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Viewing / Editing File: rateLimiter.js

import * as Duration from "../Duration.js";
import * as Effect from "../Effect.js";
import * as FiberRef from "../FiberRef.js";
import { pipe } from "../Function.js";
import { globalValue } from "../GlobalValue.js";
/** @internal */
export const make = ({
  algorithm = "token-bucket",
  interval,
  limit
}) => {
  switch (algorithm) {
    case "fixed-window":
      {
        return fixedWindow(limit, interval);
      }
    case "token-bucket":
      {
        return tokenBucket(limit, interval);
      }
  }
};
const tokenBucket = (limit, window) => Effect.gen(function* () {
  const millisPerToken = Math.ceil(Duration.toMillis(window) / limit);
  const semaphore = yield* Effect.makeSemaphore(limit);
  const latch = yield* Effect.makeSemaphore(0);
  const refill = Effect.sleep(millisPerToken).pipe(Effect.zipRight(latch.releaseAll), Effect.zipRight(semaphore.release(1)), Effect.flatMap(free => free === limit ? Effect.void : refill));
  yield* pipe(latch.take(1), Effect.zipRight(refill), Effect.forever, Effect.forkScoped, Effect.interruptible);
  const take = Effect.uninterruptibleMask(restore => Effect.flatMap(FiberRef.get(currentCost), cost => Effect.zipRight(restore(semaphore.take(cost)), latch.release(1))));
  return effect => Effect.zipRight(take, effect);
});
const fixedWindow = (limit, window) => Effect.gen(function* () {
  const semaphore = yield* Effect.makeSemaphore(limit);
  const latch = yield* Effect.makeSemaphore(0);
  yield* pipe(latch.take(1), Effect.zipRight(Effect.sleep(window)), Effect.zipRight(latch.releaseAll), Effect.zipRight(semaphore.releaseAll), Effect.forever, Effect.forkScoped, Effect.interruptible);
  const take = Effect.uninterruptibleMask(restore => Effect.flatMap(FiberRef.get(currentCost), cost => Effect.zipRight(restore(semaphore.take(cost)), latch.release(1))));
  return effect => Effect.zipRight(take, effect);
});
/** @internal */
const currentCost = /*#__PURE__*/globalValue(/*#__PURE__*/Symbol.for("effect/RateLimiter/currentCost"), () => FiberRef.unsafeMake(1));
/** @internal */
export const withCost = cost => Effect.locally(currentCost, cost);
//# sourceMappingURL=rateLimiter.js.map

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