1 files changed, 55 insertions, 0 deletions
diff --git a/third_party/python/virtualenv/virtualenv.py b/third_party/python/virtualenv/virtualenv.py
new file mode 100644
index 0000000000..2435b9dfdd
--- /dev/null
+++ b/third_party/python/virtualenv/virtualenv.py
@@ -0,0 +1,55 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# This script is not to be imported.
+assert __name__ == '__main__'
+import os
+import sys
+# If some older version of virtualenv is installed, it may interfere with this one.
+# So filter-out site-packages and dist-packages directories where it might be installed.
+# This is kinda sorta like invoking python with -S, but invoking a virtualenv python 2.7
+# with -S is broken (sys.path becomes completely wrong, and even `import os` fails).
+# (And while yes, it is kind of silly to use a virtualenv python to run virtualenv, we
+# do)
+sys.path = [p for p in sys.path if os.path.basename(p) not in ('site-packages', 'dist-packages')]
+try:
+    import importlib.util
+    spec = importlib.util.spec_from_file_location('main', os.path.join(os.path.dirname(__file__), '__main__.py'))
+    mod = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(mod)
+except ImportError:
+    import imp
+    mod_info = imp.find_module('__main__', [os.path.dirname(__file__)])
+    mod = imp.load_module('main', *mod_info)
+
+
+# Fake zipfile module to make `mod.VersionedFindLoad` able to read the extracted
+# files rather than the zipapp.
+class fake_zipfile(object):
+    class ZipFile(object):
+        def __init__(self, path, mode):
+            self._path = path
+            self._mode = mode
+
+        def open(self, path):
+            #  The caller expects a raw file object, with no unicode handling.
+            return open(os.path.join(self._path, path), self._mode + 'b')
+
+        def close(self):
+            pass
+
+mod.zipfile = fake_zipfile
+
+
+def run():
+    with mod.VersionedFindLoad() as finder:
+        sys.meta_path.insert(0, finder)
+        finder._register_distutils_finder()
+        from virtualenv.__main__ import run as run_virtualenv
+
+        run_virtualenv()
+
+
+if __name__ == "__main__":
+    run()