open-consul/vendor/github.com/googleapis/gnostic/compiler/reader.go

176 lines
4.0 KiB
Go

// 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 (
"errors"
"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
}
if verboseReader {
log.Printf("Fetching %s", fileurl)
}
response, err := http.Get(fileurl)
if err != nil {
return nil, err
}
if response.StatusCode != 200 {
return nil, errors.New(fmt.Sprintf("Error downloading %s: %s", fileurl, response.Status))
}
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
}
if len(filename) > 0 {
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
}