Split up _asciidoc_fallback_path from qute_help

qutebrowser/browser/qutescheme.py

@@ -349,6 +349,23 @@ def qute_gpl(_url):
     return 'text/html', utils.read_file('html/license.html')
 
 
+def _asciidoc_fallback_path(path):
+    """Fall back to plaintext asciidoc if the HTML is unavailable."""
+    asciidoc_path = path.replace('.html', '.asciidoc')
+    asciidoc_paths = [asciidoc_path]
+    if asciidoc_path.startswith('html/doc/'):
+        asciidoc_paths += [asciidoc_path.replace('html/doc/', '../doc/help/'),
+                           asciidoc_path.replace('html/doc/', '../doc/')]
+
+    for path in asciidoc_paths:
+        try:
+            return utils.read_file(path)
+        except OSError:
+            pass
+
+    return None
+
+
 @add_handler('help')
 def qute_help(url):
     """Handler for qute://help."""
@@ -373,22 +390,7 @@ def qute_help(url):
     try:
         data = utils.read_file(path)
     except OSError:
-        # No .html around, let's see if we find the asciidoc
+        asciidoc = _asciidoc_fallback_path(path)
-        asciidoc_path = path.replace('.html', '.asciidoc')
-        asciidoc_paths = [asciidoc_path]
-        if asciidoc_path.startswith('html/doc/'):
-            asciidoc_paths += [asciidoc_path.replace('html/doc/', '../doc/help/'),
-                               asciidoc_path.replace('html/doc/', '../doc/')]
-
-        asciidoc = None
-
-        for path in asciidoc_paths:
-            try:
-                asciidoc = utils.read_file(path)
-            except OSError:
-                pass
-            else:
-                break
 
         if asciidoc is None:
             raise