pep517: add module

Add a module that implements the PEP 517 specification.

setuptools/dist.py

@@ -30,6 +30,14 @@
 __import__('pkg_resources.extern.packaging.version')
 
 
+skip_install_eggs = False
+
+
+class SetupRequirementsError(BaseException):
+    def __init__(self, specifiers):
+        self.specifiers = specifiers
+
+
 def _get_unpatched(cls):
     warnings.warn("Do not call this function", DeprecationWarning)
     return get_unpatched(cls)
@@ -332,7 +340,10 @@ def __init__(self, attrs=None):
             self.dependency_links = attrs.pop('dependency_links', [])
             assert_string_list(self, 'dependency_links', self.dependency_links)
         if attrs and 'setup_requires' in attrs:
-            self.fetch_build_eggs(attrs['setup_requires'])
+            if skip_install_eggs:
+                raise SetupRequirementsError(attrs['setup_requires'])
+            else:
+                self.fetch_build_eggs(attrs['setup_requires'])
         for ep in pkg_resources.iter_entry_points('distutils.setup_keywords'):
             vars(self).setdefault(ep.name, None)
         _Distribution.__init__(self, attrs)

setuptools/pep517.py

@@ -0,0 +1,70 @@
+import os
+import sys
+import subprocess
+import tokenize
+import shutil
+import tempfile
+
+from setuptools import dist
+from setuptools.dist import SetupRequirementsError
+
+
+SETUPTOOLS_IMPLEMENTATION_REVISION = 0.1
+
+def _run_setup(setup_script='setup.py'): #
+    # Note that we can reuse our build directory between calls
+    # Correctness comes first, then optimization later    
+    __file__=setup_script
+    f=getattr(tokenize, 'open', open)(__file__)
+    code=f.read().replace('\\r\\n', '\\n')
+    f.close()
+    exec(compile(code, __file__, 'exec'))
+
+
+def get_build_requires(config_settings):
+    requirements = ['setuptools', 'wheel']
+    dist.skip_install_eggs = True
+
+    sys.argv = sys.argv[:1] + ['egg_info'] + \
+        config_settings["--global-option"]
+    try:
+        _run_setup()
+    except SetupRequirementsError as e:
+        requirements += e.specifiers
+
+    dist.skip_install_eggs = False
+
+    return requirements
+
+
+def get_requires_for_build_wheel(config_settings=None):
+    return get_build_requires(config_settings)
+
+
+def get_requires_for_build_sdist(config_settings=None):
+    return get_build_requires(config_settings)
+
+
+def prepare_metadata_for_build_wheel(metadata_directory, config_settings=None):
+    sys.argv = sys.argv[:1] + ['dist_info', '--egg-base', metadata_directory]
+    _run_setup()
+
+def build_wheel(wheel_directory, config_settings=None,
+                metadata_directory=None):
+    wheel_directory = os.path.abspath(wheel_directory)
+    sys.argv = sys.argv[:1] + ['bdist_wheel'] + \
+        config_settings["--global-option"]
+    _run_setup()
+    if wheel_directory != 'dist':
+        shutil.rmtree(wheel_directory)
+        shutil.copytree('dist', wheel_directory)
+
+
+def build_sdist(sdist_directory, config_settings=None):
+    sdist_directory = os.path.abspath(sdist_directory)
+    sys.argv = sys.argv[:1] + ['sdist'] + \
+        config_settings["--global-option"]
+    _run_setup()
+    if sdist_directory != 'dist':
+        shutil.rmtree(sdist_directory)
+        shutil.copytree('dist', sdist_directory)