329 lines
8.1 KiB
JavaScript
329 lines
8.1 KiB
JavaScript
import { EventEmitter } from 'node:events'
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var s = 0,
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STATE_DICT = {
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PARSER_UNINITIALIZED: s++,
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START: s++,
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START_BOUNDARY: s++,
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HEADER_FIELD_START: s++,
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HEADER_FIELD: s++,
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HEADER_VALUE_START: s++,
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HEADER_VALUE: s++,
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HEADER_VALUE_ALMOST_DONE: s++,
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HEADERS_ALMOST_DONE: s++,
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PART_DATA_START: s++,
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PART_DATA: s++,
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PART_END: s++,
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END: s++
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},
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f = 1,
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F = {
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PART_BOUNDARY: f,
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LAST_BOUNDARY: (f *= 2)
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},
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LF = 10,
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CR = 13,
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SPACE = 32,
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HYPHEN = 45,
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COLON = 58,
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A = 97,
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Z = 122,
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lower = function (c) {
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return c | 0x20
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}
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function stateToString(stateNumber) {
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for (let state in STATE_DICT) {
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let number = STATE_DICT[state]
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if (number === stateNumber) {
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return state
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}
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}
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}
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export class MultipartParser extends EventEmitter {
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boundary = null
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boundaryChars = null
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lookbehind = null
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state = STATE_DICT.PARSER_UNINITIALIZED
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index = null
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flags = 0
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constructor(str) {
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super()
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this.boundary = Buffer.alloc(str.length + 4)
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this.boundary.write('\r\n--', 0)
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this.boundary.write(str, 4)
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this.lookbehind = Buffer.alloc(this.boundary.length + 8)
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this.state = STATE_DICT.START
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this.boundaryChars = {}
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for (let i = 0; i < this.boundary.length; i++) {
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this.boundaryChars[this.boundary[i]] = true
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}
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}
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write(buffer) {
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var i = 0,
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len = buffer.length,
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prevIndex = this.index,
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index = this.index,
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state = this.state,
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flags = this.flags,
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lookbehind = this.lookbehind,
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boundary = this.boundary,
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boundaryChars = this.boundaryChars,
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boundaryLength = this.boundary.length,
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boundaryEnd = boundaryLength - 1,
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bufferLength = buffer.length,
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c,
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cl
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let mark = (name) => {
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this[name + 'Mark'] = i
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},
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dataCallback = (name, clear) => {
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var markSymbol = name + 'Mark'
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if ((markSymbol in this)) {
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if (clear) {
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this.emit(name, buffer, this[markSymbol], i)
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delete this[markSymbol]
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} else {
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this.emit(name, buffer, this[markSymbol], buffer.length)
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this[markSymbol] = 0
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}
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}
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}
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// console.log('???? ', state, 'len: ', len);
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for (i = 0; i < len; i++) {
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c = buffer[i]
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switch (state) {
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case STATE_DICT.PARSER_UNINITIALIZED:
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return i
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case STATE_DICT.START:
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index = 0
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state = STATE_DICT.START_BOUNDARY
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case STATE_DICT.START_BOUNDARY:
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// console.log('=====>>>', index, c, boundary);
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if (index == boundary.length - 2) {
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if (c == HYPHEN) {
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flags |= F.LAST_BOUNDARY
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} else if (c != CR) {
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return i
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}
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index++
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break
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} else if (index - 1 == boundary.length - 2) {
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if (flags & F.LAST_BOUNDARY && c == HYPHEN) {
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this.emit('end')
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state = STATE_DICT.END
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flags = 0
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} else if (!(flags & F.LAST_BOUNDARY) && c == LF) {
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index = 0
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this.emit('partBegin')
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state = STATE_DICT.HEADER_FIELD_START
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} else {
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return i
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}
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break
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}
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if (c != boundary[index + 2]) {
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index = -2
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}
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if (c == boundary[index + 2]) {
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index++
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}
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break
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case STATE_DICT.HEADER_FIELD_START:
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state = STATE_DICT.HEADER_FIELD
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mark('headerField')
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index = 0
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case STATE_DICT.HEADER_FIELD:
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if (c == CR) {
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delete this.headerFieldMark
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state = STATE_DICT.HEADERS_ALMOST_DONE
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break
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}
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index++
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if (c == HYPHEN) {
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break
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}
