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
15package mem
16
17import (
18	"bytes"
19	"errors"
20	"io"
21	"os"
22	"path/filepath"
23	"sync"
24	"sync/atomic"
25	"time"
26)
27
28const FilePathSeparator = string(filepath.Separator)
29
30type File struct {
31	// atomic requires 64-bit alignment for struct field access
32	at           int64
33	readDirCount int64
34	closed       bool
35	readOnly     bool
36	fileData     *FileData
37}
38
39func NewFileHandle(data *FileData) *File {
40	return &File{fileData: data}
41}
42
43func NewReadOnlyFileHandle(data *FileData) *File {
44	return &File{fileData: data, readOnly: true}
45}
46
47func (f File) Data() *FileData {
48	return f.fileData
49}
50
51type FileData struct {
52	sync.Mutex
53	name    string
54	data    []byte
55	memDir  Dir
56	dir     bool
57	mode    os.FileMode
58	modtime time.Time
59	uid     int
60	gid     int
61}
62
63func (d *FileData) Name() string {
64	d.Lock()
65	defer d.Unlock()
66	return d.name
67}
68
69func CreateFile(name string) *FileData {
70	return &FileData{name: name, mode: os.ModeTemporary, modtime: time.Now()}
71}
72
73func CreateDir(name string) *FileData {
74	return &FileData{name: name, memDir: &DirMap{}, dir: true}
75}
76
77func ChangeFileName(f *FileData, newname string) {
78	f.Lock()
79	f.name = newname
80	f.Unlock()
81}
82
83func SetMode(f *FileData, mode os.FileMode) {
84	f.Lock()
85	f.mode = mode
86	f.Unlock()
87}
88
89func SetModTime(f *FileData, mtime time.Time) {
90	f.Lock()
91	setModTime(f, mtime)
92	f.Unlock()
93}
94
95func setModTime(f *FileData, mtime time.Time) {
96	f.modtime = mtime
97}
98
99func SetUID(f *FileData, uid int) {
100	f.Lock()
101	f.uid = uid
102	f.Unlock()
103}
104
105func SetGID(f *FileData, gid int) {
106	f.Lock()
107	f.gid = gid
108	f.Unlock()
109}
110
111func GetFileInfo(f *FileData) *FileInfo {
112	return &FileInfo{f}
113}
114
115func (f *File) Open() error {
116	atomic.StoreInt64(&f.at, 0)
117	atomic.StoreInt64(&f.readDirCount, 0)
118	f.fileData.Lock()
119	f.closed = false
120	f.fileData.Unlock()
121	return nil
122}
123
124func (f *File) Close() error {
125	f.fileData.Lock()
126	f.closed = true
127	if !f.readOnly {
128		setModTime(f.fileData, time.Now())
129	}
130	f.fileData.Unlock()
131	return nil
132}
133
134func (f *File) Name() string {
135	return f.fileData.Name()
136}
137
138func (f *File) Stat() (os.FileInfo, error) {
139	return &FileInfo{f.fileData}, nil
140}
141
142func (f *File) Sync() error {
143	return nil
144}
145
146func (f *File) Readdir(count int) (res []os.FileInfo, err error) {
147	if !f.fileData.dir {
148		return nil, &os.PathError{Op: "readdir", Path: f.fileData.name, Err: errors.New("not a dir")}
149	}
150	var outLength int64
151
152	f.fileData.Lock()
153	files := f.fileData.memDir.Files()[f.readDirCount:]
154	if count > 0 {
155		if len(files) < count {
156			outLength = int64(len(files))
157		} else {
158			outLength = int64(count)
159		}
160		if len(files) == 0 {
161			err = io.EOF
162		}
163	} else {
164		outLength = int64(len(files))
165	}
166	f.readDirCount += outLength
167	f.fileData.Unlock()
168
169	res = make([]os.FileInfo, outLength)
170	for i := range res {
171		res[i] = &FileInfo{files[i]}
172	}
173
174	return res, err
175}
176
177func (f *File) Readdirnames(n int) (names []string, err error) {
178	fi, err := f.Readdir(n)
179	names = make([]string, len(fi))
180	for i, f := range fi {
181		_, names[i] = filepath.Split(f.Name())
182	}
183	return names, err
184}
185
186func (f *File) Read(b []byte) (n int, err error) {
187	f.fileData.Lock()
188	defer f.fileData.Unlock()
189	if f.closed == true {
190		return 0, ErrFileClosed
191	}
192	if len(b) > 0 && int(f.at) == len(f.fileData.data) {
193		return 0, io.EOF
194	}
195	if int(f.at) > len(f.fileData.data) {
196		return 0, io.ErrUnexpectedEOF
197	}
198	if len(f.fileData.data)-int(f.at) >= len(b) {
199		n = len(b)
200	} else {
201		n = len(f.fileData.data) - int(f.at)
202	}
203	copy(b, f.fileData.data[f.at:f.at+int64(n)])
204	atomic.AddInt64(&f.at, int64(n))
205	return
206}
207
208func (f *File) ReadAt(b []byte, off int64) (n int, err error) {
209	prev := atomic.LoadInt64(&f.at)
210	atomic.StoreInt64(&f.at, off)
211	n, err = f.Read(b)
212	atomic.StoreInt64(&f.at, prev)
213	return
214}
215
216func (f *File) Truncate(size int64) error {
217	if f.closed == true {
218		return ErrFileClosed
219	}
220	if f.readOnly {
221		return &os.PathError{Op: "truncate", Path: f.fileData.name, Err: errors.New("file handle is read only")}
222	}
223	if size < 0 {
224		return ErrOutOfRange
225	}
226	f.fileData.Lock()
227	defer f.fileData.Unlock()
228	if size > int64(len(f.fileData.data)) {
229		diff := size - int64(len(f.fileData.data))
230		f.fileData.data = append(f.fileData.data, bytes.Repeat([]byte{00}, int(diff))...)
