1 files changed, 47 insertions, 4 deletions
diff --git a/pip/_vendor/distlib/util.py b/pip/_vendor/distlib/util.py
index e64d078b6..29ec519ab 100644
--- a/pip/_vendor/distlib/util.py
+++ b/pip/_vendor/distlib/util.py
@@ -154,9 +154,9 @@ def in_venv():
 
 
 def get_executable():
-    if sys.platform == 'darwin' and ('__VENV_LAUNCHER__'
+    if sys.platform == 'darwin' and ('__PYVENV_LAUNCHER__'
                                      in os.environ):
-        result =  os.environ['__VENV_LAUNCHER__']
+        result =  os.environ['__PYVENV_LAUNCHER__']
     else:
         result = sys.executable
     return result
@@ -595,7 +595,6 @@ def get_cache_base(suffix=None):
     else:
         # Assume posix, or old Windows
         result = os.path.expanduser('~')
-    result = os.path.join(result, suffix)
     # we use 'isdir' instead of 'exists', because we want to
     # fail if there's a file with that name
     if os.path.isdir(result):
@@ -612,7 +611,7 @@ def get_cache_base(suffix=None):
     if not usable:
         result = tempfile.mkdtemp()
         logger.warning('Default location unusable, using %s', result)
-    return result
+    return os.path.join(result, suffix)
 
 
 def path_to_cache_dir(path):
@@ -768,6 +767,50 @@ def get_package_data(name, version):
     return _get_external_data(url)
 
 
+class Cache(object):
+    """
+    A class implementing a cache for resources that need to live in the file system
+    e.g. shared libraries. This class was moved from resources to here because it
+    could be used by other modules, e.g. the wheel module.
+    """
+
+    def __init__(self, base):
+        """
+        Initialise an instance.
+
+        :param base: The base directory where the cache should be located.
+        """
+        # we use 'isdir' instead of 'exists', because we want to
+        # fail if there's a file with that name
+        if not os.path.isdir(base):
+            os.makedirs(base)
+        if (os.stat(base).st_mode & 0o77) != 0:
+            logger.warning('Directory \'%s\' is not private', base)
+        self.base = os.path.abspath(os.path.normpath(base))
+
+    def prefix_to_dir(self, prefix):
+        """
+        Converts a resource prefix to a directory name in the cache.
+        """
+        return path_to_cache_dir(prefix)
+
+    def clear(self):
+        """
+        Clear the cache.
+        """
+        not_removed = []
+        for fn in os.listdir(self.base):
+            fn = os.path.join(self.base, fn)
+            try:
+                if os.path.islink(fn) or os.path.isfile(fn):
+                    os.remove(fn)
+                elif os.path.isdir(fn):
+                    shutil.rmtree(fn)
+            except Exception:
+                not_removed.append(fn)
+        return not_removed
+
+
 class EventMixin(object):
     """
     A very simple publish/subscribe system.