text: """
  Support for installing and building the "wheel" binary package format.
  """
  from __future__ import absolute_import
  
  import compileall
  import csv
  import errno
  import functools
  import hashlib
  import logging
  import os
  import os.path
  import re
  import shutil
  import stat
  import sys
  import tempfile
  import warnings
  
  from base64 import urlsafe_b64encode
  from email.parser import Parser
  
  from pip._vendor.six import StringIO
  
  import pip
  from pip.download import path_to_url, unpack_url
  from pip.exceptions import InvalidWheelFilename, UnsupportedWheel
  from pip.locations import distutils_scheme, PIP_DELETE_MARKER_FILENAME
  from pip import pep425tags
  from pip.utils import (
      call_subprocess, ensure_dir, make_path_relative, captured_stdout,
      rmtree)
  from pip.utils.logging import indent_log
  from pip._vendor.distlib.scripts import ScriptMaker
  from pip._vendor import pkg_resources
  from pip._vendor.six.moves import configparser
  
  
  wheel_ext = '.whl'
  
  VERSION_COMPATIBLE = (1, 0)
  
  
  logger = logging.getLogger(__name__)
  
  
  class WheelCache(object):
      """A cache of wheels for future installs."""
  
      def __init__(self, cache_dir, format_control):
          """Create a wheel cache.
  
          :param cache_dir: The root of the cache.
          :param format_control: A pip.index.FormatControl object to limit
              binaries being read from the cache.
          """
          self._cache_dir = os.path.expanduser(cache_dir) if cache_dir else None
          self._format_control = format_control
  
      def cached_wheel(self, link, package_name):
          return cached_wheel(
              self._cache_dir, link, self._format_control, package_name)
  
  
  def _cache_for_link(cache_dir, link):
      """
      Return a directory to store cached wheels in for link.
  
      Because there are M wheels for any one sdist, we provide a directory
      to cache them in, and then consult that directory when looking up
      cache hits.
  
      We only insert things into the cache if they have plausible version
      numbers, so that we don't contaminate the cache with things that were not
      unique. E.g. ./package might have dozens of installs done for it and build
      a version of 0.0...and if we built and cached a wheel, we'd end up using
      the same wheel even if the source has been edited.
  
      :param cache_dir: The cache_dir being used by pip.
      :param link: The link of the sdist for which this will cache wheels.
      """
  
      # We want to generate an url to use as our cache key, we don't want to just
      # re-use the URL because it might have other items in the fragment and we
      # don't care about those.
      key_parts = [link.url_without_fragment]
      if link.hash_name is not None and link.hash is not None:
          key_parts.append("=".join([link.hash_name, link.hash]))
      key_url = "#".join(key_parts)
  
      # Encode our key url with sha224, we'll use this because it has similar
      # security properties to sha256, but with a shorter total output (and thus
      # less secure). However the differences don't make a lot of difference for
      # our use case here.
      hashed = hashlib.sha224(key_url.encode()).hexdigest()
  
      # We want to nest the directories some to prevent having a ton of top level
      # directories where we might run out of sub directories on some FS.
      parts = [hashed[:2], hashed[2:4], hashed[4:6], hashed[6:]]
  
      # Inside of the base location for cached wheels, expand our parts and join
      # them all together.
      return os.path.join(cache_dir, "wheels", *parts)
  
  
  def cached_wheel(cache_dir, link, format_control, package_name):
      if not cache_dir:
          return link
      if not link:
          return link
      if link.is_wheel:
          return link
      if not link.is_artifact:
          return link
      if not package_name:
          return link
      canonical_name = pkg_resources.safe_name(package_name).lower()
      formats = pip.index.fmt_ctl_formats(format_control, canonical_name)
      if "binary" not in formats:
          return link
      root = _cache_for_link(cache_dir, link)
      try:
          wheel_names = os.listdir(root)
      except OSError as e:
          if e.errno in (errno.ENOENT, errno.ENOTDIR):
              return link
          raise
      candidates = []
      for wheel_name in wheel_names:
          try:
              wheel = Wheel(wheel_name)
          except InvalidWheelFilename:
              continue
          if not wheel.supported():
              # Built for a different python/arch/etc
              continue
          candidates.append((wheel.support_index_min(), wheel_name))
      if not candidates:
          return link
      candidates.sort()
      path = os.path.join(root, candidates[0][1])
      return pip.index.Link(path_to_url(path), trusted=True)
  
