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, see <http://www.gnu.org/licenses/>.
  18 ##
  19
  20 import qtcompat
  21 import sigrok.core as sr
  22
  23 QtCore = qtcompat.QtCore
  24 QtGui = qtcompat.QtGui
  25
  26 class Setting(QtCore.QObject):
  27     '''Wrapper class around the raw 'QSettings' class that emits signals
  28     when the value of the setting changes.'''
  29
  30     '''Signal emitted when the setting has changed.'''
  31     changed = QtCore.Signal(object)
  32
  33     def __init__(self, key, default=None, s=None, d=None):
  34         '''Initializes the Settings object.
  35
  36         :param key: The key of the used 'QSettings' object.
  37         :param default: Value returned if the setting doesn't already exist.
  38         :param s: Function used to serialize the value into a string.
  39         :param d: Function used to convert a string into a value.
  40         '''
  41
  42         super(self.__class__, self).__init__()
  43
  44         self._key = key
  45         self._default = default
  46         self._serialize = s if s else (lambda x: x)
  47         self._deserialize = d if d else (lambda x: x)
  48         self._value = None
  49
  50     def value(self):
  51         s = QtCore.QSettings()
  52         v = s.value(self._key, self._default)
  53         self._value = self._deserialize(v)
  54         return self._value
  55
  56     @QtCore.Slot(object)
  57     def setValue(self, value):
  58         if value != self._value:
  59             s = QtCore.QSettings()
  60             s.setValue(self._key, self._serialize(value))
  61             s.sync()
  62             self._value = value
  63             self.changed.emit(self._value)
  64
  65 class _SettingsGroup(object):
  66     '''Dummy class to group multiple 'Setting' objects together.'''
  67     pass
  68
  69 _default_loglevel = 'WARN'
  70
  71 def _d_loglevel(s):
  72     '''Converts a string into a sr.LogLevel.'''
  73     d = {
  74         'NONE': sr.LogLevel.NONE,
  75         'ERR':  sr.LogLevel.ERR,
  76         'WARN': sr.LogLevel.WARN,
  77         'INFO': sr.LogLevel.INFO,
  78         'DBG':  sr.LogLevel.DBG,
  79         'SPEW': sr.LogLevel.SPEW
  80     }
  81
  82     if not (s in d):
  83         s = _default_loglevel
  84
  85     return d[s]
  86
  87 def _s_loglevel(l):
  88     '''Converts a sr.LogLevel into a string.'''
  89     return l.name
  90
  91 def init():
  92     '''Creates the 'Settings' objects for all known settings and places them
  93     into the module's namespace.
  94
  95     A QApplication must have been created before this function can be called.
  96     '''
  97
  98     app = QtGui.QApplication.instance()
  99     app.setApplicationName('sigrok-meter')
 100     app.setOrganizationName('sigrok')
 101     app.setOrganizationDomain('sigrok.org')
 102
 103     mainwindow = _SettingsGroup()
 104     mainwindow.size = Setting('mainwindow/size', QtCore.QSize(900, 550))
 105     mainwindow.pos  = Setting('mainwindow/pos')
 106     globals()['mainwindow'] = mainwindow
 107
 108     graph = _SettingsGroup()
 109     graph.backlog = Setting('graph/backlog', 30, d=int)
 110     globals()['graph'] = graph
 111
 112     logging = _SettingsGroup()
 113     logging.level = Setting('logging/level', _default_loglevel,
 114         s=_s_loglevel, d=_d_loglevel)
 115     logging.lines = Setting('logging/lines', 1000, d=int)
 116     logging.filename = Setting('logging/filename', '')
 117     globals()['logging'] = logging