Extract requirement_is_installed() from setuptools_supports_wheels()

pip_accel/__init__.py

@@ -62,6 +62,7 @@
  makedirs,
  match_option,
  match_option_with_value,
+ requirement_is_installed,
  same_directories,
  uninstall,
 )
@@ -70,7 +71,6 @@
 from humanfriendly import concatenate, Timer, pluralize
 from pip import index as pip_index_module
 from pip import wheel as pip_wheel_module
-from pip._vendor import pkg_resources
 from pip.commands import install as pip_install_module
 from pip.commands.install import InstallCommand
 from pip.exceptions import DistributionNotFound
@@ -247,20 +247,10 @@ def setuptools_supports_wheels(self):
  """
  Check whether setuptools should be upgraded to ``>= 0.8`` for wheel support.
 
- :returns: :data:`True` when setuptools needs to be upgraded, :data:`False` otherwise.
+ :returns: :data:`True` when setuptools 0.8 or higher is already
+ installed, :data:`False` otherwise (it needs to be upgraded).
  """
- # Don't use pkg_resources.Requirement.parse, to avoid the override
- # in distribute, that converts `setuptools' to `distribute'.
- setuptools_requirement = next(pkg_resources.parse_requirements('setuptools >= 0.8'))
- try:
- installed_setuptools = pkg_resources.get_distribution('setuptools')
- if installed_setuptools in setuptools_requirement:
- # setuptools >= 0.8 is already installed; nothing to do.
- return True
- except pkg_resources.DistributionNotFound:
- pass
- # We need to install setuptools >= 0.8.
- return False
+ return requirement_is_installed('setuptools >= 0.8')
 
  def get_requirements(self, arguments, max_retries=None, use_wheels=False):
  """

pip_accel/utils.py

@@ -1,7 +1,7 @@
 # Utility functions for the pip accelerator.
 #
 # Author: Peter Odding <[email protected]>
-# Last Change: December 28, 2015
+# Last Change: January 10, 2016
 # URL: https://github.com/paylogic/pip-accel
 
 """
@@ -26,7 +26,12 @@
 # External dependencies.
 from humanfriendly import parse_path
 from pip.commands.uninstall import UninstallCommand
-from pkg_resources import WorkingSet
+from pip._vendor.pkg_resources import (
+ DistributionNotFound,
+ WorkingSet,
+ get_distribution,
+ parse_requirements,
+)
 
 # Initialize a logger for this module.
 logger = logging.getLogger(__name__)
@@ -254,6 +259,23 @@ def __exit__(self, exc_type=None, exc_value=None, traceback=None):
  replace_file(self.temporary_file, self.filename)
 
 
+def requirement_is_installed(expr):
+ """
+ Check whether a requirement is installed.
+
+ :param expr: A requirement specification similar to those used in pip
+ requirement files (a string).
+ :returns: :data:`True` if the requirement is available (installed),
+ :data:`False` otherwise.
+ """
+ required_dist = next(parse_requirements(expr))
+ try:
+ installed_dist = get_distribution(required_dist.key)
+ return installed_dist in required_dist
+ except DistributionNotFound:
+ return False
+
+
 def is_installed(package_name):
  """
  Check whether a package is installed in the current environment.