From dd6b0c7efc5bfd6b3f94857180a25896502366a8 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Mon, 3 Jan 2011 15:13:05 -0700
Subject: [PATCH] ImageMagick interface: Don't crash when asked to open empty
 image files

---
 src/calibre/utils/magick/__init__.py | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/calibre/utils/magick/__init__.py b/src/calibre/utils/magick/__init__.py
index bf0f48db7d..834a798de5 100644
--- a/src/calibre/utils/magick/__init__.py
+++ b/src/calibre/utils/magick/__init__.py
@@ -106,13 +106,16 @@ class Image(_magick.Image): # {{{
         return ans
 
     def load(self, data):
-        return _magick.Image.load(self, bytes(data))
+        data = bytes(data)
+        if not data:
+            raise ValueError('Cannot open image from empty data string')
+        return _magick.Image.load(self, data)
 
     def open(self, path_or_file):
         if not hasattr(path_or_file, 'read') and \
             path_or_file.lower().endswith('.wmf'):
             # Special handling for WMF files as ImageMagick seems
-            # to hand while reading them from a blob on linux
+            # to hang while reading them from a blob on linux
             if isinstance(path_or_file, unicode):
                 path_or_file = path_or_file.encode(filesystem_encoding)
             return _magick.Image.read(self, path_or_file)
@@ -121,6 +124,8 @@ class Image(_magick.Image): # {{{
             data = data.read()
         else:
             data = open(data, 'rb').read()
+        if not data:
+            raise ValueError('%r is an empty file'%path_or_file)
         self.load(data)
 
     @dynamic_property