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Unified Diff: third_party/WebKit/Source/build/scripts/make_computed_style_base.py

Issue 2786883002: Generate subgroup StyleSurroundData in ComputedStyle. (Closed)
Patch Set: Fix things Created 3 years, 8 months ago
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Index: third_party/WebKit/Source/build/scripts/make_computed_style_base.py
diff --git a/third_party/WebKit/Source/build/scripts/make_computed_style_base.py b/third_party/WebKit/Source/build/scripts/make_computed_style_base.py
index 8bce1cf151b3e2148836b41409a0f3e14e364160..aec595111d91a99eb44f61cd7935b39eca0758a7 100755
--- a/third_party/WebKit/Source/build/scripts/make_computed_style_base.py
+++ b/third_party/WebKit/Source/build/scripts/make_computed_style_base.py
@@ -12,10 +12,12 @@ import make_style_builder
from name_utilities import (
enum_for_css_keyword, enum_type_name, enum_value_name, class_member_name, method_name,
- join_name
+ class_name, join_name
)
-from collections import OrderedDict
+from collections import defaultdict, OrderedDict
+from itertools import chain
+# TODO(shend): Improve documentation and add docstrings.
# Temporary hard-coded list of extra fields.
# TODO(shend): Put this into its own JSON5 file.
@@ -74,9 +76,58 @@ EXTRA_FIELDS = [
# once we can support union fields and groups.
{'name': 'VerticalAlign', 'field_template': 'storage_only', 'field_size': 4, 'default_value': 'EVerticalAlign::kBaseline',
'type_name': 'EVerticalAlign', 'inherited': False, 'independent': False},
+ # Fields that are shared by multiple properties.
+ # TODO(shend): Try to split these up to one field per property.
+ {'name': 'margin', 'field_template': 'storage_only', 'field_size': None, 'field_type_path': 'platform/LengthBox',
+ 'type_name': 'LengthBox', 'field_group': 'surround', 'default_value': 'LengthBox(kFixed)', 'inherited': False,
+ 'independent': False, 'has_custom_compare_and_copy': False},
+ {'name': 'padding', 'field_template': 'storage_only', 'field_size': None, 'field_type_path': 'platform/LengthBox',
+ 'type_name': 'LengthBox', 'field_group': 'surround', 'default_value': 'LengthBox(kFixed)', 'inherited': False,
+ 'independent': False, 'has_custom_compare_and_copy': False},
+ {'name': 'border', 'field_template': 'storage_only', 'field_size': None, 'field_type_path': 'core/style/BorderData',
+ 'type_name': 'BorderData', 'field_group': 'surround', 'default_value': 'BorderData()', 'inherited': False,
+ 'independent': False, 'has_custom_compare_and_copy': False},
]
+def _flatten_list(x):
+ """Flattens a list of lists into a single list."""
+ return list(chain.from_iterable(x))
+
+
+def _num_32_bit_words_for_bit_fields(bit_fields):
+ """Gets the number of 32 bit unsigned integers needed store a list of bit fields."""
+ num_buckets, cur_bucket = 0, 0
+ for field in bit_fields:
+ if field.size + cur_bucket > 32:
+ num_buckets += 1
+ cur_bucket = 0
+ cur_bucket += field.size
+ return num_buckets + (cur_bucket > 0)
+
+
+class Group(object):
+ """Represents a group of fields stored together in a class.
+
+ Attributes:
+ name: The name of the group as a string.
+ subgroups: List of Group instances that are stored as subgroups under this group.
+ fields: List of Field instances stored directly under this group.
+ """
+ def __init__(self, name, subgroups, fields):
+ self.name = name
+ self.subgroups = subgroups
+ self.fields = fields
+ self.type_name = class_name(join_name('style', name, ' data'))
+ self.member_name = class_member_name(name)
+ self.num_32_bit_words_for_bit_fields = _num_32_bit_words_for_bit_fields(
+ field for field in fields if field.is_bit_field
+ )
+
+ # Recursively get all the fields in the subgroups as well
+ self.all_fields = _flatten_list(subgroup.all_fields for subgroup in subgroups) + fields
+
+
class Field(object):
"""
The generated ComputedStyle object is made up of a series of Fields.
