#!/usr/bin/env python2
"""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
"""

from __future__ import print_function

import os
import shlex
import sys

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, 'rb') 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:]))