#!/usr/bin/env python # -*- coding: utf-8 -*- # ***************************************************************************** # 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., # 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA # # Module authors: # Markus Zolliker # ***************************************************************************** """command handler Utility class for cases, where multiple parameters are treated with a common command. The support for LakeShore and similar protocols is already included. For read, instead of the methods read_ we write one method analyze_ for all parameters with the same handler. Before analyze_ is called, the reply is parsed and converted to values, which are then given as arguments. def analyze_(self, value1, value2, ...): # we have to calculate parameters from the values (value1, value2 ...) # and assign them to self. # no return value is expected For write, instead of the methods write_" we write one method change_ for all parameters with the same handler. def change_(self, new, value1, value2, ...): # is a wrapper object around the module, containing already the new values. # if READ_BEFORE_WRITE is True (the default), the additional arguments (value1, ...) # must be in the argument list. They contain the values read from the hardware. # If they are not needed, set READ_BEFORE_WRITE to False, or declare them as '*args'. # The expression ('' in new) returns a boolean indicating, whether # this parameter is subject to change. # The return value must be either a sequence of values to be written to the hardware, # which will be formatted by the handler, or None. The latter is used only in some # special cases, when nothing has to be written. """ import re from secop.metaclass import Done from secop.errors import ProgrammingError class CmdParser: """helper for parsing replies using a subset of old style python formatting the same format can be used or formatting command arguments """ # make a map of cast functions CAST_MAP = {letter: cast for letters, cast in ( ('d', int), ('s', str), # 'c' is treated separately ('o', lambda x:int(x, 8)), ('xX', lambda x:int(x, 16)), ('eEfFgG', float), ) for letter in letters } # pattern for chacaters to be escaped ESC_PAT = re.compile('([\\%s])' % '\\'.join('|^$-.+*?()[]{}<>')) # format pattern FMT_PAT = re.compile('(%%|%[^diouxXfFgGeEcrsa]*(?:.|$))') def __init__(self, argformat): # replace named patterns self.fmt = argformat spl = self.FMT_PAT.split(argformat) spl_iter = iter(spl) def escaped(text): return self.ESC_PAT.sub(lambda x: '\\' + x.group(1), text) casts = [] # the first item in spl is just plain text pat = [escaped(next(spl_iter))] todofmt = None # format set aside to be treated in next loop # loop over found formats and separators for fmt, sep in zip(spl_iter,spl_iter): if fmt == '%%': if todofmt is None: pat.append('%' + escaped(sep)) # plain text continue fmt = todofmt todofmt = None sep = '%' + sep elif todofmt: raise ValueError("a separator must follow '%s'" % todofmt) cast = self.CAST_MAP.get(fmt[-1], None) if cast is None: # special or unknown case if fmt != '%c': raise ValueError("unsupported format: '%s'" % fmt) # we do not need a separator after %c pat.append('(.)') casts.append(str) pat.append(escaped(sep)) continue if sep == '': # missing separator. postpone handling for '%%' case or end of pattern todofmt = fmt continue casts.append(cast) # accepting everything up to a separator pat.append('([^%s]*)' % escaped(sep[0]) + escaped(sep)) if todofmt: casts.append(cast) pat.append('(.*)') self.casts = casts self.pat = re.compile(''.join(pat)) try: argformat % ((0,) * len(casts)) # validate argformat except ValueError as e: raise ValueError("%s in %r" % (e, argformat)) def format(self, *values): return self.fmt % values def parse(self, reply): match = self.pat.match(reply) if not match: raise ValueError('reply "%s" does not match pattern "%s"' % (reply, self.fmt)) return [c(v) for c, v in zip(self.casts, match.groups())] class Change: """contains new values for the call to change_ A Change instance is used as the 'new' argument for the change_ method. new. is either the new, changed value or the old value from the module. In addition '' in new indicates, whether is to be changed. new. can not be changed """ def __init__(self, module, parameters, valuedict): self.__dict__.update(valuedict, _module=module, _parameters=parameters) def __getattr__(self, pname): """get current values from _module for unchanged parameters""" if not pname in self._parameters: raise AttributeError("parameter '%s' is not within the handlers group" % pname) return getattr(self._module, pname) def __setattr__(self, pname, value): raise AttributeError("can't set attribute ") def __contains__(self, pname): """check whether a specific parameter is to be changed""" return pname in self.