/
memory.go
393 lines (310 loc) · 7.57 KB
/
memory.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
// Package memfs provides a billy filesystem base on memory.
package memfs // import "gopkg.in/src-d/go-billy.v4/memfs"
import (
"errors"
"fmt"
"io"
"os"
"path/filepath"
"strings"
"time"
"gopkg.in/src-d/go-billy.v4"
"gopkg.in/src-d/go-billy.v4/helper/chroot"
"gopkg.in/src-d/go-billy.v4/util"
)
const separator = filepath.Separator
// Memory a very convenient filesystem based on memory files
type Memory struct {
s *storage
tempCount int
}
//New returns a new Memory filesystem.
func New() billy.Filesystem {
fs := &Memory{s: newStorage()}
return chroot.New(fs, string(separator))
}
func (fs *Memory) Create(filename string) (billy.File, error) {
return fs.OpenFile(filename, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0666)
}
func (fs *Memory) Open(filename string) (billy.File, error) {
return fs.OpenFile(filename, os.O_RDONLY, 0)
}
func (fs *Memory) OpenFile(filename string, flag int, perm os.FileMode) (billy.File, error) {
f, has := fs.s.Get(filename)
if !has {
if !isCreate(flag) {
return nil, os.ErrNotExist
}
var err error
f, err = fs.s.New(filename, perm, flag)
if err != nil {
return nil, err
}
} else {
if target, isLink := fs.resolveLink(filename, f); isLink {
return fs.OpenFile(target, flag, perm)
}
}
if f.mode.IsDir() {
return nil, fmt.Errorf("cannot open directory: %s", filename)
}
return f.Duplicate(filename, perm, flag), nil
}
var errNotLink = errors.New("not a link")
func (fs *Memory) resolveLink(fullpath string, f *file) (target string, isLink bool) {
if !isSymlink(f.mode) {
return fullpath, false
}
target = string(f.content.bytes)
if !isAbs(target) {
target = fs.Join(filepath.Dir(fullpath), target)
}
return target, true
}
// On Windows OS, IsAbs validates if a path is valid based on if stars with a
// unit (eg.: `C:\`) to assert that is absolute, but in this mem implementation
// any path starting by `separator` is also considered absolute.
func isAbs(path string) bool {
return filepath.IsAbs(path) || strings.HasPrefix(path, string(separator))
}
func (fs *Memory) Stat(filename string) (os.FileInfo, error) {
f, has := fs.s.Get(filename)
if !has {
return nil, os.ErrNotExist
}
fi, _ := f.Stat()
var err error
if target, isLink := fs.resolveLink(filename, f); isLink {
fi, err = fs.Stat(target)
if err != nil {
return nil, err
}
}
// the name of the file should always the name of the stated file, so we
// overwrite the Stat returned from the storage with it, since the
// filename may belong to a link.
fi.(*fileInfo).name = filepath.Base(filename)
return fi, nil
}
func (fs *Memory) Lstat(filename string) (os.FileInfo, error) {
f, has := fs.s.Get(filename)
if !has {
return nil, os.ErrNotExist
}
return f.Stat()
}
func (fs *Memory) ReadDir(path string) ([]os.FileInfo, error) {
if f, has := fs.s.Get(path); has {
if target, isLink := fs.resolveLink(path, f); isLink {
return fs.ReadDir(target)
}
}
var entries []os.FileInfo
for _, f := range fs.s.Children(path) {
fi, _ := f.Stat()
entries = append(entries, fi)
}
return entries, nil
}
func (fs *Memory) MkdirAll(path string, perm os.FileMode) error {
_, err := fs.s.New(path, perm|os.ModeDir, 0)
return err
}
func (fs *Memory) TempFile(dir, prefix string) (billy.File, error) {
return util.TempFile(fs, dir, prefix)
}
func (fs *Memory) getTempFilename(dir, prefix string) string {
fs.tempCount++
filename := fmt.Sprintf("%s_%d_%d", prefix, fs.tempCount, time.Now().UnixNano())
return fs.Join(dir, filename)
}
func (fs *Memory) Rename(from, to string) error {
return fs.s.Rename(from, to)
}
func (fs *Memory) Remove(filename string) error {
return fs.s.Remove(filename)
}
func (fs *Memory) Join(elem ...string) string {
return filepath.Join(elem...)
