##// END OF EJS Templates
Merge pull request #3162 from ivanov/output-stream-kwarg...
Merge pull request #3162 from ivanov/output-stream-kwarg adding stream kwarg to current.new_output This was missing, and made unnecessarily clunky to create output cells of stream type using the nbformat API. Before this commit, you had to do something like from IPython.nbformat import current as c output = c.new_output('stream', the_text) output['stream'] = 'stdout' after this commit from IPython.nbformat import current as c output = c.new_output('stream', the_text, stream='stdout') and actually, that stream= argument defaults to 'stdout' if it isn't given. I modified a test that will break if this functionality is ever removed.

File last commit:

r9815:41801a16
r10190:c3b429bd merge
Show More
qt_loaders.py
258 lines | 7.0 KiB | text/x-python | PythonLexer
"""
This module contains factory functions that attempt
to return Qt submodules from the various python Qt bindings.
It also protects against double-importing Qt with different
bindings, which is unstable and likely to crash
This is used primarily by qt and qt_for_kernel, and shouldn't
be accessed directly from the outside
"""
import sys
from functools import partial
from IPython.utils.version import check_version
# Available APIs.
QT_API_PYQT = 'pyqt'
QT_API_PYQTv1 = 'pyqtv1'
QT_API_PYQT_DEFAULT = 'pyqtdefault' # don't set SIP explicitly
QT_API_PYSIDE = 'pyside'
class ImportDenier(object):
"""Import Hook that will guard against bad Qt imports
once IPython commits to a specific binding
"""
def __init__(self):
self.__forbidden = None
def forbid(self, module_name):
sys.modules.pop(module_name, None)
self.__forbidden = module_name
def find_module(self, mod_name, pth):
if pth:
return
if mod_name == self.__forbidden:
return self
def load_module(self, mod_name):
raise ImportError("""
Importing %s disabled by IPython, which has
already imported an Incompatible QT Binding: %s
""" % (mod_name, loaded_api()))
ID = ImportDenier()
sys.meta_path.append(ID)
def commit_api(api):
"""Commit to a particular API, and trigger ImportErrors on subsequent
dangerous imports"""
if api == QT_API_PYSIDE:
ID.forbid('PyQt4')
else:
ID.forbid('PySide')
def loaded_api():
"""Return which API is loaded, if any
If this returns anything besides None,
importing any other Qt binding is unsafe.
Returns
-------
None, 'pyside', 'pyqt', or 'pyqtv1'
"""
if 'PyQt4.QtCore' in sys.modules:
if qtapi_version() == 2:
return QT_API_PYQT
else:
return QT_API_PYQTv1
elif 'PySide.QtCore' in sys.modules:
return QT_API_PYSIDE
return None
def has_binding(api):
"""Safely check for PyQt4 or PySide, without importing
submodules
Parameters
----------
api : str [ 'pyqtv1' | 'pyqt' | 'pyside' | 'pyqtdefault']
Which module to check for
Returns
-------
True if the relevant module appears to be importable
"""
# we can't import an incomplete pyside and pyqt4
# this will cause a crash in sip (#1431)
# check for complete presence before importing
module_name = {QT_API_PYSIDE: 'PySide',
QT_API_PYQT: 'PyQt4',
QT_API_PYQTv1: 'PyQt4',
QT_API_PYQT_DEFAULT: 'PyQt4'}
module_name = module_name[api]
import imp
try:
#importing top level PyQt4/PySide module is ok...
mod = __import__(module_name)
#...importing submodules is not
imp.find_module('QtCore', mod.__path__)
imp.find_module('QtGui', mod.__path__)
imp.find_module('QtSvg', mod.__path__)
#we can also safely check PySide version
if api == QT_API_PYSIDE:
return check_version(mod.__version__, '1.0.3')
else:
return True
except ImportError:
return False
def qtapi_version():
"""Return which QString API has been set, if any
Returns
-------
The QString API version (1 or 2), or None if not set
"""
try:
import sip
except ImportError:
return
try:
return sip.getapi('QString')
except ValueError:
return
def can_import(api):
"""Safely query whether an API is importable, without importing it"""
if not has_binding(api):
return False
current = loaded_api()
if api == QT_API_PYQT_DEFAULT:
return current in [QT_API_PYQT, QT_API_PYQTv1, None]
else:
return current in [api, None]
def import_pyqt4(version=2):
"""
Import PyQt4
Parameters
----------
version : 1, 2, or None
Which QString/QVariant API to use. Set to None to use the system
default
ImportErrors rasied within this function are non-recoverable
"""
# The new-style string API (version=2) automatically
# converts QStrings to Unicode Python strings. Also, automatically unpacks
# QVariants to their underlying objects.
import sip
if version is not None:
sip.setapi('QString', version)
sip.setapi('QVariant', version)
from PyQt4 import QtGui, QtCore, QtSvg
if not check_version(QtCore.PYQT_VERSION_STR, '4.7'):
raise ImportError("IPython requires PyQt4 >= 4.7, found %s" %
QtCore.PYQT_VERSION_STR)
# Alias PyQt-specific functions for PySide compatibility.
QtCore.Signal = QtCore.pyqtSignal
QtCore.Slot = QtCore.pyqtSlot
# query for the API version (in case version == None)
version = sip.getapi('QString')
api = QT_API_PYQTv1 if version == 1 else QT_API_PYQT
return QtCore, QtGui, QtSvg, api
def import_pyside():
"""
Import PySide
ImportErrors raised within this function are non-recoverable
"""
from PySide import QtGui, QtCore, QtSvg
return QtCore, QtGui, QtSvg, QT_API_PYSIDE
def load_qt(api_options):
"""
Attempt to import Qt, given a preference list
of permissible bindings
It is safe to call this function multiple times.
Parameters
----------
api_options: List of strings
The order of APIs to try. Valid items are 'pyside',
'pyqt', and 'pyqtv1'
Returns
-------
A tuple of QtCore, QtGui, QtSvg, QT_API
The first three are the Qt modules. The last is the
string indicating which module was loaded.
Raises
------
ImportError, if it isn't possible to import any requested
bindings (either becaues they aren't installed, or because
an incompatible library has already been installed)
"""
loaders = {QT_API_PYSIDE: import_pyside,
QT_API_PYQT: import_pyqt4,
QT_API_PYQTv1: partial(import_pyqt4, version=1),
QT_API_PYQT_DEFAULT: partial(import_pyqt4, version=None)
}
for api in api_options:
if api not in loaders:
raise RuntimeError(
"Invalid Qt API %r, valid values are: %r, %r, %r, %r" %
(api, QT_API_PYSIDE, QT_API_PYQT,
QT_API_PYQTv1, QT_API_PYQT_DEFAULT))
if not can_import(api):
continue
#cannot safely recover from an ImportError during this
result = loaders[api]()
api = result[-1] # changed if api = QT_API_PYQT_DEFAULT
commit_api(api)
return result
else:
raise ImportError("""
Could not load requested Qt binding. Please ensure that
PyQt4 >= 4.7 or PySide >= 1.0.3 is available,
and only one is imported per session.
Currently-imported Qt library: %r
PyQt4 installed: %s
PySide >= 1.0.3 installed: %s
Tried to load: %r
""" % (loaded_api(),
has_binding(QT_API_PYQT),
has_binding(QT_API_PYSIDE),
api_options))