Add emulator metadata generator script

#!/usr/bin/python3

#

# Script for generation of VHAL properties metadata .json from AIDL interface

#

# This metadata is used to display human property names, names of enum

# data types for their values, change and access modes and other information,

# available from AIDL block comments, but not at runtime.

#

# Usage example:

#  ./emu_metadata/generate_emulator_metadata.py android/hardware/automotive/vehicle $OUT/android.hardware.automotive.vehicle-types-meta.json

#  (Note, that the resulting file has to match a '*types-meta.json' pattern to be parsed by the emulator).

#

import json

import os

import re

import sys

from pathlib import Path

RE_ENUM = re.compile(r"\s*enum\s+(\w*) {\n(.*)}", re.MULTILINE | re.DOTALL)

RE_COMMENT = re.compile(r"(?:(?:\/\*\*)((?:.|\n)*?)(?:\*\/))?(?:\n|^)\s*(\w*)(?:\s+=\s*)?((?:[a-zA-Z0-9]|\s|\+|)*),", re.DOTALL)

RE_BLOCK_COMMENT_TITLE = re.compile("^(?:\s|\*)*((?:\w|\s|\.)*)\n(?:\s|\*)*(?:\n|$)")

RE_BLOCK_COMMENT_ANNOTATION = re.compile("^(?:\s|\*)*@(\w*)\s+((?:\w|:)*)", re.MULTILINE)

RE_HEX_NUMBER = re.compile("([0-9A-Fa-fxX]+)")

class JEnum:

    def __init__(self, name):

        self.name = name

        self.values = []

class Converter:

    # Only addition is supported for now, but that covers all existing properties except

    # OBD diagnostics, which use bitwise shifts

    def calculateValue(self, expression, default_value):

        numbers = RE_HEX_NUMBER.findall(expression)

        if len(numbers) == 0:

            return default_value

        result = 0

        base = 10

        if numbers[0].lower().startswith("0x"):

            base = 16

        for number in numbers:

            result += int(number, base)

        return result

    def parseBlockComment(self, value, blockComment):

        titles = RE_BLOCK_COMMENT_TITLE.findall(blockComment)

        for title in titles:

            value['name'] = title

            break

        annots_res = RE_BLOCK_COMMENT_ANNOTATION.findall(blockComment)

        for annot in annots_res:

            value[annot[0]] = annot[1]

    def parseEnumContents(self, enum: JEnum, enumValue):

        matches = RE_COMMENT.findall(enumValue)

        defaultValue = 0

        for match in matches:

            value = dict()

            value['name'] = match[1]

            value['value'] = self.calculateValue(match[2], defaultValue)

            defaultValue = value['value'] + 1

            if enum.name == "VehicleProperty":

                block_comment = match[0]

                self.parseBlockComment(value, block_comment)

            enum.values.append(value)

    def convert(self, input):

        text = Path(input).read_text()

        matches = RE_ENUM.findall(text)

        jenums = []

        for match in matches:

            enum = JEnum(match[0])

            self.parseEnumContents(enum, match[1])

            jenums.append(enum)

        return jenums

def main():

    if (len(sys.argv) != 3):

        print("Usage: ", sys.argv[0], " INPUT_PATH OUTPUT")

        sys.exit(1)

    aidl_path = sys.argv[1]

    out_path = sys.argv[2]

    result = []

    for file in os.listdir(aidl_path):

        result.extend(Converter().convert(os.path.join(aidl_path, file)))

    json_result = json.dumps(result, default=vars, indent=2)

    with open(out_path, 'w') as f:

        f.write(json_result)

if __name__ == "__main__":

    main()