1 files changed, 31 insertions, 4 deletions
diff --git a/lib/spack/llnl/util/filesystem.py b/lib/spack/llnl/util/filesystem.py
index bee6e1e43c..5e08273677 100644
--- a/lib/spack/llnl/util/filesystem.py
+++ b/lib/spack/llnl/util/filesystem.py
@@ -2,7 +2,6 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
-
 import collections
 import errno
 import hashlib
@@ -377,17 +376,17 @@ def install(src, dest):
     copy(src, dest, _permissions=True)
 
 
-def resolve_link_target_relative_to_the_link(l):
+def resolve_link_target_relative_to_the_link(link):
     """
     os.path.isdir uses os.path.exists, which for links will check
     the existence of the link target. If the link target is relative to
     the link, we need to construct a pathname that is valid from
     our cwd (which may not be the same as the link's directory)
     """
-    target = os.readlink(l)
+    target = os.readlink(link)
     if os.path.isabs(target):
         return target
-    link_dir = os.path.dirname(os.path.abspath(l))
+    link_dir = os.path.dirname(os.path.abspath(link))
     return os.path.join(link_dir, target)
 
 
@@ -1571,6 +1570,19 @@ def can_access_dir(path):
 
 
 @memoized
+def can_write_to_dir(path):
+    """Return True if the argument is a directory in which we can write.
+
+    Args:
+        path: path to be tested
+
+    Returns:
+        True if ``path`` is an writeable directory, else False
+    """
+    return os.path.isdir(path) and os.access(path, os.R_OK | os.X_OK | os.W_OK)
+
+
+@memoized
 def files_in(*search_paths):
     """Returns all the files in paths passed as arguments.
 
@@ -1683,3 +1695,18 @@ def prefixes(path):
         pass
 
     return paths
+
+
+def md5sum(file):
+    """Compute the MD5 sum of a file.
+
+    Args:
+        file (str): file to be checksummed
+
+    Returns:
+        MD5 sum of the file's content
+    """
+    md5 = hashlib.md5()
+    with open(file, "rb") as f:
+        md5.update(f.read())
+    return md5.digest()