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depot_tools/metadata/parse.py

138 lines
5.3 KiB
Python

#!/usr/bin/env python3
# Copyright 2023 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 os
import re
import sys
from typing import List
_THIS_DIR = os.path.abspath(os.path.dirname(__file__))
# The repo's root directory.
_ROOT_DIR = os.path.abspath(os.path.join(_THIS_DIR, ".."))
# Add the repo's root directory for clearer imports.
sys.path.insert(0, _ROOT_DIR)
import metadata.fields.known as known_fields
import metadata.dependency_metadata as dm
import metadata.fields.custom.mitigated
# Line used to separate dependencies within the same metadata file.
DEPENDENCY_DIVIDER = re.compile(r"^-{20} DEPENDENCY DIVIDER -{20}$")
# Delimiter used to separate a field's name from its value.
FIELD_DELIMITER = ":"
# Heuristic for detecting unknown field names.
_PATTERN_FIELD_NAME_WORD_HEURISTIC = r"[A-Z]\w+"
_PATTERN_FIELD_NAME_HEURISTIC = re.compile(r"^({}(?: {})*){}[\b\s]".format(
_PATTERN_FIELD_NAME_WORD_HEURISTIC, _PATTERN_FIELD_NAME_WORD_HEURISTIC,
FIELD_DELIMITER))
_DEFAULT_TO_STRUCTURED_TEXT = False
# Pattern used to check if a line from a metadata file declares a new
# field. This includes all valid vulnerability IDs.
_PATTERN_KNOWN_FIELD_DECLARATION = re.compile(
"^({}){}".format(
"|".join(
list(known_fields.ALL_FIELD_NAMES) +
[metadata.fields.custom.mitigated.PATTERN_VULN_ID.pattern]),
FIELD_DELIMITER), re.IGNORECASE)
def parse_content(content: str) -> List[dm.DependencyMetadata]:
"""Reads and parses the metadata from the given string.
Args:
content: the string to parse metadata from.
Returns: all the metadata, which may be for zero or more
dependencies, from the given string.
"""
dependencies = []
current_metadata = dm.DependencyMetadata()
current_field_spec = None
current_field_name = None
current_field_value = ""
for line_number, line in enumerate(content.splitlines(keepends=True), 1):
# Whether the current line should be part of a structured value.
if current_field_spec:
expect_structured_field_value = current_field_spec.is_structured()
else:
expect_structured_field_value = _DEFAULT_TO_STRUCTURED_TEXT
# Check if a new dependency is being described.
if DEPENDENCY_DIVIDER.match(line):
if current_field_name:
# Save the field value for the previous dependency.
current_metadata.add_entry(current_field_name,
current_field_value)
if current_metadata.has_entries():
# Add the previous dependency to the results.
dependencies.append(current_metadata)
# Reset for the new dependency's metadata,
# and reset the field state.
current_metadata = dm.DependencyMetadata()
current_field_spec = None
current_field_name = None
current_field_value = ""
elif _PATTERN_KNOWN_FIELD_DECLARATION.match(line) or (
expect_structured_field_value
and _PATTERN_FIELD_NAME_HEURISTIC.match(line)):
# Save the field value to the current dependency's metadata.
if current_field_name:
current_metadata.add_entry(current_field_name,
current_field_value)
current_field_name, current_field_value = line.split(
FIELD_DELIMITER, 1)
current_field_spec = known_fields.get_field(current_field_name)
current_metadata.record_line(line_number)
if current_field_spec:
current_metadata.record_field_line_number(
current_field_spec, line_number)
elif current_field_name:
if line.strip():
current_metadata.record_line(line_number)
if current_field_spec:
current_metadata.record_field_line_number(
current_field_spec, line_number)
# The field is on multiple lines, so add this line to the
# field value.
current_field_value += line
else:
# Text that aren't part of any field (e.g. free form text).
# Record the line number if the line is non-empty.
if line.strip():
current_metadata.record_line(line_number)
# Check if current field value indicates end of the field.
if current_field_spec and current_field_spec.should_terminate_field(
current_field_value):
assert current_field_name
current_metadata.record_line(line_number)
if current_field_spec:
current_metadata.record_field_line_number(
current_field_spec, line_number)
current_metadata.add_entry(current_field_name, current_field_value)
current_field_spec = None
current_field_name = None
current_field_value = ""
# At this point, the end of the file has been reached.
# Save any remaining field data and metadata.
if current_field_name:
current_metadata.add_entry(current_field_name, current_field_value)
if current_metadata.has_entries():
dependencies.append(current_metadata)
return dependencies