E-book viewer: When viewing EPUB files, do not parse html as xhtml even if it has svg tags embedded.

src/calibre/ebooks/oeb/display/webview.py

@@ -31,7 +31,8 @@ def self_closing_sub(match):
     return '<%s%s></%s>'%(match.group(1), match.group(2), match.group(1))
 
 def load_html(path, view, codec='utf-8', mime_type=None,
-        pre_load_callback=lambda x:None, path_is_html=False):
+        pre_load_callback=lambda x:None, path_is_html=False,
+              force_as_html=False):
     from PyQt4.Qt import QUrl, QByteArray
     if mime_type is None:
         mime_type = guess_type(path)[0]
@@ -44,18 +45,20 @@ def load_html(path, view, codec='utf-8', mime_type=None,
             html = f.read().decode(codec, 'replace')
 
     html = EntityDeclarationProcessor(html).processed_html
-    has_svg = re.search(r'<[:a-zA-Z]*svg', html) is not None
     self_closing_pat = re.compile(r'<\s*([A-Za-z1-6]+)([^>]*)/\s*>')
     html = self_closing_pat.sub(self_closing_sub, html)
 
     loading_url = QUrl.fromLocalFile(path)
     pre_load_callback(loading_url)
 
-    if has_svg:
+    if force_as_html or re.search(r'<[:a-zA-Z]*svg', html) is None:
+        view.setHtml(html, loading_url)
+    else:
         view.setContent(QByteArray(html.encode(codec)), mime_type,
                 loading_url)
-    else:
-        view.setHtml(html, loading_url)
-
-
+        mf = view.page().mainFrame()
+        elem = mf.findFirstElement('parsererror')
+        if not elem.isNull():
+            return False
+    return True
 

src/calibre/gui2/viewer/documentview.py

@@ -790,7 +790,8 @@ class DocumentView(QWebView): # {{{
                 self.manager.load_started()
 
         load_html(path, self, codec=getattr(path, 'encoding', 'utf-8'), mime_type=getattr(path,
-            'mime_type', 'text/html'), pre_load_callback=callback)
+            'mime_type', 'text/html'), pre_load_callback=callback,
+                  force_as_html=True)
         entries = set()
         for ie in getattr(path, 'index_entries', []):
             if ie.start_anchor: