ChangeSet.py

Go to the documentation of this file.

#
# Copyright 2009, MeVis Medical Solutions AG
#
# The user may use this file in accordance with the license agreement provided with
# the Software or, alternatively, in accordance with the terms contained in a
# written agreement between the user and MeVis Medical Solutions AG.
#
# For further information use the contact form at https://www.mevislab.de/contact
#
 
 
 
# -- local imports -----------------------------------------------------------------------------{{{-
import mevis
 
# ----------------------------------------------------------------------------------------------}}}-
 
 
# -- class ChangeSet ---------------------------------------------------------------------------{{{-
 
class ChangeSet:
    # -- member variables ------------------------------------------------------------------------{{{-
    
    __changeDict = None
    
    __changeStack = None
    
    __ctx = None
    # --------------------------------------------------------------------------------------------}}}-
 
    # -- def __init__ ----------------------------------------------------------------------------{{{-
    
    def __init__(self, context):
        self.__changeDict = {}
        self.__changeStack = []
        self.__ctx = context
        self.__enableAutoRevert = True
 
    # --------------------------------------------------------------------------------------------}}}-
 
    # -- def __del__ -----------------------------------------------------------------------------{{{-
    
    def __del__(self):
        self.autoRevert()
 
    # --------------------------------------------------------------------------------------------}}}-
 
    # -- def _logInfo ----------------------------------------------------------------------------{{{-
    def _logInfo(self, message):
        mevis.MLAB.log(message)
 
    # --------------------------------------------------------------------------------------------}}}-
 
    # -- def _logError ---------------------------------------------------------------------------{{{-
    def _logError(self, message):
        mevis.MLAB.logError(message)
 
    # --------------------------------------------------------------------------------------------}}}-
 
    # -- def setFieldValue -----------------------------------------------------------------------{{{-
    
    def setFieldValue(self, fieldName, fieldValue, verbose=False) -> bool:
        if not self.__ctx.hasField(fieldName):
            self._logError("Field %s not found in the used context!" % (fieldName))
            return False
        field = self.__ctx.field(fieldName)
        fieldType = field.type
        if (fieldType in ("Trigger",)) or fieldValue is None:
            if verbose:
                self._logInfo("Touched field %s" % (fieldName))
            field.touch()
        else:
            # Store old field value.
            oldFieldValue = getFieldValue(field)
            if fieldName not in self.__changeDict:
                self.__changeStack.append(fieldName)
            self.__changeDict.setdefault(fieldName, oldFieldValue)
            setFieldValue(field, fieldValue)
            if verbose:
                self._logInfo("Set field %s to value %s" % (fieldName, fieldValue))
        return True
 
    # -- def updateFieldValue -----------------------------------------------------------------------{{{-
    
    def updateFieldValue(self, fieldName, fieldValue, verbose=False) -> bool:
        if not self.__ctx.hasField(fieldName):
            self._logError("Field %s not found in the used context!" % (fieldName))
            return False
        field = self.__ctx.field(fieldName)
        fieldType = field.type
        if (fieldType in ("Trigger",)) or fieldValue is None:
            if verbose:
                self._logInfo("Touched field %s" % (fieldName))
            field.touch()
        else:
            # Store old field value.
            oldFieldValue = getFieldValue(field)
            if oldFieldValue != fieldValue:
                if fieldName not in self.__changeDict:
                    self.__changeStack.append(fieldName)
                self.__changeDict.setdefault(fieldName, oldFieldValue)
                setFieldValue(field, fieldValue)
                if verbose:
                    self._logInfo("Set field %s to value %s" % (fieldName, fieldValue))
            else:
                if verbose:
                    self._logInfo(
                        "Ensured field %s already has value %s, skipping field touch." % (fieldName, fieldValue)
                    )
 
        return True
 
    # --------------------------------------------------------------------------------------------}}}-
 
    # -- def addField ----------------------------------------------------------------------------{{{-
    
    def addField(self, fieldName, verbose=False):
        if not self.__ctx.hasField(fieldName):
            self._logError("Field %s not found in the used context!" % (fieldName))
            return False
        field = self.__ctx.field(fieldName)
        self.__changeDict.setdefault(fieldName, getFieldValue(field))
        return True
 
    # --------------------------------------------------------------------------------------------}}}-
 
    # -- def autoRevert --------------------------------------------------------------------------{{{-
    
    def autoRevert(self):
        if self.__enableAutoRevert and self.__ctx:  # the module might not exist anymore, so check
            self.revert()
 
    # --------------------------------------------------------------------------------------------}}}-
 
    # -- def revert ------------------------------------------------------------------------------{{{-
    
    def revert(self):
        # For each changed field restore the original value.
        while len(self.__changeStack) > 0:
            fieldName = self.__changeStack.pop(-1)
            field = self.__ctx.field(fieldName)
            setFieldValue(field, self.__changeDict[fieldName])
        self.__changeDict = {}
 
    # --------------------------------------------------------------------------------------------}}}-
 
    def enableAutoRevert(self, enable):
        # Enable/disable revert on destruction. Can be disabled for debugging purposes (to leave the
        # network state as it was on error occurrence).
        self.__enableAutoRevert = enable
 
    # --------------------------------------------------------------------------------------------}}}-
 
 
# ----------------------------------------------------------------------------------------------}}}-
 
 
def getFieldValue(field):
    if "Vector6" in field.type:
        return field.stringValue()
    elif "MLBase" in field.type:
        return field.object()
    else:
        return field.value
 
 
def setFieldValue(field, fieldValue):
    if "Vector6" in field.type:
        if isinstance(fieldValue, (str, bytes)):
            field.setStringValue(fieldValue)
        else:
            field.setVectorValue(fieldValue)
    elif "MLBase" in field.type:
        field.setObject(fieldValue)
    else:
        field.value = fieldValue