Use an LRU cache for stylesheets

qutebrowser/app.py

@@ -394,7 +394,7 @@ class Application(QApplication):
             status.prompt.prompter.ask_question, Qt.DirectConnection)
 
         # config
-        self.config.style_changed.connect(style.invalidate_caches)
+        self.config.style_changed.connect(style.get_stylesheet.cache_clear)
         for obj in (tabs, completion, self.mainwindow, self.cmd_history,
                     websettings, kp[utypes.KeyMode.normal], self.modeman,
                     status, status.txt):

qutebrowser/config/style.py

@@ -17,12 +17,7 @@
 # You should have received a copy of the GNU General Public License
 # along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.
 
-"""Utilities related to the look&feel of qutebrowser.
-
-Module attributes:
-    _colordict: The global cached ColorDict.
-    _fontdict: The global cached FontDict.
-"""
+"""Utilities related to the look&feel of qutebrowser."""
 
 import functools
 
@@ -32,10 +27,7 @@ from qutebrowser.config import config
 from qutebrowser.utils import log, utils
 
 
-_colordict = None
-_fontdict = None
-
-
+@functools.lru_cache(maxsize=16)
 def get_stylesheet(template):
     """Format a stylesheet based on a template.
 
@@ -45,12 +37,9 @@ def get_stylesheet(template):
     Return:
         The formatted template as string.
     """
-    global _colordict, _fontdict
-    if _colordict is None:
-        _colordict = ColorDict(config.section('colors'))
-    if _fontdict is None:
-        _fontdict = FontDict(config.section('fonts'))
-    return template.strip().format(color=_colordict, font=_fontdict,
+    colordict = ColorDict(config.section('colors'))
+    fontdict = FontDict(config.section('fonts'))
+    return template.strip().format(color=colordict, font=fontdict,
                                    config=config.instance())
 
 
@@ -78,15 +67,6 @@ def _update_stylesheet(obj, _section, _option):
     obj.setStyleSheet(get_stylesheet(obj.STYLESHEET))
 
 
-def invalidate_caches(section, _option):
-    """Invalidate cached dicts."""
-    global _colordict, _fontdict
-    if section == 'colors':
-        _colordict = None
-    elif section == 'fonts':
-        _fontdict = None
-
-
 class ColorDict(dict):
 
     """A dict aimed at Qt stylesheet colors."""

qutebrowser/utils/debug.py

@@ -29,7 +29,7 @@ from PyQt5.QtCore import pyqtRemoveInputHook, QEvent, QCoreApplication
 
 from qutebrowser.utils import log, utils
 from qutebrowser.commands import cmdutils
-from qutebrowser.config import config
+from qutebrowser.config import config, style
 
 
 @cmdutils.register(debug=True, name='debug-set-trace')
@@ -87,9 +87,11 @@ def debug_all_objects():
 
 @cmdutils.register(debug=True)
 def debug_cache_stats():
-    """Print config LRU cache stats."""
-    info = config.instance().get.cache_info()
-    log.misc.debug(info)
+    """Print LRU cache stats."""
+    config_info = config.instance().get.cache_info()
+    style_info = style.get_stylesheet.cache_info()
+    log.misc.debug('config: {}'.format(config_info))
+    log.misc.debug('style: {}'.format(style_info))
 
 
 def log_events(klass):