# codegenUtilitiesAutomatic.py - Utilities for Code Generation with the ElementTree
# Library

# This code is released under the BSD License below.
# 
# Copyright (c) 2008-2009, Jason Breti (http://breti.org/codegen)
# 
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# 
#   * Redistributions of source code must retain the above copyright notice,
#     this list of conditions and the following disclaimer.
#   * The name of the contributor may not be used to endorse or promote products
#     derived from this software without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.


#------------------------------------------------------------------------------

import sys
import xml.etree.ElementTree as et

#------------------------------------------------------------------------------

# This is used to figure out which nodes are implemented or not.
# You will also get Not Implemented exceptions when this is set to true
debugCodegen = False

#------------------------------------------------------------------------------
class CodegenException(Exception):
  "General error during the codegen processing."
  def __init__(self, *args):
    Exception.__init__(self, *args)
    self.wrapped_exc = sys.exc_info()
  
#------------------------------------------------------------------------------
class CodegenHandler(object):

  def __init__(self, codegenFactory, thisNode, rootNode):
    self.codegenFactory = codegenFactory
    self.thisNode = thisNode
    self.rootNode = rootNode
    
  def process(self):
    if debugCodegen:
      print 'CodegenHandler for node', self.thisNode.tag

#------------------------------------------------------------------------------
class CodegenHandler_NotImplementedError(CodegenHandler):

  def process(self):
    CodegenHandler.process(self)
    output = "A handler is not implemented for node " + self.thisNode.tag
    raise CodegenException, output
  
#------------------------------------------------------------------------------
class CodegenHandler_HandleChildNodes(CodegenHandler):

  def process(self):
    CodegenHandler.process(self)

    for node in self.thisNode.getchildren():
      object = self.codegenFactory.makeObject(node)
      object.process()
  
#------------------------------------------------------------------------------
class CodegenHandler_IgnoreNode(CodegenHandler_HandleChildNodes):
  """
  This class does not extend any methods from the base class.
  """

#------------------------------------------------------------------------------
class CodegenFactory(object):

  def __init__(self, classPrefix, nodeNotFound, rootNode):
    self.classPrefix = classPrefix
    self.nodeNotFound = nodeNotFound
    self.rootNode = rootNode
    
    # Artificially create an exception.  This allows Python to use the
    # traceback facility to gain access to the globals() namespace for the
    # parent.  The parent's globals() namespace contains the list of classes
    # that can be used by the factory.
    try:
      raise CodegenException

    except CodegenException:
      # Get the traceback information for the exception namespace
      (ignore , ignore, traceBack) = sys.exc_info()
      exceptionTraceBackFrame = traceBack.tb_frame
      
      # Get the traceback information for the codegenUtilities parent
      parentTraceBackFrame = exceptionTraceBackFrame.f_back

      # Get the traceback information for the codegen parent
      parentTraceBackFrame = parentTraceBackFrame.f_back
      
      # Save the parent's globals() namespace that contains the list of 
      # classes that can be used by the factory.
      self.nodeLookup = parentTraceBackFrame.f_globals
      
  def makeObject(self, node):
    nodeName = self.classPrefix + node.tag
    if nodeName in self.nodeLookup:
      object = self.nodeLookup[nodeName](self, node, self.rootNode)
    else:
      object = self.nodeNotFound(self, node, self.rootNode)
      
    return object
    

#------------------------------------------------------------------------------
class CodegenPhase(object):
  nodeNotFound = CodegenHandler_NotImplementedError
  
  def __init__(self, rootNode, classPrefix):
    self.rootNode = rootNode
    self.classPrefix = classPrefix

    if not debugCodegen:
      self.nodeNotFound = CodegenHandler_IgnoreNode
    
    self.codegenFactory = \
      CodegenFactory(self.classPrefix,
                     self.nodeNotFound,
                     self.rootNode)

  def process(self):
    for node in self.rootNode.getchildren():
      object = self.codegenFactory.makeObject(node)
      object.process()
      

#------------------------------------------------------------------------------