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file.go (7605B)

      1 // Copyright © 2015 Steve Francia <spf@spf13.com>.
      2 // Copyright 2013 tsuru authors. All rights reserved.
      3 //
      4 // Licensed under the Apache License, Version 2.0 (the "License");
      5 // you may not use this file except in compliance with the License.
      6 // You may obtain a copy of the License at
      7 // http://www.apache.org/licenses/LICENSE-2.0
      8 //
      9 // Unless required by applicable law or agreed to in writing, software
     10 // distributed under the License is distributed on an "AS IS" BASIS,
     11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     12 // See the License for the specific language governing permissions and
     13 // limitations under the License.
     14 
     15 package mem
     16 
     17 import (
     18 	"bytes"
     19 	"errors"
     20 	"io"
     21 	"io/fs"
     22 	"os"
     23 	"path/filepath"
     24 	"sync"
     25 	"sync/atomic"
     26 	"time"
     27 
     28 	"github.com/spf13/afero/internal/common"
     29 )
     30 
     31 const FilePathSeparator = string(filepath.Separator)
     32 
     33 var _ fs.ReadDirFile = &File{}
     34 
     35 type File struct {
     36 	// atomic requires 64-bit alignment for struct field access
     37 	at           int64
     38 	readDirCount int64
     39 	closed       bool
     40 	readOnly     bool
     41 	fileData     *FileData
     42 }
     43 
     44 func NewFileHandle(data *FileData) *File {
     45 	return &File{fileData: data}
     46 }
     47 
     48 func NewReadOnlyFileHandle(data *FileData) *File {
     49 	return &File{fileData: data, readOnly: true}
     50 }
     51 
     52 func (f File) Data() *FileData {
     53 	return f.fileData
     54 }
     55 
     56 type FileData struct {
     57 	sync.Mutex
     58 	name    string
     59 	data    []byte
     60 	memDir  Dir
     61 	dir     bool
     62 	mode    os.FileMode
     63 	modtime time.Time
     64 	uid     int
     65 	gid     int
     66 }
     67 
     68 func (d *FileData) Name() string {
     69 	d.Lock()
     70 	defer d.Unlock()
     71 	return d.name
     72 }
     73 
     74 func CreateFile(name string) *FileData {
     75 	return &FileData{name: name, mode: os.ModeTemporary, modtime: time.Now()}
     76 }
     77 
     78 func CreateDir(name string) *FileData {
     79 	return &FileData{name: name, memDir: &DirMap{}, dir: true, modtime: time.Now()}
     80 }
     81 
     82 func ChangeFileName(f *FileData, newname string) {
     83 	f.Lock()
     84 	f.name = newname
     85 	f.Unlock()
     86 }
     87 
     88 func SetMode(f *FileData, mode os.FileMode) {
     89 	f.Lock()
     90 	f.mode = mode
     91 	f.Unlock()
     92 }
     93 
     94 func SetModTime(f *FileData, mtime time.Time) {
     95 	f.Lock()
     96 	setModTime(f, mtime)
     97 	f.Unlock()
     98 }
     99 
    100 func setModTime(f *FileData, mtime time.Time) {
    101 	f.modtime = mtime
    102 }
    103 
    104 func SetUID(f *FileData, uid int) {
    105 	f.Lock()
    106 	f.uid = uid
    107 	f.Unlock()
    108 }
    109 
    110 func SetGID(f *FileData, gid int) {
    111 	f.Lock()
    112 	f.gid = gid
    113 	f.Unlock()
    114 }
    115 
    116 func GetFileInfo(f *FileData) *FileInfo {
    117 	return &FileInfo{f}
    118 }
    119 
    120 func (f *File) Open() error {
    121 	atomic.StoreInt64(&f.at, 0)
    122 	atomic.StoreInt64(&f.readDirCount, 0)
    123 	f.fileData.Lock()
    124 	f.closed = false
    125 	f.fileData.Unlock()
    126 	return nil
    127 }
    128 
