35f0b26f4a
Our implementation was broken, and the BufferedIOBase mixin does a better job at doing this.
370 lines
10 KiB
Python
370 lines
10 KiB
Python
# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
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# Copyright 2014-2015 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
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#
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# This file is part of qutebrowser.
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#
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# qutebrowser is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# qutebrowser is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with qutebrowser. If not, see <http://www.gnu.org/licenses/>.
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"""Misc. utilities related to Qt.
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Module attributes:
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MAXVALS: A dictionary of C/Qt types (as string) mapped to their maximum
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value.
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MINVALS: A dictionary of C/Qt types (as string) mapped to their minimum
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value.
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"""
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import io
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import os
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import sys
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import operator
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import distutils.version # pylint: disable=no-name-in-module,import-error
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# https://bitbucket.org/logilab/pylint/issue/73/
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import contextlib
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from PyQt5.QtCore import (qVersion, QEventLoop, QDataStream, QByteArray,
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QIODevice, QSaveFile)
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from PyQt5.QtWidgets import QApplication
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MAXVALS = {
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'int': 2 ** 31 - 1,
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'int64': 2 ** 63 - 1,
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}
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MINVALS = {
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'int': -(2 ** 31),
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'int64': -(2 ** 63),
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}
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def version_check(version, op=operator.ge):
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"""Check if the Qt runtime version is the version supplied or newer.
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Args:
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version: The version to check against.
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op: The operator to use for the check.
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"""
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# pylint: disable=no-member
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# https://bitbucket.org/logilab/pylint/issue/73/
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return op(distutils.version.StrictVersion(qVersion()),
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distutils.version.StrictVersion(version))
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def check_overflow(arg, ctype, fatal=True):
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"""Check if the given argument is in bounds for the given type.
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Args:
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arg: The argument to check
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ctype: The C/Qt type to check as a string.
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fatal: Wether to raise exceptions (True) or truncate values (False)
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Return
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The truncated argument if fatal=False
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The original argument if it's in bounds.
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"""
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maxval = MAXVALS[ctype]
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minval = MINVALS[ctype]
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if arg > maxval:
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if fatal:
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raise OverflowError(arg)
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else:
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return maxval
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elif arg < minval:
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if fatal:
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raise OverflowError(arg)
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else:
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return minval
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else:
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return arg
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def get_args(namespace):
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"""Get the Qt QApplication arguments based on an argparse namespace.
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Args:
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namespace: The argparse namespace.
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Return:
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The argv list to be passed to Qt.
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"""
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argv = [sys.argv[0]]
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for argname, val in vars(namespace).items():
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if not argname.startswith('qt_'):
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continue
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elif val is None:
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# flag/argument not given
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continue
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elif val is True:
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argv.append('-' + argname[3:])
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else:
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argv.append('-' + argname[3:])
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argv.append(val)
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return argv
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def check_print_compat():
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"""Check if printing should work in the given Qt version."""
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# WORKAROUND (remove this when we bump the requirements to 5.3.0)
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return not (os.name == 'nt' and version_check('5.3.0', operator.lt))
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def ensure_valid(obj):
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"""Ensure a Qt object with an .isValid() method is valid."""
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if not obj.isValid():
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raise QtValueError(obj)
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def ensure_not_null(obj):
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"""Ensure a Qt object with an .isNull() method is not null."""
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if obj.isNull():
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raise QtValueError(obj, null=True)
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def check_qdatastream(stream):
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"""Check the status of a QDataStream and raise OSError if it's not ok."""
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status_to_str = {
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QDataStream.Ok: "The data stream is operating normally.",
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QDataStream.ReadPastEnd: ("The data stream has read past the end of "
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"the data in the underlying device."),
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QDataStream.ReadCorruptData: "The data stream has read corrupt data.",
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QDataStream.WriteFailed: ("The data stream cannot write to the "
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"underlying device."),
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}
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if stream.status() != QDataStream.Ok:
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raise OSError(status_to_str[stream.status()])
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def serialize(obj):
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"""Serialize an object into a QByteArray."""
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data = QByteArray()
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stream = QDataStream(data, QIODevice.WriteOnly)
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serialize_stream(stream, obj)
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return data
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def deserialize(data, obj):
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"""Deserialize an object from a QByteArray."""
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stream = QDataStream(data, QIODevice.ReadOnly)
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deserialize_stream(stream, obj)
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def serialize_stream(stream, obj):
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"""Serialize an object into a QDataStream."""
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check_qdatastream(stream)
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stream << obj # pylint: disable=pointless-statement
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check_qdatastream(stream)
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def deserialize_stream(stream, obj):
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"""Deserialize a QDataStream into an object."""
