Fix problem with qutesettings scope in pages

Fix to make sure the js bridge code is only enabled when qute: pages are shown.
Previously it would only be available to the first page (and before that it
was available to all pages).

qutebrowser/app.py

@@ -154,6 +154,9 @@ class Application(QApplication):
         config.init(self._args)
         log.init.debug("Initializing crashlog...")
         self._handle_segfault()
+        log.init.debug("Initializing js-bridge...")
+        js_bridge = qutescheme.JSBridge(self)
+        objreg.register('js-bridge', js_bridge)
         log.init.debug("Initializing websettings...")
         websettings.init()
         log.init.debug("Initializing adblock...")

qutebrowser/config/config.py

@@ -520,13 +520,6 @@ class ConfigManager(QObject):
             if self._initialized:
                 self._after_set(sectname, optname)
 
-    @pyqtSlot(int, str, str, str)
-    def set_javascript(self, win_id, sectname, optname, value):
-        try:
-            self.set('conf', sectname, optname, value)
-        except configtypes.ValidationError as e:
-            message.error(win_id, e)
-
     @cmdutils.register(instance='config')
     def save(self):
         """Save the config file."""

qutebrowser/html/settings.html

@@ -4,7 +4,7 @@
 var win_id = {{ win_id }};
 var cset = function(section, option, el) {
   value = el.value;
-  window.qutesettings.set_javascript(win_id, section, option, value);
+  window.qute.set(win_id, section, option, value);
 }
 {% endblock %}
 
@@ -17,6 +17,7 @@ th pre { color: grey; text-align: left; }
 {% endblock %}
 
 {% block content %}
+<noscript><h1>View Only</h1><p>Changing settings requires javascript to be enabled</p></noscript>
 <header><h1>{{ title }}</h1></header>
 <table>
 {% for section in config.DATA %}

qutebrowser/network/qutescheme.py

@@ -27,12 +27,14 @@ Module attributes:
     pyeval_output: The output of the last :pyeval command.
 """
 
+from PyQt5.QtCore import pyqtSlot, QObject
 from PyQt5.QtNetwork import QNetworkReply
 
 import qutebrowser
 from qutebrowser.network import schemehandler, networkreply
 from qutebrowser.utils import (version, utils, jinja, log, message, docutils,
                                objreg)
+from qutebrowser.config import configtypes
 
 
 pyeval_output = ":pyeval was never called"
@@ -79,6 +81,22 @@ class QuteSchemeHandler(schemehandler.SchemeHandler):
             request, data, 'text/html', self.parent())
 
 
+class JSBridge(QObject):
+
+    """Javascript-bridge for special qute:... pages."""
+
+    def __init__(self, parent=None):
+        super().__init__(parent)
+
+    @pyqtSlot(int, str, str, str)
+    def set(self, win_id, sectname, optname, value):
+        """Slot to set a setting from qute:settings."""
+        try:
+            objreg.get('config').set('conf', sectname, optname, value)
+        except configtypes.ValidationError as e:
+            message.error(win_id, e)
+
+
 def qute_pyeval(_win_id, _request):
     """Handler for qute:pyeval. Return HTML content as bytes."""
     html = jinja.env.get_template('pre.html').render(
@@ -151,12 +169,8 @@ def qute_settings(win_id, request):
     """Handler for qute:settings. View/change qute configuration"""
     from qutebrowser.config import configdata
 
-    cfg = objreg.get('config')
-    frame = objreg.get('webview', scope='tab').page().mainFrame()
-    frame.addToJavaScriptWindowObject("qutesettings", cfg)
-
     html = jinja.env.get_template('settings.html').render(
-        win_id=win_id, title='settings', config=configdata, cfg=cfg)
+        win_id=win_id, title='settings', config=configdata)
     return html.encode('UTF-8', errors='xmlcharrefreplace')
 
 

qutebrowser/widgets/webview.py

@@ -289,9 +289,6 @@ class WebView(QWebView):
 
         Args:
             url: The URL to load as QUrl
-
-        Return:
-            Return status of self.load
         """
         qtutils.ensure_valid(url)
         urlstr = url.toDisplayString()
@@ -299,7 +296,20 @@ class WebView(QWebView):
         self.titleChanged.emit(urlstr)
         self.cur_url = url
         self.url_text_changed.emit(url.toDisplayString())
-        return self.load(url)
+        self.load(url)
+        if url.scheme() == 'qute':
+            frame = self.page().mainFrame()
+            frame.javaScriptWindowObjectCleared.connect(self.add_js_bridge)
+
+    def add_js_bridge(self):
+        """Add the javascript bridge for qute:... pages."""
+        frame = self.sender()
+        assert frame.url().scheme() == 'qute'
+        bridge = objreg.get('js-bridge')
+        frame.addToJavaScriptWindowObject('qute', bridge)
+        # We need to make sure the bridge doesn't get added on non-qute:...
+        # pages.
+        frame.javaScriptWindowObjectCleared.disconnect(self.add_js_bridge)
 
     def zoom_perc(self, perc, fuzzyval=True):
         """Zoom to a given zoom percentage.