plugins.py

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"""
Loads plugins.
"""


from python_qt_binding.QtCore import qCritical
import sys
import traceback

import roslib
import rospkg


def load_plugins():
    """
    Finds all rqt_bag plugins.

    @return: a list of plugins
    @rtype:  list of functions which return tuples of (MessageView, TimelineRenderer, list of: message type or '*')
    """
    plugins = []

    rospack = rospkg.RosPack()
    to_check = rospack.get_depends_on('rqt_bag', implicit=False)

    for pkg in to_check:
        manifest = rospack.get_manifest(pkg)
        plugin_module_names = manifest.get_export('rqt_bag', 'plugin')
        if not plugin_module_names:
            continue
        elif len(plugin_module_names) != 1:
            qCritical("Cannot load plugin [%s]: invalid 'plugin' attribute" % (pkg))
            continue
        plugin_module_name = plugin_module_names[0]

        try:
            # Load that package's namespace
            roslib.load_manifest(pkg)

            # Import specified plugin module
            plugin_module = __import__(plugin_module_name)
            for sub_module in plugin_module_name.split('.')[1:]:
                plugin_module = getattr(plugin_module, sub_module)

            # Retrieve the function
            plugins_func = None
            try:
                plugins_func = getattr(plugin_module, 'get_rqt_bag_plugins')
            except AttributeError:
                pass

            if plugins_func:
                plugins.extend(plugins_func())
            else:
                qCritical("Cannot load plugin [%s]: no 'get_rqt_bag_plugins' attribute" % (plugin_module_name))

        except Exception:
            qCritical("Unable to load plugin [%s] from package [%s]: %s" % (plugin_module_name, pkg, traceback.format_exc()))
    return plugins