#!/usr/bin/env python
#
# Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
# for details. All rights reserved. Use of this source code is governed by a
# BSD-style license that can be found in the LICENSE file.

# Script to convert snapshot files to a C++ file which can be compiled and
# linked together with VM binary.

import getopt
import optparse
import string
import subprocess
import sys
import utils


HOST_OS = utils.GuessOS()
HOST_CPUS = utils.GuessCpus()


def BuildOptions():
  result = optparse.OptionParser()
  result.add_option("--vm_input_bin",
      action="store", type="string",
      help="input file name of the vm isolate snapshot in binary form")
  result.add_option("--input_bin",
      action="store", type="string",
      help="input file name of the isolate snapshot in binary form")
  result.add_option("--input_cc",
      action="store", type="string",
      help="input file name which contains the C buffer template")
  result.add_option("--output",
      action="store", type="string",
      help="output file name into which snapshot in C buffer form is generated")
  result.add_option("-v", "--verbose",
      help='Verbose output.',
      default=False, action="store_true")
  return result


def ProcessOptions(options):
  if not options.vm_input_bin:
    sys.stderr.write('--vm_input_bin not specified\n')
    return False
  if not options.input_bin:
    sys.stderr.write('--input_bin not specified\n')
    return False
  if not options.input_cc:
    sys.stderr.write('--input_cc not specified\n')
    return False
  if not options.output:
    sys.stderr.write('--output not specified\n')
    return False
  return True


def WriteBytesAsText(out, input_file):
  """Writes byte contents of the input_file into out file as text.

  Output is formatted as a list of comma separated integer values - one value
  for each byte.
  """
  with open(input_file, 'rb') as input:
    lineCounter = 0
    line = ' '
    for byte in input.read():
      line += ' %d,' % ord(byte)
      lineCounter += 1
      if lineCounter == 10:
        out.write(line + '\n')
        line = ' '
        lineCounter = 0
    if lineCounter != 0:
      out.write(line + '\n')


def GenerateFileFromTemplate(output_file, input_cc_file,
             vm_isolate_input_file, isolate_input_file):
  """Generates C++ file based on a input_cc_file template and two binary files

  Template is expected to have two %s placehoders which would be filled
  with binary contents of the given files each formatted as a comma separated
  list of integers.
  """
  snapshot_cc_text = open(input_cc_file).read()
  chunks = snapshot_cc_text.split("%s")
  if len(chunks) != 3:
    raise Exception("Template %s should contain exactly two %%s occurrences"
        % input_cc_file)

  with open(output_file, 'w') as out:
    out.write(chunks[0])
    WriteBytesAsText(out, vm_isolate_input_file)
    out.write(chunks[1])
    WriteBytesAsText(out, isolate_input_file)
    out.write(chunks[2])


def Main():
  # Parse options.
  parser = BuildOptions()
  (options, args) = parser.parse_args()
  if not ProcessOptions(options):
    parser.print_help()
    return 1

  # If there are additional arguments, report error and exit.
  if args:
    parser.print_help()
    return 1

  GenerateFileFromTemplate(options.output, options.input_cc,
                           options.vm_input_bin, options.input_bin)

  return 0

if __name__ == '__main__':
  sys.exit(Main())