From 0cf04c4adf2e1b033cb48aa9f0f4d1fc44e9f50f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miloslav=20Trma=C4=8D?= <mitr@redhat.com>
Date: Sat, 9 Jul 2016 05:41:47 +0200
Subject: [PATCH] Do not duplicate OCI subdirectory paths
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Instead of supplying literals to ensureParentDirectoryExists, first
compute the path of the file within the directory using the ociReference
methods, and then use that to compute the parent directory path.

Should not change behavior, except that filepath.Dir() implicitly calls
filepath.Clean(), apparently incompatible with UNIX path semantics.  But
then we always call filepath.Join() with the same d.ref.dir input, which
makes the same implicit call, and Go's handling of symlinks and .. seems
close-to-unfixably broken in general, and trying to fix that only here
is rather pointless:
https://github.com/golang/go/issues/4382

Signed-off-by: Miloslav Trmač <mitr@redhat.com>
---
 oci/oci_dest.go | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/oci/oci_dest.go b/oci/oci_dest.go
index dd0644fc..6509aba2 100644
--- a/oci/oci_dest.go
+++ b/oci/oci_dest.go
@@ -76,9 +76,6 @@ func createManifest(m []byte) ([]byte, string, error) {
 }
 
 func (d *ociImageDestination) PutManifest(m []byte) error {
-	if err := d.ensureParentDirectoryExists("refs"); err != nil {
-		return err
-	}
 	// TODO(mitr, runcom): this breaks signatures entirely since at this point we're creating a new manifest
 	// and signatures don't apply anymore. Will fix.
 	ociMan, mt, err := createManifest(m)
@@ -106,14 +103,19 @@ func (d *ociImageDestination) PutManifest(m []byte) error {
 	if err := ioutil.WriteFile(d.ref.ociLayoutPath(), []byte(`{"imageLayoutVersion": "1.0.0"}`), 0644); err != nil {
 		return err
 	}
-	return ioutil.WriteFile(d.ref.descriptorPath(d.ref.tag), data, 0644)
+	descriptorPath := d.ref.descriptorPath(d.ref.tag)
+	if err := ensureParentDirectoryExists(descriptorPath); err != nil {
+		return err
+	}
+	return ioutil.WriteFile(descriptorPath, data, 0644)
 }
 
 func (d *ociImageDestination) PutBlob(digest string, stream io.Reader) error {
-	if err := d.ensureParentDirectoryExists("blobs"); err != nil {
+	blobPath := d.ref.blobPath(digest)
+	if err := ensureParentDirectoryExists(blobPath); err != nil {
 		return err
 	}
-	blob, err := os.Create(d.ref.blobPath(digest))
+	blob, err := os.Create(blobPath)
 	if err != nil {
 		return err
 	}
@@ -127,10 +129,11 @@ func (d *ociImageDestination) PutBlob(digest string, stream io.Reader) error {
 	return nil
 }
 
-func (d *ociImageDestination) ensureParentDirectoryExists(parent string) error {
-	path := filepath.Join(d.ref.dir, parent)
-	if _, err := os.Stat(path); err != nil && os.IsNotExist(err) {
-		if err := os.MkdirAll(path, 0755); err != nil {
+// ensureParentDirectoryExists ensures the parent of the supplied path exists.
+func ensureParentDirectoryExists(path string) error {
+	parent := filepath.Dir(path)
+	if _, err := os.Stat(parent); err != nil && os.IsNotExist(err) {
+		if err := os.MkdirAll(parent, 0755); err != nil {
 			return err
 		}
 	}