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1'use strict'
2
3const WritableStream = require('node:stream').Writable
4const inherits = require('node:util').inherits
5
6const StreamSearch = require('../../streamsearch/sbmh')
7
8const PartStream = require('./PartStream')
9const HeaderParser = require('./HeaderParser')
10
11const DASH = 45
12const B_ONEDASH = Buffer.from('-')
13const B_CRLF = Buffer.from('\r\n')
14const EMPTY_FN = function () {}
15
16function Dicer (cfg) {
17  if (!(this instanceof Dicer)) { return new Dicer(cfg) }
18  WritableStream.call(this, cfg)
19
20  if (!cfg || (!cfg.headerFirst && typeof cfg.boundary !== 'string')) { throw new TypeError('Boundary required') }
21
22  if (typeof cfg.boundary === 'string') { this.setBoundary(cfg.boundary) } else { this._bparser = undefined }
23
24  this._headerFirst = cfg.headerFirst
25
26  this._dashes = 0
27  this._parts = 0
28  this._finished = false
29  this._realFinish = false
30  this._isPreamble = true
31  this._justMatched = false
32  this._firstWrite = true
33  this._inHeader = true
34  this._part = undefined
35  this._cb = undefined
36  this._ignoreData = false
37  this._partOpts = { highWaterMark: cfg.partHwm }
38  this._pause = false
39
40  const self = this
41  this._hparser = new HeaderParser(cfg)
42  this._hparser.on('header', function (header) {
43    self._inHeader = false
44    self._part.emit('header', header)
45  })
46}
47inherits(Dicer, WritableStream)
48
49Dicer.prototype.emit = function (ev) {
50  if (ev === 'finish' && !this._realFinish) {
51    if (!this._finished) {
52      const self = this
53      process.nextTick(function () {
54        self.emit('error', new Error('Unexpected end of multipart data'))
55        if (self._part && !self._ignoreData) {
56          const type = (self._isPreamble ? 'Preamble' : 'Part')
57          self._part.emit('error', new Error(type + ' terminated early due to unexpected end of multipart data'))
58          self._part.push(null)
59          process.nextTick(function () {
60            self._realFinish = true
61            self.emit('finish')
62            self._realFinish = false
63          })
64          return
65        }
66        self._realFinish = true
67        self.emit('finish')
68        self._realFinish = false
69      })
70    }
71  } else { WritableStream.prototype.emit.apply(this, arguments) }
72}
73
74Dicer.prototype._write = function (data, encoding, cb) {
75  // ignore unexpected data (e.g. extra trailer data after finished)
76  if (!this._hparser && !this._bparser) { return cb() }
77
78  if (this._headerFirst && this._isPreamble) {
79    if (!this._part) {
80      this._part = new PartStream(this._partOpts)
81      if (this.listenerCount('preamble') !== 0) { this.emit('preamble', this._part) } else { this._ignore() }
82    }
83    const r = this._hparser.push(data)
84    if (!this._inHeader && r !== undefined && r < data.length) { data = data.slice(r) } else { return cb() }
85  }
86
87  // allows for "easier" testing
88  if (this._firstWrite) {
89    this._bparser.push(B_CRLF)
90    this._firstWrite = false
91  }
92
93  this._bparser.push(data)
94
95  if (this._pause) { this._cb = cb } else { cb() }
96}
97
98Dicer.prototype.reset = function () {
99  this._part = undefined
100  this._bparser = undefined
101  this._hparser = undefined
102}
103
104Dicer.prototype.setBoundary = function (boundary) {
105  const self = this
106  this._bparser = new StreamSearch('\r\n--' + boundary)
107  this._bparser.on('info', function (isMatch, data, start, end) {
108    self._oninfo(isMatch, data, start, end)
109  })
110}
111
112Dicer.prototype._ignore = function () {
113  if (this._part && !this._ignoreData) {
114    this._ignoreData = true
115    this._part.on('error', EMPTY_FN)
116    // we must perform some kind of read on the stream even though we are
117    // ignoring the data, otherwise node's Readable stream will not emit 'end'
118    // after pushing null to the stream
119    this._part.resume()
120  }
121}
122
123Dicer.prototype._oninfo = function (isMatch, data, start, end) {
124  let buf; const self = this; let i = 0; let r; let shouldWriteMore = true
125
126  if (!this._part && this._justMatched && data) {
127    while (this._dashes < 2 && (start + i) < end) {
128      if (data[start + i] === DASH) {
129        ++i
130        ++this._dashes
131      } else {
132        if (this._dashes) { buf = B_ONEDASH }
133        this._dashes = 0
134        break
135      }
136    }
137    if (this._dashes === 2) {
138      if ((start + i) < end && this.listenerCount('trailer') !== 0) { this.emit('trailer', data.slice(start + i, end)) }
139      this.reset()
140      this._finished = true
141      // no more parts will be added
142      if (self._parts === 0) {
143        self._realFinish = true
144        self.emit('finish')
145        self._realFinish = false
146      }
147    }
148    if (this._dashes) { return }
149  }
150  if (this._justMatched) { this._justMatched = false }
151  if (!this._part) {
152    this._part = new PartStream(this._partOpts)
153    this._part._read = function (n) {
154      self._unpause()
155    }
156    if (this._isPreamble && this.listenerCount('preamble') !== 0) {
157      this.emit('preamble', this._part)
158    } else if (this._isPreamble !== true && this.listenerCount('part') !== 0) {
159      this.emit('part', this._part)
160    } else {
161      this._ignore()
162    }
163    if (!this._isPreamble) { this._inHeader = true }
164  }
165  if (data && start < end && !this._ignoreData) {
166    if (this._isPreamble || !this._inHeader) {
167      if (buf) { shouldWriteMore = this._part.push(buf) }
168      shouldWriteMore = this._part.push(data.slice(start, end))
169      if (!shouldWriteMore) { this._pause = true }
170    } else if (!this._isPreamble && this._inHeader) {
171      if (buf) { this._hparser.push(buf) }
172      r = this._hparser.push(data.slice(start, end))
173      if (!this._inHeader && r !== undefined && r < end) { this._oninfo(false, data, start + r, end) }
174    }
175  }
176  if (isMatch) {
177    this._hparser.reset()
178    if (this._isPreamble) { this._isPreamble = false } else {
179      if (start !== end) {
180        ++this._parts
181        this._part.on('end', function () {
182          if (--self._parts === 0) {
183            if (self._finished) {
184              self._realFinish = true
185              self.emit('finish')
186              self._realFinish = false
187            } else {
188              self._unpause()
189            }
190          }
191        })
192      }
193    }
194    this._part.push(null)
195    this._part = undefined
196    this._ignoreData = false
197    this._justMatched = true
198    this._dashes = 0
199  }
200}
201
202Dicer.prototype._unpause = function () {
203  if (!this._pause) { return }
204
205  this._pause = false
206  if (this._cb) {
207    const cb = this._cb
208    this._cb = undefined
209    cb()
210  }
211}
212
213module.exports = Dicer
214