urlutils: Add fallback to filename_from_url

This makes the callers a bit simpler because they don't need to take
care of falling back themselves.

2 files changed, 10 insertions, 3 deletions

diff --git a/qutebrowser/utils/urlutils.py b/qutebrowser/utils/urlutils.py
index 3f1fb021c..24285404a 100644
--- a/qutebrowser/utils/urlutils.py
+++ b/qutebrowser/utils/urlutils.py
@@ -439,24 +439,26 @@ def parse_data_url(url: QUrl) -> Tuple[str, str, bytes]:
     return media_type, params, data
 
 
-def filename_from_url(url: QUrl) -> Optional[str]:
+def filename_from_url(url: QUrl, fallback: str = None) -> Optional[str]:
     """Get a suitable filename from a URL.
 
     Args:
         url: The URL to parse, as a QUrl.
+        fallback: Value to use if no name can be determined.
 
     Return:
         The suggested filename as a string, or None.
     """
     if not url.isValid():
-        return None
+        return fallback
+
     pathname = posixpath.basename(url.path())
     if pathname:
         return pathname
     elif url.host():
         return url.host() + '.html'
     else:
-        return None
+        return fallback
 
 
 HostTupleType = Tuple[str, str, int]
diff --git a/tests/unit/utils/test_urlutils.py b/tests/unit/utils/test_urlutils.py
index c2ff0042f..54d195d1a 100644
--- a/tests/unit/utils/test_urlutils.py
+++ b/tests/unit/utils/test_urlutils.py
@@ -656,6 +656,11 @@ def test_filename_from_url(qurl, output):
     assert urlutils.filename_from_url(qurl) == output
 
 
+@pytest.mark.parametrize('qurl', [QUrl(), QUrl('qute://')])
+def test_filename_from_url_fallback(qurl):
+    assert urlutils.filename_from_url(qurl, fallback='fallback') == 'fallback'
+
+
 @pytest.mark.parametrize('qurl, expected', [
     (QUrl('ftp://example.com/'), ('ftp', 'example.com', 21)),
     (QUrl('ftp://example.com:2121/'), ('ftp', 'example.com', 2121)),