initial version of parameter table
This commit is contained in:
Michael Davidsaver
@ -61,6 +61,7 @@ PY += devsup/db.py
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PY += devsup/hooks.py
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PY += devsup/interfaces.py
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PY += devsup/util.py
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PY += devsup/ptable.py
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#===========================
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@ -23,4 +23,6 @@ except ImportError:
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epicsver = (0,0,0,0,"0","")
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pydevver = (0,0)
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INVALID_ALARM = UDF_ALARM = 0
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__all__ = []
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338
devsupApp/src/devsup/ptable.py
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338
devsupApp/src/devsup/ptable.py
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@ -0,0 +1,338 @@
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# -*- coding: utf-8 -*-
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import logging
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LOG = logging.getLogger(__name__)
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import threading
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_tables = {}
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from devsup.db import IOScanListThread
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from devsup import INVALID_ALARM, UDF_ALARM
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__all__ = [
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'Parameter',
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'ParameterGroup',
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'TableBase',
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'build'
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]
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# Reason code to cause a record to read a new value from a table paramter
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_INTERNAL = object()
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# action types
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# Default action, call whenever a record associated with the parameter
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# is processed
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_ONPROC = lambda n,o:True
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# Run action when the value of a parameter changes
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_ONCHANGE = lambda n,o:n!=o
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_ISVALID = lambda n,o:n is not None
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_ISNOTVALID = lambda n,o:n is None
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def _add_action(self, act, fn):
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try:
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L = fn._ptable_action
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except AttributeError:
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L = fn._ptable_action = []
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L.append((self,act,fn))
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return fn
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class Parameter(object):
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"""Define a parameter in a table.
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When a sub-class of TableBase is instancianted, parameters become
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py:class:`_ParamInstance` instances.
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>>> class MyTable(TableBase):
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A = Parameter()
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B = Parameter(name='bb')
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C = Parameter(iointr=True)
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>>>
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Defines a table with three parameters. The second 'B' defines a different
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parameter name and attribute name. The parameter name 'bb' will be used
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in .db files, which self.B will be used for access from the table instance.
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When _iointr_ is True, then attached device support may use SCAN='I/O Intr',
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which is triggered with the method self.B.notify().
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This class has several methods which may be used decorate member functions
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as actions when the value of a parameter is (possibly) changed.
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"""
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def __init__(self, name=None, iointr=False):
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self.name, self._iointr = name, iointr
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def onproc(self, fn):
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"""Decorator run a member function action whenever
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an attached device support processes.
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>>> class MyTable(TableBase):
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A = Parameter()
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@A.onproc
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def action(self, oldval):
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print 'A changed from',oldval,'to',self.A.value
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"""
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return _add_action(self, _ONPROC, fn)
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def onchange(self, fn):
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"Decorator to run an action when the value of a parameter is changed."
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return _add_action(self, _ONCHANGE, fn)
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def isvalid(self, fn):
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"Decorator to run an action when the value is valid"
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return _add_action(self, _ISVALID, fn)
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def isnotvalid(self, fn):
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"Decorator to run an action when the value is *not* valid"
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return _add_action(self, _ISNOTVALID, fn)
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def oncondition(self, cond):
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"""Decorator which allows a custom condition function to be specified.
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This function will be invoked with two argument cond(newval,oldval)
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and is expected to retur a bool.
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>>> class MyTable(TableBase):
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A = Parameter()
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@A.oncondition(lambda n,o:n<5)
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def action(self, oldval):
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print self.A.value,'is less than 5'
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"""
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def decorate(fn, cond=cond, self=self):
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return _add_action(self, cond, fn)
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return decorate
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class ParameterGroup(object):
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"""A helper for defining actions on groups of parameters
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When a sub-class of TableBase is instancianted, parameter groups become
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py:class:`_ParamGroupInstance` instances.
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>>> class MyTable(TableBase):
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A = Parameter()
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B = Parameter(name='bb')
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grp = ParameterGroup([A,B])
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>>>
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This class has several methods which may be used decorate member functions
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as actions based on the value of parameters in this group.
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"""
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def __init__(self, params, name=None):
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self.params, self.name = params, name
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def onproc(self, fn):
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"""Decorator run a member function action whenever
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a device support attached to any paramter in the group processes.
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>>> class MyTable(TableBase):
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A, B = Parameter(), Parameter()
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grp = ParameterGroup([A,B])
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@grp.onproc
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def action(self):
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print self.A.value, self.B.value
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"""
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return _add_action(self, _ONPROC, fn)
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def allvalid(self, fn):
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"Decorator to run an action when all parameters have valid values"
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return _add_action(self, (all, lambda p:p.isvalid), fn)
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def anynotvalid(self, fn):
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"Decorator to run an action when any parameters has an invalid value"
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return _add_action(self, (any, lambda p:not p.isvalid), fn)
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def oncondition(self, fmap, freduce=all):
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"""Decorator for a custom condtion.
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The condition is specified in two parts, a map function, and a reduce function.
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The map function is applied to each parameter in the group. Then a list
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of the results is passed to the reduce function. If not specified,
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the default reducing function is all (map func must return bool).
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>>> class MyTable(TableBase):
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A, B = Parameter(), Parameter()
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grp = ParameterGroup([A,B])
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@grp.oncondition(lambda v:v>5, any)
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def action(self):
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# either A or B is greater than 5
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print self.A.value, self.B.value
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"""
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def decorate(fn, fmap=fmap, freduce=freduce, self=self):
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return _add_action(self, (freduce, fmap), fn)
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return decorate
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class _ParamInstance(object):
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"""Access to a parameter at runtime.
