vendor: add buildkit

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/moby/buildkit/client/ociindex/ociindex.go

@@ -0,0 +1,113 @@
+package ociindex
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"os"
+
+	"github.com/gofrs/flock"
+	"github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/pkg/errors"
+)
+
+const (
+	// IndexJSONLockFileSuffix is the suffix of the lock file
+	IndexJSONLockFileSuffix = ".lock"
+)
+
+// PutDescToIndex puts desc to index with tag.
+// Existing manifests with the same tag will be removed from the index.
+func PutDescToIndex(index *v1.Index, desc v1.Descriptor, tag string) error {
+	if index == nil {
+		index = &v1.Index{}
+	}
+	if index.SchemaVersion == 0 {
+		index.SchemaVersion = 2
+	}
+	if tag != "" {
+		if desc.Annotations == nil {
+			desc.Annotations = make(map[string]string)
+		}
+		desc.Annotations[v1.AnnotationRefName] = tag
+		// remove existing manifests with the same tag
+		var manifests []v1.Descriptor
+		for _, m := range index.Manifests {
+			if m.Annotations[v1.AnnotationRefName] != tag {
+				manifests = append(manifests, m)
+			}
+		}
+		index.Manifests = manifests
+	}
+	index.Manifests = append(index.Manifests, desc)
+	return nil
+}
+
+func PutDescToIndexJSONFileLocked(indexJSONPath string, desc v1.Descriptor, tag string) error {
+	lockPath := indexJSONPath + IndexJSONLockFileSuffix
+	lock := flock.New(lockPath)
+	locked, err := lock.TryLock()
+	if err != nil {
+		return errors.Wrapf(err, "could not lock %s", lockPath)
+	}
+	if !locked {
+		return errors.Errorf("could not lock %s", lockPath)
+	}
+	defer func() {
+		lock.Unlock()
+		os.RemoveAll(lockPath)
+	}()
+	f, err := os.OpenFile(indexJSONPath, os.O_RDWR|os.O_CREATE, 0644)
+	if err != nil {
+		return errors.Wrapf(err, "could not open %s", indexJSONPath)
+	}
+	defer f.Close()
+	var idx v1.Index
+	b, err := ioutil.ReadAll(f)
+	if err != nil {
+		return errors.Wrapf(err, "could not read %s", indexJSONPath)
+	}
+	if len(b) > 0 {
+		if err := json.Unmarshal(b, &idx); err != nil {
+			return errors.Wrapf(err, "could not unmarshal %s (%q)", indexJSONPath, string(b))
+		}
+	}
+	if err = PutDescToIndex(&idx, desc, tag); err != nil {
+		return err
+	}
+	b, err = json.Marshal(idx)
+	if err != nil {
+		return err
+	}
+	if _, err = f.WriteAt(b, 0); err != nil {
+		return err
+	}
+	if err = f.Truncate(int64(len(b))); err != nil {
+		return err
+	}
+	return nil
+}
+
+func ReadIndexJSONFileLocked(indexJSONPath string) (*v1.Index, error) {
+	lockPath := indexJSONPath + IndexJSONLockFileSuffix
+	lock := flock.New(lockPath)
+	locked, err := lock.TryRLock()
+	if err != nil {
+		return nil, errors.Wrapf(err, "could not lock %s", lockPath)
+	}
+	if !locked {
+		return nil, errors.Errorf("could not lock %s", lockPath)
+	}
+	defer func() {
+		lock.Unlock()
+		os.RemoveAll(lockPath)
+	}()
+	b, err := ioutil.ReadFile(indexJSONPath)
+	if err != nil {
+		return nil, errors.Wrapf(err, "could not read %s", indexJSONPath)
+	}
+	var idx v1.Index
+	if err := json.Unmarshal(b, &idx); err != nil {
+		return nil, errors.Wrapf(err, "could not unmarshal %s (%q)", indexJSONPath, string(b))
+	}
+	return &idx, nil
+}