1 | const RandomAccessStorage = require('random-access-storage')
|
2 | const fs = require('fs')
|
3 | const path = require('path')
|
4 | const constants = fs.constants || require('constants')
|
5 |
|
6 | let fsext = null
|
7 | try {
|
8 | fsext = require('fs-native-extensions')
|
9 | } catch {
|
10 | try {
|
11 | fsext = {
|
12 | tryLock: require('fsctl').lock,
|
13 | sparse: () => Promise.resolve()
|
14 | }
|
15 | } catch {}
|
16 | }
|
17 |
|
18 | const RDWR = constants.O_RDWR
|
19 | const RDONLY = constants.O_RDONLY
|
20 | const WRONLY = constants.O_WRONLY
|
21 | const CREAT = constants.O_CREAT
|
22 |
|
23 | class Pool {
|
24 | constructor (maxSize) {
|
25 | this.maxSize = maxSize
|
26 | this.active = []
|
27 | }
|
28 |
|
29 | _onactive (file) {
|
30 |
|
31 | if (this.active.length >= this.maxSize) {
|
32 | const r = Math.floor(Math.random() * this.active.length)
|
33 | this.active[r].suspend()
|
34 | }
|
35 |
|
36 | file._pi = this.active.push(file) - 1
|
37 | }
|
38 |
|
39 | _oninactive (file) {
|
40 | const head = this.active.pop()
|
41 | if (head !== file) {
|
42 | head._pi = file._pi
|
43 | this.active[head._pi] = head
|
44 | }
|
45 | }
|
46 | }
|
47 |
|
48 | module.exports = class RandomAccessFile extends RandomAccessStorage {
|
49 | constructor (filename, opts = {}) {
|
50 | const size = opts.size || (opts.truncate ? 0 : -1)
|
51 |
|
52 | super()
|
53 |
|
54 | if (opts.directory) filename = path.join(opts.directory, path.resolve('/', filename).replace(/^\w+:\\/, ''))
|
55 |
|
56 | this.directory = opts.directory || null
|
57 | this.filename = filename
|
58 | this.fd = 0
|
59 |
|
60 | const {
|
61 | readable = true,
|
62 | writable = true
|
63 | } = opts
|
64 |
|
65 | this.mode = readable && writable ? RDWR : (readable ? RDONLY : WRONLY)
|
66 |
|
67 | this._pi = 0
|
68 | this._pool = opts.pool || null
|
69 | this._size = size
|
70 | this._rmdir = !!opts.rmdir
|
71 | this._lock = opts.lock === true
|
72 | this._sparse = opts.sparse === true
|
73 | this._alloc = opts.alloc || Buffer.allocUnsafe
|
74 | this._alwaysCreate = size >= 0
|
75 | }
|
76 |
|
77 | static createPool (maxSize) {
|
78 | return new Pool(maxSize)
|
79 | }
|
80 |
|
81 | _open (req) {
|
82 | const create = this._alwaysCreate || this.writing
|
83 | const self = this
|
84 | const mode = this.mode | (create ? CREAT : 0)
|
85 |
|
86 | if (create) fs.mkdir(path.dirname(this.filename), { recursive: true }, ondir)
|
87 | else ondir(null)
|
88 |
|
89 | function ondir (err) {
|
90 | if (err) return req.callback(err)
|
91 | fs.open(self.filename, mode, onopen)
|
92 | }
|
93 |
|
94 | function onopen (err, fd) {
|
95 | if (err) return onerror(err)
|
96 |
|
97 | self.fd = fd
|
98 |
|
99 | if (!self._lock || !fsext) return onlock(null)
|
100 |
|
101 |
|
102 | const shared = self.mode === RDONLY
|
103 |
|
104 | if (fsext.tryLock(self.fd, { shared })) onlock(null)
|
105 | else onlock(createLockError(self.filename))
|
106 | }
|
107 |
|
108 | function onlock (err) {
|
109 | if (err) return onerrorafteropen(err)
|
110 |
|
111 | if (!self._sparse || !fsext) return onsparse(null)
|
112 |
|
113 | fsext.sparse(self.fd).then(onsparse, onsparse)
|
114 | }
|
115 |
|
116 | function onsparse (err) {
|
117 | if (err) return onerrorafteropen(err)
|
118 |
|
119 | if (self._size < 0) return ontruncate(null)
|
120 |
|
121 | fs.ftruncate(self.fd, self._size, ontruncate)
|
122 | }
|
123 |
|
124 | function ontruncate (err) {
|
125 | if (err) return onerrorafteropen(err)
|
126 | if (self._pool !== null) self._pool._onactive(self)
|
127 | req.callback(null)
|
128 | }
|
129 |
|
