From 184692b587e67d79ef35edc04ff5b97c0c27654d Mon Sep 17 00:00:00 2001
From: John Schember <john@nachtimwald.com>
Date: Tue, 12 Apr 2011 20:39:01 -0400
Subject: [PATCH] extZ metadata: Get cover, update OPF without losing other
 data such as spine, and guide.

---
 src/calibre/ebooks/metadata/extz.py | 34 +++++++++++++++++------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/src/calibre/ebooks/metadata/extz.py b/src/calibre/ebooks/metadata/extz.py
index b49f3f6ddd..338c4dd91d 100644
--- a/src/calibre/ebooks/metadata/extz.py
+++ b/src/calibre/ebooks/metadata/extz.py
@@ -7,13 +7,10 @@ __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 Read meta information from extZ (TXTZ, HTMLZ...) files.
 '''
 
-import os
-
 from cStringIO import StringIO
 
 from calibre.ebooks.metadata import MetaInformation
-from calibre.ebooks.metadata.opf2 import OPF, metadata_to_opf
-from calibre.ptempfile import TemporaryDirectory
+from calibre.ebooks.metadata.opf2 import OPF
 from calibre.utils.zipfile import ZipFile, safe_replace
 
 def get_metadata(stream, extract_cover=True):
@@ -23,23 +20,32 @@ def get_metadata(stream, extract_cover=True):
     mi = MetaInformation(_('Unknown'), [_('Unknown')])
     stream.seek(0)
 
-    with TemporaryDirectory('_untxtz_mdata') as tdir:
-        try:
-            with ZipFile(stream) as zf:
-                opf_name = get_first_opf_name(stream)
-                opf_stream = StringIO(zf.read(opf_name))
-                mi = OPF(opf_stream).to_book_metadata()
-        except:
-            return mi
+    try:
+        with ZipFile(stream) as zf:
+            opf_name = get_first_opf_name(stream)
+            opf_stream = StringIO(zf.read(opf_name))
+            opf = OPF(opf_stream)
+            mi = opf.to_book_metadata()
+            if extract_cover:
+                cover_name = opf.raster_cover
+                if cover_name:
+                    mi.cover_data = ('jpg', zf.read(cover_name))
+    except:
+        return mi
     return mi
 
 def set_metadata(stream, mi):
-    opf = StringIO(metadata_to_opf(mi))
     try:
         opf_name = get_first_opf_name(stream)
+        with ZipFile(stream) as zf:
+            opf_stream = StringIO(zf.read(opf_name))
+        opf = OPF(opf_stream)
     except:
         opf_name = 'metadata.opf'
-    safe_replace(stream, opf_name, opf)
+        opf = OPF(StringIO())
+    opf.smart_update(mi, replace_metadata=True)
+    newopf = StringIO(opf.render())
+    safe_replace(stream, opf_name, newopf)
 
 def get_first_opf_name(stream):
     with ZipFile(stream) as zf: