Add support for storage -> cache-size with QtWebEngine

CHANGELOG.asciidoc

@@ -26,6 +26,7 @@ Added
 - Printing support for QtWebEngine with Qt >= 5.8
 - Proxy support for QtWebEngine with Qt >= 5.8
 - Support for the `content -> cookies-store`  option with QtWebEngine
+- Support for the `storage -> cache-size` option with QtWebEngine
 
 Changed
 ~~~~~~~

qutebrowser/browser/webengine/webenginesettings.py

@@ -65,16 +65,40 @@ class StaticSetter(websettings.StaticSetter):
     GLOBAL_SETTINGS = QWebEngineSettings.globalSettings
 
 
-class PersistentCookiePolicy(websettings.Base):
+class ProfileSetter(websettings.Base):
+
+    """A setting set on the QWebEngineProfile."""
+
+    def __init__(self, getter, setter):
+        super().__init__()
+        profile = QWebEngineProfile.defaultProfile()
+        self._getter = getattr(profile, getter)
+        self._setter = getattr(profile, setter)
+
+    def get(self, settings=None):
+        utils.unused(settings)
+        return self._getter()
+
+    def _set(self, value, settings=None):
+        utils.unused(settings)
+        self._setter(value)
+
+
+class PersistentCookiePolicy(ProfileSetter):
 
     """The cookies -> store setting is different from other settings."""
 
+    def __init__(self):
+        super().__init__(getter='persistentCookiesPolicy',
+                         setter='setPersistentCookiesPolicy')
+
     def get(self, settings=None):
+        utils.unused(settings)
         return config.get('content', 'cookies-store')
 
     def _set(self, value, settings=None):
         utils.unused(settings)
-        QWebEngineProfile.defaultProfile().setPersistentCookiesPolicy(
+        self._setter(
             QWebEngineProfile.AllowPersistentCookies if value else
             QWebEngineProfile.NoPersistentCookies
         )
@@ -246,6 +270,9 @@ MAPPINGS = {
     'storage': {
         'local-storage':
             Attribute(QWebEngineSettings.LocalStorageEnabled),
+        'cache-size':
+            ProfileSetter(getter='httpCacheMaximumSize',
+                          setter='setHttpCacheMaximumSize')
     },
     'general': {
         'xss-auditing':

qutebrowser/browser/webkit/cache.py

@@ -48,6 +48,13 @@ class DiskCache(QNetworkDiskCache):
                               maxsize=self.maximumCacheSize(),
                               path=self.cacheDirectory())
 
+    def _set_cache_size(self):
+        """Set the cache size based on the config."""
+        size = config.get('storage', 'cache-size')
+        if size is None:
+            size = 1024 * 1024 * 50  # default from QNetworkDiskCachePrivate
+        self.setMaximumCacheSize(size)
+
     def _maybe_activate(self):
         """Activate/deactivate the cache based on the config."""
         if config.get('general', 'private-browsing'):
@@ -55,13 +62,13 @@ class DiskCache(QNetworkDiskCache):
         else:
             self._activated = True
             self.setCacheDirectory(os.path.join(self._cache_dir, 'http'))
-            self.setMaximumCacheSize(config.get('storage', 'cache-size'))
+            self._set_cache_size()
 
     @pyqtSlot(str, str)
     def on_config_changed(self, section, option):
         """Update cache size/activated if the config was changed."""
         if (section, option) == ('storage', 'cache-size'):
-            self.setMaximumCacheSize(config.get('storage', 'cache-size'))
+            self._set_cache_size()
         elif (section, option) == ('general',  # pragma: no branch
                                    'private-browsing'):
             self._maybe_activate()

qutebrowser/config/config.py

@@ -443,6 +443,7 @@ class ConfigManager(QObject):
                 'html > ::-webkit-scrollbar { width: 0px; height: 0px; }': '',
                 '::-webkit-scrollbar { width: 0px; height: 0px; }': '',
             }),
+        ('contents', 'cache-size'): _get_value_transformer({'52428800': ''}),
     }
 
     changed = pyqtSignal(str, str)

qutebrowser/config/configdata.py

@@ -795,9 +795,9 @@ def data(readonly=False):
              "enabled."),
 
             ('cache-size',
-             SettingValue(typ.Int(minval=0, maxval=MAXVALS['int64']),
+             SettingValue(typ.Int(none_ok=True, minval=0,
-                          '52428800'),
+                                  maxval=MAXVALS['int64']), ''),
-             "Size of the HTTP network cache."),
+             "Size of the HTTP network cache. Empty to use the default value."),
 
             readonly=readonly
         )),