#/usr/bin/python

"""A script to prepare version informtion for use the gtest Info.plist file.

  This script extracts the version information from the configure.ac file and
  uses it to generate a header file containing the same information. The
  #defines in this header file will be included in during the generation of
  the Info.plist of the framework, giving the correct value to the version
  shown in the Finder.

  This script makes the following assumptions (these are faults of the script,
  not problems with the Autoconf):
    1. The AC_INIT macro will be contained within the first 1024 characters
       of configure.ac
    2. The version string will be 3 integers separated by periods and will be
       surrounded by squre brackets, "[" and "]" (e.g. [1.0.1]). The first 
       segment represents the major version, the second represents the minor
       version and the third represents the fix version.
    3. No ")" character exists between the opening "(" and closing ")" of
       AC_INIT, including in comments and character strings.
"""

import sys
import re

# Read the command line argument (the output directory for Version.h)
if (len(sys.argv) < 3):
  print "Usage: /usr/bin/python versiongenerate.py input_dir output_dir"
  sys.exit(1)
else:
  input_dir = sys.argv[1]
  output_dir = sys.argv[2]

# Read the first 1024 characters of the configure.ac file
config_file = open("%s/configure.ac" % input_dir, 'r')
buffer_size = 1024
opening_string = config_file.read(buffer_size)
config_file.close()

# Extract the version string from the AC_INIT macro
#   The following init_expression means:
#     Extract three integers separated by periods and surrounded by squre
#     brackets(e.g. "[1.0.1]") between "AC_INIT(" and ")". Do not be greedy
#     (*? is the non-greedy flag) since that would pull in everything between
#     the first "(" and the last ")" in the file.
version_expression = re.compile(r"AC_INIT\(.*?\[(\d+)\.(\d+)\.(\d+)\].*?\)",
                                re.DOTALL)
version_values = version_expression.search(opening_string)
major_version = version_values.group(1)
minor_version = version_values.group(2)
fix_version = version_values.group(3)

# Write the version information to a header file to be included in the
# Info.plist file.
file_data = """//
// DO NOT MODIFY THIS FILE (but you can delete it)
//
// This file is autogenerated by the versiongenerate.py script. This script
// is executed in a "Run Script" build phase when creating gtest.framework. This
// header file is not used during compilation of C-source. Rather, it simply
// defines some version strings for substitution in the Info.plist. Because of
// this, we are not not restricted to C-syntax nor are we using include guards.
//

#define GTEST_VERSIONINFO_SHORT %s.%s
#define GTEST_VERSIONINFO_LONG %s.%s.%s

""" % (major_version, minor_version, major_version, minor_version, fix_version)
version_file = open("%s/Version.h" % output_dir, 'w')
version_file.write(file_data)
version_file.close()