Add an initial cookie filter for Qt 5.11

See #3010

doc/changelog.asciidoc

@@ -34,6 +34,8 @@ Added
   * New `{audio}` field for `window.title_format` and `tabs.title.format` which
     displays `[M]`/`[A]` for muted/recently audible tabs.
   * New `:tab-mute` command (bound to `<Alt-m>`) to mute/unmute a tab.
+- QtWebEngine: Support for `content.cookies.accept` with third-party cookies
+  blocked by default (requires Qt 5.11).
 - QtWebEngine: New settings:
   * Support for requesting persistent storage via
     `navigator.webkitPersistentStorage.requestQuota` with a new

doc/help/settings.asciidoc

@@ -1540,12 +1540,12 @@ Valid values:
 
  * +all+: Accept all cookies.
  * +no-3rdparty+: Accept cookies from the same origin only.
- * +no-unknown-3rdparty+: Accept cookies from the same origin only, unless a cookie is already set for the domain.
+ * +no-unknown-3rdparty+: Accept cookies from the same origin only, unless a cookie is already set for the domain. On QtWebEngine, this is the same as no-3rdparty.
  * +never+: Don't accept cookies at all.
 
 Default: +pass:[no-3rdparty]+
 
-This setting is only available with the QtWebKit backend.
+On QtWebEngine, this setting requires Qt 5.11 or newer.
 
 [[content.cookies.store]]
 === content.cookies.store

qutebrowser/browser/webengine/cookies.py

@@ -0,0 +1,48 @@
+# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
+
+# Copyright 2018 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
+#
+# This file is part of qutebrowser.
+#
+# qutebrowser is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# qutebrowser is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Filter for QtWebEngine cookies."""
+
+from qutebrowser.config import config
+from qutebrowser.utils import utils
+
+
+def _accept_cookie(request):
+    """Check whether the given cookie should be accepted."""
+    accept = config.val.content.cookies.accept
+    if accept == 'all':
+        return True
+    elif accept in ['no-3rdparty', 'no-unknown-3rdparty']:
+        return not request.thirdParty
+    elif accept == 'never':
+        return False
+    else:
+        raise utils.Unreachable
+
+
+def install_filter(profile):
+    """Install the cookie filter on the given profile.
+
+    On Qt < 5.11, the filter isn't installed.
+    """
+    store = profile.cookieStore()
+    try:
+        store.setCookieFilter(_accept_cookie)
+    except AttributeError:
+        pass

qutebrowser/browser/webengine/webenginetab.py

@@ -37,7 +37,7 @@ from qutebrowser.config import configdata, config
 from qutebrowser.browser import browsertab, mouse, shared
 from qutebrowser.browser.webengine import (webview, webengineelem, tabhistory,
                                            interceptor, webenginequtescheme,
-                                           webenginedownloads,
+                                           cookies, webenginedownloads,
                                            webenginesettings)
 from qutebrowser.misc import miscwidgets
 from qutebrowser.utils import (usertypes, qtutils, log, javascript, utils,
@@ -74,6 +74,10 @@ def init():
     download_manager.install(webenginesettings.private_profile)
     objreg.register('webengine-download-manager', download_manager)
 
+    log.init.debug("Initializing cookie filter...")
+    cookies.install_filter(webenginesettings.default_profile)
+    cookies.install_filter(webenginesettings.private_profile)
+
     # Clear visited links on web history clear
     hist = objreg.get('web-history')
     for p in [webenginesettings.default_profile,

qutebrowser/config/configdata.yml

@@ -281,14 +281,17 @@ content.cache.appcache:
 
 content.cookies.accept:
   default: no-3rdparty
-  backend: QtWebKit
+  backend:
+    QtWebKit: true
+    QtWebEngine: Qt 5.11
   type:
     name: String
     valid_values:
       - all: "Accept all cookies."
       - no-3rdparty: "Accept cookies from the same origin only."
       - no-unknown-3rdparty: "Accept cookies from the same origin only, unless
-          a cookie is already set for the domain."
+          a cookie is already set for the domain. On QtWebEngine, this is the
+          same as no-3rdparty."
       - never: "Don't accept cookies at all."
   desc: Which cookies to accept.