Merge pull request #25 from astrofrog/patch-qcombobox

Add patched version of QComboBox

qtpy/QtWidgets.py

@@ -20,7 +20,7 @@
 from qtpy import PYQT4_API
 from qtpy import PYSIDE_API
 from qtpy import PythonQtError
-
+from qtpy._patch.qcombobox import patch_qcombobox
 
 if os.environ[QT_API] in PYQT5_API:
     from PyQt5.QtWidgets import *
@@ -65,6 +65,10 @@
     # These objects belong to QtCore
     del (QItemSelection, QItemSelectionModel, QItemSelectionRange,
          QSortFilterProxyModel)
+
+    # Patch QComboBox to allow Python objects to be passed to userData
+    patch_qcombobox(QComboBox)
+
 elif os.environ[QT_API] in PYSIDE_API:
     from PySide.QtGui import *
     QStyleOptionViewItem = QStyleOptionViewItemV4
@@ -106,5 +110,9 @@
     # These objects belong to QtCore
     del (QItemSelection, QItemSelectionModel, QItemSelectionRange,
          QSortFilterProxyModel)
+
+    # Patch QComboBox to allow Python objects to be passed to userData
+    patch_qcombobox(QComboBox)
+
 else:
     raise PythonQtError('No Qt bindings could be found')

qtpy/_patch/qcombobox.py

@@ -0,0 +1,103 @@
+# The code below, as well as the associated test were adapted from
+# qt-helpers, which was released under a 3-Clause BSD license:
+#
+# Copyright (c) 2015, Chris Beaumont and Thomas Robitaille
+#
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#  * Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+#  * Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the
+#    distribution.
+#  * Neither the name of the Glue project nor the names of its
+#    contributors may be used to endorse or promote products derived
+#    from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+# IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+def patch_qcombobox(QComboBox):
+    """
+    In PySide, using Python objects as userData in QComboBox causes
+    Segmentation faults under certain conditions. Even in cases where it
+    doesn't, findData does not work correctly. Likewise, findData also does not
+    work correctly with Python objects when using PyQt4. On the other hand,
+    PyQt5 deals with this case correctly. We therefore patch QComboBox when
+    using PyQt4 and PySide to avoid issues.
+    """
+
+    from qtpy.QtGui import QIcon
+    from qtpy.QtCore import Qt, QObject
+
+    class userDataWrapper(QObject):
+        """
+        This class is used to wrap any userData object inside a QObject which
+        is then supported by all Python Qt wrappers.
+        """
+        def __init__(self, data, parent=None):
+            super(userDataWrapper, self).__init__(parent)
+            self.data = data
+
+    _addItem = QComboBox.addItem
+
+    def addItem(self, *args, **kwargs):
+        if len(args) == 3 or (not isinstance(args[0], QIcon)
+                              and len(args) == 2):
+            args, kwargs['userData'] = args[:-1], args[-1]
+        if 'userData' in kwargs:
+            kwargs['userData'] = userDataWrapper(kwargs['userData'],
+                                                 parent=self)
+        _addItem(self, *args, **kwargs)
+
+    _insertItem = QComboBox.insertItem
+
+    def insertItem(self, *args, **kwargs):
+        if len(args) == 4 or (not isinstance(args[1], QIcon)
+                              and len(args) == 3):
+            args, kwargs['userData'] = args[:-1], args[-1]
+        if 'userData' in kwargs:
+            kwargs['userData'] = userDataWrapper(kwargs['userData'],
+                                                 parent=self)
+        _insertItem(self, *args, **kwargs)
+
+    _setItemData = QComboBox.setItemData
+
+    def setItemData(self, index, value, role=Qt.UserRole):
+        value = userDataWrapper(value, parent=self)
+        _setItemData(self, index, value, role=role)
+
+    _itemData = QComboBox.itemData
+
+    def itemData(self, index, role=Qt.UserRole):
+        userData = _itemData(self, index, role=role)
+        if isinstance(userData, userDataWrapper):
+            userData = userData.data
+        return userData
+
+    def findData(self, value):
+        for i in range(self.count()):
+            if self.itemData(i) == value:
+                return i
+        return -1
+
+    QComboBox.addItem = addItem
+    QComboBox.insertItem = insertItem
+    QComboBox.setItemData = setItemData
+    QComboBox.itemData = itemData
+    QComboBox.findData = findData

tests/test_patch_qcombobox.py

@@ -0,0 +1,73 @@
+from qtpy import QtGui, QtWidgets
+
+def get_qapp(icon_path=None):
+    qapp = QtWidgets.QApplication.instance()
+    if qapp is None:
+        qapp = QtWidgets.QApplication([''])
+    return qapp
+
+
+def test_patched_qcombobox():
+    """
+    In PySide, using Python objects as userData in QComboBox causes
+    Segmentation faults under certain conditions. Even in cases where it
+    doesn't, findData does not work correctly. Likewise, findData also
+    does not work correctly with Python objects when using PyQt4. On the
+    other hand, PyQt5 deals with this case correctly. We therefore patch
+    QComboBox when using PyQt4 and PySide to avoid issues.
+    """
+
+    app = get_qapp()
+
+    class Data(object):
+        """
+        Test class to store in userData. The __getitem__ is needed in order to
+        reproduce the segmentation fault.
+        """
+        def __getitem__(self, item):
+            raise ValueError("Failing")
+
+    data1 = Data()
+    data2 = Data()
+    data3 = Data()
+    data4 = Data()
+    data5 = Data()
+    data6 = Data()
+
+    icon1 = QtGui.QIcon()
+    icon2 = QtGui.QIcon()
+
+    widget = QtWidgets.QComboBox()
+    widget.addItem('a', data1)
+    widget.insertItem(0, 'b', data2)
+    widget.addItem('c', data1)
+    widget.setItemData(2, data3)
+    widget.addItem(icon1, 'd', data4)
+    widget.insertItem(3, icon2, 'e', data5)
+    widget.addItem(icon1, 'f')
+    widget.insertItem(5, icon2, 'g')
+
+    widget.show()
+
+    assert widget.findData(data1) == 1
+    assert widget.findData(data2) == 0
+    assert widget.findData(data3) == 2
+    assert widget.findData(data4) == 4
+    assert widget.findData(data5) == 3
+    assert widget.findData(data6) == -1
+
+    assert widget.itemData(0) == data2
+    assert widget.itemData(1) == data1
+    assert widget.itemData(2) == data3
+    assert widget.itemData(3) == data5
+    assert widget.itemData(4) == data4
+    assert widget.itemData(5) is None
+    assert widget.itemData(6) is None
+
+    assert widget.itemText(0) == 'b'
+    assert widget.itemText(1) == 'a'
+    assert widget.itemText(2) == 'c'
+    assert widget.itemText(3) == 'e'
+    assert widget.itemText(4) == 'd'
+    assert widget.itemText(5) == 'g'
+    assert widget.itemText(6) == 'f'