Fixed bug in select

apps/sam/python/src/i2p/select.py

@@ -67,71 +67,99 @@ def poll():
 """
   return Poll()
 
+def _has_data(S):
+  """True if the given I2P socket has data waiting."""
+  try:
+    S.recv(1, i2p.socket.MSG_PEEK | i2p.socket.MSG_DONTWAIT)
+    return True
+  except:
+    return False
+
+def _noblock_select(readlist, writelist, errlist):
+  """Makes a single query of the given sockets, like
+     select() with timeout 0.0."""
+  Rans = []
+  Wans = []
+  Eans = []
+
+  # Check for read availability.
+  for R in readlist:
+    if isinstance(R, int) or hasattr(R, 'fileno'):
+      # Python socket
+      if len(pyselect.select([R], [], [], 0.0)[0]) > 0:
+        Rans.append(R)
+    else:
+      # SAM Socket
+      if _has_data(R):
+        Rans.append(R)
+#      if R.type == i2p.socket.SOCK_STREAM:
+#        try:
+#          R._verify_connected()
+#          Rans.append(R)
+#        except:
+#          pass
+#      else:
+#        if len(R.sessobj) > 0: Rans.append(R)
+
+  # Check for write availability.
+  for W in writelist:
+    if isinstance(W, int) or hasattr(W, 'fileno'):
+      # Python socket
+      if len(pyselect.select([], [W], [], 0.0)[1]) > 0:
+        Wans.append(W)
+    else:
+      # SAM Socket
+      if W.type == i2p.socket.SOCK_STREAM:
+        try:
+          W._verify_connected()
+          Wans.append(W)
+        except:
+          pass
+      else:
+        Wans.append(W)
+
+  # Check for error conditions.
+  # These can only be stream errors.
+  for E in errlist:
+    if isinstance(E, int) or hasattr(E, 'fileno'):
+      # Python socket
+      if len(pyselect.select([], [], [E], 0.0)[2]) > 0:
+        Eans.append(E)
+    else:
+      if E.type == i2p.socket.SOCK_STREAM:
+        try:
+          # FIXME: Use a ._get_error() function for errors.
+          # Socket can only have an error if it connected.
+          E._verify_connected()
+          if E.sessobj.err != None:
+            Eans.append(E)
+        except:
+          pass
+
+  return (Rans, Wans, Eans)
+
+
 def select(readlist, writelist, errlist, timeout=None):
   """Performs a select call.  Works on SAM sockets and Python
      sockets.  See select.select() in the Python library for more
      information."""
-  Rans = []
-  Wans = []
-  Eans = []
+
   if timeout != None: end = time.clock() + timeout
   while True:
     # FIXME: Check performance.
     # Use pyselect.poll for Python sockets, if needed for speed.
+    (Rans, Wans, Eans) = _noblock_select(readlist,writelist,errlist)
 
-    # Check for read availability.
-    for R in readlist:
-      if isinstance(R, int) or hasattr(R, 'fileno'):
-        # Python socket
-        if len(pyselect.select([R], [], [], 0.0)[0]) > 0:
-          Rans.append(R)
-      else:
-        # SAM Socket
-        if R.type == i2p.socket.SOCK_STREAM:
-          try:
-            R._verify_connected()
-            Rans.append(R)
-          except:
-            pass
-        else:
-          if len(R) > 0: Rans.append(R)
-
-    # Check for write availability.
-    for W in writelist:
-      if isinstance(W, int) or hasattr(W, 'fileno'):
-        # Python socket
-        if len(pyselect.select([], [W], [], 0.0)[1]) > 0:
-          Wans.append(W)
-      else:
-        # SAM Socket
-        if W.type == i2p.socket.SOCK_STREAM:
-          try:
-            W._verify_connected()
-            Wans.append(W)
-          except:
-            pass
-        else:
-          Wans.append(W)
-
-    # Check for error conditions.
-    # These can only be stream errors.
-    for E in errlist:
-      if isinstance(E, int) or hasattr(E, 'fileno'):
-        # Python socket
-        if len(pyselect.select([], [], [E], 0.0)[2]) > 0:
-          Eans.append(E)
-      else:
-        if E.type == i2p.socket.SOCK_STREAM:
-          try:
-            # FIXME: Use a ._get_error() function for errors.
-            # Socket can only have an error if it connected.
-            E._verify_connected()
-            if E.sessobj.err != None:
-              Eans.append(E)
-          except:
-            pass
     if timeout != None and time.clock() >= end: break
-    if len(Rans) != 0 or len(Wans) != 0 or len(Eans) != 0: break
+    if len(Rans) != 0 or len(Wans) != 0 or len(Eans) != 0:
+      # One or more sockets are ready.
+      if timeout != 0.0:
+        # Check again, because sockets may have changed state while
+        # we did _noblock_select (it's safer to check twice, since
+        # they usually go from no data => data ready, and so forth).
+        (Rans, Wans, Eans) = _noblock_select(readlist, writelist,
+                                             errlist)
+        return (Rans, Wans, Eans)
 
     time.sleep(0.01)