#!/usr/bin/env python
#
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"""fuse_gtest_files.py v0.2.0
Fuses Google Test source code into a .h file and a .cc file.

SYNOPSIS
       fuse_gtest_files.py [GTEST_ROOT_DIR] OUTPUT_DIR

       Scans GTEST_ROOT_DIR for Google Test source code, and generates
       two files: OUTPUT_DIR/gtest/gtest.h and OUTPUT_DIR/gtest/gtest-all.cc.
       Then you can build your tests by adding OUTPUT_DIR to the include
       search path and linking with OUTPUT_DIR/gtest/gtest-all.cc.  These
       two files contain everything you need to use Google Test.  Hence
       you can "install" Google Test by copying them to wherever you want.

       GTEST_ROOT_DIR can be omitted and defaults to the parent
       directory of the directory holding this script.

EXAMPLES
       ./fuse_gtest_files.py fused_gtest
       ./fuse_gtest_files.py path/to/unpacked/gtest fused_gtest

This tool is experimental.  In particular, it assumes that there is no
conditional inclusion of Google Test headers.  Please report any
problems to googletestframework@googlegroups.com.  You can read
http://code.google.com/p/googletest/wiki/GoogleTestAdvancedGuide for
more information.
"""

__author__ = 'wan@google.com (Zhanyong Wan)'

import os
import re
import sets
import sys

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

# Regex for matching '#include <gtest/...>'.
INCLUDE_GTEST_FILE_REGEX = re.compile(r'^\s*#\s*include\s*<(gtest/.+)>')

# Regex for matching '#include "src/..."'.
INCLUDE_SRC_FILE_REGEX = re.compile(r'^\s*#\s*include\s*"(src/.+)"')

# Where to find the source seed files.
GTEST_H_SEED = 'include/gtest/gtest.h'
GTEST_SPI_H_SEED = 'include/gtest/gtest-spi.h'
GTEST_ALL_CC_SEED = 'src/gtest-all.cc'

# Where to put the generated files.
GTEST_H_OUTPUT = 'gtest/gtest.h'
GTEST_ALL_CC_OUTPUT = 'gtest/gtest-all.cc'


def VerifyFileExists(directory, relative_path):
  """Verifies that the given file exists; aborts on failure.

  relative_path is the file path relative to the given directory.
  """

  if not os.path.isfile(os.path.join(directory, relative_path)):
    print 'ERROR: Cannot find %s in directory %s.' % (relative_path,
                                                      directory)
    print ('Please either specify a valid project root directory '
           'or omit it on the command line.')
    sys.exit(1)


def ValidateGTestRootDir(gtest_root):
  """Makes sure gtest_root points to a valid gtest root directory.

  The function aborts the program on failure.
  """

  VerifyFileExists(gtest_root, GTEST_H_SEED)
  VerifyFileExists(gtest_root, GTEST_ALL_CC_SEED)


def VerifyOutputFile(output_dir, relative_path):
  """Verifies that the given output file path is valid.

  relative_path is relative to the output_dir directory.
  """

  # Makes sure the output file either doesn't exist or can be overwritten.
  output_file = os.path.join(output_dir, relative_path)
  if os.path.exists(output_file):
    # TODO(wan@google.com): The following user-interaction doesn't
    # work with automated processes.  We should provide a way for the
    # Makefile to force overwriting the files.
    print ('%s already exists in directory %s - overwrite it? (y/N) ' %
           (relative_path, output_dir))
    answer = sys.stdin.readline().strip()
    if answer not in ['y', 'Y']:
      print 'ABORTED.'
      sys.exit(1)

  # Makes sure the directory holding the output file exists; creates
  # it and all its ancestors if necessary.
  parent_directory = os.path.dirname(output_file)
  if not os.path.isdir(parent_directory):
    os.makedirs(parent_directory)


def ValidateOutputDir(output_dir):
  """Makes sure output_dir points to a valid output directory.

