oci: update to image-spec v1 RC5

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

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

@@ -1,109 +0,0 @@
-// 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 (
-	"encoding/json"
-	"io"
-	"io/ioutil"
-	"net/http"
-	"os"
-
-	"github.com/opencontainers/image-spec/schema"
-	"github.com/pkg/errors"
-)
-
-// supported autodetection types
-const (
-	TypeImageLayout  = "imageLayout"
-	TypeImage        = "image"
-	TypeManifest     = "manifest"
-	TypeManifestList = "manifestList"
-	TypeConfig       = "config"
-)
-
-// Autodetect detects the validation type for the given path
-// or an error if the validation type could not be resolved.
-func Autodetect(path string) (string, error) {
-	fi, err := os.Stat(path)
-	if err != nil {
-		return "", errors.Wrapf(err, "unable to access path") // err from os.Stat includes path name
-	}
-
-	if fi.IsDir() {
-		return TypeImageLayout, nil
-	}
-
-	f, err := os.Open(path)
-	if err != nil {
-		return "", errors.Wrap(err, "unable to open file") // os.Open includes the filename
-	}
-	defer f.Close()
-
-	buf, err := ioutil.ReadAll(io.LimitReader(f, 512)) // read some initial bytes to detect content
-	if err != nil {
-		return "", errors.Wrap(err, "unable to read")
-	}
-
-	mimeType := http.DetectContentType(buf)
-
-	switch mimeType {
-	case "application/x-gzip", "application/octet-stream":
-		return TypeImage, nil
-
-	case "text/plain; charset=utf-8":
-		// might be a JSON file, will be handled below
-
-	default:
-		return "", errors.New("unknown file type")
-	}
-
-	if _, err := f.Seek(0, os.SEEK_SET); err != nil {
-		return "", errors.Wrap(err, "unable to seek")
-	}
-
-	header := struct {
-		SchemaVersion int         `json:"schemaVersion"`
-		MediaType     string      `json:"mediaType"`
-		Config        interface{} `json:"config"`
-	}{}
-
-	if err := json.NewDecoder(f).Decode(&header); err != nil {
-		if _, errSeek := f.Seek(0, os.SEEK_SET); errSeek != nil {
-			return "", errors.Wrap(err, "unable to seek")
-		}
-
-		e := errors.Wrap(
-			schema.WrapSyntaxError(f, err),
-			"unable to parse JSON",
-		)
-
-		return "", e
-	}
-
-	switch {
-	case header.MediaType == string(schema.MediaTypeManifest):
-		return TypeManifest, nil
-
-	case header.MediaType == string(schema.MediaTypeManifestList):
-		return TypeManifestList, nil
-
-	case header.MediaType == "" && header.SchemaVersion == 0 && header.Config != nil:
-		// config files don't have mediaType/schemaVersion header
-		return TypeConfig, nil
-	}
-
-	return "", errors.New("unknown media type")
-}