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if (c == COLON) {
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if (index == 1) {
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// empty header field
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return i
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}
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dataCallback('headerField', true)
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state = STATE_DICT.HEADER_VALUE_START
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break
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}
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cl = lower(c)
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if (cl < A || cl > Z) {
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return i
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}
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break
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case STATE_DICT.HEADER_VALUE_START:
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if (c == SPACE) {
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break
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}
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mark('headerValue')
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state = STATE_DICT.HEADER_VALUE
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case STATE_DICT.HEADER_VALUE:
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if (c == CR) {
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dataCallback('headerValue', true)
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this.emit('headerEnd')
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state = STATE_DICT.HEADER_VALUE_ALMOST_DONE
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}
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break
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case STATE_DICT.HEADER_VALUE_ALMOST_DONE:
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if (c != LF) {
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return i
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}
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state = STATE_DICT.HEADER_FIELD_START
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break
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case STATE_DICT.HEADERS_ALMOST_DONE:
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if (c != LF) {
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return i
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}
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this.emit('headersEnd')
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state = STATE_DICT.PART_DATA_START
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break
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case STATE_DICT.PART_DATA_START:
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state = STATE_DICT.PART_DATA
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mark('partData')
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case STATE_DICT.PART_DATA:
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prevIndex = index
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if (index === 0) {
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// boyer-moore derrived algorithm to safely skip non-boundary data
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i += boundaryEnd
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while (i < bufferLength && !(buffer[i] in boundaryChars)) {
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i += boundaryLength
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}
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i -= boundaryEnd
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c = buffer[i]
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}
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if (index < boundary.length) {
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if (boundary[index] == c) {
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if (index === 0) {
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dataCallback('partData', true)
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}
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index++
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} else {
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index = 0
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}
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} else if (index == boundary.length) {
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index++
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if (c == CR) {
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// CR = part boundary
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flags |= F.PART_BOUNDARY
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} else if (c == HYPHEN) {
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// HYPHEN = end boundary
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flags |= F.LAST_BOUNDARY
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} else {
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index = 0
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}
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} else if (index - 1 == boundary.length) {
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if (flags & F.PART_BOUNDARY) {
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index = 0
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if (c == LF) {
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// unset the PART_BOUNDARY flag
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flags &= ~F.PART_BOUNDARY
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this.emit('partEnd')
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this.emit('partBegin')
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state = STATE_DICT.HEADER_FIELD_START
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break
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}
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} else if (flags & F.LAST_BOUNDARY) {
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if (c == HYPHEN) {
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this.emit('partEnd')
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this.emit('end')
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state = STATE_DICT.END
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flags = 0
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} else {
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index = 0
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}
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} else {
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index = 0
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}
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}
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if (index > 0) {
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// when matching a possible boundary, keep a lookbehind reference
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// in case it turns out to be a false lead
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lookbehind[index - 1] = c
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} else if (prevIndex > 0) {
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// if our boundary turned out to be rubbish, the captured lookbehind
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// belongs to partData
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this.emit('partData', lookbehind, 0, prevIndex)
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prevIndex = 0
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mark('partData')
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// reconsider the current character even so it interrupted the sequence
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// it could be the beginning of a new sequence
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i--
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}
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break
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case STATE_DICT.END:
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break
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default:
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return i
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}
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}
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dataCallback('headerField')
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dataCallback('headerValue')
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dataCallback('partData')
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this.index = index
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this.state = state
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this.flags = flags
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}
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end() {
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if (
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(this.state === STATE_DICT.HEADER_FIELD_START && this.index === 0) ||
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(this.state === STATE_DICT.PART_DATA && this.index == this.boundary.length)
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) {
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this.emit('end')
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} else if (this.state !== STATE_DICT.END) {
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return new Error(
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'MultipartParser.end(): stream ended unexpectedly: ' + this.explain()
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)
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}
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}
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explain() {
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return 'state = ' + stateToString(this.state)
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}
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}
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