Revert vendor directory to support old golang (GOPATH mode)

gomodule is still in progress to migrate for now, hence multus
team decide to keep vendor directory to support build without
gomodule.

vendor/github.com/googleapis/gnostic/compiler/reader.go

@@ -0,0 +1,167 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// 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 compiler
+
+import (
+	"fmt"
+	"gopkg.in/yaml.v2"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"net/url"
+	"path/filepath"
+	"strings"
+)
+
+var fileCache map[string][]byte
+var infoCache map[string]interface{}
+var count int64
+
+var verboseReader = false
+
+func initializeFileCache() {
+	if fileCache == nil {
+		fileCache = make(map[string][]byte, 0)
+	}
+}
+
+func initializeInfoCache() {
+	if infoCache == nil {
+		infoCache = make(map[string]interface{}, 0)
+	}
+}
+
+// FetchFile gets a specified file from the local filesystem or a remote location.
+func FetchFile(fileurl string) ([]byte, error) {
+	initializeFileCache()
+	bytes, ok := fileCache[fileurl]
+	if ok {
+		if verboseReader {
+			log.Printf("Cache hit %s", fileurl)
+		}
+		return bytes, nil
+	}
+	log.Printf("Fetching %s", fileurl)
+	response, err := http.Get(fileurl)
+	if err != nil {
+		return nil, err
+	}
+	defer response.Body.Close()
+	bytes, err = ioutil.ReadAll(response.Body)
+	if err == nil {
+		fileCache[fileurl] = bytes
+	}
+	return bytes, err
+}
+
+// ReadBytesForFile reads the bytes of a file.
+func ReadBytesForFile(filename string) ([]byte, error) {
+	// is the filename a url?
+	fileurl, _ := url.Parse(filename)
+	if fileurl.Scheme != "" {
+		// yes, fetch it
+		bytes, err := FetchFile(filename)
+		if err != nil {
+			return nil, err
+		}
+		return bytes, nil
+	}
+	// no, it's a local filename
+	bytes, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	return bytes, nil
+}
+
+// ReadInfoFromBytes unmarshals a file as a yaml.MapSlice.
+func ReadInfoFromBytes(filename string, bytes []byte) (interface{}, error) {
+	initializeInfoCache()
+	cachedInfo, ok := infoCache[filename]
+	if ok {
+		if verboseReader {
+			log.Printf("Cache hit info for file %s", filename)
+		}
+		return cachedInfo, nil
+	}
+	if verboseReader {
+		log.Printf("Reading info for file %s", filename)
+	}
+	var info yaml.MapSlice
+	err := yaml.Unmarshal(bytes, &info)
+	if err != nil {
+		return nil, err
+	}
+	infoCache[filename] = info
+	return info, nil
+}
+
+// ReadInfoForRef reads a file and return the fragment needed to resolve a $ref.
+func ReadInfoForRef(basefile string, ref string) (interface{}, error) {
+	initializeInfoCache()
+	{
+		info, ok := infoCache[ref]
+		if ok {
+			if verboseReader {
+				log.Printf("Cache hit for ref %s#%s", basefile, ref)
+			}
+			return info, nil
+		}
+	}
+	if verboseReader {
+		log.Printf("Reading info for ref %s#%s", basefile, ref)
+	}
+	count = count + 1
+	basedir, _ := filepath.Split(basefile)
+	parts := strings.Split(ref, "#")
+	var filename string
+	if parts[0] != "" {
+		filename = basedir + parts[0]
+	} else {
+		filename = basefile
+	}
+	bytes, err := ReadBytesForFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	info, err := ReadInfoFromBytes(filename, bytes)
+	if err != nil {
+		log.Printf("File error: %v\n", err)
+	} else {
+		if len(parts) > 1 {
+			path := strings.Split(parts[1], "/")
+			for i, key := range path {
+				if i > 0 {
+					m, ok := info.(yaml.MapSlice)
+					if ok {
+						found := false
+						for _, section := range m {
+							if section.Key == key {
+								info = section.Value
+								found = true
+							}
+						}
+						if !found {
+							infoCache[ref] = nil
+							return nil, NewError(nil, fmt.Sprintf("could not resolve %s", ref))
+						}
+					}
+				}
+			}
+		}
+	}
+	infoCache[ref] = info
+	return info, nil
+}