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"""
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def __init__(self, table, name, scan):
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self.name = name
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self.table, self.scan, self._value = table, scan, None
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self.alarm, self.actions = 0, []
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self._groups = set()
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def _get_value(self):
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return self._value
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def _set_value(self, val):
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self._value = val
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self.alarm = 3 if val is None else 0
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value = property(_get_value, _set_value, doc="The current parameter value")
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@property
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def isvalid(self):
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"""Is the parameter value valid (not None and no INVALID_ALARM)
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"""
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return self.alarm < INVALID_ALARM and self._value is not None
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def notify(self):
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"""Notify attached records of parameter value change.
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A no-op unless Parameter(iointr=True)
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"""
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if self.scan:
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self.scan.interrupt(_INTERNAL)
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def addAction(self, fn, cond=None):
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"""Add an arbitrary action at runtime
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"""
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self.actions.append((cond, fn))
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def _exec(self, oldval=None):
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for C, F in self.actions:
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if C(self.value, oldval):
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F()
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class _ParamGroupInstance(object):
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"""Runtime access to a group of parameters.
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"""
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def __init__(self, table, name):
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self.table, self.name = table, name
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self.actions, self._params = [], None
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def __iter__(self):
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"Iterate over all parameter instances in this group"
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return iter(self._params)
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def addAction(self, fn, fmap, freduce=all):
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"Add an arbitrary action at runtime"
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self.actions.append((fmap, freduce, fn))
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def _exec(self):
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for M, R, F in self.actions:
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if R(map(M, self._params)):
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F()
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def allValid(self):
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"Quick test if all parameters are valid"
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for P in self._params:
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if not P.isvalid:
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return False
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return True
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class _ParamSup(object):
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def __init__(self, inst, rec, info):
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self.inst, self.info = inst, info
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# Determine which field to use to store the value
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fname = rec.info('pyfield','VAL')
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self.raw = fname!='RVAL'
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self.vfld = rec.field(fname)
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self.vdata = None
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if len(self.vfld)>1:
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self.vdata = self.vfld.getarray()
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def detach(self, rec):
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pass
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def allowScan(self, rec):
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if self.inst.scan:
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return self.inst.scan.add(rec)
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def process(self, rec, reason=None):
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with self.inst.table.lock:
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if reason is _INTERNAL:
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# sync table to record
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self.inst.table.log.debug('-> %s (%s)', rec.NAME, self.inst.value)
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nval = self.inst.value
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if nval is not None:
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if self.vdata is None:
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self.vfld.putval(nval)
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else:
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if len(nval)>len(self.vdata):
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nval = nval[:len(self.vdata)]
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self.vdata[:len(nval)] = nval
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self.vfld.putarraylen(len(nval))
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if self.inst.alarm:
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rec.setSevr(self.inst.alarm)
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else:
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# undefined value
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rec.setSevr(INVALID_ALARM, UDF_ALARM)
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else:
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# sync record to table
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self.inst.table.log.debug('<- %s (%s)', rec.NAME, rec.VAL)
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if self.vdata is None:
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nval = self.vfld.getval()
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else:
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# A copy is made which can be used without locking the record
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nval = self.vdata[:self.vfld.getarraylen()].copy()
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oval, self.inst.value = self.inst.value, nval
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# Execute actions
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self.inst._exec(oval)
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for G in self.inst._groups:
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G._exec()
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class TableBase(object):
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"""Base class for all parameter tables.
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Sub-class this and populate with :py:class:`Parameter` and :py:class:`ParameterGroup`.
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When a table is instanciated it must be given a unique name.
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>>> class MyTable(TableBase):
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...
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>>> x=MyTable(name='xyz')
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>>>
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"""
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log = LOG
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ParamSupport = _ParamSup
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def __init__(self, **kws):
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self.name = kws.pop('name')
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if self.name in _tables:
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raise KeyError("Table named '%s' already exists"%self.name)
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self.lock = threading.Lock()
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self._parameters = {}
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# Find Parameters and ParameterGroup in the class dictionary
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# and place approprate things in the instance dictionary
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rparams = {}
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rgroups = {}
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for k,v in self.__class__.__dict__.items():
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if isinstance(v, Parameter):
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scan = None
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if not v.name:
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v.name = k
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if v._iointr:
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scan = IOScanListThread()
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P = _ParamInstance(self, v.name, scan)
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self._parameters[v.name] = P
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rparams[v] = P
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setattr(self, k, P)
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elif isinstance(v, ParameterGroup):
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if not v.name:
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v.name = k
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G = _ParamGroupInstance(self, v.name)
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rgroups[v] = G
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setattr(self, k, G)
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# Populate groups with parameters
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for g,G in rgroups.iteritems():
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ps = G._params = [rparams[v] for v in g.params]
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# reverse mapping from parameter to group(s)
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for P in ps:
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P._groups.add(G)
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# second pass to attach actions
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for k,v in self.__class__.__dict__.items():
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if hasattr(v, '_ptable_action'):
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for src,cond,cmeth in v._ptable_action:
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# src is instance parameter or group
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# cond is a callable for parameters, or a tuple for groups
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# cmeth is the unbound method which is the action to take
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if isinstance(src, Parameter):
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P = rparams[src]
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P.addAction(cmeth.__get__(self), cond)
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elif isinstance(src, ParameterGroup):
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G = rgroups[src]
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G.addAction(cmeth.__get__(self), cond[1], cond[0])
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super(TableBase, self).__init__(**kws)
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self.log.info("Initialized ptable '%s'",self.name)
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_tables[self.name] = self
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def build(rec, args):
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parts = args.split(None,2)
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table, param = parts[:2]
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info = None if len(parts)<3 else parts[2]
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T = _tables[table]
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P = T._parameters[param]
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T.log.debug("Attaching ptable '%s, %s' to %s", T.name, P.name, rec.NAME)
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return T.ParamSupport(P, rec, info)
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