From 74f4b46ab44016f9e7ad56cde5916ffbc45723d3 Mon Sep 17 00:00:00 2001
From: "noelallen@google.com"
 <noelallen@google.com@0039d316-1c4b-4281-b951-d872f2087c98>
Date: Tue, 19 Jul 2011 16:32:59 +0000
Subject: Add missing IDL Visistor class

This class provides a simple mechanism for recursively traversing the AST
for both simple and version aware traversal.

TBR= sehr@google.com
BUG= http://code.google.com/p/chromium/issues/detail?id=87684
TEST= python idl_c_header.py
Review URL: http://codereview.chromium.org/7448001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@93036 0039d316-1c4b-4281-b951-d872f2087c98
---
 ppapi/generators/idl_visitor.py | 81 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 ppapi/generators/idl_visitor.py

diff --git a/ppapi/generators/idl_visitor.py b/ppapi/generators/idl_visitor.py
new file mode 100644
index 0000000..40a8579
--- /dev/null
+++ b/ppapi/generators/idl_visitor.py
@@ -0,0 +1,81 @@
+#!/usr/bin/python
+#
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+""" Visitor Object for traversing AST """
+
+#
+# IDLVisitor
+#
+# The IDLVisitor class will traverse an AST truncating portions of the tree
+# that fail due to class or version filters.  For each node, after the filter
+# passes, the visitor will call the 'Arive' member passing in the node and
+# and data passing in from the parent call.   It will then Visit the children.
+# When done processing children, the visitor will call the 'Depart' member
+# before returning
+#
+
+class IDLVisitor(object):
+  def __init__(self):
+    self.depth = 0
+
+  # Return TRUE if the node should be visited
+  def VisitFilter(self, node, data):
+    return True
+
+  # Return TRUE if data should be added to the childdata list
+  def AgrigateFilter(self, data):
+    return data is not None
+
+  def Visit(self, node, data):
+    self.depth += 1
+    if not self.VisitFilter(node, data): return None
+
+    childdata = []
+    newdata = self.Arrive(node, data)
+    for child in node.GetChildren():
+      ret = self.Visit(child, newdata)
+      if self.AgrigateFilter(ret):
+        childdata.append(ret)
+    out = self.Depart(node, newdata, childdata)
+
+    self.depth -= 1
+    return out
+
+  def Arrive(self, node, data):
+    return data
+
+  def Depart(self, node, data, childdata):
+    return data
+
+
+#
+# IDLVersionVisitor
+#
+# The IDLVersionVisitor will only visit nodes with intervals that include the
+# version.  It will also optionally filter based on a class list
+#
+class IDLVersionVisitor(object):
+  def __init__(self, version, classList):
+    self.version = version
+    self.classes = classes
+
+  def Filter(self, node, data):
+    if self.classList and node.cls not in self.classList: return False
+    if not node.IsVersion(self.version): return False
+    return True
+
+class IDLRangeVisitor(object):
+  def __init__(self, vmin, vmax, classList):
+    self.vmin = vmin
+    self.vmax = vmax
+    self.classList = classList
+
+  def Filter(self, node, data):
+    if self.classList and node.cls not in self.classList: return False
+    if not node.IsVersion(self.version): return False
+    return True
+
+
-- 
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