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Source file src/github.com/spf13/afero/mem/file.go

Documentation: github.com/spf13/afero/mem

     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  )
   360  

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