  
  def rehash(path, algo='sha256', blocksize=1 << 20):
      """Return (hash, length) for path using hashlib.new(algo)"""
      h = hashlib.new(algo)
      length = 0
      with open(path, 'rb') as f:
          block = f.read(blocksize)
          while block:
              length += len(block)
              h.update(block)
              block = f.read(blocksize)
      digest = 'sha256=' + urlsafe_b64encode(
          h.digest()
      ).decode('latin1').rstrip('=')
      return (digest, length)
  
  
  def open_for_csv(name, mode):
      if sys.version_info[0] < 3:
          nl = {}
          bin = 'b'
      else:
          nl = {'newline': ''}
          bin = ''
      return open(name, mode + bin, **nl)
  
  
  def fix_script(path):
      """Replace #!python with #!/path/to/python
      Return True if file was changed."""
      # XXX RECORD hashes will need to be updated
      if os.path.isfile(path):
          with open(path, 'rb') as script:
              firstline = script.readline()
              if not firstline.startswith(b'#!python'):
                  return False
              exename = sys.executable.encode(sys.getfilesystemencoding())
              firstline = b'#!' + exename + os.linesep.encode("ascii")
              rest = script.read()
          with open(path, 'wb') as script:
              script.write(firstline)
              script.write(rest)
          return True
  
  dist_info_re = re.compile(r"""^(?P<namever>(?P<name>.+?)(-(?P<ver>\d.+?))?)
                                  \.dist-info$""", re.VERBOSE)
  
  
  def root_is_purelib(name, wheeldir):
      """
      Return True if the extracted wheel in wheeldir should go into purelib.
      """
      name_folded = name.replace("-", "_")
      for item in os.listdir(wheeldir):
          match = dist_info_re.match(item)
          if match and match.group('name') == name_folded:
              with open(os.path.join(wheeldir, item, 'WHEEL')) as wheel:
                  for line in wheel:
                      line = line.lower().rstrip()
                      if line == "root-is-purelib: true":
                          return True
      return False
  
  
  def get_entrypoints(filename):
      if not os.path.exists(filename):
          return {}, {}
  
      # This is done because you can pass a string to entry_points wrappers which
      # means that they may or may not be valid INI files. The attempt here is to
      # strip leading and trailing whitespace in order to make them valid INI
      # files.
      with open(filename) as fp:
          data = StringIO()
          for line in fp:
              data.write(line.strip())
              data.write("\n")
          data.seek(0)
  
      cp = configparser.RawConfigParser()
      cp.readfp(data)
  
      console = {}
      gui = {}
      if cp.has_section('console_scripts'):
          console = dict(cp.items('console_scripts'))
      if cp.has_section('gui_scripts'):
          gui = dict(cp.items('gui_scripts'))
      return console, gui
  
  
  def move_wheel_files(name, req, wheeldir, user=False, home=None, root=None,
                       pycompile=True, scheme=None, isolated=False):
      """Install a wheel"""
  
      if not scheme:
          scheme = distutils_scheme(
              name, user=user, home=home, root=root, isolated=isolated
          )
  
      if root_is_purelib(name, wheeldir):
          lib_dir = scheme['purelib']
      else:
          lib_dir = scheme['platlib']
  
      info_dir = []
      data_dirs = []
      source = wheeldir.rstrip(os.path.sep) + os.path.sep
  