130 | function onerror (err) {
|
131 | req.callback(err)
|
132 | }
|
133 |
|
134 | function onerrorafteropen (err) {
|
135 | fs.close(self.fd, function () {
|
136 | self.fd = 0
|
137 | onerror(err)
|
138 | })
|
139 | }
|
140 | }
|
141 |
|
142 | _write (req) {
|
143 | const data = req.data
|
144 | const fd = this.fd
|
145 |
|
146 | fs.write(fd, data, 0, req.size, req.offset, onwrite)
|
147 |
|
148 | function onwrite (err, wrote) {
|
149 | if (err) return req.callback(err)
|
150 |
|
151 | req.size -= wrote
|
152 | req.offset += wrote
|
153 |
|
154 | if (!req.size) return req.callback(null)
|
155 | fs.write(fd, data, data.length - req.size, req.size, req.offset, onwrite)
|
156 | }
|
157 | }
|
158 |
|
159 | _read (req) {
|
160 | const self = this
|
161 | const data = req.data || this._alloc(req.size)
|
162 | const fd = this.fd
|
163 |
|
164 | if (!req.size) return process.nextTick(readEmpty, req)
|
165 | fs.read(fd, data, 0, req.size, req.offset, onread)
|
166 |
|
167 | function onread (err, read) {
|
168 | if (err) return req.callback(err)
|
169 | if (!read) return req.callback(createReadError(self.filename, req.offset, req.size))
|
170 |
|
171 | req.size -= read
|
172 | req.offset += read
|
173 |
|
174 | if (!req.size) return req.callback(null, data)
|
175 | fs.read(fd, data, data.length - req.size, req.size, req.offset, onread)
|
176 | }
|
177 | }
|
178 |
|
179 | _del (req) {
|
180 | if (req.size === Infinity) return this._truncate(req)
|
181 |
|
182 | if (!fsext) return req.callback(null)
|
183 |
|
184 | fsext.trim(this.fd, req.offset, req.size).then(ontrim, ontrim)
|
185 |
|
186 | function ontrim (err) {
|
187 | req.callback(err)
|
188 | }
|
189 | }
|
190 |
|
191 | _truncate (req) {
|
192 | fs.ftruncate(this.fd, req.offset, ontruncate)
|
193 |
|
194 | function ontruncate (err) {
|
195 | req.callback(err)
|
196 | }
|
197 | }
|
198 |
|
199 | _stat (req) {
|
200 | fs.fstat(this.fd, onstat)
|
201 |
|
202 | function onstat (err, st) {
|
203 | req.callback(err, st)
|
204 | }
|
205 | }
|
206 |
|
207 | _close (req) {
|
208 | const self = this
|
209 |
|
210 | fs.close(this.fd, onclose)
|
211 |
|
212 | function onclose (err) {
|
213 | if (err) return req.callback(err)
|
214 | if (self._pool !== null) self._pool._oninactive(self)
|
215 | self.fd = 0
|
216 | req.callback(null)
|
217 | }
|
218 | }
|
219 |
|
220 | _unlink (req) {
|
221 | const self = this
|
222 |
|
223 | const root = this.directory && path.resolve(path.join(this.directory, '.'))
|
224 | let dir = path.resolve(path.dirname(this.filename))
|
225 |
|
226 | fs.unlink(this.filename, onunlink)
|
227 |
|
228 | function onunlink (err) {
|
229 |
|
230 | if (err && err.code === 'ENOENT') err = null
|
231 |
|
232 | if (err || !self._rmdir || !root || dir === root) return req.callback(err)
|
233 | fs.rmdir(dir, onrmdir)
|
234 | }
|
235 |
|
236 | function onrmdir (err) {
|
237 | dir = path.join(dir, '..')
|
238 | if (err || dir === root) return req.callback(null)
|
239 | fs.rmdir(dir, onrmdir)
|
240 | }
|
241 | }
|
242 | }
|
243 |
|
244 | function readEmpty (req) {
|
245 | req.callback(null, Buffer.alloc(0))
|
246 | }
|
247 |
|
248 | function createLockError (path) {
|
249 | const err = new Error('ELOCKED: File is locked')
|
250 | err.code = 'ELOCKED'
|
251 | err.path = path
|
252 | return err
|
253 | }
|
254 |
|
255 | function createReadError (path, offset, size) {
|
256 | const err = new Error('EPARTIALREAD: Could not satisfy length')
|
257 | err.code = 'EPARTIALREAD'
|
258 | err.path = path
|
259 | err.offset = offset
|
260 | err.size = size
|
261 | return err
|
262 | }
|