From 3caa7f86ded7f7afb13301c34be0b475469aa733 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 18 Jan 2017 19:02:52 +0530
Subject: [PATCH] A better error message when users attempt to open KFX books
 as MOBI files

---
 src/calibre/ebooks/mobi/reader/mobi6.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/calibre/ebooks/mobi/reader/mobi6.py b/src/calibre/ebooks/mobi/reader/mobi6.py
index bba572f8dd..eef167655e 100644
--- a/src/calibre/ebooks/mobi/reader/mobi6.py
+++ b/src/calibre/ebooks/mobi/reader/mobi6.py
@@ -29,6 +29,10 @@ class TopazError(ValueError):
     pass
 
 
+class KFXError(ValueError):
+    pass
+
+
 class MobiReader(object):
     PAGE_BREAK_PAT = re.compile(
         r'<\s*/{0,1}\s*mbp:pagebreak((?:\s+[^/>]*){0,1})/{0,1}\s*>\s*(?:<\s*/{0,1}\s*mbp:pagebreak\s*/{0,1}\s*>)*',
@@ -71,6 +75,8 @@ class MobiReader(object):
         raw = stream.read()
         if raw.startswith('TPZ'):
             raise TopazError(_('This is an Amazon Topaz book. It cannot be processed.'))
+        if raw.startswith(b'\xeaDRMION\xee'):
+            raise KFXError(_('This is an Amazon KFX book. It cannot be processed.'))
 
         self.header   = raw[0:72]
         self.name     = self.header[:32].replace('\x00', '')
@@ -890,5 +896,3 @@ def test_mbp_regex():
         ans = MobiReader.PAGE_BREAK_PAT.sub(r'\1', raw)
         if ans != m:
             raise Exception('%r != %r for %r'%(ans, m, raw))
-
-