}
func (fs *Memory) Symlink(target, link string) error {
_, err := fs.Stat(link)
if err == nil {
return os.ErrExist
}
if !os.IsNotExist(err) {
return err
}
return util.WriteFile(fs, link, []byte(target), 0777|os.ModeSymlink)
}
func (fs *Memory) Readlink(link string) (string, error) {
f, has := fs.s.Get(link)
if !has {
return "", os.ErrNotExist
}
if !isSymlink(f.mode) {
return "", &os.PathError{
Op: "readlink",
Path: link,
Err: fmt.Errorf("not a symlink"),
}
}
return string(f.content.bytes), nil
}
// Capabilities implements the Capable interface.
func (fs *Memory) Capabilities() billy.Capability {
return billy.WriteCapability |
billy.ReadCapability |
billy.ReadAndWriteCapability |
billy.SeekCapability |
billy.TruncateCapability
}
type file struct {
name string
content *content
position int64
flag int
mode os.FileMode
isClosed bool
}
func (f *file) Name() string {
return f.name
}
func (f *file) Read(b []byte) (int, error) {
n, err := f.ReadAt(b, f.position)
f.position += int64(n)
if err == io.EOF && n != 0 {
err = nil
}
return n, err
}
func (f *file) ReadAt(b []byte, off int64) (int, error) {
if f.isClosed {
return 0, os.ErrClosed
}
if !isReadAndWrite(f.flag) && !isReadOnly(f.flag) {
return 0, errors.New("read not supported")
}
n, err := f.content.ReadAt(b, off)
return n, err
}
func (f *file) Seek(offset int64, whence int) (int64, error) {
if f.isClosed {
return 0, os.ErrClosed
}
switch whence {
case io.SeekCurrent:
f.position += offset
case io.SeekStart:
f.position = offset
case io.SeekEnd:
f.position = int64(f.content.Len()) + offset
}
return f.position, nil
}
func (f *file) Write(p []byte) (int, error) {
if f.isClosed {
return 0, os.ErrClosed
}
if !isReadAndWrite(f.flag) && !isWriteOnly(f.flag) {
return 0, errors.New("write not supported")
}
n, err := f.content.WriteAt(p, f.position)
f.position += int64(n)
return n, err
}
func (f *file) Close() error {
if f.isClosed {
return os.ErrClosed
}
f.isClosed = true
return nil
}
func (f *file) Truncate(size int64) error {
if size < int64(len(f.content.bytes)) {
f.content.bytes = f.content.bytes[:size]
} else if more := int(size) - len(f.content.bytes); more > 0 {
f.content.bytes = append(f.content.bytes, make([]byte, more)...)
}
return nil
}
func (f *file) Duplicate(filename string, mode os.FileMode, flag int) billy.File {
new := &file{
name: filename,
content: f.content,
mode: mode,
flag: flag,
}
if isAppend(flag) {
new.position = int64(new.content.Len())
}
if isTruncate(flag) {
new.content.Truncate()
}
return new
}
func (f *file) Stat() (os.FileInfo, error) {
return &fileInfo{
name: f.Name(),
mode: f.mode,
size: f.content.Len(),
}, nil
}
// Lock is a no-op in memfs.
func (f *file) Lock() error {
return nil
}
// Unlock is a no-op in memfs.
func (f *file) Unlock() error {
return nil
}
type fileInfo struct {
name string
size int
mode os.FileMode
}
func (fi *fileInfo) Name() string {
return fi.name
}
func (fi *fileInfo) Size() int64 {
return int64(fi.size)
}
func (fi *fileInfo) Mode() os.FileMode {
return fi.mode
}
func (*fileInfo) ModTime() time.Time {
return time.Now()
}
func (fi *fileInfo) IsDir() bool {
return fi.mode.IsDir()
}
func (*fileInfo) Sys() interface{} {
return nil
}
func (c *content) Truncate() {
c.bytes = make([]byte, 0)
}
func (c *content) Len() int {
return len(c.bytes)
}
func isCreate(flag int) bool {
return flag&os.O_CREATE != 0
}
func isAppend(flag int) bool {
return flag&os.O_APPEND != 0
}
func isTruncate(flag int) bool {
return flag&os.O_TRUNC != 0
}
func isReadAndWrite(flag int) bool {
return flag&os.O_RDWR != 0
}
func isReadOnly(flag int) bool {
return flag == os.O_RDONLY
}
func isWriteOnly(flag int) bool {
return flag&os.O_WRONLY != 0
}
func isSymlink(m os.FileMode) bool {
return m&os.ModeSymlink != 0
}