#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2020 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Prototype compiler wrapper.

Only tested with: gcc, g++, clang, clang++
Installation instructions:
  1. Rename compiler from <compiler_name> to <compiler_name>.real
  2. Create symlink from this script (compiler_wrapper.py), and name it
     <compiler_name>. compiler_wrapper.py can live anywhere as long as it is
     executable.

Reference page:
https://sites.google.com/a/google.com/chromeos-toolchain-team-home2/home/team-tools-and-scripts/bisecting-chromeos-compiler-problems/bisection-compiler-wrapper

Design doc:
https://docs.google.com/document/d/1yDgaUIa2O5w6dc3sSTe1ry-1ehKajTGJGQCbyn0fcEM
"""


import os
import shlex
import sys

from binary_search_tool import bisect_driver


WRAPPED = "%s.real" % sys.argv[0]
BISECT_STAGE = os.environ.get("BISECT_STAGE")
DEFAULT_BISECT_DIR = os.path.expanduser("~/ANDROID_BISECT")
BISECT_DIR = os.environ.get("BISECT_DIR") or DEFAULT_BISECT_DIR


def ProcessArgFile(arg_file):
    args = []
    # Read in entire file at once and parse as if in shell
    with open(arg_file, "r", encoding="utf-8") as f:
        args.extend(shlex.split(f.read()))

    return args


def Main(_):
    if not os.path.islink(sys.argv[0]):
        print("Compiler wrapper can't be called directly!")
        return 1

    execargs = [WRAPPED] + sys.argv[1:]

    if BISECT_STAGE not in bisect_driver.VALID_MODES or "-o" not in execargs:
        os.execv(WRAPPED, [WRAPPED] + sys.argv[1:])

    # Handle @file argument syntax with compiler
    for idx, _ in enumerate(execargs):
        # @file can be nested in other @file arguments, use While to re-evaluate
        # the first argument of the embedded file.
        while execargs[idx][0] == "@":
            args_in_file = ProcessArgFile(execargs[idx][1:])
            execargs = execargs[0:idx] + args_in_file + execargs[idx + 1 :]

    bisect_driver.bisect_driver(BISECT_STAGE, BISECT_DIR, execargs)


if __name__ == "__main__":
    sys.exit(Main(sys.argv[1:]))