    129 func (f *File) Close() error {
    130 	f.fileData.Lock()
    131 	f.closed = true
    132 	if !f.readOnly {
    133 		setModTime(f.fileData, time.Now())
    134 	}
    135 	f.fileData.Unlock()
    136 	return nil
    137 }
    138 
    139 func (f *File) Name() string {
    140 	return f.fileData.Name()
    141 }
    142 
    143 func (f *File) Stat() (os.FileInfo, error) {
    144 	return &FileInfo{f.fileData}, nil
    145 }
    146 
    147 func (f *File) Sync() error {
    148 	return nil
    149 }
    150 
    151 func (f *File) Readdir(count int) (res []os.FileInfo, err error) {
    152 	if !f.fileData.dir {
    153 		return nil, &os.PathError{Op: "readdir", Path: f.fileData.name, Err: errors.New("not a dir")}
    154 	}
    155 	var outLength int64
    156 
    157 	f.fileData.Lock()
    158 	files := f.fileData.memDir.Files()[f.readDirCount:]
    159 	if count > 0 {
    160 		if len(files) < count {
    161 			outLength = int64(len(files))
    162 		} else {
    163 			outLength = int64(count)
    164 		}
    165 		if len(files) == 0 {
    166 			err = io.EOF
    167 		}
    168 	} else {
    169 		outLength = int64(len(files))
    170 	}
    171 	f.readDirCount += outLength
    172 	f.fileData.Unlock()
    173 
    174 	res = make([]os.FileInfo, outLength)
    175 	for i := range res {
    176 		res[i] = &FileInfo{files[i]}
    177 	}
    178 
    179 	return res, err
    180 }
    181 
    182 func (f *File) Readdirnames(n int) (names []string, err error) {
    183 	fi, err := f.Readdir(n)
    184 	names = make([]string, len(fi))
    185 	for i, f := range fi {
    186 		_, names[i] = filepath.Split(f.Name())
    187 	}
    188 	return names, err
    189 }
    190 
    191 // Implements fs.ReadDirFile
    192 func (f *File) ReadDir(n int) ([]fs.DirEntry, error) {
    193 	fi, err := f.Readdir(n)
    194 	if err != nil {
    195 		return nil, err
    196 	}
    197 	di := make([]fs.DirEntry, len(fi))
    198 	for i, f := range fi {
    199 		di[i] = common.FileInfoDirEntry{FileInfo: f}
    200 	}
    201 	return di, nil
    202 }
    203 
    204 func (f *File) Read(b []byte) (n int, err error) {
    205 	f.fileData.Lock()
    206 	defer f.fileData.Unlock()
    207 	if f.closed {
    208 		return 0, ErrFileClosed
    209 	}
    210 	if len(b) > 0 && int(f.at) == len(f.fileData.data) {
    211 		return 0, io.EOF
    212 	}
    213 	if int(f.at) > len(f.fileData.data) {
    214 		return 0, io.ErrUnexpectedEOF
    215 	}
    216 	if len(f.fileData.data)-int(f.at) >= len(b) {
    217 		n = len(b)
    218 	} else {
    219 		n = len(f.fileData.data) - int(f.at)
    220 	}
    221 	copy(b, f.fileData.data[f.at:f.at+int64(n)])
    222 	atomic.AddInt64(&f.at, int64(n))
    223 	return
    224 }
    225 
    226 func (f *File) ReadAt(b []byte, off int64) (n int, err error) {
    227 	prev := atomic.LoadInt64(&f.at)
    228 	atomic.StoreInt64(&f.at, off)
    229 	n, err = f.Read(b)
    230 	atomic.StoreInt64(&f.at, prev)
    231 	return
    232 }
    233 
    234 func (f *File) Truncate(size int64) error {
    235 	if f.closed {
    236 		return ErrFileClosed
    237 	}
    238 	if f.readOnly {
    239 		return &os.PathError{Op: "truncate", Path: f.fileData.name, Err: errors.New("file handle is read only")}
    240 	}
    241 	if size < 0 {
    242 		return ErrOutOfRange
    243 	}
    244 	f.fileData.Lock()
    245 	defer f.fileData.Unlock()
    246 	if size > int64(len(f.fileData.data)) {
    247 		diff := size - int64(len(f.fileData.data))
    248 		f.fileData.data = append(f.fileData.data, bytes.Repeat([]byte{0o0}, int(diff))...)
