|
|
""" Defines a convenient mix-in class for implementing Qt frontends.
|
|
|
"""
|
|
|
|
|
|
class BaseFrontendMixin(object):
|
|
|
""" A mix-in class for implementing Qt frontends.
|
|
|
|
|
|
To handle messages of a particular type, frontends need only define an
|
|
|
appropriate handler method. For example, to handle 'stream' messaged, define
|
|
|
a '_handle_stream(msg)' method.
|
|
|
"""
|
|
|
|
|
|
#---------------------------------------------------------------------------
|
|
|
# 'BaseFrontendMixin' concrete interface
|
|
|
#---------------------------------------------------------------------------
|
|
|
|
|
|
def _get_kernel_manager(self):
|
|
|
""" Returns the current kernel manager.
|
|
|
"""
|
|
|
return self._kernel_manager
|
|
|
|
|
|
def _set_kernel_manager(self, kernel_manager):
|
|
|
""" Disconnect from the current kernel manager (if any) and set a new
|
|
|
kernel manager.
|
|
|
"""
|
|
|
# Disconnect the old kernel manager, if necessary.
|
|
|
old_manager = self._kernel_manager
|
|
|
if old_manager is not None:
|
|
|
old_manager.started_channels.disconnect(self._started_channels)
|
|
|
old_manager.stopped_channels.disconnect(self._stopped_channels)
|
|
|
|
|
|
# Disconnect the old kernel manager's channels.
|
|
|
old_manager.sub_channel.message_received.disconnect(self._dispatch)
|
|
|
old_manager.xreq_channel.message_received.disconnect(self._dispatch)
|
|
|
old_manager.rep_channel.message_received.connect(self._dispatch)
|
|
|
|
|
|
# Handle the case where the old kernel manager is still listening.
|
|
|
if old_manager.channels_running:
|
|
|
self._stopped_channels()
|
|
|
|
|
|
# Set the new kernel manager.
|
|
|
self._kernel_manager = kernel_manager
|
|
|
if kernel_manager is None:
|
|
|
return
|
|
|
|
|
|
# Connect the new kernel manager.
|
|
|
kernel_manager.started_channels.connect(self._started_channels)
|
|
|
kernel_manager.stopped_channels.connect(self._stopped_channels)
|
|
|
|
|
|
# Connect the new kernel manager's channels.
|
|
|
kernel_manager.sub_channel.message_received.connect(self._dispatch)
|
|
|
kernel_manager.xreq_channel.message_received.connect(self._dispatch)
|
|
|
kernel_manager.rep_channel.message_received.connect(self._dispatch)
|
|
|
|
|
|
# Handle the case where the kernel manager started channels before
|
|
|
# we connected.
|
|
|
if kernel_manager.channels_running:
|
|
|
self._started_channels()
|
|
|
|
|
|
kernel_manager = property(_get_kernel_manager, _set_kernel_manager)
|
|
|
|
|
|
#---------------------------------------------------------------------------
|
|
|
# 'BaseFrontendMixin' abstract interface
|
|
|
#---------------------------------------------------------------------------
|
|
|
|
|
|
def _started_channels(self):
|
|
|
""" Called when the KernelManager channels have started listening or
|
|
|
when the frontend is assigned an already listening KernelManager.
|
|
|
"""
|
|
|
|
|
|
def _stopped_channels(self):
|
|
|
""" Called when the KernelManager channels have stopped listening or
|
|
|
when a listening KernelManager is removed from the frontend.
|
|
|
"""
|
|
|
|
|
|
#---------------------------------------------------------------------------
|
|
|
# 'BaseFrontendMixin' protected interface
|
|
|
#---------------------------------------------------------------------------
|
|
|
|
|
|
def _dispatch(self, msg):
|
|
|
""" Calls the frontend handler associated with the message type of the
|
|
|
given message.
|
|
|
"""
|
|
|
msg_type = msg['msg_type']
|
|
|
handler = getattr(self, '_handle_' + msg_type, None)
|
|
|
if handler:
|
|
|
handler(msg)
|
|
|
|
|
|
def _is_from_this_session(self, msg):
|
|
|
""" Returns whether a reply from the kernel originated from a request
|
|
|
from this frontend.
|
|
|
"""
|
|
|
session = self._kernel_manager.session.session
|
|
|
return msg['parent_header']['session'] == session
|
|
|
|