@@ -102,18 +153,20 @@ class Field(object):
type_name: Name of the C++ type exposed by the generated interface (e.g. EClear, int).
field_template: Determines the interface generated for the field. Can be one of:
keyword, flag, or monotonic_flag.
+ group_member_name: The class member name representing the group.
meade_UTC10 2017/04/20 03:08:40 This is the first time you mention groups in this
shend 2017/04/20 03:22:34 Clarified the comment.
size: Number of bits needed for storage.
default_value: Default value for this field when it is first initialized.
"""
def __init__(self, field_role, name_for_methods, property_name, type_name,
- field_template, size, default_value, getter_method_name, setter_method_name,
- initial_method_name, **kwargs):
+ field_template, field_group, size, default_value,
+ getter_method_name, setter_method_name, initial_method_name, **kwargs):
"""Creates a new field."""
self.name = class_member_name(name_for_methods)
self.property_name = property_name
self.type_name = type_name
self.field_template = field_template
+ self.group_member_name = class_member_name(field_group) if field_group else None
self.size = size
self.default_value = default_value
@@ -154,6 +207,17 @@ def _get_include_paths(properties):
return list(sorted(include_paths))
+def _group_fields(fields):
+ """Groups a list of fields by their group_member_name and returns the root group."""
+ groups = defaultdict(list)
+ for field in fields:
+ groups[field.group_member_name].append(field)
+
+ no_group = groups.pop(None)
+ subgroups = [Group(group_member_name, [], _reorder_fields(fields)) for group_member_name, fields in groups.items()]
+ return Group('', subgroups=subgroups, fields=_reorder_fields(no_group))
+
+
def _create_enums(properties):
"""
Returns an OrderedDict of enums to be generated, enum name -> [list of enum values]
@@ -221,6 +285,7 @@ def _create_field(field_role, property_):
independent=property_['independent'],
type_name=type_name,
field_template=property_['field_template'],
+ field_group=property_['field_group'],
size=size,
default_value=default_value,
getter_method_name=property_['getter'],
@@ -241,6 +306,7 @@ def _create_inherited_flag_field(property_):
property_name=property_['name'],
type_name='bool',
field_template='primitive',
+ field_group=property_['field_group'],
size=1,
default_value='true',
getter_method_name=method_name(name_for_methods),
@@ -271,11 +337,14 @@ def _create_fields(properties):
return fields
-def _pack_fields(fields):
+def _reorder_fields(fields):
"""
- Group a list of fields into buckets to minimise padding.
- Returns a list of buckets, where each bucket is a list of Field objects.
+ Returns a list of fields ordered to minimise padding.
"""
+ # Separate out bit fields from normal fields
+ bit_fields = [field for field in fields if field.is_bit_field]
+ normal_fields = [field for field in fields if not field.is_bit_field]
meade_UTC10 2017/04/20 03:08:40 normal -> fields that are some type other than a b
shend 2017/04/20 03:22:34 Changed to non_bit_fields.
+
# Since fields cannot cross word boundaries, in order to minimize
# padding, group fields into buckets so that as many buckets as possible
# are exactly 32 bits. Although this greedy approach may not always
@@ -288,7 +357,7 @@ def _pack_fields(fields):
field_buckets = []
# Consider fields in descending order of size to reduce fragmentation
# when they are selected. Ties broken in alphabetical order by name.
- for field in sorted(fields, key=lambda f: (-f.size, f.name)):
+ for field in sorted(bit_fields, key=lambda f: (-f.size, f.name)):
added_to_bucket = False
# Go through each bucket and add this field if it will not increase
# the bucket's size to larger than 32 bits. Otherwise, make a new
@@ -301,7 +370,8 @@ def _pack_fields(fields):
if not added_to_bucket:
field_buckets.append([field])
- return field_buckets
+ # Normal fields go first, then the bit fields.
