# Copyright 2021 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import re
_NON_SEMANTIC_CSS_COLOR_PATTERNS = [
"var(--google-",
"var(--paper-",
": #",
"rgb",
"hsl",
]
class SemanticCssChecker(object):
"""Checks that only semantic CSS colors are used.
Checks that only values defined in ui/chromeos/styles/cros_colors.json5
are used. A motivation for this is to support Dark Mode, as each color
has a separate light and dark mode value that is substituted at runtime
whenever the device changes from light to dark mode or vice versa. This
check doesn't cover all scenarios as it is difficult to cover everything
without creating false positives.
"""
@staticmethod
def RunChecks(input_api, output_api):
"""Runs check for any non-semantic CSS colors used.
Checks if the affected lines of code in input_api use non-semantic CSS
colors, and if so, returns a list containing the warnings that should
be displayed for each violation.
Args:
input_api: presubmit.InputApi containing information of the files
in the change.
output_api: presubmit.OutputApi used to display the warnings.
Returns:
A list of presubmit warnings, each containing the line the violation
occurred and the warning message.
"""
results = []
for f in input_api.AffectedFiles():
exts = ['html', 'css']
if not any(f.LocalPath().endswith(ext) for ext in exts):
continue
for line_num, line in f.ChangedContents():
for pattern in _NON_SEMANTIC_CSS_COLOR_PATTERNS:
if pattern in line:
results.append(output_api.PresubmitPromptWarning(
"%s:%d:\n\n %s\n\n"
"Use of non-semantic color in CSS. Please make sure that all "
"colors in\nCSS use semantic values defined in "
"ui/chromeos/styles/cros_colors.json5\ninstead of constant "
"color values." %
(f.LocalPath(), line_num, line.strip())))
break
return results
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