Use hook system for config_changed hook

qutebrowser/api/config.py

@@ -24,8 +24,6 @@ import typing
 from PyQt5.QtCore import QUrl
 
 from qutebrowser.config import config
-# pylint: disable=unused-import
-from qutebrowser.config.config import change_filter
 
 val = typing.cast('config.ConfigContainer', None)
 

qutebrowser/api/hook.py

@@ -26,14 +26,31 @@ import typing
 from qutebrowser.extensions import loader
 
 
+def _add_module_info(func: typing.Callable) -> loader.ModuleInfo:
+    """Add module info to the given function."""
+    module = importlib.import_module(func.__module__)
+    return loader.add_module_info(module)
+
+
 class init:  # noqa: N801,N806 pylint: disable=invalid-name
 
     """Decorator to mark a function to run when initializing."""
 
     def __call__(self, func: typing.Callable) -> typing.Callable:
-        module = importlib.import_module(func.__module__)
-        info = loader.add_module_info(module)
+        info = _add_module_info(func)
         if info.init_hook is not None:
             raise ValueError("init hook is already registered!")
         info.init_hook = func
         return func
+
+
+class config_changed:
+
+    """Decorator to get notified about changed configs."""
+
+    def __init__(self, option_filter=None):
+        self._filter = option_filter
+
+    def __call__(self, func: typing.Callable) -> typing.Callable:
+        info = _add_module_info(func)
+        info.config_changed_hooks.append((self._filter, func))

qutebrowser/components/adblock.py

@@ -294,7 +294,6 @@ class HostBlocker:
             message.info("adblock: Read {} hosts from {} sources.".format(
                 len(self._blocked_hosts), self._done_count))
 
-    @config.change_filter('content.host_blocking.lists')
     def update_files(self):
         """Update files when the config changed."""
         if not config.val.content.host_blocking.lists:
@@ -337,6 +336,11 @@ def adblock_update():
     _host_blocker.adblock_update()
 
 
+@hook.config_changed('content.host_blocking.lists')
+def on_config_changed():
+    _host_blocker.update_files()
+
+
 @hook.init()
 def init(context):
     global _host_blocker
@@ -344,6 +348,4 @@ def init(context):
                                 config_dir=context.config_dir,
                                 args=context.args)
     _host_blocker.read_hosts()
-
-    context.signals.config_changed.connect(_host_blocker.update_files)
     requests.register_filter(_host_blocker.filter_request)

qutebrowser/config/config.py

@@ -86,7 +86,7 @@ class change_filter:  # noqa: N801,N806 pylint: disable=invalid-name
                 not configdata.is_valid_prefix(self._option)):
             raise configexc.NoOptionError(self._option)
 
-    def _check_match(self, option: typing.Optional[str]) -> bool:
+    def check_match(self, option: typing.Optional[str]) -> bool:
         """Check if the given option matches the filter."""
         if option is None:
             # Called directly, not from a config change event.
@@ -119,7 +119,7 @@ class change_filter:  # noqa: N801,N806 pylint: disable=invalid-name
             @functools.wraps(func)
             def func_wrapper(option: str = None) -> typing.Any:
                 """Call the underlying function."""
-                if self._check_match(option):
+                if self.check_match(option):
                     return func()
                 return None
             return func_wrapper
@@ -128,7 +128,7 @@ class change_filter:  # noqa: N801,N806 pylint: disable=invalid-name
             def meth_wrapper(wrapper_self: typing.Any,
                              option: str = None) -> typing.Any:
                 """Call the underlying function."""
-                if self._check_match(option):
+                if self.check_match(option):
                     return func(wrapper_self)
                 return None
             return meth_wrapper

qutebrowser/extensions/loader.py

@@ -28,13 +28,17 @@ import pathlib
 
 import attr
 
-from PyQt5.QtCore import pyqtSignal, QObject
+from PyQt5.QtCore import pyqtSlot, QObject
 
 from qutebrowser import components
 from qutebrowser.config import config
 from qutebrowser.utils import log, standarddir, objreg
 
 
+# ModuleInfo objects for all loaded plugins
+_module_infos = []
+
+
 @attr.s
 class InitContext:
 
@@ -43,14 +47,6 @@ class InitContext:
     data_dir = attr.ib()  # type: pathlib.Path
     config_dir = attr.ib()  # type: pathlib.Path
     args = attr.ib()  # type: argparse.Namespace
-    signals = attr.ib()  # type: ExtensionSignals
-
-
-class ExtensionSignals(QObject):
-
-    """Signals exposed to an extension."""
-
-    config_changed = pyqtSignal(str)
 
 
 @attr.s
@@ -61,7 +57,11 @@ class ModuleInfo:
     This gets used by qutebrowser.api.hook.
     """
 
+    _ConfigChangedHooksType = typing.List[typing.Tuple[str, typing.Callable]]
+
     init_hook = attr.ib(None)  # type: typing.Optional[typing.Callable]
+    config_changed_hooks = attr.ib(
+        attr.Factory(list))  # type: _ConfigChangedHooksType
 
 
 @attr.s
@@ -72,12 +72,6 @@ class ExtensionInfo:
     name = attr.ib()  # type: str
 
 
-# Global extension signals, shared between all extensions.
-# At some point we might want to make this per-extension, but then we'll need
-# to find out what to set as its Qt parent so it's kept alive.
-_extension_signals = ExtensionSignals()
-
-
 def add_module_info(module: types.ModuleType) -> ModuleInfo:
     """Add ModuleInfo to a module (if not added yet)."""
     # pylint: disable=protected-access
@@ -138,8 +132,7 @@ def _get_init_context() -> InitContext:
     """Get an InitContext object."""
     return InitContext(data_dir=pathlib.Path(standarddir.data()),
                        config_dir=pathlib.Path(standarddir.config()),
-                       args=objreg.get('args'),
-                       signals=_extension_signals)
+                       args=objreg.get('args'))
 
 
 def _load_component(info: ExtensionInfo) -> types.ModuleType:
@@ -153,8 +146,21 @@ def _load_component(info: ExtensionInfo) -> types.ModuleType:
                              .format(mod_info.init_hook.__name__))
         mod_info.init_hook(_get_init_context())
 
+    _module_infos.append(mod_info)
+
     return mod
 
 
+@pyqtSlot(str)
+def _on_config_changed(changed_name: str) -> None:
+    """Call config_changed hooks if the config changed."""
+    for mod_info in _module_infos:
+        for option, hook in mod_info.config_changed_hooks:
+            cfilter = config.change_filter(option)
+            cfilter.validate()
+            if cfilter.check_match(changed_name):
+                hook()
+
+
 def init() -> None:
-    config.instance.changed.connect(_extension_signals.config_changed)
+    config.instance.changed.connect(_on_config_changed)