settings.py

   1 ##
   2 ## This file is part of the sigrok-meter project.
   3 ##
   4 ## Copyright (C) 2015 Jens Steinhauser <jens.steinhauser@gmail.com>
   5 ##
   6 ## This program is free software; you can redistribute it and/or modify
   7 ## it under the terms of the GNU General Public License as published by
   8 ## the Free Software Foundation; either version 2 of the License, or
   9 ## (at your option) any later version.
  10 ##
  11 ## This program is distributed in the hope that it will be useful,
  12 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ## GNU General Public License for more details.
  15 ##
  16 ## You should have received a copy of the GNU General Public License
  17 ## along with this program; if not, write to the Free Software
  18 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19 ##
  20
  21 import qtcompat
  22 import sigrok.core as sr
  23
  24 QtCore = qtcompat.QtCore
  25 QtGui = qtcompat.QtGui
  26
  27 class Setting(QtCore.QObject):
  28     '''Wrapper class around the raw 'QSettings' class that emits signals
  29     when the value of the setting changes.'''
  30
  31     '''Signal emitted when the setting has changed.'''
  32     changed = QtCore.Signal(object)
  33
  34     def __init__(self, key, default=None, s=None, d=None):
  35         '''Initializes the Settings object.
  36
  37         :param key: The key of the used 'QSettings' object.
  38         :param default: Value returned if the setting doesn't already exist.
  39         :param s: Function used to serialize the value into a string.
  40         :param d: Function used to convert a string into a value.
  41         '''
  42
  43         super(self.__class__, self).__init__()
  44
  45         self._key = key
  46         self._default = default
  47         self._serialize = s if s else (lambda x: x)
  48         self._deserialize = d if d else (lambda x: x)
  49         self._value = None
  50
  51     def value(self):
  52         s = QtCore.QSettings()
  53         v = s.value(self._key, self._default)
  54         self._value = self._deserialize(v)
  55         return self._value
  56
  57     @QtCore.Slot(object)
  58     def setValue(self, value):
  59         if value != self._value:
  60             s = QtCore.QSettings()
  61             s.setValue(self._key, self._serialize(value))
  62             s.sync()
  63             self._value = value
  64             self.changed.emit(self._value)
  65
  66 class _SettingsGroup(object):
  67     '''Dummy class to group multiple 'Setting' objects together.'''
  68     pass
  69
  70 _default_loglevel = 'WARN'
  71
  72 def _d_loglevel(s):
  73     '''Converts a string into a sr.LogLevel.'''
  74     d = {
  75         'NONE': sr.LogLevel.NONE,
  76         'ERR':  sr.LogLevel.ERR,
  77         'WARN': sr.LogLevel.WARN,
  78         'INFO': sr.LogLevel.INFO,
  79         'DBG':  sr.LogLevel.DBG,
  80         'SPEW': sr.LogLevel.SPEW
  81     }
  82
  83     if not (s in d):
  84         s = _default_loglevel
  85
  86     return d[s]
  87
  88 def _s_loglevel(l):
  89     '''Converts a sr.LogLevel into a string.'''
  90     return l.name
  91
  92 def init():
  93     '''Creates the 'Settings' objects for all known settings and places them
  94     into the module's namespace.
  95
  96     A QApplication must have been created before this function can be called.
  97     '''
  98
  99     app = QtGui.QApplication.instance()
 100     app.setApplicationName('sigrok-meter')
 101     app.setOrganizationName('sigrok')
 102     app.setOrganizationDomain('sigrok.org')
 103
 104     mainwindow = _SettingsGroup()
 105     mainwindow.size = Setting('mainwindow/size', QtCore.QSize(900, 550))
 106     mainwindow.pos  = Setting('mainwindow/pos')
 107     globals()['mainwindow'] = mainwindow
 108
 109     graph = _SettingsGroup()
 110     graph.backlog = Setting('graph/backlog', 30, d=int)
 111     globals()['graph'] = graph
 112
 113     logging = _SettingsGroup()
 114     logging.level = Setting('logging/level', _default_loglevel,
 115         s=_s_loglevel, d=_d_loglevel)
 116     logging.lines = Setting('logging/lines', 1000, d=int)
 117     logging.filename = Setting('logging/filename', '')
 118     globals()['logging'] = logging