vendor/github.com/spf13/afero/mem/file.go

   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         "os"
  22         "path/filepath"
  23         "sync"
  24         "sync/atomic"
  25 )
  26
  27 import "time"
  28
  29 const FilePathSeparator = string(filepath.Separator)
  30
  31 type File struct {
  32         // atomic requires 64-bit alignment for struct field access
  33         at           int64
  34         readDirCount int64
  35         closed       bool
  36         readOnly     bool
  37         fileData     *FileData
  38 }
  39
  40 func NewFileHandle(data *FileData) *File {
  41         return &File{fileData: data}
  42 }
  43
  44 func NewReadOnlyFileHandle(data *FileData) *File {
  45         return &File{fileData: data, readOnly: true}
  46 }
  47
  48 func (f File) Data() *FileData {
  49         return f.fileData
  50 }
  51
  52 type FileData struct {
  53         sync.Mutex
  54         name    string
  55         data    []byte
  56         memDir  Dir
  57         dir     bool
  58         mode    os.FileMode
  59         modtime time.Time
  60 }
  61
  62 func (d *FileData) Name() string {
  63         d.Lock()
  64         defer d.Unlock()
  65         return d.name
  66 }
  67
  68 func CreateFile(name string) *FileData {
  69         return &FileData{name: name, mode: os.ModeTemporary, modtime: time.Now()}
  70 }
  71
  72 func CreateDir(name string) *FileData {
  73         return &FileData{name: name, memDir: &DirMap{}, dir: true}
  74 }
  75
  76 func ChangeFileName(f *FileData, newname string) {
  77         f.Lock()
  78         f.name = newname
  79         f.Unlock()
  80 }
  81
  82 func SetMode(f *FileData, mode os.FileMode) {
  83         f.Lock()
  84         f.mode = mode
  85         f.Unlock()
  86 }
  87
  88 func SetModTime(f *FileData, mtime time.Time) {
  89         f.Lock()
  90         setModTime(f, mtime)
  91         f.Unlock()
  92 }
  93
  94 func setModTime(f *FileData, mtime time.Time) {
  95         f.modtime = mtime
  96 }
  97
  98 func GetFileInfo(f *FileData) *FileInfo {
  99         return &FileInfo{f}
 100 }
 101
 102 func (f *File) Open() error {
 103         atomic.StoreInt64(&f.at, 0)
 104         atomic.StoreInt64(&f.readDirCount, 0)
 105         f.fileData.Lock()
 106         f.closed = false
 107         f.fileData.Unlock()
 108         return nil
 109 }
 110
 111 func (f *File) Close() error {
 112         f.fileData.Lock()
 113         f.closed = true
 114         if !f.readOnly {
 115                 setModTime(f.fileData, time.Now())
 116         }
 117         f.fileData.Unlock()
 118         return nil
 119 }
 120
 121 func (f *File) Name() string {
 122         return f.fileData.Name()
 123 }
 124
 125 func (f *File) Stat() (os.FileInfo, error) {
 126         return &FileInfo{f.fileData}, nil
 127 }
 128
 129 func (f *File) Sync() error {
 130         return nil
 131 }
 132
 133 func (f *File) Readdir(count int) (res []os.FileInfo, err error) {
 134         if !f.fileData.dir {
 135                 return nil, &os.PathError{Op: "readdir", Path: f.fileData.name, Err: errors.New("not a dir")}
 136         }
 137         var outLength int64
 138
 139         f.fileData.Lock()
 140         files := f.fileData.memDir.Files()[f.readDirCount:]
 141         if count > 0 {
 142                 if len(files) < count {
 143                         outLength = int64(len(files))
 144                 } else {
 145                         outLength = int64(count)
 146                 }
 147                 if len(files) == 0 {
 148                         err = io.EOF
 149                 }
 150         } else {
 151                 outLength = int64(len(files))
 152         }
 153         f.readDirCount += outLength
 154         f.fileData.Unlock()
 155
 156         res = make([]os.FileInfo, outLength)
 157         for i := range res {
 158                 res[i] = &FileInfo{files[i]}
 159         }
 160
 161         return res, err
 162 }
 163
 164 func (f *File) Readdirnames(n int) (names []string, err error) {
 165         fi, err := f.Readdir(n)
 166         names = make([]string, len(fi))
 167         for i, f := range fi {
 168                 _, names[i] = filepath.Split(f.Name())
 169         }
 170         return names, err
 171 }
 172
 173 func (f *File) Read(b []byte) (n int, err error) {
 174         f.fileData.Lock()
 175         defer f.fileData.Unlock()
 176         if f.closed == true {
 177                 return 0, ErrFileClosed
 178         }
 179         if len(b) > 0 && int(f.at) == len(f.fileData.data) {
 180                 return 0, io.EOF
 181         }
 182         if int(f.at) > len(f.fileData.data) {
 183                 return 0, io.ErrUnexpectedEOF
 184         }
 185         if len(f.fileData.data)-int(f.at) >= len(b) {
 186                 n = len(b)
 187         } else {
 188                 n = len(f.fileData.data) - int(f.at)
 189         }
 190         copy(b, f.fileData.data[f.at:f.at+int64(n)])
 191         atomic.AddInt64(&f.at, int64(n))
 192         return
 193 }
 194
 195 func (f *File) ReadAt(b []byte, off int64) (n int, err error) {
 196         atomic.StoreInt64(&f.at, off)
 197         return f.Read(b)
 198 }
 199
 200 func (f *File) Truncate(size int64) error {
 201         if f.closed == true {
 202                 return ErrFileClosed
 203         }
 204         if f.readOnly {
 205                 return &os.PathError{Op: "truncate", Path: f.fileData.name, Err: errors.New("file handle is read only")}
 206         }
 207         if size < 0 {
 208                 return ErrOutOfRange
 209         }
 210         if size > int64(len(f.fileData.data)) {
 211                 diff := size - int64(len(f.fileData.data))
 212                 f.fileData.data = append(f.fileData.data, bytes.Repeat([]byte{00}, int(diff))...)
