Made a generator for CSSPropertyDescriptor.cpp

third_party/WebKit/Source/build/scripts/make_css_property_descriptor.py

+#!/usr/bin/env python
+# Copyright 2016 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 sys
+
+import in_generator
+import template_expander
+import make_style_builder
+from collections import namedtuple, defaultdict
+
+
+class CSSPropertyAPIWriter(make_style_builder.StyleBuilderWriter):
+    def __init__(self, in_file_path):
+        super(CSSPropertyAPIWriter, self).__init__(in_file_path)
+        self._outputs = {
+            'CSSPropertyDescriptor.cpp': self.generate_property_descriptor_h,
+        }
+
+        # Temporary map of classname to list of propertyIDs
+        classnames = defaultdict(list)
+        for property in self._properties.values():
+            if property['api_class'] is not None:

[alancutter (OOO until 2018), 2016/12/13 03:29:54]

The indent level is getting a bit much here. Invert this to if is None:
continue.

[aazzam, 2016/12/13 05:01:09]

done :)

+                if property['api_class'] is True:
+                    # This property had the generated_api_class flag set in CSSProperties.in,
+                    # but did not specify a class name.
+                    classnames["CSSPropertyAPI" + property['upper_camel_name']].append("CSSProperty" + property['upper_camel_name'])
+                elif isinstance(property['api_class'], str):

[alancutter (OOO until 2018), 2016/12/13 03:29:54]

Assert this condition, the else: case should never be reached.

[aazzam, 2016/12/13 05:01:09]

done :)

+                    # This property has a specified class name.
+                    classnames[property['api_class']].append("CSSProperty" + property['upper_camel_name'])

[alancutter (OOO until 2018), 2016/12/13 03:29:54]

I think something like
classname = get_classname(api_class)
properties_for_class[classname].append(property_id)
would be a less heavy to read.

Also use ' over ".

+
+        # Stores a list of classes with elements (index, classname, [propertyIDs, ..])
+        self._api_classes = []
+
+        api_class = namedtuple('api_class', ('index', 'classname', 'propertyIDs'))

[alancutter (OOO until 2018), 2016/12/13 03:29:54]

Use CamelCase for types.

I don't think a namedtuple is necessary anyway.
self._api_classes.append({
    'index': i + 1,
    ...
})
would be perfectly fine.

[aazzam, 2016/12/13 05:01:09]

The reason we thought of using a namedtuple instead of a hash map since it's
immutable (which is better in this case, since we aren't changing it).
Also, the fields which we have in each classname are better defined - if we have
it as a hashmap you can access any key from it, it'll just have an error. And
from what I've seen (and what sasha has told me) there's nowhere in our jinja
templates which access a key of a hashmap from within the .tmpl file.

Does that make sense? :)

+        for i, classname in enumerate(classnames.keys()):
+            self._api_classes.append(api_class(index=i + 1, classname=classname, propertyIDs=classnames[classname]))

[alancutter (OOO until 2018), 2016/12/13 03:29:54]

Use snake_case for propertyIDs.

[aazzam, 2016/12/13 05:01:09]

done! :)

+
+    @template_expander.use_jinja('CSSPropertyDescriptor.cpp.tmpl')
+    def generate_property_descriptor_h(self):
+        return {
+            'api_classes': self._api_classes,
+        }
+
+if __name__ == '__main__':
+    in_generator.Maker(CSSPropertyAPIWriter).main(sys.argv)