# -*- coding: utf-8 -*-
# Copyright 2018 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""check whether intended components exists in the given dso."""


import os
import subprocess

from allowlist import is_allowlisted


def check_debug_info(dso_path, readelf_content):
    """Check whether debug info section exists in the elf file.

    Args:
      dso_path: path to the dso.
      readelf_content: debug info dumped by command readelf.

    Returns:
      True if debug info section exists, otherwise False.
    """

    # Return True if it is allowlisted
    if is_allowlisted("exist_debug_info", dso_path):
        return True

    for l in readelf_content:
        if "debug_info" in l:
            return True
    return False


def check_producer(dso_path, readelf_content):
    """Check whether DW_AT_producer exists in each compile unit.

    Args:
      dso_path: path to the dso.
      readelf_content: debug info dumped by command readelf.

    Returns:
      True if DW_AT_producer exists in each compile unit, otherwise False.
      Notice: If no compile unit in DSO, also return True.
    """

    # Return True if it is allowlisted
    if is_allowlisted("exist_producer", dso_path):
        return True

    # Indicate if there is a producer under each cu
    cur_producer = False

    first_cu = True
    producer_exist = True

    for l in readelf_content:
        if "DW_TAG_compile_unit" in l:
            if not first_cu and not cur_producer:
                producer_exist = False
                break
            first_cu = False
            cur_producer = False
        elif "DW_AT_producer" in l:
            cur_producer = True

    # Check whether last producer of compile unit exists in the elf,
    # also return True if no cu in the DSO.
    if not first_cu and not cur_producer:
        producer_exist = False

    return producer_exist


def check_exist_all(dso_path):
    """check whether intended components exists in the given dso.

    Args:
      dso_path: path to the dso.

    Returns:
      True if everything looks fine otherwise False.
    """

    readelf = subprocess.Popen(
        ["llvm-dwarfdump", "--recurse-depth=0", dso_path],
        stdout=subprocess.PIPE,
        stderr=open(os.devnull, "w"),
        encoding="utf-8",
    )
    readelf_content = list(readelf.stdout)

    exist_checks = [check_debug_info, check_producer]

    for e in exist_checks:
        if not e(dso_path, readelf_content):
            check_failed = e.__module__ + ": " + e.__name__
            print("%s failed check: %s" % (dso_path, check_failed))
            return False

    return True