Recipe package system.

recipe_engine/third_party/setuptools/extension.py

Index: recipe_engine/third_party/setuptools/extension.py
diff --git a/recipe_engine/third_party/setuptools/extension.py b/recipe_engine/third_party/setuptools/extension.py
new file mode 100644
index 0000000000000000000000000000000000000000..8178ed33d7f095f59c624e728fd850f938bd37e8
--- /dev/null
+++ b/recipe_engine/third_party/setuptools/extension.py
@@ -0,0 +1,57 @@
+import sys
+import re
+import functools
+import distutils.core
+import distutils.errors
+import distutils.extension
+
+from .dist import _get_unpatched
+from . import msvc9_support
+
+_Extension = _get_unpatched(distutils.core.Extension)
+
+msvc9_support.patch_for_specialized_compiler()
+
+def have_pyrex():
+    """
+    Return True if Cython or Pyrex can be imported.
+    """
+    pyrex_impls = 'Cython.Distutils.build_ext', 'Pyrex.Distutils.build_ext'
+    for pyrex_impl in pyrex_impls:
+        try:
+            # from (pyrex_impl) import build_ext
+            __import__(pyrex_impl, fromlist=['build_ext']).build_ext
+            return True
+        except Exception:
+            pass
+    return False
+
+
+class Extension(_Extension):
+    """Extension that uses '.c' files in place of '.pyx' files"""
+
+    def __init__(self, *args, **kw):
+        _Extension.__init__(self, *args, **kw)
+        self._convert_pyx_sources_to_lang()
+
+    def _convert_pyx_sources_to_lang(self):
+        """
+        Replace sources with .pyx extensions to sources with the target
+        language extension. This mechanism allows language authors to supply
+        pre-converted sources but to prefer the .pyx sources.
+        """
+        if have_pyrex():
+            # the build has Cython, so allow it to compile the .pyx files
+            return
+        lang = self.language or ''
+        target_ext = '.cpp' if lang.lower() == 'c++' else '.c'
+        sub = functools.partial(re.sub, '.pyx$', target_ext)
+        self.sources = list(map(sub, self.sources))
+
+class Library(Extension):
+    """Just like a regular Extension, but built as a library instead"""
+
+distutils.core.Extension = Extension
+distutils.extension.Extension = Extension
+if 'distutils.command.build_ext' in sys.modules:
+    sys.modules['distutils.command.build_ext'].Extension = Extension