GreaseMonkey: Force document-end for known-broken scripts

See #4322

1 files changed, 36 insertions, 1 deletions

diff --git a/qutebrowser/browser/greasemonkey.py b/qutebrowser/browser/greasemonkey.py
index 9314f81c6..2aac71e18 100644
--- a/qutebrowser/browser/greasemonkey.py
+++ b/qutebrowser/browser/greasemonkey.py
@@ -31,7 +31,8 @@ import attr
 from PyQt5.QtCore import pyqtSignal, QObject, QUrl
 
 from qutebrowser.utils import (log, standarddir, jinja, objreg, utils,
-                               javascript, urlmatch, version, usertypes)
+                               javascript, urlmatch, version, usertypes,
+                               qtutils)
 from qutebrowser.api import cmdutils
 from qutebrowser.browser import downloads
 from qutebrowser.misc import objects
@@ -116,6 +117,40 @@ class GreasemonkeyScript:
             script.includes = ['*']
         return script
 
+    def force_document_end(self):
+        """Check whether to force @run-at document-end.
+
+        This needs to be done on QtWebEngine with Qt 5.12 for known-broken
+        scripts.
+
+        On Qt 5.12, accessing the DOM isn't possible with "@run-at
+        document-start". It was documented to be impossible before, but seems
+        to work fine.
+
+        However, some scripts do DOM access with "@run-at document-start". Fix
+        those by forcing them to use document-end instead.
+        """
+        if objects.backend != usertypes.Backend.QtWebEngine:
+            return False
+        elif not qtutils.version_check('5.12', compiled=False):
+            return False
+
+        broken_scripts = [
+            ('http://userstyles.org', None),
+            ('https://github.com/ParticleCore', 'Iridium'),
+        ]
+        return any(self._matches_id(namespace=namespace, name=name)
+                   for namespace, name in broken_scripts)
+
+    def _matches_id(self, *, namespace, name):
+        """Check if this script matches the given namespace/name.
+
+        Both namespace and name can be None in order to match any script.
+        """
+        matches_namespace = namespace is None or self.namespace == namespace
+        matches_name = name is None or self.name == name
+        return matches_namespace and matches_name
+
     def code(self):
         """Return the processed JavaScript code of this script.