ppapi/generators/idl_visitor.py

   1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 """ Visitor Object for traversing AST """
   6
   7 #
   8 # IDLVisitor
   9 #
  10 # The IDLVisitor class will traverse an AST truncating portions of the tree
  11 # when 'VisitFilter' returns false.  After the filter returns true, for each
  12 # node, the visitor will call the 'Arrive' member passing in the node and
  13 # and generic data object from the parent call.  The returned value is then
  14 # passed to all children who's results are aggregated into a list.  The child
  15 # results along with the original Arrive result are passed to the Depart
  16 # function which returns the final result of the Visit.  By default this is
  17 # the exact value that was return from the original arrive.
  18 #
  19
  20 class IDLVisitor(object):
  21   def __init__(self):
  22     self.depth = 0
  23
  24   # Return TRUE if the node should be visited
  25   def VisitFilter(self, node, data):
  26     return True
  27
  28   # Return TRUE if data should be added to the childdata list
  29   def AgrigateFilter(self, data):
  30     return data is not None
  31
  32   def Visit(self, node, data):
  33     self.depth += 1
  34     if not self.VisitFilter(node, data): return None
  35
  36     childdata = []
  37     newdata = self.Arrive(node, data)
  38     for child in node.GetChildren():
  39       ret = self.Visit(child, newdata)
  40       if self.AgrigateFilter(ret):
  41         childdata.append(ret)
  42     out = self.Depart(node, newdata, childdata)
  43
  44     self.depth -= 1
  45     return out
  46
  47   def Arrive(self, node, data):
  48     __pychecker__ = 'unusednames=node'
  49     return data
  50
  51   def Depart(self, node, data, childdata):
  52     __pychecker__ = 'unusednames=node,childdata'
  53     return data
  54
  55
  56 #
  57 # IDLVersionVisitor
  58 #
  59 # The IDLVersionVisitor will only visit nodes with intervals that include the
  60 # version.  It will also optionally filter based on a class list
  61 #
  62 class IDLVersionVisitor(object):
  63   def __init__(self, version, classList):
  64     self.version = version
  65     self.classes = classes
  66
  67   def Filter(self, node, data):
  68     if self.classList and node.cls not in self.classList: return False
  69     if not node.IsVersion(self.version): return False
  70     return True
  71
  72 class IDLRangeVisitor(object):
  73   def __init__(self, vmin, vmax, classList):
  74     self.vmin = vmin
  75     self.vmax = vmax
  76     self.classList = classList
  77
  78   def Filter(self, node, data):
  79     if self.classList and node.cls not in self.classList: return False
  80     if not node.IsVersion(self.version): return False
  81     return True