qtpy/compat.py

   1 #
   2 # Copyright © 2009- The Spyder Development Team
   3 # Licensed under the terms of the MIT License
   4
   5 """
   6 Compatibility functions
   7 """
   8 import sys
   9
  10 from . import (
  11     PYQT5,
  12     PYQT6,
  13     PYSIDE2,
  14     PYSIDE6,
  15 )
  16
  17 from .QtWidgets import QFileDialog
  18
  19
  20 TEXT_TYPES = (str,)
  21
  22
  23 def is_text_string(obj):
  24     """Return True if `obj` is a text string, False if it is anything else,
  25     like binary data."""
  26     return isinstance(obj, str)
  27
  28
  29 def to_text_string(obj, encoding=None):
  30     """Convert `obj` to (unicode) text string"""
  31     if encoding is None:
  32         return str(obj)
  33     elif isinstance(obj, str):
  34         # In case this function is not used properly, this could happen
  35         return obj
  36     else:
  37         return str(obj, encoding)
  38
  39
  40 # =============================================================================
  41 # QVariant conversion utilities
  42 # =============================================================================
  43 PYQT_API_1 = False
  44 def to_qvariant(obj=None):  # analysis:ignore
  45     """Convert Python object to QVariant
  46     This is a transitional function from PyQt API#1 (QVariant exist)
  47     to PyQt API#2 and Pyside (QVariant does not exist)"""
  48     return obj
  49
  50 def from_qvariant(qobj=None, pytype=None):  # analysis:ignore
  51     """Convert QVariant object to Python object
  52     This is a transitional function from PyQt API #1 (QVariant exist)
  53     to PyQt API #2 and Pyside (QVariant does not exist)"""
  54     return qobj
  55
  56
  57 # =============================================================================
  58 # Wrappers around QFileDialog static methods
  59 # =============================================================================
  60 def getexistingdirectory(parent=None, caption='', basedir='',
  61                          options=QFileDialog.ShowDirsOnly):
  62     """Wrapper around QtGui.QFileDialog.getExistingDirectory static method
  63     Compatible with PyQt >=v4.4 (API #1 and #2) and PySide >=v1.0"""
  64     # Calling QFileDialog static method
  65     if sys.platform == "win32":
  66         # On Windows platforms: redirect standard outputs
  67         _temp1, _temp2 = sys.stdout, sys.stderr
  68         sys.stdout, sys.stderr = None, None
  69     try:
  70         result = QFileDialog.getExistingDirectory(parent, caption, basedir,
  71                                                   options)
  72     finally:
  73         if sys.platform == "win32":
  74             # On Windows platforms: restore standard outputs
  75             sys.stdout, sys.stderr = _temp1, _temp2
  76     if not is_text_string(result):
  77         # PyQt API #1
  78         result = to_text_string(result)
  79     return result
  80
  81
  82 def _qfiledialog_wrapper(attr, parent=None, caption='', basedir='',
  83                          filters='', selectedfilter='', options=None):
  84     if options is None:
  85         options = QFileDialog.Option(0)
  86
  87     func = getattr(QFileDialog, attr)
  88
  89     # Calling QFileDialog static method
  90     if sys.platform == "win32":
  91         # On Windows platforms: redirect standard outputs
  92         _temp1, _temp2 = sys.stdout, sys.stderr
  93         sys.stdout, sys.stderr = None, None
  94     result = func(parent, caption, basedir, filters, selectedfilter, options)
  95     if sys.platform == "win32":
  96         # On Windows platforms: restore standard outputs
  97         sys.stdout, sys.stderr = _temp1, _temp2
  98
  99     output, selectedfilter = result
 100
 101     # Always returns the tuple (output, selectedfilter)
 102     return output, selectedfilter
 103
 104
 105 def getopenfilename(parent=None, caption='', basedir='', filters='',
 106                     selectedfilter='', options=None):
 107     """Wrapper around QtGui.QFileDialog.getOpenFileName static method
 108     Returns a tuple (filename, selectedfilter) -- when dialog box is canceled,
 109     returns a tuple of empty strings
 110     Compatible with PyQt >=v4.4 (API #1 and #2) and PySide >=v1.0"""
 111     return _qfiledialog_wrapper('getOpenFileName', parent=parent,
 112                                 caption=caption, basedir=basedir,
 113                                 filters=filters, selectedfilter=selectedfilter,
 114                                 options=options)
 115
 116
 117 def getopenfilenames(parent=None, caption='', basedir='', filters='',
 118                      selectedfilter='', options=None):
 119     """Wrapper around QtGui.QFileDialog.getOpenFileNames static method
 120     Returns a tuple (filenames, selectedfilter) -- when dialog box is canceled,
 121     returns a tuple (empty list, empty string)
 122     Compatible with PyQt >=v4.4 (API #1 and #2) and PySide >=v1.0"""
 123     return _qfiledialog_wrapper('getOpenFileNames', parent=parent,
 124                                 caption=caption, basedir=basedir,
 125                                 filters=filters, selectedfilter=selectedfilter,
 126                                 options=options)
 127
 128
 129 def getsavefilename(parent=None, caption='', basedir='', filters='',
 130                     selectedfilter='', options=None):
 131     """Wrapper around QtGui.QFileDialog.getSaveFileName static method
 132     Returns a tuple (filename, selectedfilter) -- when dialog box is canceled,
 133     returns a tuple of empty strings
 134     Compatible with PyQt >=v4.4 (API #1 and #2) and PySide >=v1.0"""
 135     return _qfiledialog_wrapper('getSaveFileName', parent=parent,
 136                                 caption=caption, basedir=basedir,
 137                                 filters=filters, selectedfilter=selectedfilter,
 138                                 options=options)
 139
 140 # =============================================================================
 141 def isalive(object):
 142     """Wrapper around sip.isdeleted and shiboken.isValid which tests whether
 143     an object is currently alive."""
 144     if PYQT5 or PYQT6:
 145         from . import sip
 146         return not sip.isdeleted(object)
 147     elif PYSIDE2 or PYSIDE6:
 148         from . import shiboken
 149         return shiboken.isValid(object)