googletest/scripts/generate_gtest_def.py

#!/usr/bin/env python
#
# Copyright 2009 Google Inc. All Rights Reserved.
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# modification, are permitted provided that the following conditions are
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#     * Redistributions of source code must retain the above copyright
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"""Generates the gtest.def file to build Google Test as a DLL on Windows.

SYNOPSIS
       Put diagnostic messages from building gtest_dll_test_.exe into
       BUILD_RESULTS_FILE and invoke

         generate_gtest_def.py <BUILD_RESULTS_FILE

       Reads output of VC++ linker and re-generates the src/gtest.def file
       required for building gtest as a DLL.

       Use this script if you modify Google Test's source code and Visual
       Studio linker starts complaining about unresolved external symbols.
       You may have to repeate the build/re-generate cycle several times
       because VC++ limits the number of unresolved external symbols it can
       report at a time.

EXAMPLES
         scons\scons.py | scripts\generate_gtest_def.py

This tool is experimental.  Please report any problems to
googletestframework@googlegroups.com.  You can read
http://code.google.com/p/googletest/wiki/GoogleTestAdvancedGuide for more
information.
"""

__author__ = 'vladl@google.com (Vlad Losev)'

import os
import re
import sets
import sys

# We assume that this file is in the scripts/ directory in the Google
# Test root directory.
GTEST_DEF_PATH = os.path.join(os.path.dirname(__file__), '../src/gtest.def')

# Locates the header of the EXPORTS section.
EXPORTS_SECTION_REGEX = re.compile(r'^EXPORTS\s*$', re.IGNORECASE)

# Determines if a line looks like an export definition in the EXPORTS
# section of a module definition file.
EXPORT_REGEX = re.compile(r'^\s+(\S+)')

# Determines if a given line contains an error message about unresolved
# linker symbol.
IS_UNRESOLVED_SYMBOL_REGEX = re.compile(r'\bunresolved external symbol\b')

# Fetches the symbol name from a line that contains an unresolved linker
# symbol message.
UNRESOLVED_SYMBOL_REGEX = re.compile(r'^.*?"[^"]+" \((\S+)\)')


def ReadDefExports(stream):
  """Reads contents of a def file and returns a list of exported symbols."""

  is_export = False
  exports = sets.Set()
  for line in stream:
    if EXPORTS_SECTION_REGEX.match(line):
      is_export = True
    elif EXPORT_REGEX.match(line):
      if is_export:
        exports.add(EXPORT_REGEX.match(line).group(1))
    else:
      is_export = False

  return exports


def ReadUnresolvedExternals(stream):
  """Reads linker output and returns list of unresolved linker symbols."""

  unresolved = sets.Set()

  for line in stream:
    if IS_UNRESOLVED_SYMBOL_REGEX.search(line):
      unresolved.add(UNRESOLVED_SYMBOL_REGEX.match(line).group(1))

  return unresolved


def AdjustExports(exports, unresolved):
  """Adjusts exports list based on the list of unresolved symbols."""

  if unresolved & exports:
    # There are symbols that are listed as exported but are also reported
    # unresolved. This is most likely because they have been removed from
    # Google Test but their mentions in gtest.def constitute references. We
    # need to remove such symbols from the EXPORTS section. Also, their
    # presence means that the Google Test DLL has failed to link and
    # consequently linking of the test .exe was not attempted, meaning that
    # at this time, there will be no unresolved externals that need to be
    # added to the exports list.
    exports -= unresolved
  else:
    # Finding unresolved exports means that the Google Test DLL had link
    # errors and the build script did not build gtest_dll_test_.exe. The user
    # has to build the test once again and run this script on the diagnostic
    # output of the build.
    exports |= unresolved

  return exports


def WriteGtestDefFile(stream, exports):
  """Writes contents of gtest.def given a list of exported symbols."""

  stream.write('; This file is auto-generated. DO NOT EDIT DIRECTLY.\n'
               '; For more information, see scripts/generate_gtest_def.py.\n'
               '\nLIBRARY\n'
               '\nEXPORTS\n')
  for symbol in sorted(exports):
    stream.write('  %s\n' % symbol)


def main():
  unresolved = ReadUnresolvedExternals(sys.stdin)
  if unresolved:
    try:
      gtest_def = open(GTEST_DEF_PATH, 'r')
      exports = ReadDefExports(gtest_def)
      gtest_def.close()
    except IOError:
      exports = sets.Set()

    exports = AdjustExports(exports, unresolved)
    WriteGtestDefFile(open(GTEST_DEF_PATH, 'w'), exports)
    sys.stderr.write('Updated test/gtest.def. Please clean the .dll file\n'
                     'produced by your Google Test DLL build, run the build\n'
                     'again and pass its diagnostic output to this script\n'
                     'unless the build succeeds.\n')
  else:
    sys.stderr.write('The build diagnostic output indicates no unresolved\n'
                     'externals.  test/gtest.def is likely up to date and\n'
                     'has not been updated.\n')

if __name__ == '__main__':
  main()