def register_message_listener(self, listener):
"""Register a object so the application dispatch messages to it.
The message listener is registered using a Weak Reference, so the
messages system will not keep the objects alive when all the other
references are deleted.
Parameters
----------
listener : obj
The object that will receive the message.
Returns
-------
int
An unique identifier to use when referencing the this listener in
the messages system.
Raises
------
ValueError : If the listener object is already registered
"""
#Check if the listener is in the list already
for r in self._message_listeners.itervaluerefs():
if r() is listener:
raise ValueError("The object is already registered")
id_ = find_free_key(self._message_listeners)
self._message_listeners[id_] = listener
return id_
def _load_plugin(self, plugin_name):
# The `Plugin` class holds information about the plugin.
# The loaded_ui_objects is a list of the loaded ui objects, but these
# ui are those located in the plugin's `ui` dir, and their names are
# local to the 'plugin scope', thus they have their own list.
class Plugin(object):
def __init__(slf, plugin_type, plugin_name, root_path, instance):
slf.plugin_type = plugin_type
slf.plugin_name = plugin_name
slf.root_path = root_path
slf.instance = instance
slf.loaded_ui_objects = {}
slf.gui_interface = None
slf.info = None
join = os.path.join
listdir = os.listdir
isdir = os.path.isdir
isfile = os.path.isfile
app = get_app()
# A plugin folder should contain the following structure
#
# Plugin_Folder -> info.xml
# -> main.py
# -> ui -> [.ui files only]
# Get a list to the installed plugins
plist = self._list_plugins()
# Check if the plugin is in the list and get it
p = [p_data for p_data in plist if p_data[1] == plugin_name]
if not p:
raise ValueError("There is no plugin '{}' installed".format(plugin_name))
# Unpack the data
ptype, pname, ppath, pinfo = p[0]
# Check if there is a main.py file in the root folder
main_path = join(ppath, "main.py")
if not isfile(main_path):
raise IOError("The plugin '{}' doesn't have a main module".format(plugin_name))
# Load the module containing the main() function and call it to create
# the plugin instance
instance = None
try:
with open(main_path, "r") as f:
#Load the plugin module
plugin_module = imp.load_module("main", f, main_path, (".py", "r", imp.PY_SOURCE))
#Call the main method to construct the plugin instance
instance = plugin_module.main(ppath)
except:
raise
# Create the plugin object that will be hold in the dictionary
plugin = Plugin(ptype, pname, ppath, instance)
# Find a free id
id_ = find_free_key(self._loaded_plugins)
# Save it to the dictionary and return the plugin object
self._loaded_plugins[id_] = plugin
app.post_message("plugin_loaded",
{"id": id_, "type": plugin.plugin_type,
"plugin": plugin}, -1)
return (id_, plugin)
