peridot/vendor/github.com/go-git/go-billy/v5/util/util.go

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2022-07-07 20:11:50 +00:00
package util
import (
"io"
"os"
"path/filepath"
"strconv"
"sync"
"time"
"github.com/go-git/go-billy/v5"
)
// RemoveAll removes path and any children it contains. It removes everything it
// can but returns the first error it encounters. If the path does not exist,
// RemoveAll returns nil (no error).
func RemoveAll(fs billy.Basic, path string) error {
fs, path = getUnderlyingAndPath(fs, path)
if r, ok := fs.(removerAll); ok {
return r.RemoveAll(path)
}
return removeAll(fs, path)
}
type removerAll interface {
RemoveAll(string) error
}
func removeAll(fs billy.Basic, path string) error {
// This implementation is adapted from os.RemoveAll.
// Simple case: if Remove works, we're done.
err := fs.Remove(path)
if err == nil || os.IsNotExist(err) {
return nil
}
// Otherwise, is this a directory we need to recurse into?
dir, serr := fs.Stat(path)
if serr != nil {
if os.IsNotExist(serr) {
return nil
}
return serr
}
if !dir.IsDir() {
// Not a directory; return the error from Remove.
return err
}
dirfs, ok := fs.(billy.Dir)
if !ok {
return billy.ErrNotSupported
}
// Directory.
fis, err := dirfs.ReadDir(path)
if err != nil {
if os.IsNotExist(err) {
// Race. It was deleted between the Lstat and Open.
// Return nil per RemoveAll's docs.
return nil
}
return err
}
// Remove contents & return first error.
err = nil
for _, fi := range fis {
cpath := fs.Join(path, fi.Name())
err1 := removeAll(fs, cpath)
if err == nil {
err = err1
}
}
// Remove directory.
err1 := fs.Remove(path)
if err1 == nil || os.IsNotExist(err1) {
return nil
}
if err == nil {
err = err1
}
return err
}
// WriteFile writes data to a file named by filename in the given filesystem.
// If the file does not exist, WriteFile creates it with permissions perm;
// otherwise WriteFile truncates it before writing.
func WriteFile(fs billy.Basic, filename string, data []byte, perm os.FileMode) error {
f, err := fs.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm)
if err != nil {
return err
}
n, err := f.Write(data)
if err == nil && n < len(data) {
err = io.ErrShortWrite
}
if err1 := f.Close(); err == nil {
err = err1
}
return err
}
// Random number state.
// We generate random temporary file names so that there's a good
// chance the file doesn't exist yet - keeps the number of tries in
// TempFile to a minimum.
var rand uint32
var randmu sync.Mutex
func reseed() uint32 {
return uint32(time.Now().UnixNano() + int64(os.Getpid()))
}
func nextSuffix() string {
randmu.Lock()
r := rand
if r == 0 {
r = reseed()
}
r = r*1664525 + 1013904223 // constants from Numerical Recipes
rand = r
randmu.Unlock()
return strconv.Itoa(int(1e9 + r%1e9))[1:]
}
// TempFile creates a new temporary file in the directory dir with a name
// beginning with prefix, opens the file for reading and writing, and returns
// the resulting *os.File. If dir is the empty string, TempFile uses the default
// directory for temporary files (see os.TempDir). Multiple programs calling
// TempFile simultaneously will not choose the same file. The caller can use
// f.Name() to find the pathname of the file. It is the caller's responsibility
// to remove the file when no longer needed.
func TempFile(fs billy.Basic, dir, prefix string) (f billy.File, err error) {
// This implementation is based on stdlib ioutil.TempFile.
if dir == "" {
dir = getTempDir(fs)
}
nconflict := 0
for i := 0; i < 10000; i++ {
name := filepath.Join(dir, prefix+nextSuffix())
f, err = fs.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600)
if os.IsExist(err) {
if nconflict++; nconflict > 10 {
randmu.Lock()
rand = reseed()
randmu.Unlock()
}
continue
}
break
}
return
}
// TempDir creates a new temporary directory in the directory dir
// with a name beginning with prefix and returns the path of the
// new directory. If dir is the empty string, TempDir uses the
// default directory for temporary files (see os.TempDir).
// Multiple programs calling TempDir simultaneously
// will not choose the same directory. It is the caller's responsibility
// to remove the directory when no longer needed.
func TempDir(fs billy.Dir, dir, prefix string) (name string, err error) {
// This implementation is based on stdlib ioutil.TempDir
if dir == "" {
dir = getTempDir(fs.(billy.Basic))
}
nconflict := 0
for i := 0; i < 10000; i++ {
try := filepath.Join(dir, prefix+nextSuffix())
err = fs.MkdirAll(try, 0700)
if os.IsExist(err) {
if nconflict++; nconflict > 10 {
randmu.Lock()
rand = reseed()
randmu.Unlock()
}
continue
}
if os.IsNotExist(err) {
if _, err := os.Stat(dir); os.IsNotExist(err) {
return "", err
}
}
if err == nil {
name = try
}
break
}
return
}
func getTempDir(fs billy.Basic) string {
ch, ok := fs.(billy.Chroot)
if !ok || ch.Root() == "" || ch.Root() == "/" || ch.Root() == string(filepath.Separator) {
return os.TempDir()
}
return ".tmp"
}
type underlying interface {
Underlying() billy.Basic
}
func getUnderlyingAndPath(fs billy.Basic, path string) (billy.Basic, string) {
u, ok := fs.(underlying)
if !ok {
return fs, path
}
if ch, ok := fs.(billy.Chroot); ok {
path = fs.Join(ch.Root(), path)
}
return u.Underlying(), path
}
// ReadFile reads the named file and returns the contents from the given filesystem.
// A successful call returns err == nil, not err == EOF.
// Because ReadFile reads the whole file, it does not treat an EOF from Read
// as an error to be reported.
func ReadFile(fs billy.Basic, name string) ([]byte, error) {
f, err := fs.Open(name)
if err != nil {
return nil, err
}
defer f.Close()
var size int
if info, err := fs.Stat(name); err == nil {
size64 := info.Size()
if int64(int(size64)) == size64 {
size = int(size64)
}
}
size++ // one byte for final read at EOF
// If a file claims a small size, read at least 512 bytes.
// In particular, files in Linux's /proc claim size 0 but
// then do not work right if read in small pieces,
// so an initial read of 1 byte would not work correctly.
if size < 512 {
size = 512
}
data := make([]byte, 0, size)
for {
if len(data) >= cap(data) {
d := append(data[:cap(data)], 0)
data = d[:len(data)]
}
n, err := f.Read(data[len(data):cap(data)])
data = data[:len(data)+n]
if err != nil {
if err == io.EOF {
err = nil
}
return data, err
}
}
}