Clearer error message when parsing Android XML resource fails.

build/android/gyp/generate_v14_compatible_resources.py

 #!/usr/bin/env python
 #
 # Copyright 2013 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.
 
 """Convert Android xml resources to API 14 compatible.
 
 There are two reasons that we cannot just use API 17 attributes,
 so we are generating another set of resources by this script.
@@ skipping 47 matching lines @@
 def IterateXmlElements(node):
   """minidom helper function that iterates all the element nodes.
   Iteration order is pre-order depth-first."""
   if node.nodeType == node.ELEMENT_NODE:
     yield node
   for child_node in node.childNodes:
     for child_node_element in IterateXmlElements(child_node):
       yield child_node_element
 
 
+def ParseAndReportErrors(filename):
+  try:
+    return minidom.parse(filename)
+  except Exception:
+    import traceback
+    traceback.print_exc()

[Kibeom Kim (inactive), 2014/10/30 07:07:39]

Just a question: it looks this is a common practice among chromium python
scripts, but if we just want some additional information in addition to what it
reports already, wouldn't this be more natural?

1. printing the additional information first. (#74)
2. throwing the Exception we caught.

[Kibeom Kim (inactive), 2014/10/30 07:10:44]

Though, having the most important message at the last line is much more
noticeable I guess.

+    sys.stderr.write('Failed to parse XML file: %s\n' % filename)
+    sys.exit(1)
+
+
 def AssertNotDeprecatedAttribute(name, value, filename):
   """Raises an exception if the given attribute is deprecated."""
   msg = None
   if name in ATTRIBUTES_TO_MAP_REVERSED:
     msg = '{0} should use {1} instead of {2}'.format(filename,
         ATTRIBUTES_TO_MAP_REVERSED[name], name)
   elif name in GRAVITY_ATTRIBUTES and ('left' in value or 'right' in value):
     msg = '{0} should use start/end instead of left/right for {1}'.format(
         filename, name)
 
@@ skipping 15 matching lines @@
 def HasStyleResource(dom):
   """Return True if the dom is a style resource, False otherwise."""
   root_node = IterateXmlElements(dom).next()
   return bool(root_node.nodeName == 'resources' and
               list(root_node.getElementsByTagName('style')))
 
 
 def ErrorIfStyleResourceExistsInDir(input_dir):
   """If a style resource is in input_dir, raises an exception."""
   for input_filename in build_utils.FindInDirectory(input_dir, '*.xml'):
-    dom = minidom.parse(input_filename)
+    dom = ParseAndReportErrors(input_filename)
     if HasStyleResource(dom):
       raise Exception('error: style file ' + input_filename +
                       ' should be under ' + input_dir +
                       '-v17 directory. Please refer to '
                       'http://crbug.com/243952 for the details.')
 
 
 def GenerateV14LayoutResourceDom(dom, filename, assert_not_deprecated=True):
   """Convert layout resource to API 14 compatible layout resource.
 
@@ skipping 56 matching lines @@
 def GenerateV14LayoutResource(input_filename, output_v14_filename,
                               output_v17_filename):
   """Convert API 17 layout resource to API 14 compatible layout resource.
 
   It's mostly a simple replacement, s/Start/Left s/End/Right,
   on the attribute names.
   If the generated resource is identical to the original resource,
   don't do anything. If not, write the generated resource to
   output_v14_filename, and copy the original resource to output_v17_filename.
   """
-  dom = minidom.parse(input_filename)
+  dom = ParseAndReportErrors(input_filename)
   is_modified = GenerateV14LayoutResourceDom(dom, input_filename)
 
   if is_modified:
     # Write the generated resource.
     WriteDomToFile(dom, output_v14_filename)
 
     # Copy the original resource.
     build_utils.MakeDirectory(os.path.dirname(output_v17_filename))
     shutil.copy2(input_filename, output_v17_filename)
 
 
 def GenerateV14StyleResource(input_filename, output_v14_filename):
   """Convert API 17 style resources to API 14 compatible style resource.
 
   Write the generated style resource to output_v14_filename.
   It's mostly a simple replacement, s/Start/Left s/End/Right,
   on the attribute names.
   """
-  dom = minidom.parse(input_filename)
+  dom = ParseAndReportErrors(input_filename)
   GenerateV14StyleResourceDom(dom, input_filename)
 
   # Write the generated resource.
   WriteDomToFile(dom, output_v14_filename)
 
 
 def GenerateV14LayoutResourcesInDir(input_dir, output_v14_dir, output_v17_dir):
   """Convert layout resources to API 14 compatible resources in input_dir."""
   for input_filename in build_utils.FindInDirectory(input_dir, '*.xml'):
     rel_filename = os.path.relpath(input_filename, input_dir)
@@ skipping 14 matching lines @@
 def VerifyV14ResourcesInDir(input_dir, resource_type):
   """Verify that the resources in input_dir is compatible with v14, i.e., they
   don't use attributes that cause crashes on certain devices. Print an error if
   they have."""
   for input_filename in build_utils.FindInDirectory(input_dir, '*.xml'):
     exception_message = ('error : ' + input_filename + ' has an RTL attribute, '
                         'i.e., attribute that has "start" or "end" in its name.'
                         ' Pre-v17 resources should not include it because it '
                         'can cause crashes on certain devices. Please refer to '
                         'http://crbug.com/243952 for the details.')
-    dom = minidom.parse(input_filename)
+    dom = ParseAndReportErrors(input_filename)
     if resource_type in ('layout', 'xml'):
       if GenerateV14LayoutResourceDom(dom, input_filename, False):
         raise Exception(exception_message)
     elif resource_type == 'values':
       if GenerateV14StyleResourceDom(dom, input_filename, False):
         raise Exception(exception_message)
 
 
 def AssertNoDeprecatedAttributesInDir(input_dir, resource_type):
   """Raises an exception if resources in input_dir have deprecated attributes,
   e.g., paddingLeft, paddingRight"""
   for input_filename in build_utils.FindInDirectory(input_dir, '*.xml'):
-    dom = minidom.parse(input_filename)
+    dom = ParseAndReportErrors(input_filename)
     if resource_type in ('layout', 'xml'):
       GenerateV14LayoutResourceDom(dom, input_filename)
     elif resource_type == 'values':
       GenerateV14StyleResourceDom(dom, input_filename)
 
 
 def ParseArgs():
   """Parses command line options.
 
   Returns:
@@ skipping 82 matching lines @@
   build_utils.MakeDirectory(res_v14_dir)
 
   GenerateV14Resources(options.res_dir, res_v14_dir, options.verify_only)
 
   if options.stamp:
     build_utils.Touch(options.stamp)
 
 if __name__ == '__main__':
   sys.exit(main())