aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/node_modules/undici/lib/fileapi/util.js
blob: 1d10899cee8291e162038bd2889576a63582d2a2 (plain) (blame)
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
'use strict'

const {
  kState,
  kError,
  kResult,
  kAborted,
  kLastProgressEventFired
} = require('./symbols')
const { ProgressEvent } = require('./progressevent')
const { getEncoding } = require('./encoding')
const { DOMException } = require('../fetch/constants')
const { serializeAMimeType, parseMIMEType } = require('../fetch/dataURL')
const { types } = require('util')
const { StringDecoder } = require('string_decoder')
const { btoa } = require('buffer')

/** @type {PropertyDescriptor} */
const staticPropertyDescriptors = {
  enumerable: true,
  writable: false,
  configurable: false
}

/**
 * @see https://w3c.github.io/FileAPI/#readOperation
 * @param {import('./filereader').FileReader} fr
 * @param {import('buffer').Blob} blob
 * @param {string} type
 * @param {string?} encodingName
 */
function readOperation (fr, blob, type, encodingName) {
  // 1. If fr’s state is "loading", throw an InvalidStateError
  //    DOMException.
  if (fr[kState] === 'loading') {
    throw new DOMException('Invalid state', 'InvalidStateError')
  }

  // 2. Set fr’s state to "loading".
  fr[kState] = 'loading'

  // 3. Set fr’s result to null.
  fr[kResult] = null

  // 4. Set fr’s error to null.
  fr[kError] = null

  // 5. Let stream be the result of calling get stream on blob.
  /** @type {import('stream/web').ReadableStream} */
  const stream = blob.stream()

  // 6. Let reader be the result of getting a reader from stream.
  const reader = stream.getReader()

  // 7. Let bytes be an empty byte sequence.
  /** @type {Uint8Array[]} */
  const bytes = []

  // 8. Let chunkPromise be the result of reading a chunk from
  //    stream with reader.
  let chunkPromise = reader.read()

  // 9. Let isFirstChunk be true.
  let isFirstChunk = true

  // 10. In parallel, while true:
  // Note: "In parallel" just means non-blocking
  // Note 2: readOperation itself cannot be async as double
  // reading the body would then reject the promise, instead
  // of throwing an error.
  ;(async () => {
    while (!fr[kAborted]) {
      // 1. Wait for chunkPromise to be fulfilled or rejected.
      try {
        const { done, value } = await chunkPromise

        // 2. If chunkPromise is fulfilled, and isFirstChunk is
        //    true, queue a task to fire a progress event called
        //    loadstart at fr.
        if (isFirstChunk && !fr[kAborted]) {
          queueMicrotask(() => {
            fireAProgressEvent('loadstart', fr)
          })
        }

        // 3. Set isFirstChunk to false.
        isFirstChunk = false

        // 4. If chunkPromise is fulfilled with an object whose
        //    done property is false and whose value property is
        //    a Uint8Array object, run these steps:
        if (!done && types.isUint8Array(value)) {
          // 1. Let bs be the byte sequence represented by the
          //    Uint8Array object.

          // 2. Append bs to bytes.
          bytes.push(value)

          // 3. If roughly 50ms have passed since these steps
          //    were last invoked, queue a task to fire a
          //    progress event called progress at fr.
          if (
            (
              fr[kLastProgressEventFired] === undefined ||
              Date.now() - fr[kLastProgressEventFired] >= 50
            ) &&
            !fr[kAborted]
          ) {
            fr[kLastProgressEventFired] = Date.now()
            queueMicrotask(() => {
              fireAProgressEvent('progress', fr)
            })
          }

          // 4. Set chunkPromise to the result of reading a
          //    chunk from stream with reader.
          chunkPromise = reader.read()
        } else if (done) {
          // 5. Otherwise, if chunkPromise is fulfilled with an
          //    object whose done property is true, queue a task
          //    to run the following steps and abort this algorithm:
          queueMicrotask(() => {
            // 1. Set fr’s state to "done".
            fr[kState] = 'done'

            // 2. Let result be the result of package data given
            //    bytes, type, blob’s type, and encodingName.
            try {
              const result = packageData(bytes, type, blob.type, encodingName)

              // 4. Else:

              if (fr[kAborted]) {
                return
              }

              // 1. Set fr’s result to result.
              fr[kResult] = result

              // 2. Fire a progress event called load at the fr.
              fireAProgressEvent('load', fr)
            } catch (error) {
              // 3. If package data threw an exception error:

              // 1. Set fr’s error to error.
              fr[kError] = error

              // 2. Fire a progress event called error at fr.
              fireAProgressEvent('error', fr)
            }

            // 5. If fr’s state is not "loading", fire a progress
            //    event called loadend at the fr.
            if (fr[kState] !== 'loading') {
              fireAProgressEvent('loadend', fr)
            }
          })

          break
        }
      } catch (error) {
        if (fr[kAborted]) {
          return
        }

        // 6. Otherwise, if chunkPromise is rejected with an
        //    error error, queue a task to run the following
        //    steps and abort this algorithm:
        queueMicrotask(() => {
          // 1. Set fr’s state to "done".
          fr[kState] = 'done'

          // 2. Set fr’s error to error.
          fr[kError] = error

          // 3. Fire a progress event called error at fr.
          fireAProgressEvent('error', fr)

