refactor: move errTracker to libkernel

src/errTracker.ts

@@ -1,101 +0,0 @@
-// errTracker.ts defines an 'ErrTracker' type which keeps track of historical
-// errors. When the number of errors gets too large, it randomly starts pruning
-// errors. It always keeps 250 of the most recent errors, and then keeps up to
-// 500 historic errors, where the first few errors after runtime are always
-// kept, and the ones in the middle are increasingly likely to be omitted from
-// the history.
-
-import { Err } from "./types.js";
-
-// MAX_ERRORS defines the maximum number of errors that will be held in the
-// HistoricErr object.
-const MAX_ERRORS = 1000;
-
-// HistoricErr is a wrapper that adds a date to the Err type.
-interface HistoricErr {
-  err: Err;
-  date: Date;
-}
-
-// ErrTracker keeps track of errors that have happened, randomly dropping
-// errors to prevent the tracker from using too much memory if there happen to
-// be a large number of errors.
-interface ErrTracker {
-  recentErrs: HistoricErr[];
-  oldErrs: HistoricErr[];
-
-  addErr: (err: Err) => void;
-  viewErrs: () => HistoricErr[];
-}
-
-// newErrTracker returns an ErrTracker object that is ready to have errors
-// added to it.
-function newErrTracker(): ErrTracker {
-  const et: ErrTracker = {
-    recentErrs: [],
-    oldErrs: [],
-
-    addErr: function (err: Err): void {
-      addHistoricErr(et, err);
-    },
-    viewErrs: function (): HistoricErr[] {
-      return viewErrs(et);
-    },
-  };
-  return et;
-}
-
-// addHistoricErr is a function that will add an error to a set of historic
-// errors. It uses randomness to prune errors once the error object is too
-// large.
-function addHistoricErr(et: ErrTracker, err: Err): void {
-  // Add this error to the set of most recent errors.
-  et.recentErrs.push({
-    err,
-    date: new Date(),
-  });
-
-  // Determine whether some of the most recent errors need to be moved into
-  // logTermErrs. If the length of the mostRecentErrs is not at least half of
-  // the MAX_ERRORS, we don't need to do anything.
-  if (et.recentErrs.length < MAX_ERRORS / 2) {
-    return;
-  }
-
-  // Iterate through the recentErrs. For the first half of the recentErrs, we
-  // will use randomness to either toss them or move them to oldErrs. The
-  // second half of the recentErrs will be kept as the new recentErrs array.
-  const newRecentErrs : HistoricErr[] = [];
-  for (let i = 0; i < et.recentErrs.length; i++) {
-    // If we are in the second half of the array, add the element to
-    // newRecentErrs.
-    if (i > et.recentErrs.length / 2) {
-      newRecentErrs.push(et.recentErrs[i]);
-      continue;
-    }
-
-    // We are in the first half of the array, use a random number to add the
-    // error oldErrs probabilistically.
-    const rand = Math.random();
-    const target = et.oldErrs.length / (MAX_ERRORS / 2);
-    if (rand > target || et.oldErrs.length < 25) {
-      et.oldErrs.push(et.recentErrs[i]);
-    }
-  }
-  et.recentErrs = newRecentErrs;
-}
-
-// viewErrs returns the list of errors that have been retained by the
-// HistoricErr object.
-function viewErrs(et: ErrTracker): HistoricErr[] {
-  const finalErrs: HistoricErr[] = [];
-  for (let i = 0; i < et.oldErrs.length; i++) {
-    finalErrs.push(et.oldErrs[i]);
-  }
-  for (let i = 0; i < et.recentErrs.length; i++) {
-    finalErrs.push(et.recentErrs[i]);
-  }
-  return finalErrs;
-}
-
-export { ErrTracker, HistoricErr, newErrTracker };