      # Record details of the files moved
      #   installed = files copied from the wheel to the destination
      #   changed = files changed while installing (scripts #! line typically)
      #   generated = files newly generated during the install (script wrappers)
      installed = {}
      changed = set()
      generated = []
  
      # Compile all of the pyc files that we're going to be installing
      if pycompile:
          with captured_stdout() as stdout:
              with warnings.catch_warnings():
                  warnings.filterwarnings('ignore')
                  compileall.compile_dir(source, force=True, quiet=True)
          logger.debug(stdout.getvalue())
  
      def normpath(src, p):
          return make_path_relative(src, p).replace(os.path.sep, '/')
  
      def record_installed(srcfile, destfile, modified=False):
          """Map archive RECORD paths to installation RECORD paths."""
          oldpath = normpath(srcfile, wheeldir)
          newpath = normpath(destfile, lib_dir)
          installed[oldpath] = newpath
          if modified:
              changed.add(destfile)
  
      def clobber(source, dest, is_base, fixer=None, filter=None):
          ensure_dir(dest)  # common for the 'include' path
  
          for dir, subdirs, files in os.walk(source):
              basedir = dir[len(source):].lstrip(os.path.sep)
              destdir = os.path.join(dest, basedir)
              if is_base and basedir.split(os.path.sep, 1)[0].endswith('.data'):
                  continue
              for s in subdirs:
                  destsubdir = os.path.join(dest, basedir, s)
                  if is_base and basedir == '' and destsubdir.endswith('.data'):
                      data_dirs.append(s)
                      continue
                  elif (is_base and
                          s.endswith('.dist-info') and
                          # is self.req.project_name case preserving?
                          s.lower().startswith(
                              req.project_name.replace('-', '_').lower())):
                      assert not info_dir, 'Multiple .dist-info directories'
                      info_dir.append(destsubdir)
              for f in files:
                  # Skip unwanted files
                  if filter and filter(f):
                      continue
                  srcfile = os.path.join(dir, f)
                  destfile = os.path.join(dest, basedir, f)
                  # directory creation is lazy and after the file filtering above
                  # to ensure we don't install empty dirs; empty dirs can't be
                  # uninstalled.
                  ensure_dir(destdir)
  
                  # We use copyfile (not move, copy, or copy2) to be extra sure
                  # that we are not moving directories over (copyfile fails for
                  # directories) as well as to ensure that we are not copying
                  # over any metadata because we want more control over what
                  # metadata we actually copy over.
                  shutil.copyfile(srcfile, destfile)
  
                  # Copy over the metadata for the file, currently this only
                  # includes the atime and mtime.
                  st = os.stat(srcfile)
                  if hasattr(os, "utime"):
                      os.utime(destfile, (st.st_atime, st.st_mtime))
  
                  # If our file is executable, then make our destination file
                  # executable.
                  if os.access(srcfile, os.X_OK):
                      st = os.stat(srcfile)
                      permissions = (
                          st.st_mode | stat.S_IXUSR | stat.S_IXGRP | stat.S_IXOTH
                      )
                      os.chmod(destfile, permissions)
  
                  changed = False
                  if fixer:
                      changed = fixer(destfile)
                  record_installed(srcfile, destfile, changed)
  
      clobber(source, lib_dir, True)
  
      assert info_dir, "%s .dist-info directory not found" % req
  
      # Get the defined entry points
      ep_file = os.path.join(info_dir[0], 'entry_points.txt')
      console, gui = get_entrypoints(ep_file)
  
      def is_entrypoint_wrapper(name):
          # EP, EP.exe and EP-script.py are scripts generated for
          # entry point EP by setuptools
          if name.lower().endswith('.exe'):
              matchname = name[:-4]
          elif name.lower().endswith('-script.py'):
              matchname = name[:-10]
          elif name.lower().endswith(".pya"):
              matchname = name[:-4]
          else:
              matchname = name
          # Ignore setuptools-generated scripts
          return (matchname in console or matchname in gui)
  
      for datadir in data_dirs:
          fixer = None
          filter = None
          for subdir in os.listdir(os.path.join(wheeldir, datadir)):
              fixer = None
              if subdir == 'scripts':
                  fixer = fix_script
                  filter = is_entrypoint_wrapper
              source = os.path.join(wheeldir, datadir, subdir)
              dest = scheme[subdir]
              clobber(source, dest, False, fixer=fixer, filter=filter)
  
      maker = ScriptMaker(None, scheme['scripts'])
  
