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Fix race condition in javascript kernel message processing...
Fix race condition in javascript kernel message processing Because the binary messages are now deserialized using the asynchronous FileReader API, we need to have some way to force the messages to still be processed in the order they are received. This patch implements a simple processing queue using promises.

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magic_helper.py
213 lines | 7.4 KiB | text/x-python | PythonLexer
"""MagicHelper - dockable widget showing magic commands for the MainWindow
"""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
# stdlib imports
import json
import re
import sys
# System library imports
from IPython.external.qt import QtGui,QtCore
from IPython.core.magic import magic_escapes
class MagicHelper(QtGui.QDockWidget):
"""MagicHelper - dockable widget for convenient search and running of
magic command for IPython QtConsole.
"""
#---------------------------------------------------------------------------
# signals
#---------------------------------------------------------------------------
pasteRequested = QtCore.Signal(str, name = 'pasteRequested')
"""This signal is emitted when user wants to paste selected magic
command into the command line.
"""
runRequested = QtCore.Signal(str, name = 'runRequested')
"""This signal is emitted when user wants to execute selected magic command
"""
readyForUpdate = QtCore.Signal(name = 'readyForUpdate')
"""This signal is emitted when MagicHelper is ready to be populated.
Since kernel querying mechanisms are out of scope of this class,
it expects its owner to invoke MagicHelper.populate_magic_helper()
as a reaction on this event.
"""
#---------------------------------------------------------------------------
# constructor
#---------------------------------------------------------------------------
def __init__(self, name, parent):
super(MagicHelper, self).__init__(name, parent)
self.data = None
class MinListWidget(QtGui.QListWidget):
"""Temp class to overide the default QListWidget size hint
in order to make MagicHelper narrow
"""
def sizeHint(self):
s = QtCore.QSize()
s.setHeight(super(MinListWidget,self).sizeHint().height())
s.setWidth(self.sizeHintForColumn(0))
return s
# construct content
self.frame = QtGui.QFrame()
self.search_label = QtGui.QLabel("Search:")
self.search_line = QtGui.QLineEdit()
self.search_class = QtGui.QComboBox()
self.search_list = MinListWidget()
self.paste_button = QtGui.QPushButton("Paste")
self.run_button = QtGui.QPushButton("Run")
# layout all the widgets
main_layout = QtGui.QVBoxLayout()
search_layout = QtGui.QHBoxLayout()
search_layout.addWidget(self.search_label)
search_layout.addWidget(self.search_line, 10)
main_layout.addLayout(search_layout)
main_layout.addWidget(self.search_class)
main_layout.addWidget(self.search_list, 10)
action_layout = QtGui.QHBoxLayout()
action_layout.addWidget(self.paste_button)
action_layout.addWidget(self.run_button)
main_layout.addLayout(action_layout)
self.frame.setLayout(main_layout)
self.setWidget(self.frame)
# connect all the relevant signals to handlers
self.visibilityChanged[bool].connect( self._update_magic_helper )
self.search_class.activated[int].connect(
self.class_selected
)
self.search_line.textChanged[str].connect(
self.search_changed
)
self.search_list.itemDoubleClicked.connect(
self.paste_requested
)
self.paste_button.clicked[bool].connect(
self.paste_requested
)
self.run_button.clicked[bool].connect(
self.run_requested
)
#---------------------------------------------------------------------------
# implementation
#---------------------------------------------------------------------------
def _update_magic_helper(self, visible):
"""Start update sequence.
This method is called when MagicHelper becomes visible. It clears
the content and emits readyForUpdate signal. The owner of the
instance is expected to invoke populate_magic_helper() when magic
info is available.
"""
if not visible or self.data is not None:
return
self.data = {}
self.search_class.clear()
self.search_class.addItem("Populating...")
self.search_list.clear()
self.readyForUpdate.emit()
def populate_magic_helper(self, data):
"""Expects data returned by lsmagics query from kernel.
Populates the search_class and search_list with relevant items.
"""
self.search_class.clear()
self.search_list.clear()
self.data = json.loads(
data['data'].get('application/json', {})
)
self.search_class.addItem('All Magics', 'any')
classes = set()
for mtype in sorted(self.data):
subdict = self.data[mtype]
for name in sorted(subdict):
classes.add(subdict[name])
for cls in sorted(classes):
label = re.sub("([a-zA-Z]+)([A-Z][a-z])","\g<1> \g<2>", cls)
self.search_class.addItem(label, cls)
self.filter_magic_helper('.', 'any')
def class_selected(self, index):
"""Handle search_class selection changes
"""
item = self.search_class.itemData(index)
regex = self.search_line.text()
self.filter_magic_helper(regex = regex, cls = item)
def search_changed(self, search_string):
"""Handle search_line text changes.
The text is interpreted as a regular expression
"""
item = self.search_class.itemData(
self.search_class.currentIndex()
)
self.filter_magic_helper(regex = search_string, cls = item)
def _get_current_search_item(self, item = None):
"""Retrieve magic command currently selected in the search_list
"""
text = None
if not isinstance(item, QtGui.QListWidgetItem):
item = self.search_list.currentItem()
text = item.text()
return text
def paste_requested(self, item = None):
"""Emit pasteRequested signal with currently selected item text
"""
text = self._get_current_search_item(item)
if text is not None:
self.pasteRequested.emit(text)
def run_requested(self, item = None):
"""Emit runRequested signal with currently selected item text
"""
text = self._get_current_search_item(item)
if text is not None:
self.runRequested.emit(text)
def filter_magic_helper(self, regex, cls):
"""Update search_list with magic commands whose text match
regex and class match cls.
If cls equals 'any' - any class matches.
"""
if regex == "" or regex is None:
regex = '.'
if cls is None:
cls = 'any'
self.search_list.clear()
for mtype in sorted(self.data):
subdict = self.data[mtype]
prefix = magic_escapes[mtype]
for name in sorted(subdict):
mclass = subdict[name]
pmagic = prefix + name
if (re.match(regex, name) or re.match(regex, pmagic)) and \
(cls == 'any' or cls == mclass):
self.search_list.addItem(pmagic)