  The function aborts the program on failure.
  """

  VerifyOutputFile(output_dir, GTEST_H_OUTPUT)
  VerifyOutputFile(output_dir, GTEST_ALL_CC_OUTPUT)


def FuseGTestH(gtest_root, output_dir):
  """Scans folder gtest_root to generate gtest/gtest.h in output_dir."""

  output_file = file(os.path.join(output_dir, GTEST_H_OUTPUT), 'w')
  processed_files = sets.Set()  # Holds all gtest headers we've processed.

  def ProcessFile(gtest_header_path):
    """Processes the given gtest header file."""

    # We don't process the same header twice.
    if gtest_header_path in processed_files:
      return

    processed_files.add(gtest_header_path)

    # Reads each line in the given gtest header.
    for line in file(os.path.join(gtest_root, gtest_header_path), 'r'):
      m = INCLUDE_GTEST_FILE_REGEX.match(line)
      if m:
        # It's '#include <gtest/...>' - let's process it recursively.
        ProcessFile('include/' + m.group(1))
      else:
        # Otherwise we copy the line unchanged to the output file.
        output_file.write(line)

  ProcessFile(GTEST_H_SEED)
  output_file.close()


def FuseGTestAllCcToFile(gtest_root, output_file):
  """Scans folder gtest_root to generate gtest/gtest-all.cc in output_file."""

  processed_files = sets.Set()

  def ProcessFile(gtest_source_file):
    """Processes the given gtest source file."""

    # We don't process the same #included file twice.
    if gtest_source_file in processed_files:
      return

    processed_files.add(gtest_source_file)

    # Reads each line in the given gtest source file.
    for line in file(os.path.join(gtest_root, gtest_source_file), 'r'):
      m = INCLUDE_GTEST_FILE_REGEX.match(line)
      if m:
        if 'include/' + m.group(1) == GTEST_SPI_H_SEED:
          # It's '#include <gtest/gtest-spi.h>'.  This file is not
          # #included by <gtest/gtest.h>, so we need to process it.
          ProcessFile(GTEST_SPI_H_SEED)
        else:
          # It's '#include <gtest/foo.h>' where foo is not gtest-spi.
          # We treat it as '#include <gtest/gtest.h>', as all other
          # gtest headers are being fused into gtest.h and cannot be
          # #included directly.

          # There is no need to #include <gtest/gtest.h> more than once.
          if not GTEST_H_SEED in processed_files:
            processed_files.add(GTEST_H_SEED)
            output_file.write('#include <%s>\n' % (GTEST_H_OUTPUT,))
      else:
        m = INCLUDE_SRC_FILE_REGEX.match(line)
        if m:
          # It's '#include "src/foo"' - let's process it recursively.
          ProcessFile(m.group(1))
        else:
          output_file.write(line)

  ProcessFile(GTEST_ALL_CC_SEED)


def FuseGTestAllCc(gtest_root, output_dir):
  """Scans folder gtest_root to generate gtest/gtest-all.cc in output_dir."""

  output_file = file(os.path.join(output_dir, GTEST_ALL_CC_OUTPUT), 'w')
  FuseGTestAllCcToFile(gtest_root, output_file)
  output_file.close()


def FuseGTest(gtest_root, output_dir):
  """Fuses gtest.h and gtest-all.cc."""

  ValidateGTestRootDir(gtest_root)
  ValidateOutputDir(output_dir)

  FuseGTestH(gtest_root, output_dir)
  FuseGTestAllCc(gtest_root, output_dir)


def main():
  argc = len(sys.argv)
  if argc == 2:
    # fuse_gtest_files.py OUTPUT_DIR
    FuseGTest(DEFAULT_GTEST_ROOT_DIR, sys.argv[1])
  elif argc == 3:
    # fuse_gtest_files.py GTEST_ROOT_DIR OUTPUT_DIR
    FuseGTest(sys.argv[1], sys.argv[2])
  else:
    print __doc__
    sys.exit(1)


if __name__ == '__main__':
  main()