__dict__ class CmdHandlerBase: """generic command handler""" READ_BEFORE_WRITE = True # if READ_BEFORE_WRITE is True, a read is performed before a write, and the parsed # additional parameters are added to the argument list of change_. def __init__(self, group): # group is used for calling the proper analyze_ and change_ methods self.group = group self.parameters = set() self._module_class = None def parse_reply(self, reply): """return values from a raw reply""" raise NotImplementedError def make_query(self, module): """make a query""" raise NotImplementedError def make_change(self, module, *values): """make a change command from values""" raise NotImplementedError def send_command(self, module, changecmd=''): """send a command (query or change+query) and parse the reply into a list If changecmd is given, it is prepended before the query. """ querycmd = self.make_query(module) reply = module.sendRecv(changecmd + querycmd) return self.parse_reply(reply) def send_change(self, module, *values): """compose and send a command from values and send a query afterwards. This method might be overriden, if the change command can be combined with a query command, or if the change command already includes a reply. """ changecmd = self.make_change(module, *values) module.sendRecv(changecmd) # ignore result return self.send_command(module) def get_read_func(self, modclass, pname): """returns the read function passed to the metaclass and registers the parameter in this handler """ self._module_class = self._module_class or modclass if self._module_class != modclass: raise ProgrammingError("the handler '%s' for '%s.%s' is already used in module '%s'" % (self.group, modclass.__name__, pname, self._module_class.__name__)) self.parameters.add(pname) return self.read def read(self, module): """the read function passed to the metaclass overwrite with None if not used """ try: # do a read of the current hw values reply = self.send_command(module) # convert them to parameters getattr(module, 'analyze_' + self.group)(*reply) assert module.__class__ == self._module_class for pname in self.parameters: if module.parameters[pname].readerror: # clear errors on parameters, which were not updated. # this will also inform all activated clients setattr(module, pname, getattr(module, pname)) except Exception as e: # set all parameters of this handler to error for pname in self.parameters: module.setError(pname, e) raise return Done # parameters should be updated already def get_write_func(self, pname, wfunc): """returns the write function passed to the metaclass may be overriden to return None, if not used """ if wfunc: def new_wfunc(module, value, cmd=self, pname=pname, wfunc=wfunc): value = wfunc(module, value) if value is None or value is Done: return value cmd.write(module, {pname: value}) return Done else: def new_wfunc(module, value, cmd=self, pname=pname): cmd.write(module, {pname: value}) return Done return new_wfunc def write(self, module, valuedict, force_read=False): """write values to the module When called from write_, valuedict contains only one item, the single parameter to be changed. If called directly, valuedict may have more items. """ analyze = getattr(module, 'analyze_' + self.group) if module.writeDict: # collect other parameters to be written valuedict = dict(valuedict) for p in self.parameters: if p in self.writeDict: valuedict[p] = self.writeDict.pop(p) elif p not in valuedict: force_read = True if self.READ_BEFORE_WRITE or force_read: # do a read of the current hw values values = self.send_command(module) # convert them to parameters analyze(*values) if not self.READ_BEFORE_WRITE: values = () # values are not expected for change_ new = Change(module, self.parameters, valuedict) # call change_* for calculation new hw values values = getattr(module, 'change_' + self.group)(new, *values) if values is None: # this indicates that nothing has to be written return # send the change command and a query command analyze(*self.send_change(module, *values)) def change(self, module, *values): """write and read back values might be called from a write method, if change_ is not implemented """ getattr(module, 'analyze_' + self.group)(*self.send_change(module, *values)) class CmdHandler(CmdHandlerBase): """more evolved command handler this command handler works for a syntax, where the change command syntax can be build from the query command syntax, with the to be changed items at the second part of the command, using the same format as for the reply. Examples: devices from LakeShore, PPMS implementing classes have to define/override the following: """ CMDARGS = [] # list of properties or parameters to be used for building # some of the the query and change commands CMDSEPARATOR = ';' # if given, it is valid to join a command a a query with # the given separator def __init__(self, group, querycmd, replyfmt, changecmd=None): """initialize the command handler group: the handler group (used for analyze_ and change_) querycmd: the command for a query, may contain named formats for cmdargs replyfmt: the format for reading the reply with some scanf like behaviour changecmd: the first part of the change command (without values), may be omitted if no write happens """ super().__init__(group) self.querycmd = querycmd self.replyfmt = CmdParser(replyfmt) self.changecmd = changecmd def parse_reply(self, reply): """return values from a raw reply""" return self.replyfmt.parse(reply) def make_query(self, module): """make a query""" return self.querycmd % {k: getattr(module, k, None) for k in self.CMDARGS} def make_change(self, module, *values): """make a change command""" changecmd = self.changecmd % {k: getattr(module, k, None) for k in self.CMDARGS} return changecmd + self.replyfmt.format(*values) def send_change(self, module, *values): """join change and query commands""" if self.CMDSEPARATOR is None: return super().send_change(module, *values) return self.send_command(module, self.make_change(module, *values) + self.CMDSEPARATOR)