      # Ensure old scripts are overwritten.
      # See https://github.com/pypa/pip/issues/1800
      maker.clobber = True
  
      # Ensure we don't generate any variants for scripts because this is almost
      # never what somebody wants.
      # See https://bitbucket.org/pypa/distlib/issue/35/
      maker.variants = set(('', ))
  
      # This is required because otherwise distlib creates scripts that are not
      # executable.
      # See https://bitbucket.org/pypa/distlib/issue/32/
      maker.set_mode = True
  
      # Simplify the script and fix the fact that the default script swallows
      # every single stack trace.
      # See https://bitbucket.org/pypa/distlib/issue/34/
      # See https://bitbucket.org/pypa/distlib/issue/33/
      def _get_script_text(entry):
          return maker.script_template % {
              "module": entry.prefix,
              "import_name": entry.suffix.split(".")[0],
              "func": entry.suffix,
          }
  
      maker._get_script_text = _get_script_text
      maker.script_template = """# -*- coding: utf-8 -*-
  import re
  import sys
  
  from %(module)s import %(import_name)s
  
  if __name__ == '__main__':
      sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
      sys.exit(%(func)s())
  """
  
      # Special case pip and setuptools to generate versioned wrappers
      #
      # The issue is that some projects (specifically, pip and setuptools) use
      # code in setup.py to create "versioned" entry points - pip2.7 on Python
      # 2.7, pip3.3 on Python 3.3, etc. But these entry points are baked into
      # the wheel metadata at build time, and so if the wheel is installed with
      # a *different* version of Python the entry points will be wrong. The
      # correct fix for this is to enhance the metadata to be able to describe
      # such versioned entry points, but that won't happen till Metadata 2.0 is
      # available.
      # In the meantime, projects using versioned entry points will either have
      # incorrect versioned entry points, or they will not be able to distribute
      # "universal" wheels (i.e., they will need a wheel per Python version).
      #
      # Because setuptools and pip are bundled with _ensurepip and virtualenv,
      # we need to use universal wheels. So, as a stopgap until Metadata 2.0, we
      # override the versioned entry points in the wheel and generate the
      # correct ones. This code is purely a short-term measure until Metadat 2.0
      # is available.
      #
      # To add the level of hack in this section of code, in order to support
      # ensurepip this code will look for an ``ENSUREPIP_OPTIONS`` environment
      # variable which will control which version scripts get installed.
      #
      # ENSUREPIP_OPTIONS=altinstall
      #   - Only pipX.Y and easy_install-X.Y will be generated and installed
      # ENSUREPIP_OPTIONS=install
      #   - pipX.Y, pipX, easy_install-X.Y will be generated and installed. Note
      #     that this option is technically if ENSUREPIP_OPTIONS is set and is
      #     not altinstall
      # DEFAULT
      #   - The default behavior is to install pip, pipX, pipX.Y, easy_install
      #     and easy_install-X.Y.
      pip_script = console.pop('pip', None)
      if pip_script:
          if "ENSUREPIP_OPTIONS" not in os.environ:
              spec = 'pip = ' + pip_script
              generated.extend(maker.make(spec))
  
          if os.environ.get("ENSUREPIP_OPTIONS", "") != "altinstall":
              spec = 'pip%s = %s' % (sys.version[:1], pip_script)
              generated.extend(maker.make(spec))
  