    249 	} else {
    250 		f.fileData.data = f.fileData.data[0:size]
    251 	}
    252 	setModTime(f.fileData, time.Now())
    253 	return nil
    254 }
    255 
    256 func (f *File) Seek(offset int64, whence int) (int64, error) {
    257 	if f.closed {
    258 		return 0, ErrFileClosed
    259 	}
    260 	switch whence {
    261 	case io.SeekStart:
    262 		atomic.StoreInt64(&f.at, offset)
    263 	case io.SeekCurrent:
    264 		atomic.AddInt64(&f.at, offset)
    265 	case io.SeekEnd:
    266 		atomic.StoreInt64(&f.at, int64(len(f.fileData.data))+offset)
    267 	}
    268 	return f.at, nil
    269 }
    270 
    271 func (f *File) Write(b []byte) (n int, err error) {
    272 	if f.closed {
    273 		return 0, ErrFileClosed
    274 	}
    275 	if f.readOnly {
    276 		return 0, &os.PathError{Op: "write", Path: f.fileData.name, Err: errors.New("file handle is read only")}
    277 	}
    278 	n = len(b)
    279 	cur := atomic.LoadInt64(&f.at)
    280 	f.fileData.Lock()
    281 	defer f.fileData.Unlock()
    282 	diff := cur - int64(len(f.fileData.data))
    283 	var tail []byte
    284 	if n+int(cur) < len(f.fileData.data) {
    285 		tail = f.fileData.data[n+int(cur):]
    286 	}
    287 	if diff > 0 {
    288 		f.fileData.data = append(f.fileData.data, append(bytes.Repeat([]byte{0o0}, int(diff)), b...)...)
    289 		f.fileData.data = append(f.fileData.data, tail...)
    290 	} else {
    291 		f.fileData.data = append(f.fileData.data[:cur], b...)
    292 		f.fileData.data = append(f.fileData.data, tail...)
    293 	}
    294 	setModTime(f.fileData, time.Now())
    295 
    296 	atomic.AddInt64(&f.at, int64(n))
    297 	return
    298 }
    299 
    300 func (f *File) WriteAt(b []byte, off int64) (n int, err error) {
    301 	atomic.StoreInt64(&f.at, off)
    302 	return f.Write(b)
    303 }
    304 
    305 func (f *File) WriteString(s string) (ret int, err error) {
    306 	return f.Write([]byte(s))
    307 }
    308 
    309 func (f *File) Info() *FileInfo {
    310 	return &FileInfo{f.fileData}
    311 }
    312 
    313 type FileInfo struct {
    314 	*FileData
    315 }
    316 
    317 // Implements os.FileInfo
    318 func (s *FileInfo) Name() string {
    319 	s.Lock()
    320 	_, name := filepath.Split(s.name)
    321 	s.Unlock()
    322 	return name
    323 }
    324 
    325 func (s *FileInfo) Mode() os.FileMode {
    326 	s.Lock()
    327 	defer s.Unlock()
    328 	return s.mode
    329 }
    330 
    331 func (s *FileInfo) ModTime() time.Time {
    332 	s.Lock()
    333 	defer s.Unlock()
    334 	return s.modtime
    335 }
    336 
    337 func (s *FileInfo) IsDir() bool {
    338 	s.Lock()
    339 	defer s.Unlock()
    340 	return s.dir
    341 }
    342 func (s *FileInfo) Sys() interface{} { return nil }
    343 func (s *FileInfo) Size() int64 {
    344 	if s.IsDir() {
    345 		return int64(42)
    346 	}
    347 	s.Lock()
    348 	defer s.Unlock()
    349 	return int64(len(s.data))
    350 }
    351 
    352 var (
    353 	ErrFileClosed        = errors.New("File is closed")
    354 	ErrOutOfRange        = errors.New("out of range")
    355 	ErrTooLarge          = errors.New("too large")
    356 	ErrFileNotFound      = os.ErrNotExist
    357 	ErrFileExists        = os.ErrExist
    358 	ErrDestinationExists = os.ErrExist
    359 )