rb
@@ -2124,22 +2124,22 @@ def find_attachment
     end
 
     def find_attachment_filename
-      content_type_header = header[:content_type]
-      if content_type_header && (filename = content_type_header.filename)
-        return filename
-      end
+      filename_from_field(header[:content_type]) ||
+        filename_from_field(header[:content_disposition]) ||
+        filename_from_field(header[:content_location])
+    end
 
-      content_disposition_header = header[:content_disposition]
-      if content_disposition_header && (filename = content_disposition_header.filename)
-        return filename
-      end
+    def filename_from_field(field)
+      return if field.nil?
 
-      content_location_header = header[:content_location]
-      if content_location_header && (filename = content_location_header.location)
-        return filename
+      case field.field
+      when ContentLocationField
+        field.location
+      when ContentTypeField, ContentDispositionField
+        field.filename
+      else
+        nil
       end
-
-      return nil
     end
 
     def do_delivery

From ea89891d399d65a1ff0700b8ca60252f072ca787 Mon Sep 17 00:00:00 2001
From: Bob Potter <bobby.potter@gmail.com>
Date: Tue, 2 Dec 2014 09:07:11 -0800
Subject: [PATCH 3/3] Handle more field types

---
 lib/mail/message.rb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/mail/message.rb b/lib/mail/message.rb
index 5604c9904..0d117a28d 100644
--- a/lib/mail/message.rb
+++ b/lib/mail/message.rb
@@ -2137,8 +2137,10 @@ def filename_from_field(field)
         field.location
       when ContentTypeField, ContentDispositionField
         field.filename
-      else
+      when NilClass, UnstructuredField
         nil
+      else
+        raise ArgumentError, "Don't know how to extract filename from #{field}"
       end
     end