231	} else {
232		f.fileData.data = f.fileData.data[0:size]
233	}
234	setModTime(f.fileData, time.Now())
235	return nil
236}
237
238func (f *File) Seek(offset int64, whence int) (int64, error) {
239	if f.closed == true {
240		return 0, ErrFileClosed
241	}
242	switch whence {
243	case io.SeekStart:
244		atomic.StoreInt64(&f.at, offset)
245	case io.SeekCurrent:
246		atomic.AddInt64(&f.at, offset)
247	case io.SeekEnd:
248		atomic.StoreInt64(&f.at, int64(len(f.fileData.data))+offset)
249	}
250	return f.at, nil
251}
252
253func (f *File) Write(b []byte) (n int, err error) {
254	if f.closed == true {
255		return 0, ErrFileClosed
256	}
257	if f.readOnly {
258		return 0, &os.PathError{Op: "write", Path: f.fileData.name, Err: errors.New("file handle is read only")}
259	}
260	n = len(b)
261	cur := atomic.LoadInt64(&f.at)
262	f.fileData.Lock()
263	defer f.fileData.Unlock()
264	diff := cur - int64(len(f.fileData.data))
265	var tail []byte
266	if n+int(cur) < len(f.fileData.data) {
267		tail = f.fileData.data[n+int(cur):]
268	}
269	if diff > 0 {
270		f.fileData.data = append(f.fileData.data, append(bytes.Repeat([]byte{00}, int(diff)), b...)...)
271		f.fileData.data = append(f.fileData.data, tail...)
272	} else {
273		f.fileData.data = append(f.fileData.data[:cur], b...)
274		f.fileData.data = append(f.fileData.data, tail...)
275	}
276	setModTime(f.fileData, time.Now())
277
278	atomic.AddInt64(&f.at, int64(n))
279	return
280}
281
282func (f *File) WriteAt(b []byte, off int64) (n int, err error) {
283	atomic.StoreInt64(&f.at, off)
284	return f.Write(b)
285}
286
287func (f *File) WriteString(s string) (ret int, err error) {
288	return f.Write([]byte(s))
289}
290
291func (f *File) Info() *FileInfo {
292	return &FileInfo{f.fileData}
293}
294
295type FileInfo struct {
296	*FileData
297}
298
299// Implements os.FileInfo
300func (s *FileInfo) Name() string {
301	s.Lock()
302	_, name := filepath.Split(s.name)
303	s.Unlock()
304	return name
305}
306func (s *FileInfo) Mode() os.FileMode {
307	s.Lock()
308	defer s.Unlock()
309	return s.mode
310}
311func (s *FileInfo) ModTime() time.Time {
312	s.Lock()
313	defer s.Unlock()
314	return s.modtime
315}
316func (s *FileInfo) IsDir() bool {
317	s.Lock()
318	defer s.Unlock()
319	return s.dir
320}
321func (s *FileInfo) Sys() interface{} { return nil }
322func (s *FileInfo) Size() int64 {
323	if s.IsDir() {
324		return int64(42)
325	}
326	s.Lock()
327	defer s.Unlock()
328	return int64(len(s.data))
329}
330
331var (
332	ErrFileClosed        = errors.New("File is closed")
333	ErrOutOfRange        = errors.New("Out of range")
334	ErrTooLarge          = errors.New("Too large")
335	ErrFileNotFound      = os.ErrNotExist
336	ErrFileExists        = os.ErrExist
337	ErrDestinationExists = os.ErrExist
338)
339