 213         } else {
 214                 f.fileData.data = f.fileData.data[0:size]
 215         }
 216         setModTime(f.fileData, time.Now())
 217         return nil
 218 }
 219
 220 func (f *File) Seek(offset int64, whence int) (int64, error) {
 221         if f.closed == true {
 222                 return 0, ErrFileClosed
 223         }
 224         switch whence {
 225         case 0:
 226                 atomic.StoreInt64(&f.at, offset)
 227         case 1:
 228                 atomic.AddInt64(&f.at, int64(offset))
 229         case 2:
 230                 atomic.StoreInt64(&f.at, int64(len(f.fileData.data))+offset)
 231         }
 232         return f.at, nil
 233 }
 234
 235 func (f *File) Write(b []byte) (n int, err error) {
 236         if f.readOnly {
 237                 return 0, &os.PathError{Op: "write", Path: f.fileData.name, Err: errors.New("file handle is read only")}
 238         }
 239         n = len(b)
 240         cur := atomic.LoadInt64(&f.at)
 241         f.fileData.Lock()
 242         defer f.fileData.Unlock()
 243         diff := cur - int64(len(f.fileData.data))
 244         var tail []byte
 245         if n+int(cur) < len(f.fileData.data) {
 246                 tail = f.fileData.data[n+int(cur):]
 247         }
 248         if diff > 0 {
 249                 f.fileData.data = append(bytes.Repeat([]byte{00}, int(diff)), b...)
 250                 f.fileData.data = append(f.fileData.data, tail...)
 251         } else {
 252                 f.fileData.data = append(f.fileData.data[:cur], b...)
 253                 f.fileData.data = append(f.fileData.data, tail...)
 254         }
 255         setModTime(f.fileData, time.Now())
 256
 257         atomic.StoreInt64(&f.at, int64(len(f.fileData.data)))
 258         return
 259 }
 260
 261 func (f *File) WriteAt(b []byte, off int64) (n int, err error) {
 262         atomic.StoreInt64(&f.at, off)
 263         return f.Write(b)
 264 }
 265
 266 func (f *File) WriteString(s string) (ret int, err error) {
 267         return f.Write([]byte(s))
 268 }
 269
 270 func (f *File) Info() *FileInfo {
 271         return &FileInfo{f.fileData}
 272 }
 273
 274 type FileInfo struct {
 275         *FileData
 276 }
 277
 278 // Implements os.FileInfo
 279 func (s *FileInfo) Name() string {
 280         s.Lock()
 281         _, name := filepath.Split(s.name)
 282         s.Unlock()
 283         return name
 284 }
 285 func (s *FileInfo) Mode() os.FileMode {
 286         s.Lock()
 287         defer s.Unlock()
 288         return s.mode
 289 }
 290 func (s *FileInfo) ModTime() time.Time {
 291         s.Lock()
 292         defer s.Unlock()
 293         return s.modtime
 294 }
 295 func (s *FileInfo) IsDir() bool {
 296         s.Lock()
 297         defer s.Unlock()
 298         return s.dir
 299 }
 300 func (s *FileInfo) Sys() interface{} { return nil }
 301 func (s *FileInfo) Size() int64 {
 302         if s.IsDir() {
 303                 return int64(42)
 304         }
 305         s.Lock()
 306         defer s.Unlock()
 307         return int64(len(s.data))
 308 }
 309
 310 var (
 311         ErrFileClosed        = errors.New("File is closed")
 312         ErrOutOfRange        = errors.New("Out of range")
 313         ErrTooLarge          = errors.New("Too large")
 314         ErrFileNotFound      = os.ErrNotExist
 315         ErrFileExists        = os.ErrExist
 316         ErrDestinationExists = os.ErrExist
 317 )