Import LinuxCNC source tree

lib/python/gladevcp/persistence.py

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+#!/usr/bin/env python3
+# vim: sts=4 sw=4 et
+#    This is a component of EMC
+#    util.py Copyright 2010 Michael Haberler
+#
+#
+#    This program is free software; you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation; either version 2 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program; if not, write to the Free Software
+#    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.'''
+'''
+    persistence support for gladevcp widgets
+    Michael Haberler 11/2010
+'''
+import os
+import sys
+import time
+
+import gi
+gi.require_version('Gtk', '3.0')
+from gi.repository import Gtk
+from configobj import ConfigObj, flatten_errors
+from validate import Validator
+from hashlib import sha1
+from .hal_widgets import _HalWidgetBase
+from .hal_actions import _EMC_ActionBase
+from gladevcp.gladebuilder import widget_name
+
+class UselessIniError(Exception):
+    pass
+
+class BadDescriptorDictError(Exception):
+    pass
+
+# map python type names to ConfigObj type names
+co_map = {'str': 'string','int':'integer', 'str': 'string', 'bool': 'boolean'}
+debug = 0
+version_number = 1
+
+
+def warn(*args):
+    print(''.join(args), file=sys.stderr)
+
+
+def dbg(level,*args):
+    global debug
+    if debug < level: return
+    print(''.join(args))
+
+
+def set_debug(value):
+    global debug
+    debug = value
+
+
+def select_widgets(widgets, hal_only=False,output_only = False):
+    '''
+    input: a list of widget instances
+    output: a list of widget instances, pruned according to the flags:
+        hal_only = True:  only add HAL widgets which make sense restoring
+        output_only = True: only add widgets which let users
+        set a value (scale,button..)
+    '''
+    wlist = []
+    for w in widgets:
+        # always skip the following types: 
+        if isinstance(w, (_EMC_ActionBase)):
+            continue
+        if hal_only and not isinstance(w, _HalWidgetBase):
+            continue
+        if output_only and not isinstance(w, (Gtk.Range,
+                                              Gtk.SpinButton,
+                                              Gtk.ComboBox,
+                                              Gtk.CheckButton,
+                                              Gtk.ToggleButton,
+                                              Gtk.RadioButton)):
+            continue
+        wlist.append(w)
+    return wlist
+
+
+def accessors(w):
+    '''
+    retrieve getter/setter name of an 'interesting' widget
+    '''
+    if isinstance(w, (Gtk.Range, Gtk.SpinButton)):
+        return (w.get_value,w.set_value)
+    if isinstance(w, (Gtk.CheckButton, Gtk.ToggleButton,Gtk.RadioButton,Gtk.ComboBox)):
+        return (w.get_active,w.set_active)
+    return (None,None)
+
+def store_value(widget,value):
+    _,setter = accessors(widget)
+    return setter and setter(value)
+
+def get_value(widget):
+    getter,_ = accessors(widget)
+    return getter and getter()
+
+def widget_defaults(widgets):
+    '''
+    return a dict name/current value of wvalues which are to be restored
+    '''
+    wvalues = dict()
+    for w in widgets:
+        k = widget_name(w)
+        try:
+            v = get_value(w)
+            wvalues[k] = v
+        except Exception as msg:
+            warn("widget_defaults:" + msg)
+            continue
+    return wvalues
+
+
+class IniFile(object):
+
+    # well known section and variable names in INI files
+    vars = 'vars'
+    widgets = 'widgets'
+    ini = 'ini'
+    signature = 'signature'
+    version = 'version'
+
+    def _gen_spec(self,vdict):
+        '''
+        given a nested dict of sections,vars and default values,
+        derive a ConfigObj typed spec
+        NB: only single level nesting supported
+
+        FIXME: add safeguards against broken vdict()
+        '''
+        spec = ''
+        for section in sorted(vdict.keys()):
+            spec += '[' + section + ']\n'
+            for varname in sorted(vdict[section].keys()):
+                typename = type(vdict[section][varname]).__name__
+                if typename in co_map:
+                    typename = co_map[typename]
+                spec += '\t' + varname + ' = ' + typename  + '\n'
+        return spec
+
+    def restore_state(self,obj):
+        '''
+        restore attributes from INI file 'vars' section as obj attributes,
+        as well as any widget state in 'widgets' section
+        '''
+        dbg(1, "restore_state() from %s" % (self.filename))
+
+        if not IniFile.ini in self.defaults:
+            raise BadDescriptorDictError("defaults dict lacks 'ini' section")
+
+        if  self.defaults[IniFile.ini][IniFile.signature] != (
+                self.config[IniFile.ini][IniFile.signature]):
+            warn("signature mismatch in %s -  resetting to default" %
