ceph-csi/vendor/github.com/googleapis/gnostic/compiler/reader.go

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// Copyright 2017 Google LLC. All Rights Reserved.
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//
// 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"
"io/ioutil"
"log"
"net/http"
"net/url"
"path/filepath"
"strings"
"sync"
yaml "gopkg.in/yaml.v3"
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)
var verboseReader = false
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var fileCache map[string][]byte
var infoCache map[string]*yaml.Node
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var fileCacheEnable = true
var infoCacheEnable = true
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// These locks are used to synchronize accesses to the fileCache and infoCache
// maps (above). They are global state and can throw thread-related errors
// when modified from separate goroutines. The general strategy is to protect
// all public functions in this file with mutex Lock() calls. As a result, to
// avoid deadlock, these public functions should not call other public
// functions, so some public functions have private equivalents.
// In the future, we might consider replacing the maps with sync.Map and
// eliminating these mutexes.
var fileCacheMutex sync.Mutex
var infoCacheMutex sync.Mutex
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func initializeFileCache() {
if fileCache == nil {
fileCache = make(map[string][]byte, 0)
}
}
func initializeInfoCache() {
if infoCache == nil {
infoCache = make(map[string]*yaml.Node, 0)
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}
}
// EnableFileCache turns on file caching.
func EnableFileCache() {
fileCacheMutex.Lock()
defer fileCacheMutex.Unlock()
fileCacheEnable = true
}
// EnableInfoCache turns on parsed info caching.
func EnableInfoCache() {
infoCacheMutex.Lock()
defer infoCacheMutex.Unlock()
infoCacheEnable = true
}
// DisableFileCache turns off file caching.
func DisableFileCache() {
fileCacheMutex.Lock()
defer fileCacheMutex.Unlock()
fileCacheEnable = false
}
// DisableInfoCache turns off parsed info caching.
func DisableInfoCache() {
infoCacheMutex.Lock()
defer infoCacheMutex.Unlock()
infoCacheEnable = false
}
// RemoveFromFileCache removes an entry from the file cache.
func RemoveFromFileCache(fileurl string) {
fileCacheMutex.Lock()
defer fileCacheMutex.Unlock()
if !fileCacheEnable {
return
}
initializeFileCache()
delete(fileCache, fileurl)
}
// RemoveFromInfoCache removes an entry from the info cache.
func RemoveFromInfoCache(filename string) {
infoCacheMutex.Lock()
defer infoCacheMutex.Unlock()
if !infoCacheEnable {
return
}
initializeInfoCache()
delete(infoCache, filename)
}
// GetInfoCache returns the info cache map.
func GetInfoCache() map[string]*yaml.Node {
infoCacheMutex.Lock()
defer infoCacheMutex.Unlock()
if infoCache == nil {
initializeInfoCache()
}
return infoCache
}
// ClearFileCache clears the file cache.
func ClearFileCache() {
fileCacheMutex.Lock()
defer fileCacheMutex.Unlock()
fileCache = make(map[string][]byte, 0)
}
// ClearInfoCache clears the info cache.
func ClearInfoCache() {
infoCacheMutex.Lock()
defer infoCacheMutex.Unlock()
infoCache = make(map[string]*yaml.Node)
}
// ClearCaches clears all caches.
func ClearCaches() {
ClearFileCache()
ClearInfoCache()
}
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// FetchFile gets a specified file from the local filesystem or a remote location.
func FetchFile(fileurl string) ([]byte, error) {
fileCacheMutex.Lock()
defer fileCacheMutex.Unlock()
return fetchFile(fileurl)
}
func fetchFile(fileurl string) ([]byte, error) {
var bytes []byte
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initializeFileCache()
if fileCacheEnable {
bytes, ok := fileCache[fileurl]
if ok {
if verboseReader {
log.Printf("Cache hit %s", fileurl)
}
return bytes, nil
}
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if verboseReader {
log.Printf("Fetching %s", fileurl)
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}
}
response, err := http.Get(fileurl)
if err != nil {
return nil, err
}
defer response.Body.Close()
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if response.StatusCode != 200 {
return nil, fmt.Errorf("Error downloading %s: %s", fileurl, response.Status)
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}
bytes, err = ioutil.ReadAll(response.Body)
if fileCacheEnable && err == nil {
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fileCache[fileurl] = bytes
}
return bytes, err
}
// ReadBytesForFile reads the bytes of a file.
func ReadBytesForFile(filename string) ([]byte, error) {
fileCacheMutex.Lock()
defer fileCacheMutex.Unlock()
return readBytesForFile(filename)
}
func readBytesForFile(filename string) ([]byte, error) {
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// is the filename a url?
fileurl, _ := url.Parse(filename)
if fileurl.Scheme != "" {
// yes, fetch it
bytes, err := fetchFile(filename)
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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.Node.
func ReadInfoFromBytes(filename string, bytes []byte) (*yaml.Node, error) {
infoCacheMutex.Lock()
defer infoCacheMutex.Unlock()
return readInfoFromBytes(filename, bytes)
}
func readInfoFromBytes(filename string, bytes []byte) (*yaml.Node, error) {
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initializeInfoCache()
if infoCacheEnable {
cachedInfo, ok := infoCache[filename]
if ok {
if verboseReader {
log.Printf("Cache hit info for file %s", filename)
}
return cachedInfo, nil
}
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if verboseReader {
log.Printf("Reading info for file %s", filename)
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}
}
var info yaml.Node
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err := yaml.Unmarshal(bytes, &info)
if err != nil {
return nil, err
}
if infoCacheEnable && len(filename) > 0 {
infoCache[filename] = &info
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}
return &info, nil
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}
// ReadInfoForRef reads a file and return the fragment needed to resolve a $ref.
func ReadInfoForRef(basefile string, ref string) (*yaml.Node, error) {
fileCacheMutex.Lock()
defer fileCacheMutex.Unlock()
infoCacheMutex.Lock()
defer infoCacheMutex.Unlock()
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initializeInfoCache()
if infoCacheEnable {
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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)
}
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}
basedir, _ := filepath.Split(basefile)
parts := strings.Split(ref, "#")
var filename string
if parts[0] != "" {
filename = parts[0]
if _, err := url.ParseRequestURI(parts[0]); err != nil {
// It is not an URL, so the file is local
filename = basedir + parts[0]
}
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} else {
filename = basefile
}
bytes, err := readBytesForFile(filename)
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if err != nil {
return nil, err
}
info, err := readInfoFromBytes(filename, bytes)
if info != nil && info.Kind == yaml.DocumentNode {
info = info.Content[0]
}
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if err != nil {
log.Printf("File error: %v\n", err)
} else {
if info == nil {
return nil, NewError(nil, fmt.Sprintf("could not resolve %s", ref))
}
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if len(parts) > 1 {
path := strings.Split(parts[1], "/")
for i, key := range path {
if i > 0 {
m := info
if true {
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found := false
for i := 0; i < len(m.Content); i += 2 {
if m.Content[i].Value == key {
info = m.Content[i+1]
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found = true
}
}
if !found {
infoCache[ref] = nil
return nil, NewError(nil, fmt.Sprintf("could not resolve %s", ref))
}
}
}
}
}
}
if infoCacheEnable {
infoCache[ref] = info
}
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return info, nil
}