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check_qdatastream(stream)
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stream >> obj # pylint: disable=pointless-statement
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check_qdatastream(stream)
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@contextlib.contextmanager
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def savefile_open(filename, binary=False, encoding='utf-8'):
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"""Context manager to easily use a QSaveFile."""
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f = QSaveFile(filename)
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cancelled = False
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try:
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ok = f.open(QIODevice.WriteOnly)
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if not ok:
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raise OSError(f.errorString())
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if binary:
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new_f = PyQIODevice(f)
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else:
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new_f = io.TextIOWrapper(PyQIODevice(f), encoding=encoding)
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yield new_f
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except:
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f.cancelWriting()
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cancelled = True
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raise
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else:
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if new_f is not None:
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new_f.flush()
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finally:
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commit_ok = f.commit()
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if not commit_ok and not cancelled:
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raise OSError("Commit failed!")
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@contextlib.contextmanager
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def unset_organization():
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"""Temporarily unset QApplication.organizationName().
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This is primarily needed in config.py.
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"""
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qapp = QApplication.instance()
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orgname = qapp.organizationName()
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qapp.setOrganizationName(None)
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try:
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yield
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finally:
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qapp.setOrganizationName(orgname)
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class PyQIODevice(io.BufferedIOBase):
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"""Wrapper for a QIODevice which provides a python interface.
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Attributes:
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_dev: The underlying QIODevice.
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"""
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# pylint: disable=missing-docstring
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def __init__(self, dev):
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self._dev = dev
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def __len__(self):
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return self._dev.size()
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def _check_open(self):
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"""Check if the device is open, raise ValueError if not."""
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if not self._dev.isOpen():
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raise ValueError("IO operation on closed device!")
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def _check_random(self):
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"""Check if the device supports random access, raise OSError if not."""
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if not self.seekable():
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raise OSError("Random access not allowed!")
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def fileno(self):
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raise io.UnsupportedOperation
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def seek(self, offset, whence=io.SEEK_SET):
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self._check_open()
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self._check_random()
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if whence == io.SEEK_SET:
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ok = self._dev.seek(offset)
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elif whence == io.SEEK_CUR:
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ok = self._dev.seek(self.tell() + offset)
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elif whence == io.SEEK_END:
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ok = self._dev.seek(len(self) + offset)
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else:
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raise io.UnsupportedOperation("whence = {} is not "
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"supported!".format(whence))
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if not ok:
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raise OSError(self._dev.errorString())
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def truncate(self, size=None): # pylint: disable=unused-argument
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raise io.UnsupportedOperation
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def close(self):
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self._dev.close()
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@property
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def closed(self):
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return not self._dev.isOpen()
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def flush(self):
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self._check_open()
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self._dev.waitForBytesWritten(-1)
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def isatty(self):
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self._check_open()
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return False
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def readable(self):
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return self._dev.isReadable()
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def readline(self, size=-1):
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self._check_open()
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if size == -1:
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size = 0
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return self._dev.readLine(size)
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def seekable(self):
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return not self._dev.isSequential()
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def tell(self):
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self._check_open()
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self._check_random()
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return self._dev.pos()
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def writable(self):
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return self._dev.isWritable()
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def write(self, b):
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self._check_open()
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num = self._dev.write(b)
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if num == -1 or num < len(b):
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raise OSError(self._dev.errorString())
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return num
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def read(self, size=-1):
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self._check_open()
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self._check_readable()
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if size == 0:
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# Read no data
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return b''
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elif size < 0:
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# Read all data
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if self._dev.bytesAvailable() > 0:
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buf = self._dev.readAll()
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if not buf:
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raise OSError(self._dev.errorString())
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else:
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return b''
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else:
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if self._dev.bytesAvailable() > 0:
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buf = self._dev.read(size)
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if not buf:
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raise OSError(self._dev.errorString())
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else:
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return b''
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return buf
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class QtValueError(ValueError):
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"""Exception which gets raised by ensure_valid."""
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def __init__(self, obj, null=False):
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try:
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self.reason = obj.errorString()
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except AttributeError:
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self.reason = None
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if null:
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err = "{} is null".format(obj)
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else:
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err = "{} is not valid".format(obj)
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if self.reason:
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err += ": {}".format(self.reason)
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super().__init__(err)
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class EventLoop(QEventLoop):
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"""A thin wrapper around QEventLoop.
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Raises an exception when doing exec_() multiple times.
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"""
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def __init__(self, parent=None):
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super().__init__(parent)
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self._executing = False
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def exec_(self, flags=QEventLoop.AllEvents):
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"""Override exec_ to raise an exception when re-running."""
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if self._executing:
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raise AssertionError("Eventloop is already running!")
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self._executing = True
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super().exec_(flags)
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self._executing = False
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