[project @ robey@lag.net-20080323082110-o9fglwyiozn08tm9]

bug 191657:
clean up usage of the channel map by making a special object to hold the
weak value dict.

paramiko/transport.py

@@ -140,6 +140,51 @@ class SecurityOptions (object):
                            "Compression algorithms")
 
 
+class ChannelMap (object):
+    def __init__(self):
+        # (id -> Channel)
+        self._map = weakref.WeakValueDictionary()
+        self._lock = threading.Lock()
+
+    def put(self, chanid, chan):
+        self._lock.acquire()
+        try:
+            self._map[chanid] = chan
+        finally:
+            self._lock.release()
+            
+    def get(self, chanid):
+        self._lock.acquire()
+        try:
+            return self._map.get(chanid, None)
+        finally:
+            self._lock.release()
+    
+    def delete(self, chanid):
+        self._lock.acquire()
+        try:
+            try:
+                del self._map[chanid]
+            except KeyError:
+                pass
+        finally:
+            self._lock.release()
+    
+    def values(self):
+        self._lock.acquire()
+        try:
+            return self._map.values()
+        finally:
+            self._lock.release()
+    
+    def __len__(self):
+        self._lock.acquire()
+        try:
+            return len(self._map)
+        finally:
+            self._lock.release()
+
+
 class Transport (threading.Thread):
     """
     An SSH Transport attaches to a stream (usually a socket), negotiates an
@@ -271,7 +316,7 @@ class Transport (threading.Thread):
         self.lock = threading.Lock()    # synchronization (always higher level than write_lock)
 
         # tracking open channels
-        self.channels = weakref.WeakValueDictionary()   # (id -> Channel)
+        self._channels = ChannelMap()
         self.channel_events = { }       # (id -> Event)
         self.channels_seen = { }        # (id -> True)
         self._channel_counter = 1
@@ -313,10 +358,7 @@ class Transport (threading.Thread):
                 out += ' (cipher %s, %d bits)' % (self.local_cipher,
                                                   self._cipher_info[self.local_cipher]['key-size'] * 8)
             if self.is_authenticated():
-                if len(self.channels) == 1:
-                    out += ' (active; 1 open channel)'
-                else:
-                    out += ' (active; %d open channels)' % len(self.channels)
+                out += ' (active; %d open channel(s))' % len(self._channels)
             elif self.initial_kex_done:
                 out += ' (connected; awaiting auth)'
             else:
@@ -550,7 +592,7 @@ class Transport (threading.Thread):
         self.active = False
         self.packetizer.close()
         self.join()
-        for chan in self.channels.values():
+        for chan in self._channels.values():
             chan._unlink()
 
     def get_remote_server_key(self):
@@ -667,7 +709,8 @@ class Transport (threading.Thread):
             elif kind == 'x11':
                 m.add_string(src_addr[0])
                 m.add_int(src_addr[1])
-            self.channels[chanid] = chan = Channel(chanid)
+            chan = Channel(chanid)
+            self._channels.put(chanid, chan)
             self.channel_events[chanid] = event = threading.Event()
             self.channels_seen[chanid] = True
             chan._set_transport(self)
@@ -684,12 +727,9 @@ class Transport (threading.Thread):
                 raise e
             if event.isSet():
                 break
-        self.lock.acquire()
-        try:
-            if chanid in self.channels:
+        chan = self._channels.get(chanid)
+        if chan is not None:
             return chan
-        finally:
-            self.lock.release()
         e = self.get_exception()
         if e is None:
             e = SSHException('Unable to open channel.')
@@ -1334,7 +1374,7 @@ class Transport (threading.Thread):
     def _next_channel(self):
         "you are holding the lock"
         chanid = self._channel_counter
-        while chanid in self.channels:
+        while self._channels.get(chanid) is not None:
             self._channel_counter = (self._channel_counter + 1) & 0xffffff
             chanid = self._channel_counter
         self._channel_counter = (self._channel_counter + 1) & 0xffffff
@@ -1342,12 +1382,7 @@ class Transport (threading.Thread):
 
     def _unlink_channel(self, chanid):
         "used by a Channel to remove itself from the active channel list"
-        try:
-            self.lock.acquire()
-            if chanid in self.channels:
-                del self.channels[chanid]
-        finally:
-            self.lock.release()
+        self._channels.delete(chanid)
 
     def _send_message(self, data):
         self.packetizer.send_message(data)
@@ -1478,8 +1513,9 @@ class Transport (threading.Thread):
                     self._handler_table[ptype](self, m)
                 elif ptype in self._channel_handler_table:
                     chanid = m.get_int()
-                    if chanid in self.channels:
-                        self._channel_handler_table[ptype](self.channels[chanid], m)
+                    chan = self._channels.get(chanid)
+                    if chan is not None:
+                        self._channel_handler_table[ptype](chan, m)
                     elif chanid in self.channels_seen:
                         self._log(DEBUG, 'Ignoring message for dead channel %d' % chanid)
                     else:
@@ -1514,7 +1550,7 @@ class Transport (threading.Thread):
             self._log(ERROR, util.tb_strings())
             self.saved_exception = e
         _active_threads.remove(self)
-        for chan in self.channels.values():
+        for chan in self._channels.values():
             chan._unlink()
         if self.active:
             self.active = False
@@ -1872,12 +1908,12 @@ class Transport (threading.Thread):
         server_chanid = m.get_int()
         server_window_size = m.get_int()
         server_max_packet_size = m.get_int()
-        if chanid not in self.channels:
+        chan = self._channels.get(chanid)
+        if chan is None:
             self._log(WARNING, 'Success for unrequested channel! [??]')
             return
         self.lock.acquire()
         try:
-            chan = self.channels[chanid]
             chan._set_remote_channel(server_chanid, server_window_size, server_max_packet_size)
             self._log(INFO, 'Secsh channel %d opened.' % chanid)
             if chanid in self.channel_events:
@@ -1898,7 +1934,7 @@ class Transport (threading.Thread):
         try:
             self.saved_exception = ChannelException(reason, reason_text)
             if chanid in self.channel_events:
-                del self.channels[chanid]
+                self._channels.delete(chanid)
                 if chanid in self.channel_events:
                     self.channel_events[chanid].set()
                     del self.channel_events[chanid]
@@ -1967,9 +2003,9 @@ class Transport (threading.Thread):
             return
         
         chan = Channel(my_chanid)
-        try:
         self.lock.acquire()
-            self.channels[my_chanid] = chan
+        try:
+            self._channels.put(my_chanid, chan)
             self.channels_seen[my_chanid] = True
             chan._set_transport(self)
             chan._set_window(self.window_size, self.max_packet_size)