+                 (self.filename))
+            dbg(1, "expected: %s, got %s" %
+                (self.defaults[IniFile.ini][IniFile.signature],
+                 self.config[IniFile.ini][IniFile.signature]))
+            self.create_default_ini()
+        else:
+            dbg(1,"signature verified OK for %s " % (self.filename))
+
+        if IniFile.vars in self.config:
+            for k,v in list(self.defaults[IniFile.vars].items()):
+                setattr(obj,k,self.config[IniFile.vars][k])
+
+        if IniFile.widgets in self.config:
+            for k,v in list(self.config[IniFile.widgets].items()):
+                store_value(self.builder.get_object(k),v)
+
+    def save_state(self, obj):
+        '''
+        save obj attributes as listed in INI file 'IniFile.vars' section and
+        widget state to 'widgets' section
+        '''
+        if IniFile.vars in self.defaults:
+            for k,v in list(self.defaults[IniFile.vars].items()):
+                self.config[IniFile.vars][k] = getattr(obj,k,None)
+
+        if IniFile.widgets in self.config:
+            for k in list(self.defaults[IniFile.widgets].keys()):
+                self.config[IniFile.widgets][k] = get_value(self.builder.get_object(k))
+
+        self.config.final_comment = ['last update  by %s.save_state() on %s ' %
+                                         (__name__,time.asctime())]
+        self.write()
+        dbg(1, "save_state() to %s" % (self.filename))
+
+
+    def create_default_ini(self):
+        '''
+        create a default INI file with defaults derived from configspec
+        '''
+        self.config = ConfigObj(self.filename, interpolation=False,
+                                configspec=self.spec)
+        vdt = Validator()
+        self.config.validate(vdt, copy=True)
+        self.config.update(self.defaults)
+        self.config.filename = self.filename
+        self.config.initial_comment.append('generated by %s.create_default_ini() on %s' %
+                                           (__name__, time.asctime()))
+        self.config.write()
+
+    def read_ini(self):
+        '''
+        make sure current file validates OK, this will also type-convert values
+        recreate default INI file if bad things happen
+        '''
+        retries = 2
+        while True:
+            try:
+                self.config = ConfigObj(self.filename,
+                                        file_error=True,
+                                        interpolation=False,
+                                        configspec=self.spec,
+                                        raise_errors=True)
+                validator = Validator()
+                results = self.config.validate(validator,preserve_errors=True)
+                if results != True:
+                    for (section_list, key, error
+                         ) in flatten_errors(self.config, results):
+                        if key is not None:
+                            warn("key '%s' in section '%s' : %s" %
+                                 (key, ', '.join(section_list),
+                                  error if error else "missing"))
+                        else:
+                            warn("section '%s' missing" %
+                                 ', '.join(section_list))
+                    badfilename = self.filename + '.BAD'
+                    os.rename(self.filename,badfilename)
+                    retries -= 1
+                    if retries:
+                        raise UselessIniError("can not make sense of '%s', renamed to '%s'"
+                                              % (self.filename, badfilename))
+                    else:
+                        raise Exception(error)
+
+            except (IOError, TypeError,UselessIniError) as msg:
+                warn("%s - creating default" % (msg))
+                self.create_default_ini()
+                continue
+
+            except: # pass on ConfigObj's other troubles
+                raise
+
+            else: # all great
+                break
+
+    def write(self,filename=None):
+        '''
+        write out changed config
+        '''
+        if filename:
+            self.filename = filename
+        self.config.write()
+
+    def __init__(self,filename,defaults,builder):
+        defaults[IniFile.ini] =   { IniFile.signature : 'astring',
+                                    IniFile.version : version_number }
+        self.defaults = defaults
+        self.filename = filename
+        self.builder = builder
+        spec = self._gen_spec(self.defaults)
+        self.signature = sha1(spec.encode('utf-8')).hexdigest()
+        self.defaults[IniFile.ini][IniFile.signature] = self.signature
+
+        dbg(2, "auto-generated spec:\n%s\nsignature = %s" %
+            (spec, self.signature))
+        self.spec = spec.splitlines()
+        self.read_ini()