Port.py

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"""
Copyright 2008 Free Software Foundation, Inc.
This file is part of GNU Radio

GNU Radio Companion is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

GNU Radio Companion is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
"""
##@package grc.elements.Port
#Flow graph block port (source or sink).
#@author Josh Blum

from grc import Utils
from grc.elements.Element import Element

class Port(Element):

        ##possible port types
        TYPES = []

        def __init__(self, block, n):
                """
                Make a new port from nested data.
                @param block the parent element
                @param n the nested odict
                @return a new port
                """
                #grab the data
                name = n['name']
                key = n['key']
                type = n['type']
                #build the port
                Element.__init__(self, block)
                self._name = name
                self._key = key
                self._type = type

        def validate(self):
                """!
                Validate the port.
                The port must be non-empty and type must a possible type.
                """
                try: assert(not self.is_empty())
                except AssertionError: self._add_error_message('is empty.')
                try: assert(self.get_type() in self.TYPES)
                except AssertionError: self._add_error_message('Type "%s" is not a possible type.'%self.get_type())

        def __str__(self):
                if self.is_source():
                        return 'Source - %s(%s)'%(self.get_name(), self.get_key())
                if self.is_sink():
                        return 'Sink - %s(%s)'%(self.get_name(), self.get_key())

        def is_port(self): return True

        def get_color(self): return '#FFFFFF'

        def get_name(self): return self._name

        def get_key(self): return self._key

        def is_sink(self): return self in self.get_parent().get_sinks()

        def is_source(self): return self in self.get_parent().get_sources()

        def get_type(self): return self.get_parent().resolve_dependencies(self._type)

        def get_connections(self):
                """!
                Get all connections that use this port.
                @return a list of connection objects
                """
                connections = self.get_parent().get_parent().get_connections()
                connections = filter(lambda c: c.get_source() is self or c.get_sink() is self, connections)
                return connections

        def is_connected(self):
                """!
                Is this port connected?
                @return true if at least one connection
                """
                return bool(self.get_connections())

        def is_full(self):
                """!
                Is this port full of connections?
                Generally a sink can handle one connection and a source can handle many.
                @return true if the port is full
                """
                if self.is_source(): return False
                if self.is_sink(): return bool(self.get_connections())

        def is_empty(self):
                """!
                Is this port empty?
                An empty port has no connections.
                @return true if empty
                """
                return not self.get_connections()

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