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

Low level library facilitating protocol buffers based communication with Trezor devices

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.readMessageBuffer = void 0;
const utils_1 = require("@trezor/utils");
const result_1 = require("./result");
const errors_1 = require("../errors");
const readMessageBuffer = () => {
  const readBuffer = {};
  const readRequests = {};
  const onMessage = (path, data) => {
    if (readRequests[path]) {
      readRequests[path].resolve((0, result_1.success)(data));
      delete readRequests[path];
    } else {
      if (!readBuffer[path]) {
        readBuffer[path] = [];
      }
      readBuffer[path].push(data);
    }
  };
  const read = (path, signal) => {
    const bufferMessage = readBuffer[path]?.shift();
    if (bufferMessage) {
      return Promise.resolve((0, result_1.success)(bufferMessage));
    }
    if (readRequests[path]) {
      return readRequests[path].promise;
    }
    const dfd = (0, utils_1.createDeferred)();
    readRequests[path] = dfd;
    const abortListener = () => {
      dfd.resolve((0, result_1.error)({
        error: errors_1.ABORTED_BY_SIGNAL
      }));
    };
    signal?.addEventListener('abort', abortListener);
    return dfd.promise.finally(() => {
      signal?.removeEventListener('abort', abortListener);
      delete readRequests[path];
    });
  };
  const cancelRead = path => {
    if (readRequests[path]) {
      readRequests[path].resolve((0, result_1.error)({
        error: errors_1.INTERFACE_DATA_TRANSFER
      }));
    }
    delete readRequests[path];
    delete readBuffer[path];
  };
  return {
    onMessage,
    read,
    cancelRead
  };
};
exports.readMessageBuffer = readMessageBuffer;
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