wasm.ts - mozsearch

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/**

 * A minimal Parser that mimicks a small fraction of the Node.js parser

 * API.

 * To run:

 * - `npm run build-wasm`

 * - `npx ts-node examples/wasm.ts`

*/

import { readFileSync } from 'fs';

import { resolve } from 'path';

import * as constants from '../build/wasm/constants';

const bin = readFileSync(resolve(__dirname, '../build/wasm/llhttp.wasm'));

const mod = new WebAssembly.Module(bin);

const REQUEST = constants.TYPE.REQUEST;

const RESPONSE = constants.TYPE.RESPONSE;

const kOnMessageBegin = 0;

const kOnHeaders = 1;

const kOnHeadersComplete = 2;

const kOnBody = 3;

const kOnMessageComplete = 4;

const kOnExecute = 5;

const kPtr = Symbol('kPtr');

const kUrl = Symbol('kUrl');

const kStatusMessage = Symbol('kStatusMessage');

const kHeadersFields = Symbol('kHeadersFields');

const kHeadersValues = Symbol('kHeadersValues');

const kBody = Symbol('kBody');

const kReset = Symbol('kReset');

const kCheckErr = Symbol('kCheckErr');

const cstr = (ptr: number, len: number): string =>

  Buffer.from(memory.buffer, ptr, len).toString();

const wasm_on_message_begin = (p: number) => {

  const i = instMap.get(p);

  i[kReset]();

  return i[kOnMessageBegin]();

};

const wasm_on_url = (p: number, at: number, length: number) => {

  instMap.get(p)[kUrl] = cstr(at, length);

  return 0;

};

const wasm_on_status = (p: number, at: number, length: number) => {

  instMap.get(p)[kStatusMessage] = cstr(at, length);

  return 0;

};

const wasm_on_header_field = (p: number, at: number, length: number) => {

  const i= instMap.get(p)

  i[kHeadersFields].push(cstr(at, length));

  return 0;

};

const wasm_on_header_value = (p: number, at: number, length: number) => {

  const i = instMap.get(p);

  i[kHeadersValues].push(cstr(at, length));

  return 0;

};

const wasm_on_headers_complete = (p: number) => {

  const i = instMap.get(p);

  const type = get_type(p);

  const versionMajor = get_version_major(p);

  const versionMinor = get_version_minor(p);

  const rawHeaders = [];

  let method;

  let url;

  let statusCode;

  let statusMessage;

  const upgrade = get_upgrade(p);

  const shouldKeepAlive = should_keep_alive(p);

  for (let c = 0; c < i[kHeadersFields].length; c++) {

    rawHeaders.push(i[kHeadersFields][c], i[kHeadersValues][c])

  if (type === HTTPParser.REQUEST) {

    method = constants.METHODS[get_method(p)];

    url = i[kUrl];

  } else if (type === HTTPParser.RESPONSE) {

    statusCode = get_status_code(p);

    statusMessage = i[kStatusMessage];

  return i[kOnHeadersComplete](versionMajor, versionMinor, rawHeaders, method,

url, statusCode, statusMessage, upgrade, shouldKeepAlive);

};

const wasm_on_body = (p: number, at: number, length: number) => {

  const i = instMap.get(p);

  const body = Buffer.from(memory.buffer, at, length);

  return i[kOnBody](body);

};

const wasm_on_message_complete = (p: number) => {

  return instMap.get(p)[kOnMessageComplete]();

};

const instMap = new Map();

const inst = new WebAssembly.Instance(mod, {

  env: {

    wasm_on_message_begin,

    wasm_on_url,

    wasm_on_status,

    wasm_on_header_field,

    wasm_on_header_value,

    wasm_on_headers_complete,

    wasm_on_body,

    wasm_on_message_complete,

},

});

const memory = inst.exports.memory as any;

const alloc = inst.exports.llhttp_alloc as CallableFunction;

const malloc = inst.exports.malloc as CallableFunction;

const execute = inst.exports.llhttp_execute as CallableFunction;

const get_type = inst.exports.llhttp_get_type as CallableFunction;

const get_upgrade = inst.exports.llhttp_get_upgrade as CallableFunction;

const should_keep_alive = inst.exports.llhttp_should_keep_alive as CallableFunction;

const get_method = inst.exports.llhttp_get_method as CallableFunction;

const get_status_code = inst.exports.llhttp_get_status_code as CallableFunction;

const get_version_minor = inst.exports.llhttp_get_http_minor as CallableFunction;

const get_version_major = inst.exports.llhttp_get_http_major as CallableFunction;

const get_error_reason = inst.exports.llhttp_get_error_reason as CallableFunction;

const free = inst.exports.free as CallableFunction;

const initialize = inst.exports._initialize as CallableFunction;

initialize(); // wasi reactor

class HTTPParser {

  static REQUEST = REQUEST;

  static RESPONSE = RESPONSE;

  static kOnMessageBegin = kOnMessageBegin;

  static kOnHeaders = kOnHeaders;

  static kOnHeadersComplete = kOnHeadersComplete;

  static kOnBody = kOnBody;

  static kOnMessageComplete = kOnMessageComplete;

  static kOnExecute = kOnExecute;

  [kPtr]: number;

  [kUrl]: string;

  [kStatusMessage]: null|string;

  [kHeadersFields]: []|[string];

  [kHeadersValues]: []|[string];

  [kBody]: null|Buffer;

  constructor(type: constants.TYPE) {

    this[kPtr] = alloc(constants.TYPE[type]);

    instMap.set(this[kPtr], this);

    this[kUrl] = '';

    this[kStatusMessage] = null;

    this[kHeadersFields] = [];

    this[kHeadersValues] = [];

    this[kBody] = null;

  [kReset]() {

    this[kUrl] = '';

    this[kStatusMessage] = null;

    this[kHeadersFields] = [];

    this[kHeadersValues] = [];

    this[kBody] = null;

  [kOnMessageBegin]() {

    return 0;

  [kOnHeaders](rawHeaders: [string]) {}

  [kOnHeadersComplete](versionMajor: number, versionMinor: number, rawHeaders: [string], method: string,

    url: string, statusCode: number, statusMessage: string, upgrade: boolean, shouldKeepAlive: boolean) {

    return 0;

  [kOnBody](body: Buffer) {

    this[kBody] = body;

    return 0;

  [kOnMessageComplete]() {

    return 0;

  destroy() {

    instMap.delete(this[kPtr]);

    free(this[kPtr]);

  execute(data: Buffer) {

    const ptr = malloc(data.byteLength);

    const u8 = new Uint8Array(memory.buffer);

    u8.set(data, ptr);

    const ret = execute(this[kPtr], ptr, data.length);

    free(ptr);

    this[kCheckErr](ret);

    return ret;

  [kCheckErr](n: number) {

    if (n === constants.ERROR.OK) {

      return;

    const ptr = get_error_reason(this[kPtr]);

    const u8 = new Uint8Array(memory.buffer);

    const len = u8.indexOf(0, ptr) - ptr;

    throw new Error(cstr(ptr, len));

  const p = new HTTPParser(HTTPParser.REQUEST);

  p.execute(Buffer.from([

    'POST /owo HTTP/1.1',

    'X: Y',

    'Content-Length: 9',

'',

    'uh, meow?',

'',

  ].join('\r\n')));

  console.log(p);

  p.destroy();

  const p = new HTTPParser(HTTPParser.RESPONSE);

  p.execute(Buffer.from([

    'HTTP/1.1 200 OK',

    'X: Y',

    'Content-Length: 9',

'',

    'uh, meow?'

  ].join('\r\n')));

  console.log(p);

  p.destroy();