player.py
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00001 # Software License Agreement (BSD License)
00002 #
00003 # Copyright (c) 2012, Willow Garage, Inc.
00004 # All rights reserved.
00005 #
00006 # Redistribution and use in source and binary forms, with or without
00007 # modification, are permitted provided that the following conditions
00008 # are met:
00009 #
00010 #  * Redistributions of source code must retain the above copyright
00011 #    notice, this list of conditions and the following disclaimer.
00012 #  * Redistributions in binary form must reproduce the above
00013 #    copyright notice, this list of conditions and the following
00014 #    disclaimer in the documentation and/or other materials provided
00015 #    with the distribution.
00016 #  * Neither the name of Willow Garage, Inc. nor the names of its
00017 #    contributors may be used to endorse or promote products derived
00018 #    from this software without specific prior written permission.
00019 #
00020 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00021 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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00023 # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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00025 # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00026 # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00027 # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00028 # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00029 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00030 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00031 # POSSIBILITY OF SUCH DAMAGE.
00032 
00033 """
00034 Player listens to messages from the timeline and publishes them to ROS.
00035 """
00036 
00037 import rospy
00038 import rosgraph_msgs
00039 
00040 from python_qt_binding.QtCore import QObject
00041 
00042 CLOCK_TOPIC = "/clock"
00043 
00044 class Player(QObject):
00045     """
00046     This object handles publishing messages as the playhead passes over their position
00047     """
00048     def __init__(self, timeline):
00049         super(Player, self).__init__()
00050         self.timeline = timeline
00051 
00052         self._publishing = set()
00053         self._publishers = {}
00054 
00055         self._publish_clock = False
00056 
00057     def is_publishing(self, topic):
00058         return topic in self._publishing
00059 
00060     def start_publishing(self, topic):
00061         if topic in self._publishing:
00062             return
00063         self._publishing.add(topic)
00064         self.timeline.add_listener(topic, self)
00065 
00066     def stop_publishing(self, topic):
00067         if topic not in self._publishing:
00068             return
00069         self.timeline.remove_listener(topic, self)
00070 
00071         if topic in self._publishers:
00072             self._publishers[topic].unregister()
00073             del self._publishers[topic]
00074 
00075         self._publishing.remove(topic)
00076 
00077     def start_clock_publishing(self):
00078         if CLOCK_TOPIC not in self._publishers:
00079             # Activate clock publishing only if the publisher was created successful
00080             self._publish_clock = self.create_publisher(CLOCK_TOPIC, rosgraph_msgs.msg.Clock())
00081 
00082     def stop_clock_publishing(self):
00083         self._publish_clock = False
00084         if CLOCK_TOPIC in self._publishers:
00085             self._publishers[CLOCK_TOPIC].unregister()
00086             del self._publishers[CLOCK_TOPIC]
00087 
00088     def stop(self):
00089         for topic in list(self._publishing):
00090             self.stop_publishing(topic)
00091         self.stop_clock_publishing()
00092 
00093     def create_publisher(self, topic, msg):
00094         try:
00095             try:
00096                 self._publishers[topic] = rospy.Publisher(topic, type(msg), queue_size=100)
00097             except TypeError:
00098                 self._publishers[topic] = rospy.Publisher(topic, type(msg))
00099             return True
00100         except Exception as ex:
00101             # Any errors, stop listening/publishing to this topic
00102             rospy.logerr('Error creating publisher on topic %s for type %s. \nError text: %s' % (topic, str(type(msg)), str(ex)))
00103             if topic != CLOCK_TOPIC:
00104                 self.stop_publishing(topic)
00105             return False
00106 
00107     def message_viewed(self, bag, msg_data):
00108         """
00109         When a message is viewed publish it
00110         :param bag: the bag the message is in, ''rosbag.bag''
00111         :param msg_data: tuple of the message data and topic info, ''(str, msg)''
00112         """
00113         # Don't publish unless the playhead is moving.
00114         if self.timeline.play_speed <= 0.0:
00115             return
00116 
00117         topic, msg, clock = msg_data
00118 
00119         # Create publisher if this is the first message on the topic
00120         if topic not in self._publishers:
00121             self.create_publisher(topic, msg)
00122 
00123         if self._publish_clock:
00124             time_msg = rosgraph_msgs.msg.Clock()
00125             time_msg.clock = clock
00126             self._publishers[CLOCK_TOPIC].publish(time_msg)
00127 
00128         self._publishers[topic].publish(msg)
00129 
00130     def message_cleared(self):
00131         pass
00132 
00133     def event(self, event):
00134         """
00135         This function will be called to process events posted by post_event
00136         it will call message_cleared or message_viewed with the relevant data
00137         """
00138         bag, msg_data = event.data
00139         if msg_data:
00140             self.message_viewed(bag, msg_data)
00141         else:
00142             self.message_cleared()
00143         return True


rqt_bag
Author(s): Aaron Blasdel, Tim Field
autogenerated on Wed Sep 16 2015 06:58:10