vendor: revendor github.com/opencontainers/image-tools@da84dc9dddc823a32f543e60323f841d12429c51

This requires re-vendoring a bunch of other things (as well as the old
Sirupsen/logrus path), the relevant commits being:

* github.com/xeipuuv/gojsonschema@0c8571ac0ce161a5feb57375a9cdf148c98c0f70
* github.com/xeipuuv/gojsonpointer@6fe8760cad3569743d51ddbb243b26f8456742dc
* github.com/xeipuuv/gojsonreference@e02fc20de94c78484cd5ffb007f8af96be030a45
* go4.org@034d17a462f7b2dcd1a4a73553ec5357ff6e6c6e

Signed-off-by: Aleksa Sarai <asarai@suse.de>

vendor/github.com/opencontainers/image-tools/image/index.go

@@ -0,0 +1,71 @@
+// Copyright 2016 The Linux Foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package image
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/opencontainers/image-spec/schema"
+	"github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/pkg/errors"
+)
+
+func findIndex(w walker, d *v1.Descriptor) (*v1.Index, error) {
+	var index v1.Index
+	ipath := filepath.Join("blobs", string(d.Digest.Algorithm()), d.Digest.Hex())
+
+	switch err := w.walk(func(path string, info os.FileInfo, r io.Reader) error {
+		if info.IsDir() || filepath.Clean(path) != ipath {
+			return nil
+		}
+
+		buf, err := ioutil.ReadAll(r)
+		if err != nil {
+			return errors.Wrapf(err, "%s: error reading index", path)
+		}
+
+		if err := schema.ValidatorMediaTypeImageIndex.Validate(bytes.NewReader(buf)); err != nil {
+			return errors.Wrapf(err, "%s: index validation failed", path)
+		}
+
+		if err := json.Unmarshal(buf, &index); err != nil {
+			return err
+		}
+
+		return errEOW
+	}); err {
+	case errEOW:
+		return &index, nil
+	case nil:
+		return nil, fmt.Errorf("index not found")
+	default:
+		return nil, err
+	}
+}
+
+func validateIndex(index *v1.Index, w walker) error {
+	for _, manifest := range index.Manifests {
+		if err := validateDescriptor(&manifest, w, []string{v1.MediaTypeImageManifest}); err != nil {
+			return errors.Wrap(err, "manifest validation failed")
+		}
+	}
+	return nil
+}