+ return list(normal_fields) + _flatten_list(field_buckets)
class ComputedStyleBaseWriter(make_style_builder.StyleBuilderWriter):
@@ -324,8 +394,6 @@ class ComputedStyleBaseWriter(make_style_builder.StyleBuilderWriter):
# TODO(shend): Remove this once we move EXTRA_FIELDS to its own JSON file,
# since the JSON5 reader will handle missing fields and defaults.
- # TODO(shend): Remove this once we move NONPROPERTIES to its own JSON file,
- # since the JSON5 reader will handle missing fields and defaults.
for property_ in EXTRA_FIELDS:
for parameter in self.json5_file.parameters:
if parameter not in property_:
@@ -334,7 +402,8 @@ class ComputedStyleBaseWriter(make_style_builder.StyleBuilderWriter):
for property_ in EXTRA_FIELDS:
# TODO(shend): Remove the line below once we move EXTRA_FIELDS to its
# own file which would enforce defaults.
- property_['has_custom_compare_and_copy'] = True
+ if 'has_custom_compare_and_copy' not in property_:
+ property_['has_custom_compare_and_copy'] = True
make_style_builder.apply_property_naming_defaults(property_)
all_properties = css_properties + EXTRA_FIELDS
@@ -348,40 +417,9 @@ class ComputedStyleBaseWriter(make_style_builder.StyleBuilderWriter):
all_fields = _create_fields(all_properties)
- # Separate the normal fields from the bit fields
- bit_fields = [field for field in all_fields if field.is_bit_field]
- normal_fields = [field for field in all_fields if not field.is_bit_field]
-
- # Pack bit fields into buckets
- field_buckets = _pack_fields(bit_fields)
-
- # The expected size of ComputedStyleBase is equivalent to as many words
- # as the total number of buckets.
- self._expected_bit_field_bytes = len(field_buckets)
-
- # The most optimal size of ComputedStyleBase is the total sum of all the
- # field sizes, rounded up to the nearest word. If this produces the
- # incorrect value, either the packing algorithm is not optimal or there
- # is no way to pack the fields such that excess padding space is not
- # added.
- # If this fails, increase extra_padding_bytes by 1, but be aware that
- # this also increases ComputedStyleBase by 1 word.
- # We should be able to bring extra_padding_bytes back to 0 from time to
- # time.
- extra_padding_bytes = 0
- optimal_bit_field_bytes = int(math.ceil(sum(f.size for f in bit_fields) / 32.0))
- real_bit_field_bytes = optimal_bit_field_bytes + extra_padding_bytes
- assert self._expected_bit_field_bytes == real_bit_field_bytes, \
- ('The field packing algorithm produced %s bytes, optimal is %s bytes' %
- (self._expected_bit_field_bytes, real_bit_field_bytes))
-
- # Normal fields go first, then the bit fields.
- self._fields = list(normal_fields)
-
- # Order the fields so fields in each bucket are adjacent.
- for bucket in field_buckets:
- for field in bucket:
- self._fields.append(field)
+ # Organise fields into a tree structure where the root group
+ # is ComputedStyleBase.
+ self._root_group = _group_fields(all_fields)
self._include_paths = _get_include_paths(all_properties)
self._outputs = {
@@ -396,7 +434,7 @@ class ComputedStyleBaseWriter(make_style_builder.StyleBuilderWriter):
'properties': self._properties,
'enums': self._generated_enums,
'include_paths': self._include_paths,
- 'fields': self._fields,
+ 'computed_style': self._root_group,
}
@template_expander.use_jinja('ComputedStyleBase.cpp.tmpl')
@@ -404,8 +442,7 @@ class ComputedStyleBaseWriter(make_style_builder.StyleBuilderWriter):
return {
'properties': self._properties,
'enums': self._generated_enums,
- 'fields': self._fields,
- 'expected_bit_field_bytes': self._expected_bit_field_bytes,
+ 'computed_style': self._root_group,
}
@template_expander.use_jinja('ComputedStyleBaseConstants.h.tmpl')
@@ -413,7 +450,6 @@ class ComputedStyleBaseWriter(make_style_builder.StyleBuilderWriter):
return {
'properties': self._properties,
'enums': self._generated_enums,
- 'fields': self._fields,
}
if __name__ == '__main__':

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