alexion
6081e3e325
Imported as a linear vendor commit so forge rebases do not replay the upstream root tree. git-subtree-dir: third_party/pi git-subtree-split: 71023aec1546d6d677a65669c5665c0927ce0dd0
84 lines
3.1 KiB
TypeScript
84 lines
3.1 KiB
TypeScript
// Entry 8: what a change costs the provider. The diff is computed once per change; each feed (one per connection and
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// member) encodes it with its own stateful encoder and its link serializes it.
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import assert from "node:assert/strict";
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import { Type } from "typebox";
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import { describe, it, vi } from "vitest";
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import type * as delta from "../src/delta/index.ts";
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import { type Ctx, createHost, hostNamed, memoryLinkPair, method, remote } from "../src/index.ts";
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import { CountingLink, stateFrames } from "./fixtures/counting.ts";
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const counts = vi.hoisted(() => ({ encoders: 0, encodes: 0 }));
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vi.mock("../src/delta/index.ts", async (importOriginal) => {
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const original = await importOriginal<typeof delta>();
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return {
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...original,
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encoder: () => {
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counts.encoders++;
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const inner = original.encoder();
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return {
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encode: (ops: Parameters<typeof inner.encode>[0]) => {
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counts.encodes++;
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return inner.encode(ops);
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},
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};
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},
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};
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});
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const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
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const List = remote("t.e8-cost", {
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version: 1,
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input: Type.Object({}),
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host: hostNamed("server"),
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variants: { main: { state: { items: Type.Array(Type.String()) }, methods: { add: method(Type.String()) } } },
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});
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describe("provider cost", () => {
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it("one change to K clients: K encodes (one per feed), one frame per link, the same ops on every link", async () => {
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const server = createHost({ self: { kind: "host" }, name: "server", onError: () => {} });
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server.serve(List, (_input, _principal, self) => {
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const items = self.state("items", Type.Array(Type.String()), []);
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return {
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variant: "main",
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items,
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add: (text: string, ctx: Ctx) => {
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items.change(ctx, (draft) => {
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draft.push(text);
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});
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},
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};
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});
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const K = 4;
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const clients = Array.from({ length: K }, (_, i) => {
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const [down, up] = memoryLinkPair();
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// One principal: every client reaches the same object.
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server.accept(down, { principal: { user: "u" } });
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const link = new CountingLink(up);
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const host = createHost({
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self: { kind: "host" },
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name: `browser${i}`,
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kind: "client",
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upstream: { link, principal: { kind: "server" } },
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onError: () => {},
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});
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return { host, link, ref: host.hold(List, {}) };
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});
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await Promise.all(clients.map((client) => client.ref.ready));
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const encoders = counts.encoders;
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const encodes = counts.encodes;
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const before = clients.map((client) => stateFrames(client.link.received).length);
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await clients[0]!.ref.add("x");
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await sleep(10);
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assert.equal(counts.encodes - encodes, K, "one encode per feed");
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assert.equal(counts.encoders, encoders, "no new streams for a change");
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const frames = clients.map((client, i) => stateFrames(client.link.received).slice(before[i]));
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for (const list of frames) assert.equal(list.length, 1);
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const ops = frames.map((list) => JSON.stringify(list[0]?.ops));
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assert.equal(new Set(ops).size, 1, "every link carries the same ops");
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for (const client of clients) assert.deepEqual(client.ref.items.value, ["x"]);
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await server.close();
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});
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});
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