Attempt to fix connection hanging issues. Retrofit of mongoid#331.

lib/moped/sockets/connectable.rb

@@ -3,6 +3,7 @@ module Sockets
     module Connectable
 
       attr_reader :host, :port
+      attr_accessor :timeout
 
       # Is the socket connection alive?
       #
@@ -43,7 +44,13 @@ def self.included(klass)
       # @since 1.2.0
       def read(length)
         check_if_alive!
-        handle_socket_errors { super }
+        handle_socket_errors {
+          if Kernel.select([self], nil, [self], @timeout)
+           super
+          else
+            raise Errors::ConnectionFailure,  "timeout #{@timeout} exceeded on read from #{host}:#{port}"
+          end
+        }
       end
 
       # Write to the socket.
@@ -152,6 +159,7 @@ def connect(host, port, timeout)
               sock = new(host, port)
               sock.set_encoding('binary')
               timeout_val = [ timeout, 0 ].pack("l_2")
+              sock.timeout = timeout
               sock.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
               sock.setsockopt(Socket::SOL_SOCKET, Socket::SO_RCVTIMEO, timeout_val)
               sock.setsockopt(Socket::SOL_SOCKET, Socket::SO_SNDTIMEO, timeout_val)