Stefan Hacker
117 lines
4.3 KiB
JavaScript
117 lines
4.3 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.WsFrameDecoder = void 0;
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const StreamingOctetReader_1 = require("@jsonjoy.com/buffers/lib/StreamingOctetReader");
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const constants_1 = require("./constants");
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const errors_1 = require("./errors");
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const frames_1 = require("./frames");
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class WsFrameDecoder {
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constructor() {
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this.reader = new StreamingOctetReader_1.StreamingOctetReader();
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}
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push(uint8) {
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this.reader.push(uint8);
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}
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readFrameHeader() {
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try {
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const reader = this.reader;
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if (reader.size() < 2)
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return undefined;
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const b0 = reader.u8();
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const b1 = reader.u8();
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const fin = (b0 >>> 7);
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const opcode = b0 & 0b1111;
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const maskBit = b1 >>> 7;
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let length = b1 & 0b01111111;
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if (length === 126) {
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if (reader.size() < 2)
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return undefined;
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length = (reader.u8() << 8) | reader.u8();
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}
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else if (length === 127) {
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if (reader.size() < 8)
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return undefined;
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reader.skip(4);
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length = reader.u32();
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}
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let mask;
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if (maskBit) {
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if (reader.size() < 4)
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return undefined;
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mask = [reader.u8(), reader.u8(), reader.u8(), reader.u8()];
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}
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if (opcode >= constants_1.WsFrameOpcode.MIN_CONTROL_OPCODE) {
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switch (opcode) {
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case constants_1.WsFrameOpcode.CLOSE: {
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return new frames_1.WsCloseFrame(fin, opcode, length, mask, 0, '');
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}
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case constants_1.WsFrameOpcode.PING: {
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if (length > 125)
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throw new errors_1.WsFrameDecodingError();
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const data = mask ? reader.bufXor(length, mask, 0) : reader.buf(length);
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return new frames_1.WsPingFrame(fin, opcode, length, mask, data);
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}
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case constants_1.WsFrameOpcode.PONG: {
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if (length > 125)
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throw new errors_1.WsFrameDecodingError();
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const data = mask ? reader.bufXor(length, mask, 0) : reader.buf(length);
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return new frames_1.WsPongFrame(fin, opcode, length, mask, data);
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}
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default: {
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throw new errors_1.WsFrameDecodingError();
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}
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}
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}
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return new frames_1.WsFrameHeader(fin, opcode, length, mask);
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}
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catch (err) {
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if (err instanceof RangeError)
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return undefined;
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throw err;
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}
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}
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readFrameData(frame, remaining, dst, pos) {
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const reader = this.reader;
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const mask = frame.mask;
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const readSize = Math.min(reader.size(), remaining);
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if (!mask)
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reader.copy(readSize, dst, pos);
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else {
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const alreadyRead = frame.length - remaining;
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reader.copyXor(readSize, dst, pos, mask, alreadyRead);
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}
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return remaining - readSize;
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}
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copyFrameData(frame, dst, pos) {
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const reader = this.reader;
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const mask = frame.mask;
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const readSize = frame.length;
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if (!mask)
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reader.copy(readSize, dst, pos);
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else
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reader.copyXor(readSize, dst, pos, mask, 0);
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}
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readCloseFrameData(frame) {
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let length = frame.length;
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if (length > 125)
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throw new errors_1.WsFrameDecodingError();
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let code = 0;
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let reason = '';
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if (length > 0) {
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if (length < 2)
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throw new errors_1.WsFrameDecodingError();
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const reader = this.reader;
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const mask = frame.mask;
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const octet1 = reader.u8() ^ (mask ? mask[0] : 0);
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const octet2 = reader.u8() ^ (mask ? mask[1] : 0);
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code = (octet1 << 8) | octet2;
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length -= 2;
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if (length)
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reason = reader.utf8(length, mask ?? [0, 0, 0, 0], 2);
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}
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frame.code = code;
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frame.reason = reason;
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}
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}
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exports.WsFrameDecoder = WsFrameDecoder;
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//# sourceMappingURL=WsFrameDecoder.js.map
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