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Details

Type: Bug
Resolution: Done
Priority: P1: Critical
Fix Version/s: 5.9
Affects Version/s: 1.2.x
Component/s: PySide
Labels:
- easy
- methusalem
Environment:
Windows

Commits:
ca806b438e8a27dc4562ac806d189765e93e09e5

Description

http://stackoverflow.com/questions/8658212/overriding-readdata-in-qiodevice-subclass-returns-incorrect-result

from that question:
I am trying to subclass QFile in PySide to implement custom read behavior. However, as seen in the simplified code below, even if the subclass' readData implementation just calls the parent's readData function, the returned data is incorrect. Subclassing other QIODevices such as QBuffer also causes incorrect return values. Has anyone successfully subclassed a QIODevice?

from PySide import QtCore

class FileChild1(QtCore.QFile):
    pass

class FileChild2(QtCore.QFile):
    def readData(self, maxlen):
        return super(FileChild2, self).readData(maxlen)


f1 = FileChild1('test.txt')
f1.open(QtCore.QIODevice.ReadWrite|QtCore.QIODevice.Truncate)
f1.write('Test text for testing')
f1.seek(0)
print 'FileChild1: ', repr(f1.read(50))

f2 = FileChild2('test2.txt')
f2.open(QtCore.QIODevice.ReadWrite|QtCore.QIODevice.Truncate)
f2.write('Test text for testing')
f2.seek(0)
print 'FileChild2: ', repr(f2.read(50))

>>> FileChild1:  PySide.QtCore.QByteArray('Test text for testing')
>>> FileChild2:  PySide.QtCore.QByteArray('─ Q ►│A☻ @  p¼a☻Test text for testing\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')