Extract namespace handling into a separate module and mix-in class.

1 files changed, 63 insertions, 0 deletions

diff --git a/setuptools/namespaces.py b/setuptools/namespaces.py
new file mode 100755
index 00000000..13829521
--- /dev/null
+++ b/setuptools/namespaces.py
@@ -0,0 +1,63 @@
+import os
+from distutils import log
+
+from setuptools.extern.six.moves import map
+
+
+class Installer:
+
+    def install_namespaces(self):
+        nsp = self._get_all_ns_packages()
+        if not nsp:
+            return
+        filename, ext = os.path.splitext(self.target)
+        filename += '-nspkg.pth'
+        self.outputs.append(filename)
+        log.info("Installing %s", filename)
+        lines = map(self._gen_nspkg_line, nsp)
+
+        if self.dry_run:
+            # always generate the lines, even in dry run
+            list(lines)
+            return
+
+        with open(filename, 'wt') as f:
+            f.writelines(lines)
+
+    _nspkg_tmpl = (
+        "import sys, types, os",
+        "pep420 = sys.version_info > (3, 3)",
+        "p = os.path.join(sys._getframe(1).f_locals['sitedir'], *%(pth)r)",
+        "ie = os.path.exists(os.path.join(p,'__init__.py'))",
+        "m = not ie and not pep420 and "
+            "sys.modules.setdefault(%(pkg)r, types.ModuleType(%(pkg)r))",
+        "mp = (m or []) and m.__dict__.setdefault('__path__',[])",
+        "(p not in mp) and mp.append(p)",
+    )
+    "lines for the namespace installer"
+
+    _nspkg_tmpl_multi = (
+        'm and setattr(sys.modules[%(parent)r], %(child)r, m)',
+    )
+    "additional line(s) when a parent package is indicated"
+
+    @classmethod
+    def _gen_nspkg_line(cls, pkg):
+        # ensure pkg is not a unicode string under Python 2.7
+        pkg = str(pkg)
+        pth = tuple(pkg.split('.'))
+        tmpl_lines = cls._nspkg_tmpl
+        parent, sep, child = pkg.rpartition('.')
+        if parent:
+            tmpl_lines += cls._nspkg_tmpl_multi
+        return ';'.join(tmpl_lines) % locals() + '\n'
+
+    def _get_all_ns_packages(self):
+        """Return sorted list of all package namespaces"""
+        nsp = set()
+        for pkg in self.distribution.namespace_packages or []:
+            pkg = pkg.split('.')
+            while pkg:
+                nsp.add('.'.join(pkg))
+                pkg.pop()
+        return sorted(nsp)