Fix a regression in 0.8.7 that broke reading metadata from MOBI files in the Edit metadata dialog. Fixes #801981 (Private bug)

src/calibre/ebooks/mobi/reader.py

@@ -957,7 +957,10 @@ def get_metadata(stream):
         return get_metadata(stream)
     from calibre.utils.logging import Log
     log = Log()
+    try:
         mi = MetaInformation(os.path.basename(stream.name), [_('Unknown')])
+    except:
+        mi = MetaInformation(_('Unknown'), [_('Unknown')])
     mh = MetadataHeader(stream, log)
     if mh.title and mh.title != _('Unknown'):
         mi.title = mh.title

src/calibre/library/database2.py

@@ -1245,6 +1245,7 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
                     ret = tempfile.SpooledTemporaryFile(max_size=SPOOL_SIZE)
                     shutil.copyfileobj(f, ret)
                     ret.seek(0)
+                    ret.name = f.name
                 else:
                     ret = f.read()
             return ret