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 82
