lib/oe/path: Add canonicalize()

oe.path.canonicalize() is used to canonicalize paths (i.e., remove
symbolic links and "..", and make them absolute). It takes a string
with paths separated by commas, and returns the canonicalized path in
the same format.

Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/meta/lib/oe/path.py b/meta/lib/oe/path.py
index 082972457b..c8d8ad05b9 100644
--- a/meta/lib/oe/path.py
+++ b/meta/lib/oe/path.py
@@ -320,3 +320,24 @@ def which_wild(pathname, path=None, mode=os.F_OK, *, reverse=False, candidates=F
 
     return files
 
+def canonicalize(paths, sep=','):
+    """Given a string with paths (separated by commas by default), expand
+    each path using os.path.realpath() and return the resulting paths as a
+    string (separated using the same separator a the original string).
+    """
+    # Ignore paths containing "$" as they are assumed to be unexpanded bitbake
+    # variables. Normally they would be ignored, e.g., when passing the paths
+    # through the shell they would expand to empty strings. However, when they
+    # are passed through os.path.realpath(), it will cause them to be prefixed
+    # with the absolute path to the current directory and thus not be empty
+    # anymore.
+    #
+    # Also maintain trailing slashes, as the paths may actually be used as
+    # prefixes in sting compares later on, where the slashes then are important.
+    canonical_paths = []
+    for path in (paths or '').split(sep):
+        if '$' not in path:
+            trailing_slash = path.endswith('/') and '/' or ''
+            canonical_paths.append(os.path.realpath(path) + trailing_slash)
+
+    return sep.join(canonical_paths)