Revert "feat: replace docker with oras (#904)" (#1005)

This reverts commit 3cfa228.

<!-- markdownlint-disable MD041 -->
#### What this PR does / why we need it

#### Which issue(s) this PR fixes
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---------

Co-authored-by: Jakob Möller <[email protected]>

api/oci/extensions/repositories/ocireg/blobs.go

@@ -0,0 +1,109 @@
+package ocireg
+
+import (
+	"sync"
+
+	"github.com/containerd/containerd/remotes"
+	"github.com/mandelsoft/goutils/errors"
+	"github.com/opencontainers/go-digest"
+	"github.com/sirupsen/logrus"
+
+	"ocm.software/ocm/api/oci/cpi"
+	"ocm.software/ocm/api/oci/extensions/attrs/cacheattr"
+	"ocm.software/ocm/api/tech/docker/resolve"
+	"ocm.software/ocm/api/utils/accessio"
+	"ocm.software/ocm/api/utils/blobaccess/blobaccess"
+)
+
+type BlobContainer interface {
+	GetBlobData(digest digest.Digest) (int64, cpi.DataAccess, error)
+	AddBlob(blob cpi.BlobAccess) (int64, digest.Digest, error)
+	Unref() error
+}
+
+type blobContainer struct {
+	accessio.StaticAllocatable
+	fetcher resolve.Fetcher
+	pusher  resolve.Pusher
+	mime    string
+}
+
+type BlobContainers struct {
+	lock    sync.Mutex
+	cache   accessio.BlobCache
+	fetcher resolve.Fetcher
+	pusher  resolve.Pusher
+	mimes   map[string]BlobContainer
+}
+
+func NewBlobContainers(ctx cpi.Context, fetcher remotes.Fetcher, pusher resolve.Pusher) *BlobContainers {
+	return &BlobContainers{
+		cache:   cacheattr.Get(ctx),
+		fetcher: fetcher,
+		pusher:  pusher,
+		mimes:   map[string]BlobContainer{},
+	}
+}
+
+func (c *BlobContainers) Get(mime string) (BlobContainer, error) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	found := c.mimes[mime]
+	if found == nil {
+		container, err := NewBlobContainer(c.cache, mime, c.fetcher, c.pusher)
+		if err != nil {
+			return nil, err
+		}
+		c.mimes[mime] = container
+
+		return container, nil
+	}
+
+	return found, nil
+}
+
+func (c *BlobContainers) Release() error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	list := errors.ErrListf("releasing mime block caches")
+	for _, b := range c.mimes {
+		list.Add(b.Unref())
+	}
+	return list.Result()
+}
+
+func newBlobContainer(mime string, fetcher resolve.Fetcher, pusher resolve.Pusher) *blobContainer {
+	return &blobContainer{
+		mime:    mime,
+		fetcher: fetcher,
+		pusher:  pusher,
+	}
+}
+
+func NewBlobContainer(cache accessio.BlobCache, mime string, fetcher resolve.Fetcher, pusher resolve.Pusher) (BlobContainer, error) {
+	c := newBlobContainer(mime, fetcher, pusher)
+
+	if cache == nil {
+		return c, nil
+	}
+	r, err := accessio.CachedAccess(c, c, cache)
+	if err != nil {
+		return nil, err
+	}
+	return r, nil
+}
+
+func (n *blobContainer) GetBlobData(digest digest.Digest) (int64, cpi.DataAccess, error) {
+	logrus.Debugf("orig get %s %s\n", n.mime, digest)
+	acc, err := NewDataAccess(n.fetcher, digest, n.mime, false)
+	return blobaccess.BLOB_UNKNOWN_SIZE, acc, err
+}
+
+func (n *blobContainer) AddBlob(blob cpi.BlobAccess) (int64, digest.Digest, error) {
+	err := push(dummyContext, n.pusher, blob)
+	if err != nil {
+		return blobaccess.BLOB_UNKNOWN_SIZE, blobaccess.BLOB_UNKNOWN_DIGEST, err
+	}
+	return blob.Size(), blob.Digest(), err
+}