          spec = 'pip%s = %s' % (sys.version[:3], pip_script)
          generated.extend(maker.make(spec))
          # Delete any other versioned pip entry points
          pip_ep = [k for k in console if re.match(r'pip(\d(\.\d)?)?$', k)]
          for k in pip_ep:
              del console[k]
      easy_install_script = console.pop('easy_install', None)
      if easy_install_script:
          if "ENSUREPIP_OPTIONS" not in os.environ:
              spec = 'easy_install = ' + easy_install_script
              generated.extend(maker.make(spec))
  
          spec = 'easy_install-%s = %s' % (sys.version[:3], easy_install_script)
          generated.extend(maker.make(spec))
          # Delete any other versioned easy_install entry points
          easy_install_ep = [
              k for k in console if re.match(r'easy_install(-\d\.\d)?$', k)
          ]
          for k in easy_install_ep:
              del console[k]
  
      # Generate the console and GUI entry points specified in the wheel
      if len(console) > 0:
          generated.extend(
              maker.make_multiple(['%s = %s' % kv for kv in console.items()])
          )
      if len(gui) > 0:
          generated.extend(
              maker.make_multiple(
                  ['%s = %s' % kv for kv in gui.items()],
                  {'gui': True}
              )
          )
  
      record = os.path.join(info_dir[0], 'RECORD')
      temp_record = os.path.join(info_dir[0], 'RECORD.pip')
      with open_for_csv(record, 'r') as record_in:
          with open_for_csv(temp_record, 'w+') as record_out:
              reader = csv.reader(record_in)
              writer = csv.writer(record_out)
              for row in reader:
                  row[0] = installed.pop(row[0], row[0])
                  if row[0] in changed:
                      row[1], row[2] = rehash(row[0])
                  writer.writerow(row)
              for f in generated:
                  h, l = rehash(f)
                  writer.writerow((f, h, l))
              for f in installed:
                  writer.writerow((installed[f], '', ''))
      shutil.move(temp_record, record)
  
  
  def _unique(fn):
      @functools.wraps(fn)
      def unique(*args, **kw):
          seen = set()
          for item in fn(*args, **kw):
              if item not in seen:
                  seen.add(item)
                  yield item
      return unique
  
  
  # TODO: this goes somewhere besides the wheel module
  @_unique
  def uninstallation_paths(dist):
      """
      Yield all the uninstallation paths for dist based on RECORD-without-.pyc
  
      Yield paths to all the files in RECORD. For each .py file in RECORD, add
      the .pyc in the same directory.
  
      UninstallPathSet.add() takes care of the __pycache__ .pyc.
      """
      from pip.utils import FakeFile  # circular import
      r = csv.reader(FakeFile(dist.get_metadata_lines('RECORD')))
      for row in r:
          path = os.path.join(dist.location, row[0])
          yield path
          if path.endswith('.py'):
              dn, fn = os.path.split(path)
              base = fn[:-3]
              path = os.path.join(dn, base + '.pyc')
              yield path
  
  
  def wheel_version(source_dir):
      """
      Return the Wheel-Version of an extracted wheel, if possible.
  
      Otherwise, return False if we couldn't parse / extract it.
      """
      try:
          dist = [d for d in pkg_resources.find_on_path(None, source_dir)][0]
  
          wheel_data = dist.get_metadata('WHEEL')
          wheel_data = Parser().parsestr(wheel_data)
  
          version = wheel_data['Wheel-Version'].strip()
          version = tuple(map(int, version.split('.')))
          return version
      except:
          return False
  
  
  def check_compatibility(version, name):
      """
      Raises errors or warns if called with an incompatible Wheel-Version.
  
