ses/src/error/note-log-args.js

Hardened JavaScript for Fearless Cooperation

// @ts-check
/* eslint-disable @endo/no-polymorphic-call */
/* eslint-disable no-restricted-globals */

import { makeLRUCacheMap } from '../make-lru-cachemap.js';

/**
 * @import {LogArgs} from './internal-types.js';
 */

const { freeze } = Object;
const { isSafeInteger } = Number;

const defaultLoggedErrorsBudget = 1000;
const defaultArgsPerErrorBudget = 100;

/**
 * @param {number} [errorsBudget]
 * @param {number} [argsPerErrorBudget]
 */
export const makeNoteLogArgsArrayKit = (
  errorsBudget = defaultLoggedErrorsBudget,
  argsPerErrorBudget = defaultArgsPerErrorBudget,
) => {
  if (!isSafeInteger(argsPerErrorBudget) || argsPerErrorBudget < 1) {
    throw TypeError(
      'argsPerErrorBudget must be a safe positive integer number',
    );
  }

  /**
   * @type {WeakMap<Error, LogArgs[]>}
   *
   * Maps from an error to an array of log args, where each log args is
   * remembered as an annotation on that error. This can be used, for example,
   * to keep track of additional causes of the error. The elements of any
   * log args may include errors which are associated with further annotations.
   * An augmented console, like the causal console of `console.js`, could
   * then retrieve the graph of such annotations.
   */
  const noteLogArgsArrayMap = makeLRUCacheMap(errorsBudget);

  /**
   * @param {Error} error
   * @param {LogArgs} logArgs
   */
  const addLogArgs = (error, logArgs) => {
    const logArgsArray = noteLogArgsArrayMap.get(error);
    if (logArgsArray !== undefined) {
      if (logArgsArray.length >= argsPerErrorBudget) {
        logArgsArray.shift();
      }
      logArgsArray.push(logArgs);
    } else {
      noteLogArgsArrayMap.set(error, [logArgs]);
    }
  };
  freeze(addLogArgs);

  /**
   * @param {Error} error
   * @returns {LogArgs[] | undefined}
   */
  const takeLogArgsArray = error => {
    const result = noteLogArgsArrayMap.get(error);
    noteLogArgsArrayMap.delete(error);
    return result;
  };
  freeze(takeLogArgsArray);

  return freeze({
    addLogArgs,
    takeLogArgsArray,
  });
};
freeze(makeNoteLogArgsArrayKit);