remove expired connections

git-svn-id: https://linkchecker.svn.sourceforge.net/svnroot/linkchecker/trunk/linkchecker@2287 e7d03fd6-7b0d-0410-9947-9c21f3af8025

ChangeLog

@@ -23,6 +23,10 @@
     Closes: SF bug #1117839
     Changed: linkcheck/checker/fileurl.py
 
+  * Regularly remove expired connections from the connection pool.
+    Type: feature
+    Changed: linkcheck/checker/pool.py
+
 2.3 "Napoleon Dynamite" (released 3.2.2005)
 
   * Use and require Python >= 2.4.

linkcheck/checker/pool.py

@@ -39,6 +39,7 @@ class ConnectionPool (object):
         # open connections
         # {(type, host, user, pass) -> [connection, status, expiration time]}
         self.connections = {}
+        self.expiration_counter = 1
 
     def add_connection (self, key, conn, timeout):
         """
@@ -54,6 +55,11 @@ class ConnectionPool (object):
         @return: Open connection object or None if no connection is available.
         @rtype None or FTPConnection or HTTP(S)Connection
         """
+        if (self.expiration_counter % 100) == 0:
+            self.expiration_counter = 1
+            self.expire_connections()
+        else:
+            self.expiration_counter += 1
         if key not in self.connections:
             # not found
             return None
@@ -84,3 +90,15 @@ class ConnectionPool (object):
         """
         if key in self.connections:
             self.connections[key][1] = 'available'
+
+    def expire_connections (self):
+        """
+        Remove expired connections from this pool.
+        """
+        t = time.time()
+        to_delete = []
+        for key, conn_data in self.connections.iteritems():
+            if conn_data[1] == 'available' and t > conn_data[2]:
+                to_delete.append(key)
+        for key in to_delete:
+            del self.connections[key]