/
mmap.go
230 lines (204 loc) · 4.72 KB
/
mmap.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
//go:build !wasm
// +build !wasm
package storage
import (
"errors"
"fmt"
"io"
"os"
"path/filepath"
"github.com/anacrolix/missinggo/v2"
"github.com/edsrzf/mmap-go"
"github.com/anacrolix/torrent/metainfo"
"github.com/anacrolix/torrent/mmap_span"
)
type mmapClientImpl struct {
baseDir string
pc PieceCompletion
}
// TODO: Support all the same native filepath configuration that NewFileOpts provides.
func NewMMap(baseDir string) ClientImplCloser {
return NewMMapWithCompletion(baseDir, pieceCompletionForDir(baseDir))
}
func NewMMapWithCompletion(baseDir string, completion PieceCompletion) *mmapClientImpl {
return &mmapClientImpl{
baseDir: baseDir,
pc: completion,
}
}
func (s *mmapClientImpl) OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (_ TorrentImpl, err error) {
span, err := mMapTorrent(info, s.baseDir)
t := &mmapTorrentStorage{
infoHash: infoHash,
span: span,
pc: s.pc,
}
return TorrentImpl{Piece: t.Piece, Close: t.Close, Flush: t.Flush}, err
}
func (s *mmapClientImpl) Close() error {
return s.pc.Close()
}
type mmapTorrentStorage struct {
infoHash metainfo.Hash
span *mmap_span.MMapSpan
pc PieceCompletionGetSetter
}
func (ts *mmapTorrentStorage) Piece(p metainfo.Piece) PieceImpl {
return mmapStoragePiece{
pc: ts.pc,
p: p,
ih: ts.infoHash,
ReaderAt: io.NewSectionReader(ts.span, p.Offset(), p.Length()),
WriterAt: missinggo.NewSectionWriter(ts.span, p.Offset(), p.Length()),
}
}
func (ts *mmapTorrentStorage) Close() error {
errs := ts.span.Close()
if len(errs) > 0 {
return errs[0]
}
return nil
}
func (ts *mmapTorrentStorage) Flush() error {
errs := ts.span.Flush()
if len(errs) > 0 {
return errs[0]
}
return nil
}
type mmapStoragePiece struct {
pc PieceCompletionGetSetter
p metainfo.Piece
ih metainfo.Hash
io.ReaderAt
io.WriterAt
}
func (me mmapStoragePiece) pieceKey() metainfo.PieceKey {
return metainfo.PieceKey{me.ih, me.p.Index()}
}
func (sp mmapStoragePiece) Completion() Completion {
c, err := sp.pc.Get(sp.pieceKey())
if err != nil {
panic(err)
}
return c
}
func (sp mmapStoragePiece) MarkComplete() error {
sp.pc.Set(sp.pieceKey(), true)
return nil
}
func (sp mmapStoragePiece) MarkNotComplete() error {
sp.pc.Set(sp.pieceKey(), false)
return nil
}
func mMapTorrent(md *metainfo.Info, location string) (mms *mmap_span.MMapSpan, err error) {
mms = &mmap_span.MMapSpan{}
defer func() {
if err != nil {
mms.Close()
}
}()
for _, miFile := range md.UpvertedFiles() {
var safeName string
safeName, err = ToSafeFilePath(append([]string{md.Name}, miFile.Path...)...)
if err != nil {
return
}
fileName := filepath.Join(location, safeName)
var mm FileMapping
mm, err = mmapFile(fileName, miFile.Length)
if err != nil {
err = fmt.Errorf("file %q: %s", miFile.DisplayPath(md), err)
return
}
mms.Append(mm)
}
mms.InitIndex()
return
}
func mmapFile(name string, size int64) (_ FileMapping, err error) {
dir := filepath.Dir(name)
err = os.MkdirAll(dir, 0o750)
if err != nil {
err = fmt.Errorf("making directory %q: %s", dir, err)
return
}
var file *os.File
file, err = os.OpenFile(name, os.O_CREATE|os.O_RDWR, 0o666)
if err != nil {
return
}
defer func() {
if err != nil {
file.Close()
}
}()
var fi os.FileInfo
fi, err = file.Stat()
if err != nil {
return
}
if fi.Size() < size {
// I think this is necessary on HFS+. Maybe Linux will SIGBUS too if
// you overmap a file but I'm not sure.
err = file.Truncate(size)
if err != nil {
return
}
}
return func() (ret mmapWithFile, err error) {
ret.f = file
if size == 0 {
// Can't mmap() regions with length 0.
return
}
intLen := int(size)
if int64(intLen) != size {
err = errors.New("size too large for system")
return
}
ret.mmap, err = mmap.MapRegion(file, intLen, mmap.RDWR, 0, 0)
if err != nil {
err = fmt.Errorf("error mapping region: %s", err)
return
}
if int64(len(ret.mmap)) != size {
panic(len(ret.mmap))
}
return
}()
}
// Combines a mmapped region and file into a storage Mmap abstraction, which handles closing the
// mmap file handle.
func WrapFileMapping(region mmap.MMap, file *os.File) FileMapping {
return mmapWithFile{
f: file,
mmap: region,
}
}
type FileMapping = mmap_span.Mmap
// Handles closing the mmap's file handle (needed for Windows). Could be implemented differently by
// OS.
type mmapWithFile struct {
f *os.File
mmap mmap.MMap
}
func (m mmapWithFile) Flush() error {
return m.mmap.Flush()
}
func (m mmapWithFile) Unmap() (err error) {
if m.mmap != nil {
err = m.mmap.Unmap()
}
fileErr := m.f.Close()
if err == nil {
err = fileErr
}
return
}
func (m mmapWithFile) Bytes() []byte {
if m.mmap == nil {
return nil
}
return m.mmap
}