      Pip should refuse to install a Wheel-Version that's a major series
      ahead of what it's compatible with (e.g 2.0 > 1.1); and warn when
      installing a version only minor version ahead (e.g 1.2 > 1.1).
  
      version: a 2-tuple representing a Wheel-Version (Major, Minor)
      name: name of wheel or package to raise exception about
  
      :raises UnsupportedWheel: when an incompatible Wheel-Version is given
      """
      if not version:
          raise UnsupportedWheel(
              "%s is in an unsupported or invalid wheel" % name
          )
      if version[0] > VERSION_COMPATIBLE[0]:
          raise UnsupportedWheel(
              "%s's Wheel-Version (%s) is not compatible with this version "
              "of pip" % (name, '.'.join(map(str, version)))
          )
      elif version > VERSION_COMPATIBLE:
          logger.warning(
              'Installing from a newer Wheel-Version (%s)',
              '.'.join(map(str, version)),
          )
  
  
  class Wheel(object):
      """A wheel file"""
  
      # TODO: maybe move the install code into this class
  
      wheel_file_re = re.compile(
          r"""^(?P<namever>(?P<name>.+?)-(?P<ver>\d.*?))
          ((-(?P<build>\d.*?))?-(?P<pyver>.+?)-(?P<abi>.+?)-(?P<plat>.+?)
          \.whl|\.dist-info)$""",
          re.VERBOSE
      )
  
      def __init__(self, filename):
          """
          :raises InvalidWheelFilename: when the filename is invalid for a wheel
          """
          wheel_info = self.wheel_file_re.match(filename)
          if not wheel_info:
              raise InvalidWheelFilename(
                  "%s is not a valid wheel filename." % filename
              )
          self.filename = filename
          self.name = wheel_info.group('name').replace('_', '-')
          # we'll assume "_" means "-" due to wheel naming scheme
          # (https://github.com/pypa/pip/issues/1150)
          self.version = wheel_info.group('ver').replace('_', '-')
          self.pyversions = wheel_info.group('pyver').split('.')
          self.abis = wheel_info.group('abi').split('.')
          self.plats = wheel_info.group('plat').split('.')
  
          # All the tag combinations from this file
          self.file_tags = set(
              (x, y, z) for x in self.pyversions
              for y in self.abis for z in self.plats
          )
  
      def support_index_min(self, tags=None):
          """
          Return the lowest index that one of the wheel's file_tag combinations
          achieves in the supported_tags list e.g. if there are 8 supported tags,
          and one of the file tags is first in the list, then return 0.  Returns
          None is the wheel is not supported.
          """
          if tags is None:  # for mock
              tags = pep425tags.supported_tags
          indexes = [tags.index(c) for c in self.file_tags if c in tags]
          return min(indexes) if indexes else None
  
      def supported(self, tags=None):
          """Is this wheel supported on this system?"""
          if tags is None:  # for mock
              tags = pep425tags.supported_tags
          return bool(set(tags).intersection(self.file_tags))
  
  
  class WheelBuilder(object):
      """Build wheels from a RequirementSet."""
  
      def __init__(self, requirement_set, finder, build_options=None,
                   global_options=None):
          self.requirement_set = requirement_set
          self.finder = finder
          self._cache_root = requirement_set._wheel_cache._cache_dir
          self._wheel_dir = requirement_set.wheel_download_dir
          self.build_options = build_options or []
          self.global_options = global_options or []
  
      def _build_one(self, req, output_dir):
          """Build one wheel.
  
          :return: The filename of the built wheel, or None if the build failed.
          """
          tempd = tempfile.mkdtemp('pip-wheel-')
          try:
              if self.__build_one(req, tempd):
                  try:
                      wheel_name = os.listdir(tempd)[0]
                      wheel_path = os.path.join(output_dir, wheel_name)
                      shutil.move(os.path.join(tempd, wheel_name), wheel_path)
                      logger.info('Stored in directory: %s', output_dir)
                      return wheel_path
                  except:
                      return None
              return None
          finally:
              rmtree(tempd)
  
      def __build_one(self, req, tempd):
          base_args = [
              sys.executable, '-c',
              "import setuptools;__file__=%r;"
              "exec(compile(open(__file__).read().replace('\\r\\n', '\\n'), "
              "__file__, 'exec'))" % req.setup_py
          ] + list(self.global_options)
  
          logger.info('Running setup.py bdist_wheel for %s', req.name)
          logger.debug('Destination directory: %s', tempd)
          wheel_args = base_args + ['bdist_wheel', '-d', tempd] \
              + self.build_options
          try:
              call_subprocess(wheel_args, cwd=req.source_dir, show_stdout=False)
              return True
          except:
              logger.error('Failed building wheel for %s', req.name)
              return False
  
      def build(self, autobuilding=False):
          """Build wheels.
  
