1 files changed, 191 insertions, 0 deletions
diff --git a/ppapi/generators/idl_diff.py b/ppapi/generators/idl_diff.py
new file mode 100644
index 0000000..d005a20
--- /dev/null
+++ b/ppapi/generators/idl_diff.py
@@ -0,0 +1,191 @@
+#!/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.
+
+import glob
+import os
+import subprocess
+import sys
+
+from idl_option import GetOption, Option, ParseOptions
+
+#
+# IDLDiff
+#
+# IDLDiff is a tool for comparing sets of IDL generated header files
+# with the standard checked in headers.  It does this by capturing the
+# output of the standard diff tool, parsing it into separate changes, then
+# ignoring changes that are know to be safe, such as adding or removing
+# blank lines, etc...
+#
+
+Option('gen', 'IDL generated files', default='hdir')
+Option('src', 'Original ".h" files', default='../c')
+
+# Change
+#
+# A Change object contains the previous lines, new news and change type.
+#
+class Change(object):
+  def __init__(self, change):
+    self.mode = str(change['mode'])
+    self.was = list(change['was'])
+    self.now = list(change['now'])
+
+  def Dump(self):
+    if not self.was:
+      print 'Adding %s' % self.mode
+    elif not self.now:
+      print 'Missing %s' % self.mode
+    else:
+      print 'Modifying %s' % self.mode
+
+    for line in self.was:
+      print 'src: %s' % line
+    for line in self.now:
+      print 'gen: %s' % line
+    print
+
+#
+# IsCopyright
+#
+# Return True if this change is only a one line change in the copyright notice
+# such as non-matching years.
+#
+def IsCopyright(change):
+  if len(change['now']) != 1 or len(change['was']) != 1: return False
+  if 'Copyright (c)' not in change['now'][0]: return False
+  if 'Copyright (c)' not in change['was'][0]: return False
+  return True
+
+#
+# IsBlank
+#
+# Return True if this change only adds or removes blank lines
+#
+def IsBlank(change):
+  for line in change['now']:
+    if line: return False
+  for line in change['was']:
+    if line: return False
+  return True
+
+
+#
+# IsSpacing
+#
+# Return True if this change is only different in the way 'words' are spaced
+# such as in an enum:
+#   ENUM_XXX   = 1,
+#   ENUM_XYY_Y = 2,
+# vs
+#   ENUM_XXX = 1,
+#   ENUM_XYY_Y = 2,
+#
+def IsSpacing(change):
+  if len(change['now']) != len(change['was']): return False
+  for i in range(len(change['now'])):
+    # Also ignore right side comments
+    line = change['was'][i]
+    offs = line.find('//')
+    if offs == -1:
+      offs = line.find('/*')
+    if offs >-1:
+      line = line[:offs-1]
+
+    words1 = change['now'][i].split()
+    words2 = line.split()
+    if words1 != words2: return False
+  return True
+
+#
+# IsInclude
+#
+# Return True if change has extra includes
+#
+def IsInclude(change):
+  if len(change['was']): return False
+  for line in change['now']:
+    if line and '#include' not in line: return False
+  return True
+
+#
+# IsCppComment
+#
+# Return True if the change is only missing C++ comments
+#
+def IsCppComment(change):
+  if len(change['now']): return False
+  for line in change['was']:
+    line = line.strip()
+    if line[:2] != '//': return False
+  return True
+#
+# ValidChange
+#
+# Return True if none of the changes does not patch an above "bogus" change.
+#
+def ValidChange(change):
+  if IsCopyright(change): return False
+  if IsBlank(change): return False
+  if IsSpacing(change): return False
+  if IsInclude(change): return False
+  if IsCppComment(change): return False
+  return True
+
+
+
+#
+# GetChanges
+#
+# Parse the output into discrete change blocks.
+#
+def GetChanges(output):
+  lines = output.split('\n')
+  changes = []
+  change = { 'mode' : None,
+             'was': [],
+             'now': []
+            }
+  for line in lines:
+    if not line: continue
+    elif line[0] == '<':
+      change['was'].append(line[2:])
+    elif line[0] == '>':
+      change['now'].append(line[2:])
+    elif line[0] == '-':
+      continue
+    else:
+      if ValidChange(change): changes.append(Change(change))
+      change['mode'] = line
+      change['now'] = []
+      change['was'] = []
+  if ValidChange(change): changes.append(Change(change))
+  return changes
+
+def Main(args):
+  filenames = ParseOptions(args)
+  if not filenames:
+    gendir = os.path.join(GetOption('gen'), '*.h')
+    filenames = glob.glob(gendir)
+
+  for filename in filenames:
+    gen = filename
+    filename = filename[len(GetOption('gen')) + 1:]
+    src = os.path.join(GetOption('src'), filename)
+    p = subprocess.Popen(['diff', src, gen], stdout=subprocess.PIPE)
+    output, errors = p.communicate()
+
+    changes = GetChanges(output)
+    if changes:
+      print "\n\nDelta between:\n  src=%s\n  gen=%s\n" % (src, gen)
+      for change in GetChanges(output):
+        change.Dump()
+    else:
+      print "\nSAME:\n  src=%s\n  gen=%s\n" % (src, gen)
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv[1:]))
+