[tor-commits] [stem/master] Refactor cache invalidation resulting from config change into new method

[atagar at torproject.org]

commit fdd34f81b986fdb21e782993ca380d5e65036494
Author: Dave Rolek <dmr-x at riseup.net>
Date:   Mon May 14 16:20:49 2018 +0000

    Refactor cache invalidation resulting from config change into new method
    
    into: _confchanged_cache_invalidation()
    
    Also use this for _confchanged_listener(), thereby likely fixing a few
    bugs from the additional cache invalidation beyond exit_policy.
    
    See #25821
---
 stem/control.py | 41 ++++++++++++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/stem/control.py b/stem/control.py
index c2467a53..b9534f31 100644
--- a/stem/control.py
+++ b/stem/control.py
@@ -1064,9 +1064,10 @@ class Controller(BaseController):
 
     def _confchanged_listener(event):
       if self.is_caching_enabled():
-        self._set_cache(dict((k, None) for k in event.config), 'getconf')
+        to_cache = dict((k, None) for k in event.config)
+        self._set_cache(to_cache, 'getconf')
 
-        self._set_cache({'exit_policy': None})  # numerous options can change our policy
+        self._confchanged_cache_invalidation(to_cache)
 
     self.add_event_listener(_confchanged_listener, EventType.CONF_CHANGED)
 
@@ -2435,18 +2436,8 @@ class Controller(BaseController):
 
           to_cache[param] = value
 
-          if 'hidden' in param:
-            self._set_cache({'hidden_service_conf': None})
-
-        # reset any getinfo parameters that can be changed by a SETCONF
-
-        self._set_cache(dict([(k.lower(), None) for k in CACHEABLE_GETINFO_PARAMS_UNTIL_SETCONF]), 'getinfo')
-        self._set_cache(None, 'listeners')
-
         self._set_cache(to_cache, 'getconf')
-        self._set_cache({'get_custom_options': None})
-
-        self._set_cache({'exit_policy': None})  # numerous options can change our policy
+        self._confchanged_cache_invalidation(dict(params))
     else:
       log.debug('%s (failed, code: %s, message: %s)' % (query, response.code, response.message))
       immutable_params = [k for k, v in params if stem.util.str_tools._to_unicode(k).lower() in IMMUTABLE_CONFIG_OPTIONS]
@@ -3206,6 +3197,30 @@ class Controller(BaseController):
         else:
           self._request_cache[cache_key] = value
 
+  def _confchanged_cache_invalidation(self, params):
+    """
+    Drops dependent portions of the cache when configuration changes.
+
+    :param dict params: **dict** of 'config_key => value' pairs for configs
+      that changed. The entries' values are currently unused.
+    """
+
+    with self._cache_lock:
+      if not self.is_caching_enabled():
+        return
+
+      if any('hidden' in param.lower() for param in params.keys()):
+        self._set_cache({'hidden_service_conf': None})
+
+      # reset any getinfo parameters that can be changed by a SETCONF
+
+      self._set_cache(dict([(k.lower(), None) for k in CACHEABLE_GETINFO_PARAMS_UNTIL_SETCONF]), 'getinfo')
+      self._set_cache(None, 'listeners')
+
+      self._set_cache({'get_custom_options': None})
+
+      self._set_cache({'exit_policy': None})  # numerous options can change our policy
+
   def is_caching_enabled(self):
     """
     **True** if caching has been enabled, **False** otherwise.