          :param unpack: If True, replace the sdist we built from the with the
              newly built wheel, in preparation for installation.
          :return: True if all the wheels built correctly.
          """
          assert self._wheel_dir or (autobuilding and self._cache_root)
          # unpack sdists and constructs req set
          self.requirement_set.prepare_files(self.finder)
  
          reqset = self.requirement_set.requirements.values()
  
          buildset = []
          for req in reqset:
              if req.constraint:
                  continue
              if req.is_wheel:
                  if not autobuilding:
                      logger.info(
                          'Skipping %s, due to already being wheel.', req.name)
              elif req.editable:
                  if not autobuilding:
                      logger.info(
                          'Skipping bdist_wheel for %s, due to being editable',
                          req.name)
              elif autobuilding and req.link and not req.link.is_artifact:
                  pass
              elif autobuilding and not req.source_dir:
                  pass
              else:
                  if autobuilding:
                      link = req.link
                      base, ext = link.splitext()
                      if pip.index.egg_info_matches(base, None, link) is None:
                          # Doesn't look like a package - don't autobuild a wheel
                          # because we'll have no way to lookup the result sanely
                          continue
                      if "binary" not in pip.index.fmt_ctl_formats(
                              self.finder.format_control,
                              pkg_resources.safe_name(req.name).lower()):
                          logger.info(
                              "Skipping bdist_wheel for %s, due to binaries "
                              "being disabled for it.", req.name)
                          continue
                  buildset.append(req)
  
          if not buildset:
              return True
  
          # Build the wheels.
          logger.info(
              'Building wheels for collected packages: %s',
              ', '.join([req.name for req in buildset]),
          )
          with indent_log():
              build_success, build_failure = [], []
              for req in buildset:
                  if autobuilding:
                      output_dir = _cache_for_link(self._cache_root, req.link)
                      try:
                          ensure_dir(output_dir)
                      except OSError as e:
                          logger.warn("Building wheel for %s failed: %s",
                                      req.name, e)
                          build_failure.append(req)
                          continue
                  else:
                      output_dir = self._wheel_dir
                  wheel_file = self._build_one(req, output_dir)
                  if wheel_file:
                      build_success.append(req)
                      if autobuilding:
                          # XXX: This is mildly duplicative with prepare_files,
                          # but not close enough to pull out to a single common
                          # method.
                          # The code below assumes temporary source dirs -
                          # prevent it doing bad things.
                          if req.source_dir and not os.path.exists(os.path.join(
                                  req.source_dir, PIP_DELETE_MARKER_FILENAME)):
                              raise AssertionError(
                                  "bad source dir - missing marker")
                          # Delete the source we built the wheel from
                          req.remove_temporary_source()
                          # set the build directory again - name is known from
                          # the work prepare_files did.
                          req.source_dir = req.build_location(
                              self.requirement_set.build_dir)
                          # Update the link for this.
                          req.link = pip.index.Link(
                              path_to_url(wheel_file), trusted=True)
                          assert req.link.is_wheel
                          # extract the wheel into the dir
                          unpack_url(
                              req.link, req.source_dir, None, False,
                              session=self.requirement_set.session)
                  else:
                      build_failure.append(req)
  
          # notify success/failure
          if build_success:
              logger.info(
                  'Successfully built %s',
                  ' '.join([req.name for req in build_success]),
              )
          if build_failure:
              logger.info(
                  'Failed to build %s',
                  ' '.join([req.name for req in build_failure]),
              )
          # Return True if all builds were successful
          return len(build_failure) == 0
  