@trezor/transport/lib/utils/receive.js

Low level library facilitating protocol buffers based communication with Trezor devices

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.receive = receive;
exports.receiveAndParse = receiveAndParse;
const protobuf_1 = require("@trezor/protobuf");
const result_1 = require("./result");
async function receive(receiver, protocol) {
  const readResult = await receiver();
  if (!readResult.success) {
    return readResult;
  }
  const data = readResult.payload;
  const {
    length,
    messageType,
    payload,
    header
  } = protocol.decode(data);
  const result = Buffer.alloc(length);
  const [, chunkHeader] = protocol.getHeaders(Buffer.from(data));
  payload.copy(result);
  let offset = payload.length;
  while (offset < length) {
    const readResult = await receiver();
    if (!readResult.success) {
      return readResult;
    }
    const data = readResult.payload;
    const dataChunkHeader = data.subarray(0, chunkHeader.length);
    if (dataChunkHeader.compare(chunkHeader) !== 0) {
      throw new Error(`Unexpected chunkHeader ${dataChunkHeader.toString('hex')}`);
    }
    Buffer.from(data).copy(result, offset, chunkHeader.byteLength);
    offset += data.byteLength - chunkHeader.byteLength;
  }
  return (0, result_1.success)({
    messageType,
    payload: result,
    header,
    length
  });
}
async function receiveAndParse(messages, receiver, protocol) {
  const readResult = await receive(receiver, protocol);
  if (!readResult.success) return readResult;
  const {
    messageType,
    payload
  } = readResult.payload;
  const message = (0, protobuf_1.decodeMessage)(messages, messageType, payload);
  return (0, result_1.success)(message);
}
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