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 from .QtWidgets import QFileDialog
  17
  18 TEXT_TYPES = (str,)
  19
  20
  21 def is_text_string(obj):
  22     """Return True if `obj` is a text string, False if it is anything else,
  23     like binary data."""
  24     return isinstance(obj, str)
  25
  26
  27 def to_text_string(obj, encoding=None):
  28     """Convert `obj` to (unicode) text string"""
  29     if encoding is None:
  30         return str(obj)
  31     if isinstance(obj, str):
  32         # In case this function is not used properly, this could happen
  33         return obj
  34
  35     return str(obj, encoding)
  36
  37
  38 # =============================================================================
  39 # QVariant conversion utilities
  40 # =============================================================================
  41 PYQT_API_1 = False
  42
  43
  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
  51 def from_qvariant(qobj=None, pytype=None):  # analysis:ignore
  52     """Convert QVariant object to Python object
  53     This is a transitional function from PyQt API #1 (QVariant exist)
  54     to PyQt API #2 and Pyside (QVariant does not exist)"""
  55     return qobj
  56
  57
  58 # =============================================================================
  59 # Wrappers around QFileDialog static methods
  60 # =============================================================================
  61 def getexistingdirectory(
  62     parent=None,
  63     caption="",
  64     basedir="",
  65     options=QFileDialog.ShowDirsOnly,
  66 ):
  67     """Wrapper around QtGui.QFileDialog.getExistingDirectory static method
  68     Compatible with PyQt >=v4.4 (API #1 and #2) and PySide >=v1.0"""
  69     # Calling QFileDialog static method
  70     if sys.platform == "win32":
  71         # On Windows platforms: redirect standard outputs
  72         _temp1, _temp2 = sys.stdout, sys.stderr
  73         sys.stdout, sys.stderr = None, None
  74     try:
  75         result = QFileDialog.getExistingDirectory(
  76             parent,
  77             caption,
  78             basedir,
  79             options,
  80         )
  81     finally:
  82         if sys.platform == "win32":
  83             # On Windows platforms: restore standard outputs
  84             sys.stdout, sys.stderr = _temp1, _temp2
  85     if not is_text_string(result):
  86         # PyQt API #1
  87         result = to_text_string(result)
  88     return result
  89
  90
  91 def _qfiledialog_wrapper(
  92     attr,
  93     parent=None,
  94     caption="",
  95     basedir="",
  96     filters="",
  97     selectedfilter="",
  98     options=None,
  99 ):
 100     if options is None:
 101         options = QFileDialog.Option(0)
 102
 103     func = getattr(QFileDialog, attr)
 104
 105     # Calling QFileDialog static method
 106     if sys.platform == "win32":
 107         # On Windows platforms: redirect standard outputs
 108         _temp1, _temp2 = sys.stdout, sys.stderr
 109         sys.stdout, sys.stderr = None, None
 110     result = func(parent, caption, basedir, filters, selectedfilter, options)
 111     if sys.platform == "win32":
 112         # On Windows platforms: restore standard outputs
 113         sys.stdout, sys.stderr = _temp1, _temp2
 114
 115     output, selectedfilter = result
 116
 117     # Always returns the tuple (output, selectedfilter)
 118     return output, selectedfilter
 119
 120
 121 def getopenfilename(
 122     parent=None,
 123     caption="",
 124     basedir="",
 125     filters="",
 126     selectedfilter="",
 127     options=None,
 128 ):
 129     """Wrapper around QtGui.QFileDialog.getOpenFileName static method
 130     Returns a tuple (filename, selectedfilter) -- when dialog box is canceled,
 131     returns a tuple of empty strings
 132     Compatible with PyQt >=v4.4 (API #1 and #2) and PySide >=v1.0"""
 133     return _qfiledialog_wrapper(
 134         "getOpenFileName",
 135         parent=parent,
 136         caption=caption,
 137         basedir=basedir,
 138         filters=filters,
 139         selectedfilter=selectedfilter,
 140         options=options,
 141     )
 142
 143
 144 def getopenfilenames(
 145     parent=None,
 146     caption="",
 147     basedir="",
 148     filters="",
 149     selectedfilter="",
 150     options=None,
 151 ):
 152     """Wrapper around QtGui.QFileDialog.getOpenFileNames static method
 153     Returns a tuple (filenames, selectedfilter) -- when dialog box is canceled,
 154     returns a tuple (empty list, empty string)
 155     Compatible with PyQt >=v4.4 (API #1 and #2) and PySide >=v1.0"""
 156     return _qfiledialog_wrapper(
 157         "getOpenFileNames",
 158         parent=parent,
 159         caption=caption,
 160         basedir=basedir,
 161         filters=filters,
 162         selectedfilter=selectedfilter,
 163         options=options,
 164     )
 165
 166
 167 def getsavefilename(
 168     parent=None,
 169     caption="",
 170     basedir="",
 171     filters="",
 172     selectedfilter="",
 173     options=None,
 174 ):
 175     """Wrapper around QtGui.QFileDialog.getSaveFileName static method
 176     Returns a tuple (filename, selectedfilter) -- when dialog box is canceled,
 177     returns a tuple of empty strings
 178     Compatible with PyQt >=v4.4 (API #1 and #2) and PySide >=v1.0"""
 179     return _qfiledialog_wrapper(
 180         "getSaveFileName",
 181         parent=parent,
 182         caption=caption,
 183         basedir=basedir,
 184         filters=filters,
 185         selectedfilter=selectedfilter,
 186         options=options,
 187     )
 188
 189
 190 # =============================================================================
 191 def isalive(obj):
 192     """Wrapper around sip.isdeleted and shiboken.isValid which tests whether
 193     an object is currently alive."""
 194     if PYQT5 or PYQT6:
 195         from . import sip
 196
 197         return not sip.isdeleted(obj)
 198     if PYSIDE2 or PYSIDE6:
 199         from . import shiboken
 200
 201         return shiboken.isValid(obj)
 202     return None