          // 4. If fr’s state is not "loading", fire a progress
          //    event called loadend at fr.
          if (fr[kState] !== 'loading') {
            fireAProgressEvent('loadend', fr)
          }
        })

        break
      }
    }
  })()
}

/**
 * @see https://w3c.github.io/FileAPI/#fire-a-progress-event
 * @see https://dom.spec.whatwg.org/#concept-event-fire
 * @param {string} e The name of the event
 * @param {import('./filereader').FileReader} reader
 */
function fireAProgressEvent (e, reader) {
  // The progress event e does not bubble. e.bubbles must be false
  // The progress event e is NOT cancelable. e.cancelable must be false
  const event = new ProgressEvent(e, {
    bubbles: false,
    cancelable: false
  })

  reader.dispatchEvent(event)
}

/**
 * @see https://w3c.github.io/FileAPI/#blob-package-data
 * @param {Uint8Array[]} bytes
 * @param {string} type
 * @param {string?} mimeType
 * @param {string?} encodingName
 */
function packageData (bytes, type, mimeType, encodingName) {
  // 1. A Blob has an associated package data algorithm, given
  //    bytes, a type, a optional mimeType, and a optional
  //    encodingName, which switches on type and runs the
  //    associated steps:

  switch (type) {
    case 'DataURL': {
      // 1. Return bytes as a DataURL [RFC2397] subject to
      //    the considerations below:
      //  * Use mimeType as part of the Data URL if it is
      //    available in keeping with the Data URL
      //    specification [RFC2397].
      //  * If mimeType is not available return a Data URL
      //    without a media-type. [RFC2397].

      // https://datatracker.ietf.org/doc/html/rfc2397#section-3
      // dataurl    := "data:" [ mediatype ] [ ";base64" ] "," data
      // mediatype  := [ type "/" subtype ] *( ";" parameter )
      // data       := *urlchar
      // parameter  := attribute "=" value
      let dataURL = 'data:'

      const parsed = parseMIMEType(mimeType || 'application/octet-stream')

      if (parsed !== 'failure') {
        dataURL += serializeAMimeType(parsed)
      }

      dataURL += ';base64,'

      const decoder = new StringDecoder('latin1')

      for (const chunk of bytes) {
        dataURL += btoa(decoder.write(chunk))
      }

      dataURL += btoa(decoder.end())

      return dataURL
    }
    case 'Text': {
      // 1. Let encoding be failure
      let encoding = 'failure'

      // 2. If the encodingName is present, set encoding to the
      //    result of getting an encoding from encodingName.
      if (encodingName) {
        encoding = getEncoding(encodingName)
      }

      // 3. If encoding is failure, and mimeType is present:
      if (encoding === 'failure' && mimeType) {
        // 1. Let type be the result of parse a MIME type
        //    given mimeType.
        const type = parseMIMEType(mimeType)

        // 2. If type is not failure, set encoding to the result
        //    of getting an encoding from type’s parameters["charset"].
        if (type !== 'failure') {
          encoding = getEncoding(type.parameters.get('charset'))
        }
      }

      // 4. If encoding is failure, then set encoding to UTF-8.
      if (encoding === 'failure') {
        encoding = 'UTF-8'
      }

      // 5. Decode bytes using fallback encoding encoding, and
      //    return the result.
      return decode(bytes, encoding)
    }
    case 'ArrayBuffer': {
      // Return a new ArrayBuffer whose contents are bytes.
      const sequence = combineByteSequences(bytes)

      return sequence.buffer
    }
    case 'BinaryString': {
      // Return bytes as a binary string, in which every byte
      //  is represented by a code unit of equal value [0..255].
      let binaryString = ''

      const decoder = new StringDecoder('latin1')

      for (const chunk of bytes) {
        binaryString += decoder.write(chunk)
      }

      binaryString += decoder.end()

      return binaryString
    }
  }
}

/**
 * @see https://encoding.spec.whatwg.org/#decode
 * @param {Uint8Array[]} ioQueue
 * @param {string} encoding
 */
function decode (ioQueue, encoding) {
  const bytes = combineByteSequences(ioQueue)

  // 1. Let BOMEncoding be the result of BOM sniffing ioQueue.
  const BOMEncoding = BOMSniffing(bytes)

  let slice = 0

  // 2. If BOMEncoding is non-null:
  if (BOMEncoding !== null) {
    // 1. Set encoding to BOMEncoding.
    encoding = BOMEncoding

    // 2. Read three bytes from ioQueue, if BOMEncoding is
    //    UTF-8; otherwise read two bytes.
    //    (Do nothing with those bytes.)
    slice = BOMEncoding === 'UTF-8' ? 3 : 2
  }

  // 3. Process a queue with an instance of encoding’s
  //    decoder, ioQueue, output, and "replacement".

  // 4. Return output.

  const sliced = bytes.slice(slice)
  return new TextDecoder(encoding).decode(sliced)
}

/**
 * @see https://encoding.spec.whatwg.org/#bom-sniff
 * @param {Uint8Array} ioQueue
 */
function BOMSniffing (ioQueue) {
  // 1. Let BOM be the result of peeking 3 bytes from ioQueue,
  //    converted to a byte sequence.
  const [a, b, c] = ioQueue

  // 2. For each of the rows in the table below, starting with
  //    the first one and going down, if BOM starts with the
  //    bytes given in the first column, then return the
  //    encoding given in the cell in the second column of that
  //    row. Otherwise, return null.
  if (a === 0xEF && b === 0xBB && c === 0xBF) {
    return 'UTF-8'
  } else if (a === 0xFE && b === 0xFF) {
    return 'UTF-16BE'
  } else if (a === 0xFF && b === 0xFE) {
    return 'UTF-16LE'
  }

  return null
}

/**
 * @param {Uint8Array[]} sequences
 */
function combineByteSequences (sequences) {
  const size = sequences.reduce((a, b) => {
    return a + b.byteLength
  }, 0)

  let offset = 0

  return sequences.reduce((a, b) => {
    a.set(b, offset)
    offset += b.byteLength
    return a
  }, new Uint8Array(size))
}

module.exports = {
  staticPropertyDescriptors,
  readOperation,
  fireAProgressEvent
}