src/python/grpcio/_unixccompiler_patch.py

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"""Covers inadequacies in distutils."""

from distutils import ccompiler
from distutils import errors
from distutils import unixccompiler
import os
import os.path
import shutil
import sys
import tempfile


def _unix_piecemeal_link(
    self, target_desc, objects, output_filename, output_dir=None,
    libraries=None, library_dirs=None, runtime_library_dirs=None,
    export_symbols=None, debug=0, extra_preargs=None, extra_postargs=None,
    build_temp=None, target_lang=None):
  """`link` externalized method taken almost verbatim from UnixCCompiler.

  Modifies the link command for unix-like compilers by using a command file so
  that long command line argument strings don't break the command shell's
  ARG_MAX character limit.
  """
  objects, output_dir = self._fix_object_args(objects, output_dir)
  libraries, library_dirs, runtime_library_dirs = self._fix_lib_args(
      libraries, library_dirs, runtime_library_dirs)
  # filter out standard library paths, which are not explicitely needed
  # for linking
  library_dirs = [dir for dir in library_dirs
                  if not dir in ('/lib', '/lib64', '/usr/lib', '/usr/lib64')]
  runtime_library_dirs = [dir for dir in runtime_library_dirs
                          if not dir in ('/lib', '/lib64', '/usr/lib', '/usr/lib64')]
  lib_opts = ccompiler.gen_lib_options(self, library_dirs, runtime_library_dirs,
                             libraries)
  if (not (isinstance(output_dir, str) or isinstance(output_dir, bytes))
      and output_dir is not None):
    raise TypeError("'output_dir' must be a string or None")
  if output_dir is not None:
    output_filename = os.path.join(output_dir, output_filename)

  if self._need_link(objects, output_filename):
    ld_args = (objects + self.objects +
               lib_opts + ['-o', output_filename])
    if debug:
      ld_args[:0] = ['-g']
    if extra_preargs:
      ld_args[:0] = extra_preargs
    if extra_postargs:
      ld_args.extend(extra_postargs)
    self.mkpath(os.path.dirname(output_filename))
    try:
      if target_desc == ccompiler.CCompiler.EXECUTABLE:
        linker = self.linker_exe[:]
      else:
        linker = self.linker_so[:]
      if target_lang == "c++" and self.compiler_cxx:
        # skip over environment variable settings if /usr/bin/env
        # is used to set up the linker's environment.
        # This is needed on OSX. Note: this assumes that the
        # normal and C++ compiler have the same environment
        # settings.
        i = 0
        if os.path.basename(linker[0]) == "env":
          i = 1
          while '=' in linker[i]:
            i = i + 1

        linker[i] = self.compiler_cxx[i]

      if sys.platform == 'darwin':
        import _osx_support
        linker = _osx_support.compiler_fixup(linker, ld_args)

      temporary_directory = tempfile.mkdtemp()
      command_filename = os.path.abspath(
          os.path.join(temporary_directory, 'command'))
      with open(command_filename, 'w') as command_file:
        escaped_ld_args = [arg.replace('\\', '\\\\') for arg in ld_args]
        command_file.write(' '.join(escaped_ld_args))
      self.spawn(linker + ['@{}'.format(command_filename)])
    except errors.DistutilsExecError:
      raise ccompiler.LinkError
  else:
    log.debug("skipping %s (up-to-date)", output_filename)

# TODO(atash) try replacing this monkeypatch of the compiler harness' link
# operation with a monkeypatch of the distutils `spawn` that applies
# command-argument-file hacks where it can. Might be cleaner.
def monkeypatch_unix_compiler():
  """Monkeypatching is dumb, but it's either that or we become maintainers of
     something much, much bigger."""
  unixccompiler.UnixCCompiler.link = _unix_piecemeal_link