gtsocial-umbx

ioutil.go (7131B)

---

 // Copyright ©2015 The Go Authors
 // Copyright ©2015 Steve Francia <spf@spf13.com>
 //
 // 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 afero
 
 import (
 	"bytes"
 	"io"
 	"os"
 	"path/filepath"
 	"sort"
 	"strconv"
 	"strings"
 	"sync"
 	"time"
 )
 
 // byName implements sort.Interface.
 type byName []os.FileInfo
 
 func (f byName) Len() int           { return len(f) }
 func (f byName) Less(i, j int) bool { return f[i].Name() < f[j].Name() }
 func (f byName) Swap(i, j int)      { f[i], f[j] = f[j], f[i] }
 
 // ReadDir reads the directory named by dirname and returns
 // a list of sorted directory entries.
 func (a Afero) ReadDir(dirname string) ([]os.FileInfo, error) {
 	return ReadDir(a.Fs, dirname)
 }
 
 func ReadDir(fs Fs, dirname string) ([]os.FileInfo, error) {
 	f, err := fs.Open(dirname)
 	if err != nil {
 		return nil, err
 	}
 	list, err := f.Readdir(-1)
 	f.Close()
 	if err != nil {
 		return nil, err
 	}
 	sort.Sort(byName(list))
 	return list, nil
 }
 
 // ReadFile reads the file named by filename and returns the contents.
 // 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 (a Afero) ReadFile(filename string) ([]byte, error) {
 	return ReadFile(a.Fs, filename)
 }
 
 func ReadFile(fs Fs, filename string) ([]byte, error) {
 	f, err := fs.Open(filename)
 	if err != nil {
 		return nil, err
 	}
 	defer f.Close()
 	// It's a good but not certain bet that FileInfo will tell us exactly how much to
 	// read, so let's try it but be prepared for the answer to be wrong.
 	var n int64
 
 	if fi, err := f.Stat(); err == nil {
 		// Don't preallocate a huge buffer, just in case.
 		if size := fi.Size(); size < 1e9 {
 			n = size
 		}
 	}
 	// As initial capacity for readAll, use n + a little extra in case Size is zero,
 	// and to avoid another allocation after Read has filled the buffer.  The readAll
 	// call will read into its allocated internal buffer cheaply.  If the size was
 	// wrong, we'll either waste some space off the end or reallocate as needed, but
 	// in the overwhelmingly common case we'll get it just right.
 	return readAll(f, n+bytes.MinRead)
 }
 
 // readAll reads from r until an error or EOF and returns the data it read
 // from the internal buffer allocated with a specified capacity.
 func readAll(r io.Reader, capacity int64) (b []byte, err error) {
 	buf := bytes.NewBuffer(make([]byte, 0, capacity))
 	// If the buffer overflows, we will get bytes.ErrTooLarge.
 	// Return that as an error. Any other panic remains.
 	defer func() {
 		e := recover()
 		if e == nil {
 			return
 		}
 		if panicErr, ok := e.(error); ok && panicErr == bytes.ErrTooLarge {
 			err = panicErr
 		} else {
 			panic(e)
 		}
 	}()
 	_, err = buf.ReadFrom(r)
 	return buf.Bytes(), err
 }
 
 // ReadAll reads from r until an error or EOF and returns the data it read.
 // A successful call returns err == nil, not err == EOF. Because ReadAll is
 // defined to read from src until EOF, it does not treat an EOF from Read
 // as an error to be reported.
 func ReadAll(r io.Reader) ([]byte, error) {
 	return readAll(r, bytes.MinRead)
 }
 
 // WriteFile writes data to a file named by filename.
 // If the file does not exist, WriteFile creates it with permissions perm;
 // otherwise WriteFile truncates it before writing.
 func (a Afero) WriteFile(filename string, data []byte, perm os.FileMode) error {
 	return WriteFile(a.Fs, filename, data, perm)
 }
 
 func WriteFile(fs Fs, 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 (
 	randNum uint32
 	randmu  sync.Mutex
 )
 
 func reseed() uint32 {
 	return uint32(time.Now().UnixNano() + int64(os.Getpid()))
 }
 
 func nextRandom() string {
 	randmu.Lock()
 	r := randNum
 	if r == 0 {
 		r = reseed()
 	}
 	r = r*1664525 + 1013904223 // constants from Numerical Recipes
 	randNum = r
 	randmu.Unlock()
 	return strconv.Itoa(int(1e9 + r%1e9))[1:]
 }
 
 // TempFile creates a new temporary file in the directory dir,
 // opens the file for reading and writing, and returns the resulting *os.File.
 // The filename is generated by taking pattern and adding a random
 // string to the end. If pattern includes a "*", the random string
 // replaces the last "*".
 // 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 (a Afero) TempFile(dir, pattern string) (f File, err error) {
 	return TempFile(a.Fs, dir, pattern)
 }
 
 func TempFile(fs Fs, dir, pattern string) (f File, err error) {
 	if dir == "" {
 		dir = os.TempDir()
 	}
 
 	var prefix, suffix string
 	if pos := strings.LastIndex(pattern, "*"); pos != -1 {
 		prefix, suffix = pattern[:pos], pattern[pos+1:]
 	} else {
 		prefix = pattern
 	}
 
 	nconflict := 0
 	for i := 0; i < 10000; i++ {
 		name := filepath.Join(dir, prefix+nextRandom()+suffix)
 		f, err = fs.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0o600)
 		if os.IsExist(err) {
 			if nconflict++; nconflict > 10 {
 				randmu.Lock()
 				randNum = 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 (a Afero) TempDir(dir, prefix string) (name string, err error) {
 	return TempDir(a.Fs, dir, prefix)
 }
 
 func TempDir(fs Fs, dir, prefix string) (name string, err error) {
 	if dir == "" {
 		dir = os.TempDir()
 	}
 
 	nconflict := 0
 	for i := 0; i < 10000; i++ {
 		try := filepath.Join(dir, prefix+nextRandom())
 		err = fs.Mkdir(try, 0o700)
 		if os.IsExist(err) {
 			if nconflict++; nconflict > 10 {
 				randmu.Lock()
 				randNum = reseed()
 				randmu.Unlock()
 			}
 			continue
 		}
 		if err == nil {
 			name = try
 		}
 		break
 	}
 	return
 }